diagram(n) Documentation toolbox diagram(n)
__________________________________________________________________________________________________________________________________________________
NAME
diagram - Diagram drawing
SYNOPSIS
package require Tcl 8.5
package require Tk 8.5
package require diagram 1
::diagram objectName canvas ?script?
diagramObject new direction name ?key value...?
diagramObject new element name attributes cmdprefix
diagramObject new alias name cmdprefix
diagramObject new command name arguments body
diagramObject new attribute name ?key value...?
diagramObject unknown attribute cmdprefix
diagramObject draw script
arc attr...
arrow attr...
--> attr...
<--> attr...
<--> attr...
block script attr...
box attr...
circle attr...
O attr...
diamond attr...
<> attr...
drum attr...
ellipse attr...
line attr...
-- attr...
move attr
spline attr...
text attr...
west
w
left
l
south
s
down
bottom
bot
b
east
e
right
r
north
n
up
top
t
northwest
nw
up-left
upleft
leftup
northeast
ne
up-right
upright
rightup
southwest
sw
down-left
downleft
leftdown
southeast
se
down-right
downright
rightdown
number cm
number mm
number inch
number pt
number number
by distance direction
point1 + point2
point1 - point2
point by distance direction
point1 | point2
n between poin1 point2
intersect elem1 elem2
element names ?pattern?
element corner
element corner1 corner2...
element ?corner1... ?names ?pattern??]?
nth ?corner?
nth last ?corner?
nth shape ?corner?
nth last shape ?corner?
last ?corner?
last shape ?corner?
1st
2nd
3rd
_________________________________________________________________
DESCRIPTION
Welcome to diagram, a package for the easy construction of diagrams (sic), i.e. 2D vector graphics, sometimes also called pictures. Note
that this package is not a replacement for Tk's canvas, but rather a layer sitting on top of it, to make it easier to use. In other words,
using the canvas as the core graphics engine diagram abstracts away from the minutiae of handling coordinates to position and size the
drawn elements, allowing the user to concentrate on the content of the diagram instead.
This is similar to Brian Kernighan's PIC language for troff, which is the spiritual ancestor of this package.
This document contains the reference to the API and drawing (language) commands. Its intended audience are users of the package wishing to
refresh their memory. Newcomers should read the Diagram Language Tutorial first. Developers wishing to work on the internals of the pack-
age and its supporting packages should look at section Diagram Classes first, and then the comments in the sources of the packages itself.
In the remainder of the document we first describe the APIs of the diagram class and its instances, followed by the language reference for
the drawing language itself.
API
CLASS API
The package exports the API described here.
::diagram objectName canvas ?script?
The command creates a new instance of a diagram controller and returns the fully qualified name of the object command as its result.
The new instance is connected to the specified canvas object, which is used as the diagrams graphics engine. This is usually an
instance of Tk's canvas, however any object which is API compatible to Tk's canvas can be used here.
The API of this object command is described in the following section, Object API. It may be used to invoke various operations on the
object.
If the script argument is specified then method draw will be invoked on it.
OBJECT API
Instances of the diagram class support the following methods:
diagramObject new direction name ?key value...?
This method defines a new named direction and its attributes. The latter is given through the key/value pairs coming after the name.
Users are mostly free to specify arbitrary attributes with whatever meaning they desire. The exception are the names angle and oppo-
site. They are special to the diagram package and have a fixed meaning.
angle This attribute specifies the angle of the direction in degrees, where 0 points east (to the right) and 90 points north (up).
opposite
This attribute specifies the name of the direction which should be considered as complementary to the named one.
diagramObject new element name attributes cmdprefix
This method defines a new graphics element for the drawing language. I.e. name will become a new command in the language, and the
specified command prefix (cmdprefix) will be called to perform the actual drawing.
attributes specifies the set of attributes for which data has to be available. I.e. the system will run the See the method new
attribute for more information on attribute definitions.
The command prefix is expected to conform to the following signature:
cmdprefix canvas attributes
Where canvas is the handle of the canvas widget to draw to, and attributes is a dictionary holding the attributes for the
element, be they user-specified, or defaults.
The results of the command has to be a list containing at least two and at most four items. These are, in order:
[1] The list of canvas items the drawn element consists of.
[2] The dictionary of named locations in the element, its corners.
[3] An optional mode, either "relative" or "absolute". When not returned "relative" is assumed. In the case of a relative
element position the attributes "with" and "at" are used to determine the final position of the new element.
[4] An optional name of a direction. If not the empty string this is handed to the automatic layouter as the new direction
to follow.
diagramObject new alias name cmdprefix
This method defines a new command for the drawing language. I.e. name will become a new command in the language, and the specified
command prefix (cmdprefix) will be called on use of this new command. Any arguments given to the command are simply passed to the
prefix. There is no fixed siganture.
Note that the prefix is run in the context of the drawing language, allowing the direct use of any existing commands.
diagramObject new command name arguments body
This is like new alias except that the new command is defined as a procedure in the language's context, with regular argument list
and body.
diagramObject new attribute name ?key value...?
This method defines a new named attribute which can be used by graphical elements. The handling of the attribute by the processor is
declared through the key/value pairs coming after the name.
The accepted keys and their meanings are:
key The value of this key is the name of the key under which the attribute's value shall be stored in the attribute dictionary
given to the drawing command after attribute processing is complete.
This key is optional. If it is not specified it defaults to the name of the attribute.
get The value of this key is a command prefix which will be invoked to retrieve the attribute's argument(s) from the command
line.
This key is optional. If it is not specified a default is used which takes the single word after the attribute name as the
attribute's value.
The signature of the command prefix is
cmdprefix wordqueue
Where wordqueue is the handle of a queue object conforming to the API of the queues provided by package struct::queue.
This queue contains the not-yet-processed part of the attribute definitions, with one entry per word, with the first
entry the word after name of the attribute. In other words, the attribute's name has already been removed from the
queue.
The result of the command is the value of the attribute, which may have been taken from the queue, or not.
transform
The value of this key is a command prefix which will be invoked to transform the retrieved value (See get) into their final
form.
This key is optional. If it is not specified no transformation is done. The signature of the command prefix is
cmdprefix value
Where value is the value to transform.
The result of the command is the final value of the attribute.
type The value of this key is a command prefix which will be invoked to validate the attribute's argument(s).
This key is optional. If it is not specified no validation is done.
The signature of the command prefix is that of snit validation types. See the documentation of the snit package.
merge The value of this key is a command prefix which will be invoked to insert the transformed and validated attribute value into
the dictionary of collected attributes.
This key is optional. If it is not specified a default merge is chosen, based on the data for key aggregate, see below. The
signature of the command prefix is
cmdprefix value dict
Where value is the value to insert, and dict the dictionary of attributes and values collected so far.
The result of the command is the new dictionary of attributes.
aggregate
The value of this key is a boolean flag. It has an effect if and only if the key merge was not specified. This key is
optional. If it is not specified it defaults to False.
If the key is effective, the value of False means that the attribute's value is set into the dictionary using the value of
key key (see above) as index, overwriting any previously specified value.
If the key is effective, the value of True means that the attribute's value is added to the dictionary using the value of key
key (see above) as index, extending any previously specified value. This means that the final value of the attribute as seen
after processing will be a list of the collected values.
default
The value of this key is a command prefix which will be invoked after collection of attributes has been completed and this
attribute is in the list of required attributes for the drawing element (See argument attributes of method new element).
Note that the connection is made through the value of key key, not through the attribute name per se.
Further note that this command prefix is invoked even if a user specified attribute value is present. This allows the command
to go beyond simply setting defaults, it can calculate and store derived values as well.
This key is optional. If an element requires this attribute, but default is not specified then nothing will be done.
The signature of the command prefix is
cmdprefix init
This method is run when the attribute is defined, its responsibility is to initialize anything in the language names-
pace for the attribute and default processing.
The result of this method is ignored.
cmdprefix fill varname
This method is run to put defaults, or derived values into the attribute dictionary named by varname. This variable
will be found in the calling context.
The result of this method is ignored.
cmdprefix set name value
This method is run to push current a attribute value into the language namespace, to make it the new default.
The result of this method is ignored.
linked This key is effective if and only if key default is not specified. In that case is supplies a default handling for default,
linking the attribute to a variable in the language context.
The value for this key is a 2-element list containing the name of the variable to link to, and its initial value, in this
order.
diagramObject unknown attribute cmdprefix
This method registers the command prefix with the subsystem processing the attributes for element commands, telling it to call it
when it encounters an attribute it is unable to handle on its on.
It is allowed to register more than callback, these will be called in order of registration (i.e. first to last), until one of the
callbacks accepts the current input. The command prefix is expected to conform to the following signature:
cmdprefix wordqueue
Where wordqueue is the handle of a queue object conforming to the API of the queues provided by package struct::queue. This
queue contains the not-yet-processed part of the attribute definitions, with one entry per word, with the first entry the
name of the attribute which could not be processed.
The results of the command has to be a boolean value where True signals that this callback has accepted the attribute, pro-
cessed it, and the new state of the wordqueue is where the general processing shall continue.
Given the signature the command has basically two ways of handling (rewriting) the attributes it recognizes:
[1] Replace the attribute (and arguments) with a different attribute and arguments.
[2] Push additional words in front to get the general processing unstuck.
diagramObject draw script
This method runs the given script in the context of the drawing language definitions. See section Language Reference for details on
the available commands.
Note that script is trusted. It is executed in the current interpreter with access to its full abilities. For the execution of
untrusted diagram scripts this interpreter should be a safe one.
LANGUAGE REFERENCE
ELEMENTS
This section lists the commands for the predefined drawing elements, aka shapes. These commands are all defined in the language's context.
All commands of this section return the handle of the newly created element as their result. This handle also exists as a command which can
be used to query the element for its corners (names, values). See section Miscellaneous Commands. IMAGE: figure-02-basic-shapes
arc attr...
IMAGE: figure-02-arc An open element with the corresponding corners, i.e. "start", "end", and "center". Note however that it also
has the compass rose of closed elements as its corners, with the center of the arc's circle as the center of the compass and the
other points on the circle the arc is part of. It handles the attributes
anchor name
ljust
rjust
above
below IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which is to be placed at the element's center, by name.
I.e. this attribute defines the text's position relative to the element's center. The value is ignored if no text was speci-
fied for the element. If not specified the system falls back to the value taken from the language variable anchor, which
itself defaults to center. The legal values are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without arguments are all shorthands with the anchor
implied. Note that they do not combine, only the last is used. For comined directions the main attribute command, anchor has
to be used.
ljust "anchor west"
rjust "anchor east"
above "anchor south"
below "anchor north"
clockwise
cw Specifies the direction of the arc element, here going clockwise. The complementary attribute is counterclockwise. If not
specified the system falls back to the value taken from the language variable clockwise, which itself defaults to false, for
counter-clockwise direction.
color spec
IMAGE: figure-21-style-colors Specifies the color used to draw the lines of the element. If not specified the system falls
back to the value taken from the language variable linecolor, which itself defaults to black.
counterclockwise
ccw Specifies the direction of the arc element, here counter-clockwise. The complementary attribute is clockwise. If not speci-
fied the system falls back to the value taken from the language variable clockwise, which itself defaults to false, for
counter-clockwise direction.
fillcolor spec
IMAGE: figure-21-style-colors Specifies the color used to draw the inside of the element. If not specified the system falls
back to the value taken from the language variable fillcolor, which itself defaults to the empty string, signaling "no fill-
ing".
from location
Specifies the location where the arc element begins. Defaults to the current location as maintained by the layouting system.
justify left|center|right
Specifies how multi-line text associated with the element is positioned within its box. The value is ignored if no text was
specified for the element. If not specified the system falls back to the value taken from the language variable justify,
which itself defaults to left. The legal values are left, right, and center.
radius length
Specifies the radius of the arc element, or rather, the radius of the circle the shown arc is a part of. If not specified
the system falls back to the value taken from the language variable arcradius, which itself defaults to the pixel equivalent
of 1 cm.
stroke width
IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for the the element, in pixels. If not specified the
system falls back to the value taken from the language variable linewidth, which itself defaults to 1.
style spec
IMAGE: figure-18-style-dash Specifies the style used to draw the lines of the element. If not specified the system falls
back to the value taken from the language variable linestyle, which itself defaults to solid lines. The legal values are all
those accepted by Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and additionally all which are listed below:
solid, empty string
Draw solid line.
dash, dashed, -
Draw a dashed line.
dot, dotted, .
Draw a dotted line.
dash-dot, -.
Draw a dash-dotted line
dash-dot-dot, -..
Draw a dash-dot-dotted line.
Note that the values "solid", "dot(ted)", "dash(ed)", "dash-dot", and "dash-dot-dot" are all accepted as shorthands for the style
command using them as argument.
text string
Specifies the text to associate with the element. Defaults to nothing. When specified multiple times the actually shown
text is the concatenation of the individual strings, vertically stacked, with the first string specified being the topmost
element.
textcolor spec
Specifies the color used to draw the text of an element with. Ignored if there is no text. If not specified the system
falls back to the value taken from the language variable textcolor, which itself defaults to black.
textfont spec
Specifies the font used to draw the text of an element with. Ignored if there is no text. If not specified the system falls
back to the value taken from the language variable textfont, which itself defaults to Helvetica 12pt.
to location
Specifies the location where the arc element ends. Defaults to a location such that a 90-degree arc is drawn in the chosen
direction, starting at from.
arrow attr...
--> attr...
<--> attr...
<--> attr...
IMAGE: figure-02-arrow An alias for the line element (see below), with the attribute arrowhead preset to ->, <->, or <-. The arrow
is equivalent to -->.
block script attr...
A closed element with the corresponding corners, i.e. the eight directions of the compass rose, and "center". The main effect is
the aggregration of all elements created by the script into one element. This also means that while the elements created by the
script are visible in the element history while the script is executing, afterward the history contains only the block itself, and
not the elements it is composed of.
The script has access to the current state of all variables in the language context. Any changes to the variables will be reverted
after execution of the block. However, also, any variables set in the script will be exported as corners of the element, allowing
users to define their own named locations in the block.
Regarding the layout mechanism any changes made by the script are reverted after the element is done. In other words, a block is an
implicit group.
Blocks handle all attributes, propgating their settings into the script as the default values active during script execution.
box attr...
IMAGE: figure-02-box A closed element with the corresponding corners, i.e. the eight directions of the compass rose, and "center".
It handles the attributes
anchor name
ljust
rjust
above
below IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which is to be placed at the element's center, by name.
I.e. this attribute defines the text's position relative to the element's center. The value is ignored if no text was speci-
fied for the element. If not specified the system falls back to the value taken from the language variable anchor, which
itself defaults to center. The legal values are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without arguments are all shorthands with the anchor
implied. Note that they do not combine, only the last is used. For comined directions the main attribute command, anchor has
to be used.
ljust "anchor west"
rjust "anchor east"
above "anchor south"
below "anchor north"
at location
Specifies the location of the element's corner named by the attribute with. Defaults to the current location as maintained
by the layouting system.
color spec
IMAGE: figure-21-style-colors Specifies the color used to draw the lines of the element. If not specified the system falls
back to the value taken from the language variable linecolor, which itself defaults to black.
fillcolor spec
IMAGE: figure-21-style-colors Specifies the color used to draw the inside of the element. If not specified the system falls
back to the value taken from the language variable fillcolor, which itself defaults to the empty string, signaling "no fill-
ing".
height length
ht length
Specifies the height of the element. If not specified the system falls back to the value taken from the language variable
boxheight, which itself defaults to the pixel equivalent of 2 cm.
justify left|center|right
Specifies how multi-line text associated with the element is positioned within its box. The value is ignored if no text was
specified for the element. If not specified the system falls back to the value taken from the language variable justify,
which itself defaults to left. The legal values are left, right, and center.
slant angle
Specifies the angle by which the box element is slanted, in degrees. If not specified the system falls back to the value
taken from the language variable slant, which itself defaults to 90, i.e. vertical, no slant. 0 degrees is slanting straight
east, pointing to the right. 90 degrees is slanting to the north, pointing straight up.
stroke width
IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for the the element, in pixels. If not specified the
system falls back to the value taken from the language variable linewidth, which itself defaults to 1.
style spec
IMAGE: figure-18-style-dash Specifies the style used to draw the lines of the element. If not specified the system falls
back to the value taken from the language variable linestyle, which itself defaults to solid lines. The legal values are all
those accepted by Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and additionally all which are listed below:
solid, empty string
Draw solid line.
dash, dashed, -
Draw a dashed line.
dot, dotted, .
Draw a dotted line.
dash-dot, -.
Draw a dash-dotted line
dash-dot-dot, -..
Draw a dash-dot-dotted line.
Note that the values "solid", "dot(ted)", "dash(ed)", "dash-dot", and "dash-dot-dot" are all accepted as shorthands for the style
command using them as argument.
text string
Specifies the text to associate with the element. Defaults to nothing. When specified multiple times the actually shown
text is the concatenation of the individual strings, vertically stacked, with the first string specified being the topmost
element.
textcolor spec
Specifies the color used to draw the text of an element with. Ignored if there is no text. If not specified the system
falls back to the value taken from the language variable textcolor, which itself defaults to black.
textfont spec
Specifies the font used to draw the text of an element with. Ignored if there is no text. If not specified the system falls
back to the value taken from the language variable textfont, which itself defaults to Helvetica 12pt.
width length
wid length
Specifies the width of the element. If not specified the system falls back to the value taken from the language variable
boxwidth, which itself defaults to the pixel equivalent of 2 cm.
with corner
Specifies the corner of the element to place at the location given by the attribute at. Defaults to the current corner as
maintained by the layouting system, except if the value for at was specified by the user. In that case it defaults to center.
circle attr...
O attr...
IMAGE: figure-02-circle A closed element with the corresponding corners, i.e. the eight directions of the compass rose, and "cen-
ter". It handles the attributes
anchor name
ljust
rjust
above
below IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which is to be placed at the element's center, by name.
I.e. this attribute defines the text's position relative to the element's center. The value is ignored if no text was speci-
fied for the element. If not specified the system falls back to the value taken from the language variable anchor, which
itself defaults to center. The legal values are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without arguments are all shorthands with the anchor
implied. Note that they do not combine, only the last is used. For comined directions the main attribute command, anchor has
to be used.
ljust "anchor west"
rjust "anchor east"
above "anchor south"
below "anchor north"
at location
Specifies the location of the element's corner named by the attribute with. Defaults to the current location as maintained
by the layouting system.
color spec
IMAGE: figure-21-style-colors Specifies the color used to draw the lines of the element. If not specified the system falls
back to the value taken from the language variable linecolor, which itself defaults to black.
diameter length
diam length
Specifies the diameter of the circle element, as an alternative way to specify its radius. Effective if and only if the
radius was not specified. I.e. if both diameter and radius are specified then the radius infomration has precendence. This
attribute has no default, because the defaults are taken from the radius.
fillcolor spec
IMAGE: figure-21-style-colors Specifies the color used to draw the inside of the element. If not specified the system falls
back to the value taken from the language variable fillcolor, which itself defaults to the empty string, signaling "no fill-
ing".
justify left|center|right
Specifies how multi-line text associated with the element is positioned within its box. The value is ignored if no text was
specified for the element. If not specified the system falls back to the value taken from the language variable justify,
which itself defaults to left. The legal values are left, right, and center.
radius length
rad length
Specifies the radius of the circle element. If not specified the system falls back to the value taken from the language
variable circleradius, which itself defaults to the pixel equivalent of 1 cm.
stroke width
IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for the the element, in pixels. If not specified the
system falls back to the value taken from the language variable linewidth, which itself defaults to 1.
style spec
IMAGE: figure-18-style-dash Specifies the style used to draw the lines of the element. If not specified the system falls
back to the value taken from the language variable linestyle, which itself defaults to solid lines. The legal values are all
those accepted by Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and additionally all which are listed below:
solid, empty string
Draw solid line.
dash, dashed, -
Draw a dashed line.
dot, dotted, .
Draw a dotted line.
dash-dot, -.
Draw a dash-dotted line
dash-dot-dot, -..
Draw a dash-dot-dotted line.
Note that the values "solid", "dot(ted)", "dash(ed)", "dash-dot", and "dash-dot-dot" are all accepted as shorthands for the style
command using them as argument.
text string
Specifies the text to associate with the element. Defaults to nothing. When specified multiple times the actually shown
text is the concatenation of the individual strings, vertically stacked, with the first string specified being the topmost
element.
textcolor spec
Specifies the color used to draw the text of an element with. Ignored if there is no text. If not specified the system
falls back to the value taken from the language variable textcolor, which itself defaults to black.
textfont spec
Specifies the font used to draw the text of an element with. Ignored if there is no text. If not specified the system falls
back to the value taken from the language variable textfont, which itself defaults to Helvetica 12pt.
with corner
Specifies the corner of the element to place at the location given by the attribute at. Defaults to the current corner as
maintained by the layouting system, except if the value for at was specified by the user. In that case it defaults to center.
diamond attr...
<> attr...
IMAGE: figure-02-diamond A closed element with the corresponding corners, i.e. the eight directions of the compass rose, and "cen-
ter". It handles the attributes
anchor name
ljust
rjust
above
below IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which is to be placed at the element's center, by name.
I.e. this attribute defines the text's position relative to the element's center. The value is ignored if no text was speci-
fied for the element. If not specified the system falls back to the value taken from the language variable anchor, which
itself defaults to center. The legal values are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without arguments are all shorthands with the anchor
implied. Note that they do not combine, only the last is used. For comined directions the main attribute command, anchor has
to be used.
ljust "anchor west"
rjust "anchor east"
above "anchor south"
below "anchor north"
aspect number
Specifies the aspect ratio, i.e ratio of width to height, of the diamond element. The manner in which a default is calcu-
lated when not specified also depends on the specifications of the attributes width and height, if any.
If both width, and height are specified then any specification of aspect is ignored, as it is implicitly defined in the width
and height as well, and this takes precedence. A missing specification is ignored in that case well, i.e. no defaults are
required.
If the aspect is specified, and one of the attributes width or height, then the missing attribute is calculated from the two
which are specified. No defaults are required for these cases either.
If only one of the attributes width or height is specified then the system uses a fallback for the aspect, the value taken
from the language variable diamondaspect, which itselfs defaults to 2.
If none of of the attributes width or height is specified then the system uses a fallback for the width, the value taken from
the language variable boxwidth, which itselfs defaults to the pixel equivalent of 2 cm. For the aspect it uses either the
user-specified value or the default taken as described in the previous paragraph.
at location
Specifies the location of the element's corner named by the attribute with. Defaults to the current location as maintained
by the layouting system.
color spec
IMAGE: figure-21-style-colors Specifies the color used to draw the lines of the element. If not specified the system falls
back to the value taken from the language variable linecolor, which itself defaults to black.
fillcolor spec
IMAGE: figure-21-style-colors Specifies the color used to draw the inside of the element. If not specified the system falls
back to the value taken from the language variable fillcolor, which itself defaults to the empty string, signaling "no fill-
ing".
height length
Specifies the height of the diamond element. The manner in which a default is calculated when not specified also depends on
the specifications of the attributes aspect and width, if any.
If both width, and height are specified then any specification of aspect is ignored, as it is implicitly defined in the width
and height as well, and this takes precedence. A missing specification is ignored in that case well, i.e. no defaults are
required.
If the aspect is specified, and one of the attributes width or height, then the missing attribute is calculated from the two
which are specified. No defaults are required for these cases either.
If only one of the attributes width or height is specified then the system uses a fallback for the aspect, the value taken
from the language variable diamondaspect, which itselfs defaults to 2.
If none of of the attributes width or height is specified then the system uses a fallback for the width, the value taken from
the language variable boxwidth, which itselfs defaults to the pixel equivalent of 2 cm. For the aspect it uses either the
user-specified value or the default taken as described in the previous paragraph.
justify left|center|right
Specifies how multi-line text associated with the element is positioned within its box. The value is ignored if no text was
specified for the element. If not specified the system falls back to the value taken from the language variable justify,
which itself defaults to left. The legal values are left, right, and center.
stroke width
IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for the the element, in pixels. If not specified the
system falls back to the value taken from the language variable linewidth, which itself defaults to 1.
style spec
IMAGE: figure-18-style-dash Specifies the style used to draw the lines of the element. If not specified the system falls
back to the value taken from the language variable linestyle, which itself defaults to solid lines. The legal values are all
those accepted by Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and additionally all which are listed below:
solid, empty string
Draw solid line.
dash, dashed, -
Draw a dashed line.
dot, dotted, .
Draw a dotted line.
dash-dot, -.
Draw a dash-dotted line
dash-dot-dot, -..
Draw a dash-dot-dotted line.
Note that the values "solid", "dot(ted)", "dash(ed)", "dash-dot", and "dash-dot-dot" are all accepted as shorthands for the style
command using them as argument.
text string
Specifies the text to associate with the element. Defaults to nothing. When specified multiple times the actually shown
text is the concatenation of the individual strings, vertically stacked, with the first string specified being the topmost
element.
textcolor spec
Specifies the color used to draw the text of an element with. Ignored if there is no text. If not specified the system
falls back to the value taken from the language variable textcolor, which itself defaults to black.
textfont spec
Specifies the font used to draw the text of an element with. Ignored if there is no text. If not specified the system falls
back to the value taken from the language variable textfont, which itself defaults to Helvetica 12pt.
width length
Specifies the width of the diamond element. The manner in which a default is calculated when not specified also depends on
the specifications of the attributes aspect and height, if any.
If both width, and height are specified then any specification of aspect is ignored, as it is implicitly defined in the width
and height as well, and this takes precedence. A missing specification is ignored in that case well, i.e. no defaults are
required.
If the aspect is specified, and one of the attributes width or height, then the missing attribute is calculated from the two
which are specified. No defaults are required for these cases either.
If only one of the attributes width or height is specified then the system uses a fallback for the aspect, the value taken
from the language variable diamondaspect, which itselfs defaults to 2.
If none of of the attributes width or height is specified then the system uses a fallback for the width, the value taken from
the language variable boxwidth, which itselfs defaults to the pixel equivalent of 2 cm. For the aspect it uses either the
user-specified value or the default taken as described in the previous paragraph.
with corner
Specifies the corner of the element to place at the location given by the attribute at. Defaults to the current corner as
maintained by the layouting system, except if the value for at was specified by the user. In that case it defaults to center.
drum attr...
IMAGE: figure-02-drum A closed element with the corresponding corners, i.e. the eight directions of the compass rose, and "center".
It handles the attributes
anchor name
ljust
rjust
above
below IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which is to be placed at the element's center, by name.
I.e. this attribute defines the text's position relative to the element's center. The value is ignored if no text was speci-
fied for the element. If not specified the system falls back to the value taken from the language variable anchor, which
itself defaults to center. The legal values are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without arguments are all shorthands with the anchor
implied. Note that they do not combine, only the last is used. For comined directions the main attribute command, anchor has
to be used.
ljust "anchor west"
rjust "anchor east"
above "anchor south"
below "anchor north"
aspect number
Specifies the aspect ratio, i.e ratio of width to height, of the ellipses which are used to draw the top and bottom of the
drum element. If not specified the system falls back to the value taken from the language variable drumaspect, which itself
defaults to 0.35.
at location
Specifies the location of the element's corner named by the attribute with. Defaults to the current location as maintained
by the layouting system.
color spec
IMAGE: figure-21-style-colors Specifies the color used to draw the lines of the element. If not specified the system falls
back to the value taken from the language variable linecolor, which itself defaults to black.
fillcolor spec
IMAGE: figure-21-style-colors Specifies the color used to draw the inside of the element. If not specified the system falls
back to the value taken from the language variable fillcolor, which itself defaults to the empty string, signaling "no fill-
ing".
height length
ht length
Specifies the height of the element. If not specified the system falls back to the value taken from the language variable
boxheight, which itself defaults to the pixel equivalent of 2 cm.
justify left|center|right
Specifies how multi-line text associated with the element is positioned within its box. The value is ignored if no text was
specified for the element. If not specified the system falls back to the value taken from the language variable justify,
which itself defaults to left. The legal values are left, right, and center.
stroke width
IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for the the element, in pixels. If not specified the
system falls back to the value taken from the language variable linewidth, which itself defaults to 1.
style spec
IMAGE: figure-18-style-dash Specifies the style used to draw the lines of the element. If not specified the system falls
back to the value taken from the language variable linestyle, which itself defaults to solid lines. The legal values are all
those accepted by Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and additionally all which are listed below:
solid, empty string
Draw solid line.
dash, dashed, -
Draw a dashed line.
dot, dotted, .
Draw a dotted line.
dash-dot, -.
Draw a dash-dotted line
dash-dot-dot, -..
Draw a dash-dot-dotted line.
Note that the values "solid", "dot(ted)", "dash(ed)", "dash-dot", and "dash-dot-dot" are all accepted as shorthands for the style
command using them as argument.
text string
Specifies the text to associate with the element. Defaults to nothing. When specified multiple times the actually shown
text is the concatenation of the individual strings, vertically stacked, with the first string specified being the topmost
element.
textcolor spec
Specifies the color used to draw the text of an element with. Ignored if there is no text. If not specified the system
falls back to the value taken from the language variable textcolor, which itself defaults to black.
textfont spec
Specifies the font used to draw the text of an element with. Ignored if there is no text. If not specified the system falls
back to the value taken from the language variable textfont, which itself defaults to Helvetica 12pt.
width length
wid length
Specifies the width of the element. If not specified the system falls back to the value taken from the language variable
boxwidth, which itself defaults to the pixel equivalent of 2 cm.
with corner
Specifies the corner of the element to place at the location given by the attribute at. Defaults to the current corner as
maintained by the layouting system, except if the value for at was specified by the user. In that case it defaults to center.
ellipse attr...
IMAGE: figure-02-ellipse A closed element with the corresponding corners, i.e. the eight directions of the compass rose, and "cen-
ter". It handles the attributes
anchor name
ljust
rjust
above
below IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which is to be placed at the element's center, by name.
I.e. this attribute defines the text's position relative to the element's center. The value is ignored if no text was speci-
fied for the element. If not specified the system falls back to the value taken from the language variable anchor, which
itself defaults to center. The legal values are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without arguments are all shorthands with the anchor
implied. Note that they do not combine, only the last is used. For comined directions the main attribute command, anchor has
to be used.
ljust "anchor west"
rjust "anchor east"
above "anchor south"
below "anchor north"
at location
Specifies the location of the element's corner named by the attribute with. Defaults to the current location as maintained
by the layouting system.
color spec
IMAGE: figure-21-style-colors Specifies the color used to draw the lines of the element. If not specified the system falls
back to the value taken from the language variable linecolor, which itself defaults to black.
fillcolor spec
IMAGE: figure-21-style-colors Specifies the color used to draw the inside of the element. If not specified the system falls
back to the value taken from the language variable fillcolor, which itself defaults to the empty string, signaling "no fill-
ing".
height length
ht length
Specifies the height of the element. If not specified the system falls back to the value taken from the language variable
boxheight, which itself defaults to the pixel equivalent of 2 cm.
justify left|center|right
Specifies how multi-line text associated with the element is positioned within its box. The value is ignored if no text was
specified for the element. If not specified the system falls back to the value taken from the language variable justify,
which itself defaults to left. The legal values are left, right, and center.
stroke width
IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for the the element, in pixels. If not specified the
system falls back to the value taken from the language variable linewidth, which itself defaults to 1.
style spec
IMAGE: figure-18-style-dash Specifies the style used to draw the lines of the element. If not specified the system falls
back to the value taken from the language variable linestyle, which itself defaults to solid lines. The legal values are all
those accepted by Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and additionally all which are listed below:
solid, empty string
Draw solid line.
dash, dashed, -
Draw a dashed line.
dot, dotted, .
Draw a dotted line.
dash-dot, -.
Draw a dash-dotted line
dash-dot-dot, -..
Draw a dash-dot-dotted line.
Note that the values "solid", "dot(ted)", "dash(ed)", "dash-dot", and "dash-dot-dot" are all accepted as shorthands for the style
command using them as argument.
text string
Specifies the text to associate with the element. Defaults to nothing. When specified multiple times the actually shown
text is the concatenation of the individual strings, vertically stacked, with the first string specified being the topmost
element.
textcolor spec
Specifies the color used to draw the text of an element with. Ignored if there is no text. If not specified the system
falls back to the value taken from the language variable textcolor, which itself defaults to black.
textfont spec
Specifies the font used to draw the text of an element with. Ignored if there is no text. If not specified the system falls
back to the value taken from the language variable textfont, which itself defaults to Helvetica 12pt.
width length
wid length
Specifies the width of the element. If not specified the system falls back to the value taken from the language variable
boxwidth, which itself defaults to the pixel equivalent of 2 cm.
with corner
Specifies the corner of the element to place at the location given by the attribute at. Defaults to the current corner as
maintained by the layouting system, except if the value for at was specified by the user. In that case it defaults to center.
line attr...
-- attr...
IMAGE: figure-02-line An open element with the corresponding corners, i.e. "start", "end", and "center". It handles the attributes
anchor name
ljust
rjust
above
below IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which is to be placed at the element's center, by name.
I.e. this attribute defines the text's position relative to the element's center. The value is ignored if no text was speci-
fied for the element. If not specified the system falls back to the value taken from the language variable anchor, which
itself defaults to center. The legal values are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without arguments are all shorthands with the anchor
implied. Note that they do not combine, only the last is used. For comined directions the main attribute command, anchor has
to be used.
ljust "anchor west"
rjust "anchor east"
above "anchor south"
below "anchor north"
arrowhead spec
IMAGE: figure-19-style-arrowheads Specifies where to draw arrowheads on the line element, at the beginning or end, at both
ends, or none. If not specified the system falls back to the value taken from the language variable arrowhead, which itself
defaults to none. The legal values are
none, -
Draw no arrowheads, at neither end of the line.
start, first, <-
Draw an arrowhead at the beginning of the line, but not at its end.
end, last, ->
Draw an arrowhead at the end of the line, but not at its beginning.
both, <->
Draw arrowheads at both ends of the line.
Note that the values "start", "end", "-", "->", "<-", and "<->" are all accepted as shorthands for the arrowhead command using them
as argument.
at location
Line elements are normally positioned absolutely, using the locations specified through the attributes from, then, and to.
If at is specified however then these positions are translated a last time, moving the line's corner named by the attribute
with to the location given by this attribute.
chop ?length?
Specifies the length of the line element to remove from the beginning and/or end. Defaults to nothing. If specified once
the chopping applies to both beginning and end of the line. If specified twice or more the last two specifications are used,
and applied to beginning and end of the line, in this order. Whenever the attribute is specified without an explicit length,
the system falls back to the value taken from the language variable circleradius, which itself defaults to the pixel equiva-
lent of 1 cm
color spec
IMAGE: figure-21-style-colors Specifies the color used to draw the lines of the element. If not specified the system falls
back to the value taken from the language variable linecolor, which itself defaults to black.
fillcolor spec
IMAGE: figure-21-style-colors Specifies the color used to draw the inside of the element. If not specified the system falls
back to the value taken from the language variable fillcolor, which itself defaults to the empty string, signaling "no fill-
ing".
from location
Specifies the location where the line element begins. Defaults to the current location as maintained by the layouting sys-
tem.
justify left|center|right
Specifies how multi-line text associated with the element is positioned within its box. The value is ignored if no text was
specified for the element. If not specified the system falls back to the value taken from the language variable justify,
which itself defaults to left. The legal values are left, right, and center.
noturn Specifies that the direction of line element at its end is not propagated to the layout management. If not specified the
direction of the line becomes the new direction the layout.
smooth Specifies the use of bezier splines for the line element. If not specified lines are drawn exactly through the specified
waypoints, without any smooth curves.
stroke width
IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for the the element, in pixels. If not specified the
system falls back to the value taken from the language variable linewidth, which itself defaults to 1.
style spec
IMAGE: figure-18-style-dash Specifies the style used to draw the lines of the element. If not specified the system falls
back to the value taken from the language variable linestyle, which itself defaults to solid lines. The legal values are all
those accepted by Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and additionally all which are listed below:
solid, empty string
Draw solid line.
dash, dashed, -
Draw a dashed line.
dot, dotted, .
Draw a dotted line.
dash-dot, -.
Draw a dash-dotted line
dash-dot-dot, -..
Draw a dash-dot-dotted line.
Note that the values "solid", "dot(ted)", "dash(ed)", "dash-dot", and "dash-dot-dot" are all accepted as shorthands for the style
command using them as argument.
text string
Specifies the text to associate with the element. Defaults to nothing. When specified multiple times the actually shown
text is the concatenation of the individual strings, vertically stacked, with the first string specified being the topmost
element.
textcolor spec
Specifies the color used to draw the text of an element with. Ignored if there is no text. If not specified the system
falls back to the value taken from the language variable textcolor, which itself defaults to black.
textfont spec
Specifies the font used to draw the text of an element with. Ignored if there is no text. If not specified the system falls
back to the value taken from the language variable textfont, which itself defaults to Helvetica 12pt.
then location
then (<direction> ?length?)...
(<direction> ?length?)...
This attribute specifies an intermediate location the line element has to go through. It can be specified multiple times,
with each use adding one additional location to the series which the line will go through. These location will be traversed
in the order they were specified.
The location can be given explicitly, or as a series of directions with distances. In the latter case the names of all known
directions are accepted for the direction part. If no distance is specified for a direction the system falls back to the
value taken from the language variable movelength, which itself defaults to the pixel equivalent of 2 cm. The whole set of
direction,distance pairs is treated as a series of translations which are added up to provide the final translation specify-
ing the intermediate point (relative to the preceding point).
The last named direction is propagated to the layout system as the direction to follow. The use of noturn is not able to
overide this behaviour.
At last, the names of the registered directions also serve as attribute commands, with an implicit attribute then in front of
them.
If no intermediate or last location is specified for the line the system falls back to a point movelength pixels away from
the starting location, in the current direction as maintained by the layouting system
to location
Specifies the location where the line element ends. This attribute has no default. The default is handled by the attribute
then, which makes it appear as if to has a default when not specified.
with corner
Line elements are normally positioned absolutely, using the locations specified through the attributes from, then, and to.
If at is specified however then these positions are translated a last time, moving the line's corner named by the attribute
with to the location given by this attribute. This means that with is effective if and only if the attribute at was speci-
fied as well for the line.
move attr
An open element with the corresponding corners, i.e. "start", "end", and "center". A move element is in essence an invisible line.
While the main effect we are interested in is the change it makes to the layout system, it is an actual element, i.e. it has the
same corners as an ordinary line, and shows up in the history as well, allowing future references to all the places it touched. It
handles the same attibutes as line elements.
spline attr...
IMAGE: figure-02-spline An alias for the line element (see above), with the attribute smooth preset.
text attr...
IMAGE: figure-02-text A closed element with the corresponding corners, i.e. the eight directions of the compass rose, and "center".
It handles the attributes
anchor name
ljust
rjust
above
below IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which is to be placed at the element's center, by name.
I.e. this attribute defines the text's position relative to the element's center. The value is ignored if no text was speci-
fied for the element. If not specified the system falls back to the value taken from the language variable anchor, which
itself defaults to center. The legal values are all those accepted by Tk_GetAnchor
[http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without arguments are all shorthands with the anchor
implied. Note that they do not combine, only the last is used. For comined directions the main attribute command, anchor has
to be used.
ljust "anchor west"
rjust "anchor east"
above "anchor south"
below "anchor north"
at location
Specifies the location of the element's corner named by the attribute with. Defaults to the current location as maintained
by the layouting system.
height length
Specifies the height of the text element. Defaults to the natural height of its text.
justify left|center|right
Specifies how multi-line text associated with the element is positioned within its box. The value is ignored if no text was
specified for the element. If not specified the system falls back to the value taken from the language variable justify,
which itself defaults to left. The legal values are left, right, and center.
text string
Specifies the text to associate with the element. Defaults to nothing. When specified multiple times the actually shown
text is the concatenation of the individual strings, vertically stacked, with the first string specified being the topmost
element.
textcolor spec
Specifies the color used to draw the text of an element with. Ignored if there is no text. If not specified the system
falls back to the value taken from the language variable textcolor, which itself defaults to black.
textfont spec
Specifies the font used to draw the text of an element with. Ignored if there is no text. If not specified the system falls
back to the value taken from the language variable textfont, which itself defaults to Helvetica 12pt.
width length
Specifies the width of the text element. Defaults to the natural width of its text.
with corner
Specifies the corner of the element to place at the location given by the attribute at. Defaults to the current corner as
maintained by the layouting system, except if the value for at was specified by the user. In that case it defaults to center.
ATTRIBUTES
The set of all attributes supported by all the element commands is shown below. While we speak of them as commands, and provide a syntax,
they are not truly available as actual commands, but only as part of the arguments for an element command.
Note that some of the attribute names are overloaded, i.e. have multiple, different, definitions. During processing of attributes for an
element the actual definition used is chosen based on the type of the element the processing is for.
Further, as a catch-all clause, any attribute which could not be processed according to the definitions below will be treated as the argu-
ment of an implicit text attribute.
anchor name
ljust
rjust
above
below IMAGE: figure-22-text-anchoring-3 Specifies the anchor of the text which is to be placed at the element's center, by name. I.e. this
attribute defines the text's position relative to the element's center. The value is ignored if no text was specified for the ele-
ment. If not specified the system falls back to the value taken from the language variable anchor, which itself defaults to center.
The legal values are all those accepted by Tk_GetAnchor [http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm]. The commands without
arguments are all shorthands with the anchor implied. Note that they do not combine, only the last is used. For comined directions
the main attribute command, anchor has to be used.
ljust "anchor west"
rjust "anchor east"
above "anchor south"
below "anchor north"
arrowhead spec
IMAGE: figure-19-style-arrowheads Specifies where to draw arrowheads on the line element, at the beginning or end, at both ends, or
none. If not specified the system falls back to the value taken from the language variable arrowhead, which itself defaults to
none. The legal values are
none, -
Draw no arrowheads, at neither end of the line.
start, first, <-
Draw an arrowhead at the beginning of the line, but not at its end.
end, last, ->
Draw an arrowhead at the end of the line, but not at its beginning.
both, <->
Draw arrowheads at both ends of the line.
Note that the values "start", "end", "-", "->", "<-", and "<->" are all accepted as shorthands for the arrowhead command using them as
argument.
aspect number
Specifies the aspect ratio, i.e ratio of width to height, of the diamond element. The manner in which a default is calculated when
not specified also depends on the specifications of the attributes width and height, if any.
If both width, and height are specified then any specification of aspect is ignored, as it is implicitly defined in the width and
height as well, and this takes precedence. A missing specification is ignored in that case well, i.e. no defaults are required.
If the aspect is specified, and one of the attributes width or height, then the missing attribute is calculated from the two which
are specified. No defaults are required for these cases either.
If only one of the attributes width or height is specified then the system uses a fallback for the aspect, the value taken from the
language variable diamondaspect, which itselfs defaults to 2.
If none of of the attributes width or height is specified then the system uses a fallback for the width, the value taken from the
language variable boxwidth, which itselfs defaults to the pixel equivalent of 2 cm. For the aspect it uses either the user-specified
value or the default taken as described in the previous paragraph.
aspect number
Specifies the aspect ratio, i.e ratio of width to height, of the ellipses which are used to draw the top and bottom of the drum ele-
ment. If not specified the system falls back to the value taken from the language variable drumaspect, which itself defaults to
0.35.
at location
Specifies the location of the element's corner named by the attribute with. Defaults to the current location as maintained by the
layouting system.
at location
Line elements are normally positioned absolutely, using the locations specified through the attributes from, then, and to. If at is
specified however then these positions are translated a last time, moving the line's corner named by the attribute with to the loca-
tion given by this attribute.
chop ?length?
Specifies the length of the line element to remove from the beginning and/or end. Defaults to nothing. If specified once the chop-
ping applies to both beginning and end of the line. If specified twice or more the last two specifications are used, and applied to
beginning and end of the line, in this order. Whenever the attribute is specified without an explicit length, the system falls back
to the value taken from the language variable circleradius, which itself defaults to the pixel equivalent of 1 cm
clockwise
cw Specifies the direction of the arc element, here going clockwise. The complementary attribute is counterclockwise. If not speci-
fied the system falls back to the value taken from the language variable clockwise, which itself defaults to false, for counter-
clockwise direction.
color spec
IMAGE: figure-21-style-colors Specifies the color used to draw the lines of the element. If not specified the system falls back to
the value taken from the language variable linecolor, which itself defaults to black.
counterclockwise
ccw Specifies the direction of the arc element, here counter-clockwise. The complementary attribute is clockwise. If not specified the
system falls back to the value taken from the language variable clockwise, which itself defaults to false, for counter-clockwise
direction.
diameter length
diam length
Specifies the diameter of the circle element, as an alternative way to specify its radius. Effective if and only if the radius was
not specified. I.e. if both diameter and radius are specified then the radius infomration has precendence. This attribute has no
default, because the defaults are taken from the radius.
fillcolor spec
IMAGE: figure-21-style-colors Specifies the color used to draw the inside of the element. If not specified the system falls back to
the value taken from the language variable fillcolor, which itself defaults to the empty string, signaling "no filling".
from location
Specifies the location where the line element begins. Defaults to the current location as maintained by the layouting system.
from location
Specifies the location where the arc element begins. Defaults to the current location as maintained by the layouting system.
height length
ht length
Specifies the height of the element. If not specified the system falls back to the value taken from the language variable box-
height, which itself defaults to the pixel equivalent of 2 cm.
height length
Specifies the height of the diamond element. The manner in which a default is calculated when not specified also depends on the
specifications of the attributes aspect and width, if any.
If both width, and height are specified then any specification of aspect is ignored, as it is implicitly defined in the width and
height as well, and this takes precedence. A missing specification is ignored in that case well, i.e. no defaults are required.
If the aspect is specified, and one of the attributes width or height, then the missing attribute is calculated from the two which
are specified. No defaults are required for these cases either.
If only one of the attributes width or height is specified then the system uses a fallback for the aspect, the value taken from the
language variable diamondaspect, which itselfs defaults to 2.
If none of of the attributes width or height is specified then the system uses a fallback for the width, the value taken from the
language variable boxwidth, which itselfs defaults to the pixel equivalent of 2 cm. For the aspect it uses either the user-specified
value or the default taken as described in the previous paragraph.
height length
Specifies the height of the text element. Defaults to the natural height of its text.
justify left|center|right
Specifies how multi-line text associated with the element is positioned within its box. The value is ignored if no text was speci-
fied for the element. If not specified the system falls back to the value taken from the language variable justify, which itself
defaults to left. The legal values are left, right, and center.
noturn Specifies that the direction of line element at its end is not propagated to the layout management. If not specified the direction
of the line becomes the new direction the layout.
radius length
rad length
Specifies the radius of the circle element. If not specified the system falls back to the value taken from the language variable
circleradius, which itself defaults to the pixel equivalent of 1 cm.
radius length
Specifies the radius of the arc element, or rather, the radius of the circle the shown arc is a part of. If not specified the sys-
tem falls back to the value taken from the language variable arcradius, which itself defaults to the pixel equivalent of 1 cm.
slant angle
Specifies the angle by which the box element is slanted, in degrees. If not specified the system falls back to the value taken from
the language variable slant, which itself defaults to 90, i.e. vertical, no slant. 0 degrees is slanting straight east, pointing to
the right. 90 degrees is slanting to the north, pointing straight up.
smooth Specifies the use of bezier splines for the line element. If not specified lines are drawn exactly through the specified waypoints,
without any smooth curves.
stroke width
IMAGE: figure-20-style-stroke Specifies the width of the lines drawn for the the element, in pixels. If not specified the system
falls back to the value taken from the language variable linewidth, which itself defaults to 1.
style spec
IMAGE: figure-18-style-dash Specifies the style used to draw the lines of the element. If not specified the system falls back to
the value taken from the language variable linestyle, which itself defaults to solid lines. The legal values are all those accepted
by Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm], and additionally all which are listed below:
solid, empty string
Draw solid line.
dash, dashed, -
Draw a dashed line.
dot, dotted, .
Draw a dotted line.
dash-dot, -.
Draw a dash-dotted line
dash-dot-dot, -..
Draw a dash-dot-dotted line.
Note that the values "solid", "dot(ted)", "dash(ed)", "dash-dot", and "dash-dot-dot" are all accepted as shorthands for the style command
using them as argument.
text string
Specifies the text to associate with the element. Defaults to nothing. When specified multiple times the actually shown text is
the concatenation of the individual strings, vertically stacked, with the first string specified being the topmost element.
textcolor spec
Specifies the color used to draw the text of an element with. Ignored if there is no text. If not specified the system falls back
to the value taken from the language variable textcolor, which itself defaults to black.
textfont spec
Specifies the font used to draw the text of an element with. Ignored if there is no text. If not specified the system falls back
to the value taken from the language variable textfont, which itself defaults to Helvetica 12pt.
then location
then (<direction> ?length?)...
(<direction> ?length?)...
This attribute specifies an intermediate location the line element has to go through. It can be specified multiple times, with each
use adding one additional location to the series which the line will go through. These location will be traversed in the order they
were specified.
The location can be given explicitly, or as a series of directions with distances. In the latter case the names of all known direc-
tions are accepted for the direction part. If no distance is specified for a direction the system falls back to the value taken
from the language variable movelength, which itself defaults to the pixel equivalent of 2 cm. The whole set of direction,distance
pairs is treated as a series of translations which are added up to provide the final translation specifying the intermediate point
(relative to the preceding point).
The last named direction is propagated to the layout system as the direction to follow. The use of noturn is not able to overide
this behaviour.
At last, the names of the registered directions also serve as attribute commands, with an implicit attribute then in front of them.
If no intermediate or last location is specified for the line the system falls back to a point movelength pixels away from the
starting location, in the current direction as maintained by the layouting system
to location
Specifies the location where the line element ends. This attribute has no default. The default is handled by the attribute then,
which makes it appear as if to has a default when not specified.
to location
Specifies the location where the arc element ends. Defaults to a location such that a 90-degree arc is drawn in the chosen direc-
tion, starting at from.
width length
wid length
Specifies the width of the element. If not specified the system falls back to the value taken from the language variable boxwidth,
which itself defaults to the pixel equivalent of 2 cm.
width length
Specifies the width of the diamond element. The manner in which a default is calculated when not specified also depends on the
specifications of the attributes aspect and height, if any.
If both width, and height are specified then any specification of aspect is ignored, as it is implicitly defined in the width and
height as well, and this takes precedence. A missing specification is ignored in that case well, i.e. no defaults are required.
If the aspect is specified, and one of the attributes width or height, then the missing attribute is calculated from the two which
are specified. No defaults are required for these cases either.
If only one of the attributes width or height is specified then the system uses a fallback for the aspect, the value taken from the
language variable diamondaspect, which itselfs defaults to 2.
If none of of the attributes width or height is specified then the system uses a fallback for the width, the value taken from the
language variable boxwidth, which itselfs defaults to the pixel equivalent of 2 cm. For the aspect it uses either the user-specified
value or the default taken as described in the previous paragraph.
width length
Specifies the width of the text element. Defaults to the natural width of its text.
with corner
Specifies the corner of the element to place at the location given by the attribute at. Defaults to the current corner as main-
tained by the layouting system, except if the value for at was specified by the user. In that case it defaults to center.
with corner
Line elements are normally positioned absolutely, using the locations specified through the attributes from, then, and to. If at is
specified however then these positions are translated a last time, moving the line's corner named by the attribute with to the loca-
tion given by this attribute. This means that with is effective if and only if the attribute at was specified as well for the line.
CORNERS
Corners are named values for in elements, usually locations.
o The closed elements define corners for the compass rose, including the "center", and their "width" and "height".
IMAGE: figure-27-corners-closed
o block elements additionally export all variables which were set during their definition as corners.
o The open elements on the other hand define "start", "end", and "center". The first two map to the locations originally provided
through the attributes from and to of the element.
IMAGE: figure-28-corners-open
o The center of line and move elements is the location halfway between "start" and "end" corners, this is regardless of any intermedi-
ate locations the element may have.
o The line and move elements additionally name all their locations as corners using numbers as names, starting from 1 (equivalent to
"start"), in order of traversal.
IMAGE: figure-15-spline-1
o The center of arc elements is the center of the circle the arc is part off.
o The arc elements additionally define the compass rose of closed elements as well.
NAMED DIRECTIONS
The named directions are commands which tell the layout system in which direction to go when placing the next element without an explicit
position specification. They can also be used as arguments to the attribute then, and the command by for relative points, see there for
the relevant syntax.
The diagram core defines the directions of the compass rose, plus a number of aliases. See below for the full list.
IMAGE: figure-27-corners-closed
This overlaps with the pre-defined corners for closed elements. This is used by the layout system, when are going in direction X the name
of the opposite direction is the name of the corner at which the new element will be attached to the current position, and if this corner
does not exist the nearest actual corner by angle is used.
west
w
left
l
south
s
down
bottom
bot
b
east
e
right
r
north
n
up
top
t
northwest
nw
up-left
upleft
leftup
northeast
ne
up-right
upright
rightup
southwest
sw
down-left
downleft
leftdown
southeast
se
down-right
downright
rightdown
MISCELLANEOUS COMMANDS
number cm
number mm
number inch
number pt
These commands allow the specification of distances and coordinates in metric and imperial units, returning the equivalent distance
or coordinate in pixels, which is the unit used internally for all calculations.
The conversion factors are based on the result of tk scaling and are computed once, at the time the package is sourced, future
changes of the tk scaling factor have no effect.
number number
IMAGE: figure-50-point-cons-absolute
This command takes the x and y coordinates of a location and returns the absolute point for it.
by distance direction
IMAGE: figure-51-point-cons-relative
This command takes a distance and direction (angle in degress, or registered direction name) and returns the relative point for it,
i.e. the delta or translation it represents.
Note also the (dis)similarities to the directional specifications for the attribute then of line and move elements. Where we say
here
by 50 east
for the attribute we say
or just
point1 + point2
IMAGE: figure-48-point-vectoradd
This command interprets two points as vectors and adds them together. If at least one of the points is absolute the result is abso-
lute as well. The result is a relative point if and only if both points are relative.
point1 - point2
IMAGE: figure-49-point-vectorsub
This command interprets two points as vectors and subtracts the second from the first. If at least one of the points is absolute
the result is absolute as well. The result is a relative point if and only if both points are relative.
point by distance direction
This command is a more convenient, or at least shorter, form of
[$point + [by $distance $direction]]
point1 | point2
IMAGE: figure-31-point-projection
This command calculates the projection of two points, i.e. the result is the point having the x-coordinate of point1 and the y-coor-
dinate of point2.
n between poin1 point2
IMAGE: figure-29-point-interpolation-1
This command computes the point which is n*100 percent of the way between point1 and point2, and returns it as its result. This
means that for
n == 0 The result is point1.
n == 1 The result is point2.
n == 0.5
The result is half way between the two points.
etc. Note that it is allowed to use values < 0 and > 1 for n
intersect elem1 elem2
IMAGE: figure-32-point-intersection
This command takes two open elements, computes the lines going through their "start"- and "end"-corners, and returns the point where
these two lines intersect. The command throws an error if the lines do not intersect, or are coincident.
element names ?pattern?
This command returns a list containing the names of all corners for the element. If a pattern is specified then only the names
matching it (via string match are returned. Otherwise all names are returned (equivalent to a default pattern of *).
element corner
This command returns the value for the corner of the element. This can be anything, including points and elements.
element corner1 corner2...
This is a convenience shorthand for
[[[$elem $corner1] $corner2] ...]
assuming that the value for
[$elem $corner1]
again an element.
element ?corner1... ?names ?pattern??]?
This is a convenience shorthand for
[[[$elem $corner1] ...] names ?pattern?]
assuming that the value for
[$elem $corner1]
again an element.
nth ?corner?
This command asks the diagram history for the nth element
created, searching from the beginning of the history (counting from 1)
and returns it as its result.
If the corner is specified then the value for this corner is
returned instead.
nth last ?corner?
This command asks the diagram history for the nth element
created, searching from the end of the history and returns it as its
result.
If the corner is specified then the value for this corner is
returned instead.
nth shape ?corner?
This command asks the diagram history for the nth element
created, of the given shape, searching from the beginning of the
history (counting from 1) and returns it as its result.
If the corner is specified then the value for this corner is
returned instead.
nth last shape ?corner?
This command asks the diagram history for the nth element
created, of the given shape, searching from the end of the
history and returns it as its result.
If the corner is specified then the value for this corner is
returned instead.
last ?corner?
last shape ?corner?
Convenience commands mapping to "1st last"
and "1st last shape".
1st
2nd
3rd
Aliases for 1th, 2th, and 3th, for readability,
usable whereever nth can ocur.
VARIABLES
The language context contains a number of predefined variables which hold the default values for various attributes. These variables, their
uses, and values are:
anchor
The default value for the attribute anchor.
Initialized to center.
The legal values are all those accepted by Tk_GetAnchor [http://www.tcl.tk/man/tcl8.5/TkLib/GetAnchor.htm].
arcradius
The default value for the attribute radius of arc elements.
Initialized to the pixel equivalent of 1 cm.
arrowhead
The default value for the attribute arrowhead.
Initialized to none.
The legal values are
none, -
Draw no arrowheads, at neither end of the line.
start, first, <-
Draw an arrowhead at the beginning of the line, but not at its end.
end, last, ->
Draw an arrowhead at the end of the line, but not at its beginning.
both, <->
Draw arrowheads at both ends of the line.
boxheight
The default value for the attribute height of box, diamond and ellipse elements.
Initialized to the pixel equivalent of 2 cm.
boxwidth
The default value for the attribute width of box, diamond and ellipse elements.
Initialized to the pixel equivalent of 2 cm.
clockwise
The default value for the attributes clockwise and counterclockwise of arc elements.
Initialized to False, for counter-clockwise direction.
circleradius
The default value for the attribute radius of circle elements, and also the default for the attribute chop, when specified without
an explicit length.
Initialized to the pixel equivalent of 1 cm.
drumaspect
The default value for the attribute aspect of drum elements.
Initialized to 0.35.
fillcolor
The default value for the attribute fillcolor of all elements which can be filled.
Initialized to the empty string, signaling that the element is not filled.
justify
The default value for the attribute justify.
Initialized to left.
The legal values are left, right, and center.
linecolor
The default value for the attribute color of all elements having to draw lines (all but text).
Initialized to black.
linestyle
The default value for the attribute style of all elements having to draw some line.
Initialized to solid.
The legal values are all those accepted by Tk_GetDash [http://www.tcl.tk/man/tcl8.5/TkLib/GetDash.htm],
and additionally all which are listed below:
solid, empty string
Draw solid line.
dash, dashed, -
Draw a dashed line.
dot, dotted, .
Draw a dotted line.
dash-dot, -.
Draw a dash-dotted line
dash-dot-dot, -..
Draw a dash-dot-dotted line.
linewidth
The default value for the attribute stroke of all elements having to draw some line.
Initialized to 1 (pixels).
movelength
The default value for the directional specification of intermediate locations by the attribute then of line and move elements.
Initialized to the pixel equivalent of 2 cm.
slant
The default value for the attribute slant of box elements.
Initialized to 90 degrees, i.e. slant straight up.
textcolor
The default value for the attribute textcolor of all elements having to draw some text.
Initialized to black.
textfont
The default value for the attribute textfont of all elements having to draw some text.
Initialized to Helvetica 12pt.
DIAGRAM CLASSES The intended audience of this section are developers wishing to work
on the internals of the diagram package.
Regular users of diagram can skip this section without missing anything.
The main information seen here is the figure below, showing the hierarchy of the classes implementing diagram.
IMAGE: figure-00-dependencies
At the bottom, all at the same level are the supporting packages like snit, etc. These can all be found in Tcllib.
Above them is the set of diagram classes implementing the various aspects of the system, i.e.:
diagram
The main class, that which is seen by the user.
diagram::core
The core engine, itself distributed over four helper classes.
diagram::basic
The implementation of the standard shapes, like box, circle, etc., based on the extension features of the core.
diagram::element
Core support class, the database of created elements. It also keeps the history, i.e. the order in which elements were created.
diagram::attribute
Core support class, the generic handling of definition and processing of attributes.
diagram::direction
Core support class, the database of named directions.
diagram::navigation
Core support class, the state of layout engine, i.e. current position and directin, and operations on it.
diagram::point
General support class handling various vector operations.
REFERENCES
KEYWORDS
2D geometry, arc, arrow, box, canvas, circle, diagram, diamond, drawing, drum, ellipse, image, interpolation, intersection, line, move,
picture, plane geometry, plotting, point, raster image, spline, text, vector
CATEGORY
Documentation tools
diagrams 0.3 diagram(n)