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GD(3)			       User Contributed Perl Documentation			    GD(3)

       GD.pm - Interface to Gd Graphics Library

	   use GD;

	   # create a new image
	   $im = new GD::Image(100,100);

	   # allocate some colors
	   $white = $im->colorAllocate(255,255,255);
	   $black = $im->colorAllocate(0,0,0);
	   $red = $im->colorAllocate(255,0,0);
	   $blue = $im->colorAllocate(0,0,255);

	   # make the background transparent and interlaced

	   # Put a black frame around the picture

	   # Draw a blue oval

	   # And fill it with red

	   # make sure we are writing to a binary stream
	   binmode STDOUT;

	   # Convert the image to PNG and print it on standard output
	   print $im->png;

       GD.pm is a Perl interface to Thomas Boutell's gd graphics library (version 2.01 or higher;
       see below). GD allows you to create color drawings using a large number of graphics
       primitives, and emit the drawings as PNG files.

       GD defines the following four classes:

	    An image class, which holds the image data and accepts graphic primitive method

	    A font class, which holds static font information and used for text rendering.

	    A simple polygon object, used for storing lists of vertices prior to rendering a
	    polygon into an image.

	    A "simple" class that simplifies the GD::Image API and then adds a set of object-
	    oriented drawing methods using turtle graphics, simplified font handling, ability to
	    work in polar coordinates, HSV color spaces, and human-readable color names like
	    "lightblue". Please see GD::Simple for a description of these methods.

       A Simple Example:


	       use GD;

	       # create a new image
	       $im = new GD::Image(100,100);

	       # allocate some colors
	       $white = $im->colorAllocate(255,255,255);
	       $black = $im->colorAllocate(0,0,0);
	       $red = $im->colorAllocate(255,0,0);
	       $blue = $im->colorAllocate(0,0,255);

	       # make the background transparent and interlaced

	       # Put a black frame around the picture

	       # Draw a blue oval

	       # And fill it with red

	       # make sure we are writing to a binary stream
	       binmode STDOUT;

	       # Convert the image to PNG and print it on standard output
	       print $im->png;


       1. To create a new, empty image, send a new() message to GD::Image, passing it the width
       and height of the image you want to create.  An image object will be returned.  Other
       class methods allow you to initialize an image from a preexisting JPG, PNG, GD, GD2 or XBM
       2. Next you will ordinarily add colors to the image's color table. colors are added using
       a colorAllocate() method call.  The three parameters in each call are the red, green and
       blue (rgb) triples for the desired color.  The method returns the index of that color in
       the image's color table.  You should store these indexes for later use.
       3. Now you can do some drawing!	The various graphics primitives are described below.  In
       this example, we do some text drawing, create an oval, and create and draw a polygon.
       4. Polygons are created with a new() message to GD::Polygon.  You can add points to the
       returned polygon one at a time using the addPt() method. The polygon can then be passed to
       an image for rendering.
       5. When you're done drawing, you can convert the image into PNG format by sending it a
       png() message.  It will return a (potentially large) scalar value containing the binary
       data for the image.  Ordinarily you will print it out at this point or write it to a file.
       To ensure portability to platforms that differentiate between text and binary files, be
       sure to call "binmode()" on the file you are writing the image to.

Object Constructors: Creating Images
       The following class methods allow you to create new GD::Image objects.

       $image = GD::Image->new([$width,$height],[$truecolor])
       $image = GD::Image->new(*FILEHANDLE)
       $image = GD::Image->new($filename)
       $image = GD::Image->new($data)
	   The new() method is the main constructor for the GD::Image class.  Called with two
	   integer arguments, it creates a new blank image of the specified width and height. For

		   $myImage = new GD::Image(100,100) || die;

	   This will create an image that is 100 x 100 pixels wide.  If you don't specify the
	   dimensions, a default of 64 x 64 will be chosen.

	   The optional third argument, $truecolor, tells new() to create a truecolor GD::Image
	   object.  Truecolor images have 24 bits of color data (eight bits each in the red,
	   green and blue channels respectively), allowing for precise photograph-quality color
	   usage.  If not specified, the image will use an 8-bit palette for compatibility with
	   older versions of libgd.

	   Alternatively, you may create a GD::Image object based on an existing image by
	   providing an open filehandle, a filename, or the image data itself.	The image formats
	   automatically recognized and accepted are: PNG, JPEG, XPM and GD2.  Other formats,
	   including WBMP, and GD version 1, cannot be recognized automatically at this time.

	   If something goes wrong (e.g. insufficient memory), this call will return undef.

       $image = GD::Image->trueColor([0,1])
	   For backwards compatibility with scripts previous versions of GD, new images created
	   from scratch (width, height) are palette based by default.  To change this default to
	   create true color images use:


	   somewhere before creating new images.  To switch back to palette based by default,


       $image = GD::Image->newPalette([$width,$height])
       $image = GD::Image->newTrueColor([$width,$height])
	   The newPalette() and newTrueColor() methods can be used to explicitly create an
	   palette based or true color image regardless of the current setting of trueColor().

       $image = GD::Image->newFromPng($file, [$truecolor])
       $image = GD::Image->newFromPngData($data, [$truecolor])
	   The newFromPng() method will create an image from a PNG file read in through the
	   provided filehandle or file path.  The filehandle must previously have been opened on
	   a valid PNG file or pipe.  If successful, this call will return an initialized image
	   which you can then manipulate as you please.  If it fails, which usually happens if
	   the thing at the other end of the filehandle is not a valid PNG file, the call returns
	   undef.  Notice that the call doesn't automatically close the filehandle for you.  But
	   it does call "binmode(FILEHANDLE)" for you, on platforms where this matters.

	   You may use any of the following as the argument:

	     1) a simple filehandle, such as STDIN
	     2) a filehandle glob, such as *PNG
	     3) a reference to a glob, such as \*PNG
	     4) an IO::Handle object
	     5) the pathname of a file

	   In the latter case, newFromPng() will attempt to open the file for you and read the
	   PNG information from it.


	     open (PNG,"barnswallow.png") || die;
	     $myImage = newFromPng GD::Image(\*PNG) || die;
	     close PNG;

	     $myImage = newFromPng GD::Image('barnswallow.png');

	   To get information about the size and color usage of the information, you can call the
	   image query methods described below. Images created by reading PNG images will be
	   truecolor if the image file itself is truecolor. To force the image to be palette-
	   based, pass a value of 0 in the optional $truecolor argument.

	   The newFromPngData() method will create a new GD::Image initialized with the PNG
	   format data contained in $data.

       $image = GD::Image->newFromJpeg($file, [$truecolor])
       $image = GD::Image->newFromJpegData($data, [$truecolor])
	   These methods will create an image from a JPEG file.  They work just like newFromPng()
	   and newFromPngData(), and will accept the same filehandle and pathname arguments.

	   Images created by reading JPEG images will always be truecolor.  To force the image to
	   be palette-based, pass a value of 0 in the optional $truecolor argument.

       $image = GD::Image->newFromGif($file)
       $image = GD::Image->newFromGifData($data)
	   These methods will create an image from a GIF file.	They work just like newFromPng()
	   and newFromPngData(), and will accept the same filehandle and pathname arguments.

	   Images created from GIFs are always 8-bit palette images. To convert to truecolor, you
	   must create a truecolor image and then perform a copy.

       $image = GD::Image->newFromXbm($file)
	   This works in exactly the same way as "newFromPng", but reads the contents of an X
	   Bitmap (black & white) file:

		   open (XBM,"coredump.xbm") || die;
		   $myImage = newFromXbm GD::Image(\*XBM) || die;
		   close XBM;

	   There is no newFromXbmData() function, because there is no corresponding function in
	   the gd library.

       $image = GD::Image->newFromGd($file)
       $image = GD::Image->newFromGdData($data)
	   These methods initialize a GD::Image from a Gd file, filehandle, or data.  Gd is Tom
	   Boutell's disk-based storage format, intended for the rare case when you need to read
	   and write the image to disk quickly.  It's not intended for regular use, because,
	   unlike PNG or JPEG, no image compression is performed and these files can become BIG.

		   $myImage = newFromGd GD::Image("godzilla.gd") || die;
		   close GDF;

       $image = GD::Image->newFromGd2($file)
       $image = GD::Image->newFromGd2Data($data)
	   This works in exactly the same way as "newFromGd()" and newFromGdData, but use the new
	   compressed GD2 image format.

       $image = GD::Image->newFromGd2Part($file,srcX,srcY,width,height)
	   This class method allows you to read in just a portion of a GD2 image file.	In
	   addition to a filehandle, it accepts the top-left corner and dimensions (width,height)
	   of the region of the image to read.	For example:

		   open (GDF,"godzilla.gd2") || die;
		   $myImage = GD::Image->newFromGd2Part(\*GDF,10,20,100,100) || die;
		   close GDF;

	   This reads a 100x100 square portion of the image starting from position (10,20).

       $image = GD::Image->newFromXpm($filename)
	   This creates a new GD::Image object starting from a filename.  This is unlike the
	   other newFrom() functions because it does not take a filehandle.  This difference
	   comes from an inconsistency in the underlying gd library.

		   $myImage = newFromXpm GD::Image('earth.xpm') || die;

	   This function is only available if libgd was compiled with XPM support.

	   NOTE: The libgd library is unable to read certain XPM files, returning an all-black
	   image instead.

GD::Image Methods
       Once a GD::Image object is created, you can draw with it, copy it, and merge two images.
       When you are finished manipulating the object, you can convert it into a standard image
       file format to output or save to a file.

   Image Data Output Methods
       The following methods convert the internal drawing format into standard output file

       $pngdata = $image->png([$compression_level])
	   This returns the image data in PNG format.  You can then print it, pipe it to a
	   display program, or write it to a file.  Example:

		   $png_data = $myImage->png;
		   open (DISPLAY,"| display -") || die;
		   binmode DISPLAY;
		   print DISPLAY $png_data;
		   close DISPLAY;

	   Note the use of "binmode()".  This is crucial for portability to DOSish platforms.

	   The optional $compression_level argument controls the amount of compression to apply
	   to the output PNG image.  Values range from 0-9, where 0 means no compression (largest
	   files, highest quality) and 9 means maximum compression (smallest files, worst
	   quality).  A compression level of -1 uses the default compression level selected when
	   zlib was compiled on your system, and is the same as calling png() with no argument.
	   Be careful not to confuse this argument with the jpeg() quality argument, which ranges
	   from 0-100 and has the opposite meaning from compression (higher numbers give higher

       $gifdata = $image->gifanimbegin([$GlobalCM [, $Loops]])
	   For libgd version 2.0.33 and higher, this call begins an animated GIF by returning the
	   data that comprises animated gif image file header.	After you call this method, call
	   gifanimadd() one or more times to add the frames of the image. Then call gifanimend().
	   Each frame must be the same width and height.

	   A typical sequence will look like this:

	     my $gifdata = $image->gifanimbegin;
	     $gifdata	.= $image->gifanimadd;	  # first frame
	     for (1..100) {
		# make a frame of right size
		my $frame  = GD::Image->new($image->getBounds);
		add_frame_data($frame); 	     # add the data for this frame
		$gifdata   .= $frame->gifanimadd;     # add frame
	     $gifdata	.= $image->gifanimend;	 # finish the animated GIF
	     print $gifdata;			 # write animated gif to STDOUT

	   If you do not wish to store the data in memory, you can print it to stdout or a file.

	   The image that you call gifanimbegin on is used to set the image size, color
	   resolution and color map.  If argument $GlobalCM is 1, the image color map becomes the
	   GIF89a global color map.  If $Loops is given and >= 0, the NETSCAPE2.0 application
	   extension is created, with looping count.  Looping count 0 means forever.

       $gifdata = $image->gifanimadd([$LocalCM [, $LeftOfs [, $TopOfs [, $Delay [, $Disposal [,
	   Returns the data that comprises one animated gif image frame.  You can then print it,
	   pipe it to a display program, or write it to a file.  With $LeftOfs and $TopOfs you
	   can place this frame in different offset than (0,0) inside the image screen.  Delay
	   between the previous frame and this frame is in 1/100s units.  Disposal is usually and
	   by default 1.  Compression is activated by giving the previous image as a parameter.
	   This function then compares the images and only writes the changed pixels to the new
	   frame in animation.	The Disposal parameter for optimized animations must be set to 1,
	   also for the first frame.  $LeftOfs and $TopOfs parameters are ignored for optimized

       $gifdata = $image->gifanimend()
	   Returns the data for end segment of animated gif file.  It always returns string ';'.
	   This string must be printed to an animated gif file after all image frames to properly
	   terminate it according to GIF file syntax.  Image object is not used at all in this

       $jpegdata = $image->jpeg([$quality])
	   This returns the image data in JPEG format.	You can then print it, pipe it to a
	   display program, or write it to a file.  You may pass an optional quality score to
	   jpeg() in order to control the JPEG quality.  This should be an integer between 0 and
	   100.  Higher quality scores give larger files and better image quality.  If you don't
	   specify the quality, jpeg() will choose a good default.

       $gifdata = $image->gif().
	   This returns the image data in GIF format.  You can then print it, pipe it to a
	   display program, or write it to a file.

       $gddata = $image->gd
	   This returns the image data in GD format.  You can then print it, pipe it to a display
	   program, or write it to a file.  Example:

		   binmode MYOUTFILE;
		   print MYOUTFILE $myImage->gd;

       $gd2data = $image->gd2
	   Same as gd(), except that it returns the data in compressed GD2 format.

       $wbmpdata = $image->wbmp([$foreground])
	   This returns the image data in WBMP format, which is a black-and-white image format.
	   Provide the index of the color to become the foreground color.  All other pixels will
	   be considered background.

   Color Control
       These methods allow you to control and manipulate the GD::Image color table.

       $index = $image->colorAllocate(red,green,blue)
	   This allocates a color with the specified red, green and blue components and returns
	   its index in the color table, if specified.	The first color allocated in this way
	   becomes the image's background color.  (255,255,255) is white (all pixels on).
	   (0,0,0) is black (all pixels off).  (255,0,0) is fully saturated red.  (127,127,127)
	   is 50% gray.  You can find plenty of examples in /usr/X11/lib/X11/rgb.txt.

	   If no colors are allocated, then this function returns -1.


		   $white = $myImage->colorAllocate(0,0,0); #background color
		   $black = $myImage->colorAllocate(255,255,255);
		   $peachpuff = $myImage->colorAllocate(255,218,185);

       $index = $image->colorAllocateAlpha(reg,green,blue,alpha)
	   This allocates a color with the specified red, green, and blue components, plus the
	   specified alpha channel.  The alpha value may range from 0 (opaque) to 127
	   (transparent).  The "alphaBlending" function changes the way this alpha channel
	   affects the resulting image.

	   This marks the color at the specified index as being ripe for reallocation.	The next
	   time colorAllocate is used, this entry will be replaced.  You can call this method
	   several times to deallocate multiple colors.  There's no function result from this


		   $peachy = $myImage->colorAllocate(255,210,185);

       $index = $image->colorClosest(red,green,blue)
	   This returns the index of the color closest in the color table to the red green and
	   blue components specified.  If no colors have yet been allocated, then this call
	   returns -1.


		   $apricot = $myImage->colorClosest(255,200,180);

       $index = $image->colorClosestHWB(red,green,blue)
	   This also attempts to return the color closest in the color table to the red green and
	   blue components specified. It uses a Hue/White/Black color representation to make the
	   selected color more likely to match human perceptions of similar colors.

	   If no colors have yet been allocated, then this call returns -1.


		   $mostred = $myImage->colorClosestHWB(255,0,0);

       $index = $image->colorExact(red,green,blue)
	   This returns the index of a color that exactly matches the specified red green and
	   blue components.  If such a color is not in the color table, this call returns -1.

		   $rosey = $myImage->colorExact(255,100,80);
		   warn "Everything's coming up roses.\n" if $rosey >= 0;

       $index = $image->colorResolve(red,green,blue)
	   This returns the index of a color that exactly matches the specified red green and
	   blue components.  If such a color is not in the color table and there is room, then
	   this method allocates the color in the color table and returns its index.

		   $rosey = $myImage->colorResolve(255,100,80);
		   warn "Everything's coming up roses.\n" if $rosey >= 0;

       $colorsTotal = $image->colorsTotal object method
	   This returns the total number of colors allocated in the object.

		   $maxColors = $myImage->colorsTotal;

	   In the case of a TrueColor image, this call will return undef.

       $index = $image->getPixel(x,y) object method
	   This returns the color table index underneath the specified point.  It can be combined
	   with rgb() to obtain the rgb color underneath the pixel.


		   $index = $myImage->getPixel(20,100);
		   ($r,$g,$b) = $myImage->rgb($index);

       ($red,$green,$blue) = $image->rgb($index)
	   This returns a list containing the red, green and blue components of the specified
	   color index.


		   @RGB = $myImage->rgb($peachy);

	   This marks the color at the specified index as being transparent.  Portions of the
	   image drawn in this color will be invisible.  This is useful for creating paintbrushes
	   of odd shapes, as well as for making PNG backgrounds transparent for displaying on the
	   Web.  Only one color can be transparent at any time. To disable transparency, specify
	   -1 for the index.

	   If you call this method without any parameters, it will return the current index of
	   the transparent color, or -1 if none.


		   $im = newFromPng GD::Image(PNG);
		   $white = $im->colorClosest(255,255,255); # find white
		   binmode STDOUT;
		   print $im->png;

   Special Colors
       GD implements a number of special colors that can be used to achieve special effects.
       They are constants defined in the GD:: namespace, but automatically exported into your
       namespace when the GD module is loaded.

	   You can draw lines and shapes using a brush pattern.  Brushes are just images that you
	   can create and manipulate in the usual way. When you draw with them, their contents
	   are used for the color and shape of the lines.

	   To make a brushed line, you must create or load the brush first, then assign it to the
	   image using setBrush().  You can then draw in that with that brush using the gdBrushed
	   special color.  It's often useful to set the background of the brush to transparent so
	   that the non-colored parts don't overwrite other parts of your image.


		   # Create a brush at an angle
		   $diagonal_brush = new GD::Image(5,5);
		   $white = $diagonal_brush->colorAllocate(255,255,255);
		   $black = $diagonal_brush->colorAllocate(0,0,0);
		   $diagonal_brush->line(0,4,4,0,$black); # NE diagonal

		   # Set the brush

		   # Draw a circle using the brush

	   Lines drawn with line(), rectangle(), arc(), and so forth are 1 pixel thick by
	   default.  Call setThickness() to change the line drawing width.

	   Styled lines consist of an arbitrary series of repeated colors and are useful for
	   generating dotted and dashed lines.	To create a styled line, use setStyle() to
	   specify a repeating series of colors.  It accepts an array consisting of one or more
	   color indexes.  Then draw using the gdStyled special color.	Another special color,
	   gdTransparent can be used to introduce holes in the line, as the example shows.


		   # Set a style consisting of 4 pixels of yellow,
		   # 4 pixels of blue, and a 2 pixel gap

	   To combine the "gdStyled" and "gdBrushed" behaviors, you can specify
	   "gdStyledBrushed".  In this case, a pixel from the current brush pattern is rendered
	   wherever the color specified in setStyle() is neither gdTransparent nor 0.

	   Draw filled shapes and flood fills using a pattern.	The pattern is just another
	   image.  The image will be tiled multiple times in order to fill the required space,
	   creating wallpaper effects.	You must call "setTile" in order to define the particular
	   tile pattern you'll use for drawing when you specify the gdTiled color.  details.

	   The gdStyled color is used for creating dashed and dotted lines.  A styled line can
	   contain any series of colors and is created using the setStyled() command.

	   The "gdAntiAliased" color is used for drawing lines with antialiasing turned on.
	   Antialiasing will blend the jagged edges of lines with the background, creating a
	   smoother look.  The actual color drawn is set with setAntiAliased().

	   "Antialiasing" is a process by which jagged edges associated with line drawing can be
	   reduced by blending the foreground color with an appropriate percentage of the
	   background, depending on how much of the pixel in question is actually within the
	   boundaries of the line being drawn. All line-drawing methods, such as line() and
	   polygon, will draw antialiased lines if the special "color" gdAntiAliased is used when
	   calling them.

	   setAntiAliased() is used to specify the actual foreground color to be used when
	   drawing antialiased lines. You may set any color to be the foreground, however as of
	   libgd version 2.0.12 an alpha channel component is not supported.

	   Antialiased lines can be drawn on both truecolor and palette-based images. However,
	   attempts to draw antialiased lines on highly complex palette-based backgrounds may not
	   give satisfactory results, due to the limited number of colors available in the
	   palette. Antialiased line-drawing on simple backgrounds should work well with palette-
	   based images; otherwise create or fetch a truecolor image instead. When using palette-
	   based images, be sure to allocate a broad spectrum of colors in order to have
	   sufficient colors for the antialiasing to use.

	   Normally, when drawing lines with the special gdAntiAliased "color," blending with the
	   background to reduce jagged edges is the desired behavior. However, when it is desired
	   that lines not be blended with one particular color when it is encountered in the
	   background, the setAntiAliasedDontBlend() method can be used to indicate the special
	   color that the foreground should stand out more clearly against.

	   Once turned on, you can turn this feature off by calling setAntiAliasedDontBlend()
	   with a second argument of 0:


   Drawing Commands
       These methods allow you to draw lines, rectangles, and ellipses, as well as to perform
       various special operations like flood-fill.

	   This sets the pixel at (x,y) to the specified color index.  No value is returned from
	   this method.  The coordinate system starts at the upper left at (0,0) and gets larger
	   as you go down and to the right.  You can use a real color, or one of the special
	   colors gdBrushed, gdStyled and gdStyledBrushed can be specified.


		   # This assumes $peach already allocated

	   This draws a line from (x1,y1) to (x2,y2) of the specified color.  You can use a real
	   color, or one of the special colors gdBrushed, gdStyled and gdStyledBrushed.


		   # Draw a diagonal line using the currently defined
		   # paintbrush pattern.

	   DEPRECATED: The libgd library provides this method solely for backward compatibility
	   with libgd version 1.0, and there have been reports that it no longer works as
	   expected. Please use the setStyle() and gdStyled methods as described below.

	   This draws a dashed line from (x1,y1) to (x2,y2) in the specified color.  A more
	   powerful way to generate arbitrary dashed and dotted lines is to use the setStyle()
	   method described below and to draw with the special color gdStyled.



	   This draws a rectangle with the specified color.  (x1,y1) and (x2,y2) are the upper
	   left and lower right corners respectively.  Both real color indexes and the special
	   colors gdBrushed, gdStyled and gdStyledBrushed are accepted.



	   This draws a rectangle filed with the specified color.  You can use a real color, or
	   the special fill color gdTiled to fill the polygon with a pattern.


		   # read in a fill pattern and set it
		   $tile = newFromPng GD::Image('happyface.png');

		   # draw the rectangle, filling it with the pattern

	   This draws a polygon with the specified color.  The polygon must be created first (see
	   below).  The polygon must have at least three vertices.  If the last vertex doesn't
	   close the polygon, the method will close it for you.  Both real color indexes and the
	   special colors gdBrushed, gdStyled and gdStyledBrushed can be specified.


		   $poly = new GD::Polygon;

	   This draws a sequence of connected lines with the specified color, without connecting
	   the first and last point to a closed polygon.  The polygon must be created first (see
	   below).  The polygon must have at least three vertices.  Both real color indexes and
	   the special colors gdBrushed, gdStyled and gdStyledBrushed can be specified.

	   You need libgd 2.0.33 or higher to use this feature.


		   $poly = new GD::Polygon;

	   This draws a polygon filled with the specified color.  You can use a real color, or
	   the special fill color gdTiled to fill the polygon with a pattern.


		   # make a polygon
		   $poly = new GD::Polygon;

		   # draw the polygon, filling it with a color

	   These methods() draw ellipses. ($cx,$cy) is the center of the arc, and
	   ($width,$height) specify the ellipse width and height, respectively.  filledEllipse()
	   is like Ellipse() except that the former produces filled versions of the ellipse.

	   This draws arcs and ellipses.  (cx,cy) are the center of the arc, and (width,height)
	   specify the width and height, respectively.	The portion of the ellipse covered by the
	   arc are controlled by start and end, both of which are given in degrees from 0 to 360.
	   Zero is at the top of the ellipse, and angles increase clockwise.  To specify a
	   complete ellipse, use 0 and 360 as the starting and ending angles.  To draw a circle,
	   use the same value for width and height.

	   You can specify a normal color or one of the special colors gdBrushed, gdStyled, or


		   # draw a semicircle centered at 100,100

       $image->filledArc($cx,$cy,$width,$height,$start,$end,$color [,$arc_style])
	   This method is like arc() except that it colors in the pie wedge with the selected
	   color.  $arc_style is optional.  If present it is a bitwise OR of the following

	     gdArc	     connect start & end points of arc with a rounded edge
	     gdChord	     connect start & end points of arc with a straight line
	     gdPie	     synonym for gdChord
	     gdNoFill	     outline the arc or chord
	     gdEdged	     connect beginning and ending of the arc to the center

	   gdArc and gdChord are mutually exclusive.  gdChord just connects the starting and
	   ending angles with a straight line, while gdArc produces a rounded edge. gdPie is a
	   synonym for gdArc. gdNoFill indicates that the arc or chord should be outlined, not
	   filled. gdEdged, used together with gdNoFill, indicates that the beginning and ending
	   angles should be connected to the center; this is a good way to outline (rather than
	   fill) a "pie slice."



	   This method flood-fills regions with the specified color.  The color will spread
	   through the image, starting at point (x,y), until it is stopped by a pixel of a
	   different color from the starting pixel (this is similar to the "paintbucket" in many
	   popular drawing toys).  You can specify a normal color, or the special color gdTiled,
	   to flood-fill with patterns.


		   # Draw a rectangle, and then make its interior blue

	   Like "fill", this method flood-fills regions with the specified color, starting at
	   position (x,y).  However, instead of stopping when it hits a pixel of a different
	   color than the starting pixel, flooding will only stop when it hits the color
	   specified by bordercolor.  You must specify a normal indexed color for the
	   bordercolor.  However, you are free to use the gdTiled color for the fill.


		   # This has the same effect as the previous example

   Image Copying Commands
       Two methods are provided for copying a rectangular region from one image to another.  One
       method copies a region without resizing it.  The other allows you to stretch the region
       during the copy operation.

       With either of these methods it is important to know that the routines will attempt to
       flesh out the destination image's color table to match the colors that are being copied
       from the source.  If the destination's color table is already full, then the routines will
       attempt to find the best match, with varying results.


	   This is the simplest of the several copy operations, copying the specified region from
	   the source image to the destination image (the one performing the method call).
	   (srcX,srcY) specify the upper left corner of a rectangle in the source image, and
	   (width,height) give the width and height of the region to copy.  (dstX,dstY) control
	   where in the destination image to stamp the copy.  You can use the same image for both
	   the source and the destination, but the source and destination regions must not
	   overlap or strange things will happen.


		   $myImage = new GD::Image(100,100);
		   ... various drawing stuff ...
		   $srcImage = new GD::Image(50,50);
		   ... more drawing stuff ...
		   # copy a 25x25 pixel region from $srcImage to
		   # the rectangle starting at (10,10) in $myImage

	   Make a copy of the image and return it as a new object.  The new image will look
	   identical.  However, it may differ in the size of the color palette and other
	   nonessential details.


		   $myImage = new GD::Image(100,100);
		   ... various drawing stuff ...
		   $copy = $myImage->clone;


	   This copies the indicated rectangle from the source image to the destination image,
	   merging the colors to the extent specified by percent (an integer between 0 and 100).
	   Specifying 100% has the same effect as copy() -- replacing the destination pixels with
	   the source image.  This is most useful for highlighting an area by merging in a solid


		   $myImage = new GD::Image(100,100);
		   ... various drawing stuff ...
		   $redImage = new GD::Image(50,50);
		   ... more drawing stuff ...
		   # copy a 25x25 pixel region from $srcImage to
		   # the rectangle starting at (10,10) in $myImage, merging 50%


	   This is identical to copyMerge() except that it preserves the hue of the source by
	   converting all the pixels of the destination rectangle to grayscale before merging.


	   This method is similar to copy() but allows you to choose different sizes for the
	   source and destination rectangles.  The source and destination rectangle's are
	   specified independently by (srcW,srcH) and (destW,destH) respectively.  copyResized()
	   will stretch or shrink the image to accommodate the size requirements.


		   $myImage = new GD::Image(100,100);
		   ... various drawing stuff ...
		   $srcImage = new GD::Image(50,50);
		   ... more drawing stuff ...
		   # copy a 25x25 pixel region from $srcImage to
		   # a larger rectangle starting at (10,10) in $myImage


	   This method is similar to copyResized() but provides "smooth" copying from a large
	   image to a smaller one, using a weighted average of the pixels of the source area
	   rather than selecting one representative pixel. This method is identical to
	   copyResized() when the destination image is a palette image.


	   Like copyResized() but the $angle argument specifies an arbitrary amount to rotate the
	   image clockwise (in degrees).  In addition, $dstX and $dstY species the center of the
	   destination image, and not the top left corner.

       $image->trueColorToPalette([$dither], [$colors])
	   This method converts a truecolor image to a palette image. The code for this function
	   was originally drawn from the Independent JPEG Group library code, which is excellent.
	   The code has been modified to preserve as much alpha channel information as possible
	   in the resulting palette, in addition to preserving colors as well as possible. This
	   does not work as well as might be hoped. It is usually best to simply produce a
	   truecolor output image instead, which guarantees the highest output quality.  Both the
	   dithering (0/1, default=0) and maximum number of colors used (<=256, default =
	   gdMaxColors) can be specified.

   Image Transformation Commands
       Gd also provides some common image transformations:

       $image = $sourceImage->copyRotate90()
       $image = $sourceImage->copyRotate180()
       $image = $sourceImage->copyRotate270()
       $image = $sourceImage->copyFlipHorizontal()
       $image = $sourceImage->copyFlipVertical()
       $image = $sourceImage->copyTranspose()
       $image = $sourceImage->copyReverseTranspose()
	   These methods can be used to rotate, flip, or transpose an image.  The result of the
	   method is a copy of the image.

	   These methods are similar to the copy* versions, but instead modify the image in

   Character and String Drawing
       GD allows you to draw characters and strings, either in normal horizontal orientation or
       rotated 90 degrees.  These routines use a GD::Font object, described in more detail below.
       There are four built-in monospaced fonts, available in the global variables gdGiantFont,
       gdLargeFont, gdMediumBoldFont, gdSmallFont and gdTinyFont.

       In addition, you can use the load() method to load GD-formatted bitmap font files at
       runtime. You can create these bitmap files from X11 BDF-format files using the bdf2gd.pl
       script, which should have been installed with GD (see the bdf_scripts directory if it
       wasn't).  The format happens to be identical to the old-style MSDOS bitmap ".fnt" files,
       so you can use one of those directly if you happen to have one.

       For writing proportional scaleable fonts, GD offers the stringFT() method, which allows
       you to load and render any TrueType font on your system.

	   This method draws a string starting at position (x,y) in the specified font and color.
	   Your choices of fonts are gdSmallFont, gdMediumBoldFont, gdTinyFont, gdLargeFont and


		   $myImage->string(gdSmallFont,2,10,"Peachy Keen",$peach);

	   Just like the previous call, but draws the text rotated counterclockwise 90 degrees.

	   These methods draw single characters at position (x,y) in the specified font and
	   color.  They're carry-overs from the C interface, where there is a distinction between
	   characters and strings.  Perl is insensible to such subtle distinctions.

       $font = GD::Font->load($fontfilepath)
	   This method dynamically loads a font file, returning a font that you can use in
	   subsequent calls to drawing methods.  For example:

	      my $courier = GD::Font->load('./courierR12.fnt') or die "Can't load font";
	      $image->string($courier,2,10,"Peachy Keen",$peach);

	   Font files must be in GD binary format, as described above.

       @bounds = $image->stringFT($fgcolor,$fontname,$ptsize,$angle,$x,$y,$string)
       @bounds = GD::Image->stringFT($fgcolor,$fontname,$ptsize,$angle,$x,$y,$string)
       @bounds = $image->stringFT($fgcolor,$fontname,$ptsize,$angle,$x,$y,$string,\%options)
	   This method uses TrueType to draw a scaled, antialiased string using the TrueType
	   vector font of your choice.	It requires that libgd to have been compiled with
	   TrueType support, and for the appropriate TrueType font to be installed on your

	   The arguments are as follows:

	     fgcolor	Color index to draw the string in
	     fontname	A path to the TrueType (.ttf) font file or a font pattern.
	     ptsize	The desired point size (may be fractional)
	     angle	The rotation angle, in radians (positive values rotate counter clockwise)
	     x,y	X and Y coordinates to start drawing the string
	     string	The string itself

	   If successful, the method returns an eight-element list giving the boundaries of the
	   rendered string:

	    @bounds[0,1]  Lower left corner (x,y)
	    @bounds[2,3]  Lower right corner (x,y)
	    @bounds[4,5]  Upper right corner (x,y)
	    @bounds[6,7]  Upper left corner (x,y)

	   In case of an error (such as the font not being available, or FT support not being
	   available), the method returns an empty list and sets $@ to the error message.

	   The string may contain UTF-8 sequences like: "&#192;"

	   You may also call this method from the GD::Image class name, in which case it doesn't
	   do any actual drawing, but returns the bounding box using an inexpensive operation.
	   You can use this to perform layout operations prior to drawing.

	   Using a negative color index will disable antialiasing, as described in the libgd
	   manual page at <http://www.boutell.com/gd/manual2.0.9.html#gdImageStringFT>.

	   An optional 8th argument allows you to pass a hashref of options to stringFT().
	   Several hashkeys are recognized: linespacing, charmap, resolution, and kerning.

	   The value of linespacing is supposed to be a multiple of the character height, so
	   setting linespacing to 2.0 will result in double-spaced lines of text.  However the
	   current version of libgd (2.0.12) does not do this.	Instead the linespacing seems to
	   be double what is provided in this argument.  So use a spacing of 0.5 to get
	   separation of exactly one line of text.  In practice, a spacing of 0.6 seems to give
	   nice results.  Another thing to watch out for is that successive lines of text should
	   be separated by the "\r\n" characters, not just "\n".

	   The value of charmap is one of "Unicode", "Shift_JIS" and "Big5".  The interaction
	   between Perl, Unicode and libgd is not clear to me, and you should experiment a bit if
	   you want to use this feature.

	   The value of resolution is the vertical and horizontal resolution, in DPI, in the
	   format "hdpi,vdpi".	If present, the resolution will be passed to the Freetype
	   rendering engine as a hint to improve the appearance of the rendered font.

	   The value of kerning is a flag.  Set it to false to turn off the default kerning of


			 "hi there\r\nbye now",
			  charmap  => 'Unicode',

	   If GD was compiled with fontconfig support, and the fontconfig library is available on
	   your system, then you can use a font name pattern instead of a path.  Patterns are
	   described in fontconfig and will look something like this "Times:italic".  For
	   backward compatibility, this feature is disabled by default.  You must enable it by
	   calling useFontConfig(1) prior to the stringFT() call.


	   For backward compatibility with older versions of the FreeType library, the alias
	   stringTTF() is also recognized.

       $hasfontconfig = $image->useFontConfig($flag)
	   Call useFontConfig() with a value of 1 in order to enable support for fontconfig font
	   patterns (see stringFT).  Regardless of the value of $flag, this method will return a
	   true value if the fontconfig library is present, or false otherwise.

       $result =
	   This draws text in a circle. Currently (libgd 2.0.33) this function does not work for
	   me, but the interface is provided for completeness.	The call signature is somewhat
	   complex.  Here is an excerpt from the libgd manual page:

	   Draws the text strings specified by top and bottom on the image, curved along the edge
	   of a circle of radius radius, with its center at cx and cy. top is written clockwise
	   along the top; bottom is written counterclockwise along the bottom. textRadius
	   determines the "height" of each character; if textRadius is 1/2 of radius, characters
	   extend halfway from the edge to the center. fillPortion varies from 0 to 1.0, with
	   useful values from about 0.4 to 0.9, and determines how much of the 180 degrees of arc
	   assigned to each section of text is actually occupied by text; 0.9 looks better than
	   1.0 which is rather crowded. font is a freetype font; see gdImageStringFT. points is
	   passed to the freetype engine and has an effect on hinting; although the size of the
	   text is determined by radius, textRadius, and fillPortion, you should pass a point
	   size that "hints" appropriately -- if you know the text will be large, pass a large
	   point size such as 24.0 to get the best results. fgcolor can be any color, and may
	   have an alpha component, do blending, etc.

	   Returns a true value on success.

   Alpha channels
       The alpha channel methods allow you to control the way drawings are processed according to
       the alpha channel. When true color is turned on, colors are encoded as four bytes, in
       which the last three bytes are the RGB color values, and the first byte is the alpha
       channel.  Therefore the hexadecimal representation of a non transparent RGB color will be:

       When alpha blending is turned on, you can use the first byte of the color to control the
       transparency, meaning that a rectangle painted with color 0x00(rr)(bb)(bb) will be opaque,
       and another one painted with 0x7f(rr)(gg)(bb) will be transparent. The Alpha value must be
       >= 0 and <= 0x7f.

	   The alphaBlending() method allows for two different modes of drawing on truecolor
	   images. In blending mode, which is on by default (libgd 2.0.2 and above), the alpha
	   channel component of the color supplied to all drawing functions, such as "setPixel",
	   determines how much of the underlying color should be allowed to shine through. As a
	   result, GD automatically blends the existing color at that point with the drawing
	   color, and stores the result in the image. The resulting pixel is opaque. In non-
	   blending mode, the drawing color is copied literally with its alpha channel
	   information, replacing the destination pixel. Blending mode is not available when
	   drawing on palette images.

	   Pass a value of 1 for blending mode, and 0 for non-blending mode.

	   By default, GD (libgd 2.0.2 and above) does not attempt to save full alpha channel
	   information (as opposed to single-color transparency) when saving PNG images. (PNG is
	   currently the only output format supported by gd which can accommodate alpha channel
	   information.) This saves space in the output file. If you wish to create an image with
	   alpha channel information for use with tools that support it, call saveAlpha(1) to
	   turn on saving of such information, and call alphaBlending(0) to turn off alpha
	   blending within the library so that alpha channel information is actually stored in
	   the image rather than being composited immediately at the time that drawing functions
	   are invoked.

   Miscellaneous Image Methods
       These are various utility methods that are useful in some circumstances.

	   This method sets or queries the image's interlaced setting.	Interlace produces a cool
	   venetian blinds effect on certain viewers.  Provide a true parameter to set the
	   interlace attribute.  Provide undef to disable it.  Call the method without parameters
	   to find out the current setting.

       ($width,$height) = $image->getBounds()
	   This method will return a two-member list containing the width and height of the
	   image.  You query but not change the size of the image once it's created.

       $width = $image->width
       $height = $image->height
	   Return the width and height of the image, respectively.

       $is_truecolor = $image->isTrueColor()
	   This method will return a Boolean representing whether the image is true color or not.

       $flag = $image1->compare($image2)
	   Compare two images and return a bitmap describing the differences found, if any.  The
	   return value must be logically ANDed with one or more constants in order to determine
	   the differences.  The following constants are available:

	     GD_CMP_IMAGE	      The two images look different
	     GD_CMP_NUM_COLORS	      The two images have different numbers of colors
	     GD_CMP_COLOR	      The two images' palettes differ
	     GD_CMP_SIZE_X	      The two images differ in the horizontal dimension
	     GD_CMP_SIZE_Y	      The two images differ in the vertical dimension
	     GD_CMP_TRANSPARENT       The two images have different transparency
	     GD_CMP_BACKGROUND	      The two images have different background colors
	     GD_CMP_INTERLACE	      The two images differ in their interlace
	     GD_CMP_TRUECOLOR	      The two images are not both true color

	   The most important of these is GD_CMP_IMAGE, which will tell you whether the two
	   images will look different, ignoring differences in the order of colors in the color
	   palette and other invisible changes.  The constants are not imported by default, but
	   must be imported individually or by importing the :cmp tag.	Example:

	     use GD qw(:DEFAULT :cmp);
	     # get $image1 from somewhere
	     # get $image2 from somewhere
	     if ($image1->compare($image2) & GD_CMP_IMAGE) {
		warn "images differ!";

       ($x1,$y1,$x2,$y2) = $image->clip
	   Set or get the clipping rectangle.  When the clipping rectangle is set, all drawing
	   will be clipped to occur within this rectangle.  The clipping rectangle is initially
	   set to be equal to the boundaries of the whole image. Change it by calling clip() with
	   the coordinates of the new clipping rectangle.  Calling clip() without any arguments
	   will return the current clipping rectangle.

       $flag = $image->boundsSafe($x,$y)
	   The boundsSafe() method will return true if the point indicated by ($x,$y) is within
	   the clipping rectangle, or false if it is not.  If the clipping rectangle has not been
	   set, then it will return true if the point lies within the image boundaries.

   Grouping Methods
       GD does not support grouping of objects, but GD::SVG does. In that subclass, the following
       methods declare new groups of graphical objects:

       $group = $image->newGroup
	   See GD::SVG for information.

       A few primitive polygon creation and manipulation methods are provided.	They aren't part
       of the Gd library, but I thought they might be handy to have around (they're borrowed from
       my qd.pl Quickdraw library).  Also see GD::Polyline.

       $poly = GD::Polygon->new
	  Create an empty polygon with no vertices.

		  $poly = new GD::Polygon;

	  Add point (x,y) to the polygon.


       ($x,$y) = $poly->getPt($index)
	  Retrieve the point at the specified vertex.

		  ($x,$y) = $poly->getPt(2);

	  Change the value of an already existing vertex.  It is an error to set a vertex that
	  isn't already defined.


       ($x,$y) = $poly->deletePt($index)
	  Delete the specified vertex, returning its value.

		  ($x,$y) = $poly->deletePt(1);

	  Delete all vertices, restoring the polygon to its initial empty state.

	  Draw from current vertex to a new vertex, using relative (dx,dy) coordinates.  If this
	  is the first point, act like addPt().


       $vertex_count = $poly->length
	  Return the number of vertices in the polygon.

		  $points = $poly->length;

       @vertices = $poly->vertices
	  Return a list of all the vertices in the polygon object.  Each member of the list is a
	  reference to an (x,y) array.

		  @vertices = $poly->vertices;
		  foreach $v (@vertices)
		     print join(",",@$v),"\n";

       @rect = $poly->bounds
	  Return the smallest rectangle that completely encloses the polygon.  The return value
	  is an array containing the (left,top,right,bottom) of the rectangle.

		  ($left,$top,$right,$bottom) = $poly->bounds;

	  Offset all the vertices of the polygon by the specified horizontal (dh) and vertical
	  (dy) amounts.  Positive numbers move the polygon down and to the right.


	  Map the polygon from a source rectangle to an equivalent position in a destination
	  rectangle, moving it and resizing it as necessary.  See polys.pl for an example of how
	  this works.  Both the source and destination rectangles are given in
	  (left,top,right,bottom) coordinates.	For convenience, you can use the polygon's own
	  bounding box as the source rectangle.

		  # Make the polygon really tall

	  Scale each vertex of the polygon by the X and Y factors indicated by sx and sy.  For
	  example scale(2,2) will make the polygon twice as large.  For best results, move the
	  center of the polygon to position (0,0) before you scale, then move it back to its
	  previous position.

	  Run each vertex of the polygon through a transformation matrix, where sx and sy are the
	  X and Y scaling factors, rx and ry are the X and Y rotation factors, and tx and ty are
	  X and Y offsets.  See the Adobe PostScript Reference, page 154 for a full explanation,
	  or experiment.

       Please see GD::Polyline for information on creating open polygons and splines.

Font Utilities
       The libgd library (used by the Perl GD library) has built-in support for about half a
       dozen fonts, which were converted from public-domain X Windows fonts.  For more fonts,
       compile libgd with TrueType support and use the stringFT() call.

       If you wish to add more built-in fonts, the directory bdf_scripts contains two contributed
       utilities that may help you convert X-Windows BDF-format fonts into the format that libgd
       uses internally.  However these scripts were written for earlier versions of GD which
       included its own mini-gd library.  These scripts will have to be adapted for use with
       libgd, and the libgd library itself will have to be recompiled and linked!  Please do not
       contact me for help with these scripts: they are unsupported.

       Each of these fonts is available both as an imported global (e.g. gdSmallFont) and as a
       package method (e.g. GD::Font->Small).

	    This is the basic small font, "borrowed" from a well known public domain 6x12 font.

	    This is the basic large font, "borrowed" from a well known public domain 8x16 font.

	    This is a bold font intermediate in size between the small and large fonts, borrowed
	    from a public domain 7x13 font;

	    This is a tiny, almost unreadable font, 5x8 pixels wide.

	    This is a 9x15 bold font converted by Jan Pazdziora from a sans serif X11 font.

	    This returns the number of characters in the font.

		    print "The large font contains ",gdLargeFont->nchars," characters\n";

	    This returns the ASCII value of the first character in the font

       $width = $font->width
       $height = $font->height
	    These return the width and height of the font.

	      ($w,$h) = (gdLargeFont->width,gdLargeFont->height);

Obtaining the C-language version of gd
       libgd, the C-language version of gd, can be obtained at URL http://www.boutell.com/gd/.
       Directions for installing and using it can be found at that site.  Please do not contact
       me for help with libgd.

       The GD.pm interface is copyright 1995-2010, Lincoln D. Stein. This package and its
       accompanying libraries is free software; you can redistribute it and/or modify it under
       the terms of the GPL (either version 1, or at your option, any later version) or the
       Artistic License 2.0.  Refer to LICENSE for the full license text.  package for details.

       The latest versions of GD.pm are available at


       GD::Polyline, GD::SVG, GD::Simple, Image::Magick

       Hey! The above document had some coding errors, which are explained below:

       Around line 463:
	   You forgot a '=back' before '=head1'

       Around line 475:
	   '=item' outside of any '=over'

perl v5.16.3				    2013-02-26					    GD(3)
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