mlib_imagecolortrue2indexinit(3mlib) [opensolaris man page]
mlib_ImageColorTrue2IndexInit(3MLIB) mediaLib Library Functions mlib_ImageColorTrue2IndexInit(3MLIB)NAME
mlib_ImageColorTrue2IndexInit - initialization for true color to indexed color conversion
SYNOPSIS
cc [ flag... ] file... -lmlib [ library... ]
#include <mlib.h>
mlib_status mlib_ImageColorTrue2IndexInit(void **colormap, mlib_s32 bits,
mlib_type intype, mlib_type outtype, mlib_s32 channels,
mlib_s32 entries, mlib_s32 offset, const void **table);
DESCRIPTION
The mlib_ImageColorTrue2IndexInit() function creates and initializes an internal data structure based on the input lookup table and other
parameters for inverse color mapping.
The lookup table can have either three or four channels. The number of channels of the lookup table should match that of the source image
provided to the function that will use the colormap structure created by this function.
The type of the lookup table can be one of the following:
MLIB_BYTE in, MLIB_BYTE out (i.e., BYTE-to-BYTE)
MLIB_SHORT in, MLIB_SHORT out (i.e., SHORT-to-SHORT)
MLIB_SHORT in, MLIB_BYTE out (i.e., SHORT-to-BYTE)
The input type of the lookup table should match the type of the destination image; the output type of the lookup table should match the
source image type. The source and destination images are the images provided to the function that is going to use the colormap structure
created by mlib_ImageColorTrue2IndexInit() to do inverse color mapping.
PARAMETERS
The function takes the following arguments:
colormap Internal data structure for inverse color mapping.
bits Number of bits per color component used in the colorcube of the colormap structure. (If bits = 0, then no colorcube is created.
But the inverse color mapping might be done by using the original lookup table.)
intype Data type of the source image and lookup table.
outtype Data type of the destination indexed image.
channels Number of channels of the lookup table.
entries Number of entries of the lookup table.
offset The first entry offset of the lookup table.
table The lookup table (LUT).
RETURN VALUES
The function returns MLIB_SUCCESS if successful. Otherwise it returns MLIB_FAILURE.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Committed |
+-----------------------------+-----------------------------+
|MT-Level |MT-Safe |
+-----------------------------+-----------------------------+
SEE ALSO mlib_ImageColorErrorDiffusion3x3(3MLIB), mlib_ImageColorOrderedDither8x8(3MLIB), mlib_ImageColorTrue2Index(3MLIB), mlib_ImageCol-
orTrue2IndexFree(3MLIB), attributes(5)SunOS 5.11 2 Mar 2007 mlib_ImageColorTrue2IndexInit(3MLIB)
Check Out this Related Man Page
mlib_ImageColorDitherInit(3MLIB) mediaLib Library Functions mlib_ImageColorDitherInit(3MLIB)NAME
mlib_ImageColorDitherInit - initialization for image dithering
SYNOPSIS
cc [ flag... ] file... -lmlib [ library... ]
#include <mlib.h>
mlib_status mlib_ImageColorDitherInit(void **colormap, const mlib_s32 *dimensions,
mlib_type intype, mlib_type outtype, mlib_s32 channels, mlib_s32 entries,
mlib_s32 offset, void **lut);
DESCRIPTION
The mlib_ImageColorDitherInit() function creates an internal data structure, colormap, which can be used by one of the following functions
for image dithering:
mlib_ImageColorErrorDiffusion3x3
mlib_ImageColorErrorDiffusionMxN
mlib_ImageColorOrderedDither8x8
mlib_ImageColorOrderedDitherMxN
The lut might have either 1 or 3 channels. The type of the lut can be one of the following:
MLIB_BYTE in, MLIB_BYTE out (i.e., BYTE-to-BYTE)
MLIB_BIT in, MLIB_BYTE out (i.e., BIT-to-BYTE)
If dimensions == NULL, then no colorcube will be created. In this case, the user-provided lookup table, lut, will be used for dithering.
If dimensions != NULL, then a colorcube is created from scratch in a way shown in the following example.
To dither an RGB image of type MLIB_BYTE to a color-indexed image of type MLIB_BYTE, we can use the following parameters:
mlib_s32 dimensions[] = {2, 3, 4};
mlib_type intype = MLIB_BYTE;
mlib_type outtype = MLIB_BYTE;
mlib_s32 channels = 3;
mlib_s32 offset = 6;
These values would lead to the creation of a colorcube that would dither red values in the source image to one of 2 red levels, green val-
ues to one of 3 green levels, and blue values to one of 4 blue levels. You could picture this colorcube as a cube with dimensions of 2, 3,
and 4. The index values assigned to the elements in that cube can be described by the following lookup table:
| | |
Indexes | Red Values | Green Values | Blue Values
---------------+----------------+----------------+---------------
0 | | |
---------------+----------------+----------------+---------------
... | | |
---------------+----------------+----------------+---------------
5 | | |
---------------+----------------+----------------+---------------
6 | 0 | 0 |0
---------------+----------------+----------------+---------------
7 | 255 | 0 |0
---------------+----------------+----------------+---------------
8 | 0 | 128 |0
---------------+----------------+----------------+---------------
9 | 255 | 128 |0
---------------+----------------+----------------+---------------
10 | 0 | 255 |0
---------------+----------------+----------------+---------------
11 | 255 | 255 |0
---------------+----------------+----------------+---------------
12 | 0 | 0 |85
---------------+----------------+----------------+---------------
13 | 255 | 0 |85
---------------+----------------+----------------+---------------
14 | 0 | 128 |85
---------------+----------------+----------------+---------------
15 | 255 | 128 |85
---------------+----------------+----------------+---------------
16 | 0 | 255 |85
---------------+----------------+----------------+---------------
17 | 255 | 255 |85
---------------+----------------+----------------+---------------
18 | 0 | 0 |170
---------------+----------------+----------------+---------------
19 | 255 | 0 |170
---------------+----------------+----------------+---------------
20 | 0 | 128 |170
---------------+----------------+----------------+---------------
21 | 255 | 128 |170
---------------+----------------+----------------+---------------
22 | 0 | 255 |170
---------------+----------------+----------------+---------------
23 | 255 | 255 |170
---------------+----------------+----------------+---------------
24 | 0 | 0 |255
---------------+----------------+----------------+---------------
25 | 255 | 0 |255
---------------+----------------+----------------+---------------
26 | 0 | 128 |255
---------------+----------------+----------------+---------------
27 | 255 | 128 |255
---------------+----------------+----------------+---------------
28 | 0 | 255 |255
---------------+----------------+----------------+---------------
29 | 255 | 255 |255
---------------+----------------+----------------+---------------
... | | |
The distance between level changes in each channel of the lookup table is determined by the following formulas:
multipliers[0] = signof(dimensions[0])*1;
multipliers[i] = signof(dimensions[i])*
abs(multipliers[i-1]*dimension[i-1]);
A negative dimensions[i], so as to a negative multipliers[i], indicates that the values in a color ramp for channel i should appear in
decreasing as opposed to increasing order.
For each channel i, the values of the levels are determined by the following formulas:
double delta = (dataMax - dataMin)/(abs(dimensions[i]) - 1);
int levels[j] = (int)(j*delta + 0.5);
where dataMax and dataMin are the maximum and minimum values, respectively, for data type intype.
Whenever a colorcube is created, if lut != NULL, the lookup table will be filled according to the colorcube and supplied parameters like
offset. For the example shown above, the lookup table will start from line 6. In this case, it is the user's responsibility to allocate
memory for the lookup table.
PARAMETERS
The function takes the following arguments:
colormap Internal data structure for image dithering.
dimensions Dimensions of the colorcube in the colormap structure.
intype Data type of the source image and the lookup table.
outtype Data type of the destination indexed image.
channels Number of channels of the lookup table and source image.
entries Number of entries of the lookup table.
offset Index offset of the lookup table.
lut Lookup table.
RETURN VALUES
The function returns MLIB_SUCCESS if successful. Otherwise it returns MLIB_FAILURE.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Committed |
+-----------------------------+-----------------------------+
|MT-Level |MT-Safe |
+-----------------------------+-----------------------------+
SEE ALSO mlib_ImageColorDitherFree(3MLIB), mlib_ImageColorErrorDiffusion3x3(3MLIB), mlib_ImageColorErrorDiffusionMxN(3MLIB), mlib_ImageColorOrdered-
Dither8x8(3MLIB), mlib_ImageColorOrderedDitherMxN(3MLIB), attributes(5)SunOS 5.11 2 Mar 2007 mlib_ImageColorDitherInit(3MLIB)