PixelPacket Structure
The PixelPacket structure is used to represent pixels in ImageMagick.
ImageMagick may be compiled to support 32 or 64 bit pixels. The size of
PixelPacket is controlled by the value of the QuantumDepth define.
The default is 64 bit pixels, which provide the best accuracy. If memory
consumption must be minimized, or processing time must be minimized, then
ImageMagick may be compiled with QuantumDepth=8. The following table shows
the relationship between QuantumDepth, the type of Quantum,
and the overall PixelPacket size.
Effect Of QuantumDepth Values
|
QuantumDepth
|
Quantum Type
|
PixelPacket Size
|
|
8
|
unsigned char
|
32 bits
|
|
16
|
unsigned short
|
64 bits
|
The members of the PixelPacket structure, and their interpretation,
are shown in the following table:
PixelPacket Structure Members
|
Member
|
Type
|
Interpretation
|
|
RGBColorspace
|
RGBColorspace +
matte
|
CMYKColorspace
|
| red |
Quantum |
Red |
Red |
Cyan |
| green |
Quantum |
Green |
Green |
Magenta |
| blue |
Quantum |
Blue |
Blue |
Yellow |
| opacity |
Quantum |
Ignored |
Opacity |
Black |