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 |
||
red |
Quantum |
Red |
Red |
Cyan |
green |
Quantum |
Green |
Green |
Magenta |
blue |
Quantum |
Blue |
Blue |
Yellow |
opacity |
Quantum |
Ignored |
Opacity |
Black |