PgSetChroma(), PgSetChromaCx()

Set the chroma color and operation

Synopsis:

void PgSetChroma( PgColor_t ChromaColor,
                  unsigned long ChromaOp );

void PgSetChromaCx( PhGC_t *gc,
                    PgColor_t ChromaColor,
                    unsigned long ChromaOp );

Library:

ph

Description:

These functions set the current chroma color and defines the chroma operation.

PgSetChroma() works on the current graphics context, while you can specify the graphics context gc for PgSetChromaCx().

ChromaColor is the color to test against for chroma operations. ChromaOp is made up of the following bits:

Pg_CHROMA_SRC_MATCH: Test against the source data.
Pg_CHROMA_DEST_MATCH: Test against the destination data.
Pg_CHROMA_DRAW: If the test pixel matches the chroma color, draw it in the destination.
Pg_CHROMA_NODRAW: If the test pixel matches the chroma color, don't draw it in the destination.

Examples:

// Draw an image using a chroma color of full green

PhImage_t *image;
PhPoint_t p={0,0};

// Code to load the image...
   …

PgChromaOn();
// Set the chroma operation to copy every pixel in the source to
// the destination, except the color 0x0000FF00 (bright green)
PgSetChroma(0x0000FF00, Pg_CHROMA_SRC_MATCH | Pg_CHROMA_NODRAW);
PgDrawPhImagemx(&p,image,0);
PgChromaOff();
PgFlush();

Classification:

Photon

Safety:
Interrupt handler	No
Signal handler	No
Thread	No

See also:

PgChromaOff*(), PgChromaOn*(), PgColor_t,

“Chroma key support” in the Raw Drawing and Animation chapter of the Photon Programmer's Guide