Screen transparency types

Types of window transparencies

Synopsis:

#include <screen/screen.h>

enum {
    SCREEN_TRANSPARENCY_SOURCE = 0,
    SCREEN_TRANSPARENCY_TEST = 1,
    SCREEN_TRANSPARENCY_SOURCE_COLOR = 2,
    SCREEN_TRANSPARENCY_SOURCE_OVER = 3,
    SCREEN_TRANSPARENCY_NONE = 4,
    SCREEN_TRANSPARENCY_DISCARD = 5,
    SCREEN_TRANSPARENCY_REVERSED_TEST = 6
};

Data:

SCREEN_TRANSPARENCY_SOURCE: Destination pixels are replaced by source pixels, including the alpha channel.
SCREEN_TRANSPARENCY_TEST: Destination pixels are replaced by source pixels.; The replacement is based on a comparison between the source pixel's alpha value and the reference alpha value. The reference alpha value is dependent on the blitter.
SCREEN_TRANSPARENCY_SOURCE_COLOR: Destination pixels are replaced by source pixels.; The replacement is based on a comparison between the source pixel's alpha value and the reference alpha value. The reference alpha value is dependent on the blitter.
SCREEN_TRANSPARENCY_SOURCE_OVER: Typical alpha blending; the source pixels are blended over the destination pixels.
SCREEN_TRANSPARENCY_NONE: Destination pixels are replaced by fully-visible source pixels.
SCREEN_TRANSPARENCY_DISCARD: Source is considered completely transparent; the destination is not modified.
SCREEN_TRANSPARENCY_REVERSED_TEST: Destination pixels are replaced by source pixels.; The replacement is based on a comparison between the source pixel's alpha value and the reference alpha value. The reference alpha value is dependent on the blitter.

Library:

libscreen