nblend() [1/4]

CHSV & fl::nblend	(	CHSV &	existing,
		const CHSV &	overlay,
		fract8	amountOfOverlay,
		TGradientDirectionCode	directionCode )

Definition at line 157 of file colorutils.cpp.hpp.

                                                   {
    if (amountOfOverlay == 0) {
        return existing;
    }
 
    if (amountOfOverlay == 255) {
        existing = overlay;
        return existing;
    }
 
    fract8 amountOfKeep = 255 - amountOfOverlay;
 
    fl::u8 huedelta8 = overlay.hue - existing.hue;
 
    if (directionCode == SHORTEST_HUES) {
        directionCode = FORWARD_HUES;
        if (huedelta8 > 127) {
            directionCode = BACKWARD_HUES;
        }
    }
 
    if (directionCode == LONGEST_HUES) {
        directionCode = FORWARD_HUES;
        if (huedelta8 < 128) {
            directionCode = BACKWARD_HUES;
        }
    }
 
    if (directionCode == FORWARD_HUES) {
        existing.hue = existing.hue + scale8(huedelta8, amountOfOverlay);
    } else /* directionCode == BACKWARD_HUES */
    {
        huedelta8 = -huedelta8;
        existing.hue = existing.hue - scale8(huedelta8, amountOfOverlay);
    }
 
    existing.sat = scale8_LEAVING_R1_DIRTY(existing.sat, amountOfKeep) +
                   scale8_LEAVING_R1_DIRTY(overlay.sat, amountOfOverlay);
    existing.val = scale8_LEAVING_R1_DIRTY(existing.val, amountOfKeep) +
                   scale8_LEAVING_R1_DIRTY(overlay.val, amountOfOverlay);
 
    cleanup_R1();
 
    return existing;
}

References BACKWARD_HUES, FORWARD_HUES, LONGEST_HUES, and SHORTEST_HUES.