nblend() [1/4]

CHSV & nblend	(	CHSV &	existing,
		const CHSV &	overlay,
		fract8	amountOfOverlay,
		TGradientDirectionCode	directionCode = SHORTEST_HUES )

Destructively modifies one color, blending in a given fraction of an overlay color.

Parameters

existing	the color to modify
overlay	the color to blend into existing
amountOfOverlay	the fraction of overlay to blend into existing
directionCode	the direction to travel around the color wheel

Definition at line 364 of file colorutils.cpp.

{
    if( amountOfOverlay == 0) {
        return existing;
    }
 
    if( amountOfOverlay == 255) {
        existing = overlay;
        return existing;
    }
 
    fract8 amountOfKeep = 255 - amountOfOverlay;
 
    uint8_t 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, cleanup_R1(), FORWARD_HUES, LONGEST_HUES, scale8(), scale8_LEAVING_R1_DIRTY(), and SHORTEST_HUES.

Here is the call graph for this function: