nblend() [3/4]

CRGB & nblend	(	CRGB &	existing,
		const CRGB &	overlay,
		fract8	amountOfOverlay )

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

Definition at line 303 of file colorutils.cpp.

{
    if( amountOfOverlay == 0) {
        return existing;
    }
 
    if( amountOfOverlay == 255) {
        existing = overlay;
        return existing;
    }
 
#if 0
    // Old blend method which unfortunately had some rounding errors
    fract8 amountOfKeep = 255 - amountOfOverlay;
 
    existing.red   = scale8_LEAVING_R1_DIRTY( existing.red,   amountOfKeep)
                    + scale8_LEAVING_R1_DIRTY( overlay.red,    amountOfOverlay);
    existing.green = scale8_LEAVING_R1_DIRTY( existing.green, amountOfKeep)
                    + scale8_LEAVING_R1_DIRTY( overlay.green,  amountOfOverlay);
    existing.blue  = scale8_LEAVING_R1_DIRTY( existing.blue,  amountOfKeep)
                    + scale8_LEAVING_R1_DIRTY( overlay.blue,   amountOfOverlay);
 
    cleanup_R1();
#else
    // Corrected blend method, with no loss-of-precision rounding errors
    existing.red   = blend8( existing.red,   overlay.red,   amountOfOverlay);
    existing.green = blend8( existing.green, overlay.green, amountOfOverlay);
    existing.blue  = blend8( existing.blue,  overlay.blue,  amountOfOverlay);
#endif
    
    return existing;
}

References blend8(), cleanup_R1(), and scale8_LEAVING_R1_DIRTY().

Referenced by blend(), blend(), fl::Pride2015::draw(), nblend(), nblend(), and pride().

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