fill_gradient_RGB() [4/7]

void fl::fill_gradient_RGB	(	CRGB *	leds,
		u16	startpos,
		CRGB	startcolor,
		u16	endpos,
		CRGB	endcolor )

Fill a range of LEDs with a smooth RGB gradient between two RGB colors.

Unlike HSV, there is no "color wheel" in RGB space, and therefore there's only one "direction" for the gradient to go. This means there's no TGradientDirectionCode parameter for direction.

Parameters

leds	a pointer to the LED array to fill
startpos	the starting position in the array
startcolor	the starting color for the gradient
endpos	the ending position in the array
endcolor	the end color for the gradient

Definition at line 108 of file fill.cpp.hpp.

                                                               {
    // if the points are in the wrong order, straighten them
    if (endpos < startpos) {
        u16 t = endpos;
        CRGB tc = endcolor;
        endcolor = startcolor;
        endpos = startpos;
        startpos = t;
        startcolor = tc;
    }
 
    saccum87 rdistance87;
    saccum87 gdistance87;
    saccum87 bdistance87;
 
    // Each difference is in [-255, 255], so scaling fits signed Q8.7.
    rdistance87 = (endcolor.r - startcolor.r) * 128;
    gdistance87 = (endcolor.g - startcolor.g) * 128;
    bdistance87 = (endcolor.b - startcolor.b) * 128;
 
    u16 pixeldistance = endpos - startpos;
    i16 divisor = pixeldistance ? pixeldistance : 1;
 
    saccum87 rdelta87 = rdistance87 / divisor;
    saccum87 gdelta87 = gdistance87 / divisor;
    saccum87 bdelta87 = bdistance87 / divisor;
 
    rdelta87 *= 2;
    gdelta87 *= 2;
    bdelta87 *= 2;
 
    accum88 r88 = startcolor.r << 8;
    accum88 g88 = startcolor.g << 8;
    accum88 b88 = startcolor.b << 8;
    for (u16 i = startpos; i <= endpos; ++i) {
        leds[i] = CRGB(r88 >> 8, g88 >> 8, b88 >> 8);
        r88 += rdelta87;
        g88 += gdelta87;
        b88 += bdelta87;
    }
}

References FL_NO_EXCEPT, leds, saccum87, and t.

Referenced by fill_gradient_RGB(), fill_gradient_RGB(), fill_gradient_RGB(), fill_gradient_RGB(), fill_gradient_RGB(), and fill_gradient_RGB().

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