nscale8x3()

LIB8STATIC void nscale8x3	(	uint8_t &	r,
		uint8_t &	g,
		uint8_t &	b,
		fract8	scale )

Scale three one-byte values by a fourth one, which is treated as the numerator of a fraction whose demominator is 256.

In other words, it computes r,g,b * (scale / 256)

Warning

This function always modifies its arguments in place!

Parameters

r	first value to scale
g	second value to scale
b	third value to scale
scale	scale factor, in n/256 units

Definition at line 367 of file scale8.h.

                                                                            {
#if SCALE8_C == 1
#if (FASTLED_SCALE8_FIXED == 1)
    uint16_t scale_fixed = scale + 1;
    r = (((uint16_t)r) * scale_fixed) >> 8;
    g = (((uint16_t)g) * scale_fixed) >> 8;
    b = (((uint16_t)b) * scale_fixed) >> 8;
#else
    r = ((int)r * (int)(scale)) >> 8;
    g = ((int)g * (int)(scale)) >> 8;
    b = ((int)b * (int)(scale)) >> 8;
#endif
#elif SCALE8_AVRASM == 1
    r = scale8_LEAVING_R1_DIRTY(r, scale);
    g = scale8_LEAVING_R1_DIRTY(g, scale);
    b = scale8_LEAVING_R1_DIRTY(b, scale);
    cleanup_R1();
#else
#error "No implementation for nscale8x3 available."
#endif
}

References cleanup_R1(), LIB8STATIC, scale, and scale8_LEAVING_R1_DIRTY().

Referenced by fl::ColorFromPaletteExtended(), fl::ColorFromPaletteExtended(), and MyColorFromPaletteExtended().

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