downscaleHalf() [2/2]

void fl::downscaleHalf	(	const CRGB *	src,
		uint16_t	srcWidth,
		uint16_t	srcHeight,
		CRGB *	dst )

Definition at line 17 of file downscale.cpp.

                              {
    uint16_t dstWidth = srcWidth / 2;
    uint16_t dstHeight = srcHeight / 2;
 
    for (uint16_t y = 0; y < dstHeight; ++y) {
        for (uint16_t x = 0; x < dstWidth; ++x) {
            // Map to top-left of the 2x2 block in source
            uint16_t srcX = x * 2;
            uint16_t srcY = y * 2;
 
            // Fetch 2x2 block
            const CRGB &p00 = src[(srcY)*srcWidth + (srcX)];
            const CRGB &p10 = src[(srcY)*srcWidth + (srcX + 1)];
            const CRGB &p01 = src[(srcY + 1) * srcWidth + (srcX)];
            const CRGB &p11 = src[(srcY + 1) * srcWidth + (srcX + 1)];
 
            // Average each color channel
            uint16_t r =
                (p00.r + p10.r + p01.r + p11.r + 2) / 4; // +2 for rounding
            uint16_t g = (p00.g + p10.g + p01.g + p11.g + 2) / 4;
            uint16_t b = (p00.b + p10.b + p01.b + p11.b + 2) / 4;
 
            // Store result
            dst[y * dstWidth + x] = CRGB((uint8_t)r, (uint8_t)g, (uint8_t)b);
        }
    }
}

References x, and y.

Referenced by downscale(), and loop().

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