ColorFromPaletteExtended() [4/5]

CRGB fl::ColorFromPaletteExtended	(	const TProgmemRGBPalette16 &	pal,
		fl::u16	index,
		fl::u8	brightness,
		TBlendType	blendType )

Definition at line 622 of file colorutils.cpp.hpp.

                                                                                  {
    // Extract the four most significant bits of the index as a palette index.
    fl::u8 index_4bit = index >> 12;
    // Calculate the 8-bit offset from the palette index.
    fl::u8 offset = (fl::u8)(index >> 4);
    // Get the palette entry from the 4-bit index
    CRGB entry(FL_PGM_READ_DWORD_NEAR(&(pal[0]) + index_4bit));
    fl::u8 red1 = entry.red;
    fl::u8 green1 = entry.green;
    fl::u8 blue1 = entry.blue;
 
    fl::u8 blend = offset && (blendType != NOBLEND);
    if (blend) {
        if (index_4bit == 15) {
            entry = FL_PGM_READ_DWORD_NEAR(&(pal[0]));
        } else {
            entry = FL_PGM_READ_DWORD_NEAR(&(pal[1]) + index_4bit);
        }
 
        // Calculate the scaling factor and scaled values for the lower palette
        // value.
        fl::u8 f1 = 255 - offset;
        red1 = scale8_LEAVING_R1_DIRTY(red1, f1);
        green1 = scale8_LEAVING_R1_DIRTY(green1, f1);
        blue1 = scale8_LEAVING_R1_DIRTY(blue1, f1);
 
        // Calculate the scaled values for the neighbouring palette value.
        fl::u8 red2 = entry.red;
        fl::u8 green2 = entry.green;
        fl::u8 blue2 = entry.blue;
        red2 = scale8_LEAVING_R1_DIRTY(red2, offset);
        green2 = scale8_LEAVING_R1_DIRTY(green2, offset);
        blue2 = scale8_LEAVING_R1_DIRTY(blue2, offset);
        cleanup_R1();
 
        // These sums can't overflow, so no qadd8 needed.
        red1 += red2;
        green1 += green2;
        blue1 += blue2;
    }
    if (brightness != 255) {
        // nscale8x3_video(red1, green1, blue1, brightness);
        nscale8x3(red1, green1, blue1, brightness);
    }
    return CRGB(red1, green1, blue1);
}

References blend(), brightness, FL_NO_EXCEPT, FL_PGM_READ_DWORD_NEAR, and offset().

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