51 lines
1.8 KiB
C
51 lines
1.8 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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typedef struct {
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uint8_t r;
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uint8_t g;
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uint8_t b;
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} rgb888;
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int main (int argc, char *argv[])
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{
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if (argc != 2) {
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printf("Please provide a single 24 bit color of the format `0xRRGGBB` as input.\n");
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return 1;
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}
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uint32_t in_888 = strtol(argv[1], NULL, 16);
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printf(" Input, 24 bit color, 6 char hex: #%06X\n\n", in_888);
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rgb888 split;
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split.r = ((in_888 & 0x00FF0000) >> 16) & 0xF8;
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split.g = ((in_888 & 0x0000FF00) >> 8) & 0xF8;
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split.b = (in_888 & 0x000000FF) & 0xF8;
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rgb888 unrounded;
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unrounded.r = split.r & 0xF0;
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unrounded.g = split.g & 0xF0;
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unrounded.b = split.b & 0xF0;
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rgb888 rounded;
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rounded.r = unrounded.r | 8;
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rounded.g = unrounded.g | 8;
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rounded.b = unrounded.b | 8;
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int16_t rgb555 = ((split.b & 0xF8) << 7) | ((split.g & 0xF8) << 2) | (split.r >> 3);
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int16_t rgb555_unrounded = ((unrounded.b & 0xF8) << 7) | ((unrounded.g & 0xF8) << 2) | (unrounded.r >> 3);
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int16_t rgb555_rounded = ((rounded.b & 0xF8) << 7) | ((rounded.g & 0xF8) << 2) | (rounded.r >> 3);
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printf("Output, 15 bit color, 6 char hex, rounded down: #%06X\n", (uint32_t) ((split.r & 0xF8) << 16) | ((split.g & 0xF8) << 8) | (split.b & 0xF8));
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printf(" Output, 15 bit color, 6 char hex, unrounded: #%06X\n", (uint32_t) ((split.r & 0xF8) << 16) | ((split.g & 0xF8) << 8) | (split.b & 0xF8));
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printf(" Output, 15 bit color, 6 char hex, rounded up: #%06X\n", (uint32_t) ((rounded.r & 0xF8) << 16) | ((rounded.g & 0xF8) << 8) | (rounded.b & 0xF8));
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printf("Output, 15 bit color, 4 char hex, rounded down: 0x%04X\n", rgb555_unrounded);
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printf(" Output, 15 bit color, 4 char hex, unrounded: 0x%04X\n", rgb555);
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printf(" Output, 15 bit color, 4 char hex, rounded up: 0x%04X\n", rgb555_rounded);
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return 0;
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}
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