farbfeld

suckless image format with conversion tools
git clone git://git.suckless.org/farbfeld
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commit a5a5706f16408ce181775d319b264d03e67819f3
parent 6afe09e729e3428a5317c57c8315897f7110bffa
Author: Laslo Hunhold <dev@frign.de>
Date:   Fri, 14 Apr 2017 22:15:25 +0200

Improve readability of alpha-blending sections

Diffstat:
ff2jpg.c | 6++++--
ff2ppm.c | 6++++--
2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/ff2jpg.c b/ff2jpg.c @@ -106,9 +106,11 @@ main(int argc, char *argv[]) for (j = 0, k = 0; j < rowlen; j += 4, k += 3) { a = ntohs(row[j + 3]); for (l = 0; l < 3; l++) { + /* alpha blending and 8-bit-reduction */ rowout[k + l] = (a * ntohs(row[j + l]) + - (65535 - a) * mask[l]) / - (257 * 65535); + (UINT16_MAX - a) * mask[l]) / + (UINT16_MAX * + (UINT16_MAX / UINT8_MAX)); } } jpeg_write_scanlines(&jcomp, &rowout, 1); diff --git a/ff2ppm.c b/ff2ppm.c @@ -66,9 +66,11 @@ main(int argc, char *argv[]) for (j = 0, k = 0; j < rowlen; j += 4, k += 3) { a = ntohs(row[j + 3]); for (l = 0; l < 3; l++) { + /* alpha blending and 8-bit-reduction */ rowout[k + l] = (a * ntohs(row[j + l]) + - (65535 - a) * mask[l]) / - (257 * 65535); + (UINT16_MAX - a) * mask[l]) / + (UINT16_MAX * + (UINT16_MAX / UINT8_MAX)); } } if (fwrite(rowout, sizeof(uint8_t), rowoutlen, stdout) != rowoutlen) {