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imagesavealpha(…, false) should not save alpha channel #10055

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7 changes: 6 additions & 1 deletion ext/gd/libgd/gd_avif.c
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Original file line number Diff line number Diff line change
Expand Up @@ -528,6 +528,9 @@ void gdImageAvifCtx(gdImagePtr im, gdIOCtx *outfile, int quality, int speed)
avifIm->matrixCoefficients = lossless ? AVIF_MATRIX_COEFFICIENTS_IDENTITY : AVIF_MATRIX_COEFFICIENTS_BT709;

avifRGBImageSetDefaults(&rgb, avifIm);
if (!im->saveAlphaFlag) {
rgb.format = AVIF_RGB_FORMAT_RGB;
}
// this allocates memory, and sets rgb.rowBytes and rgb.pixels.
avifRGBImageAllocatePixels(&rgb);

Expand All @@ -542,7 +545,9 @@ void gdImageAvifCtx(gdImagePtr im, gdIOCtx *outfile, int quality, int speed)
*(p++) = gdTrueColorGetRed(val);
*(p++) = gdTrueColorGetGreen(val);
*(p++) = gdTrueColorGetBlue(val);
*(p++) = alpha7BitTo8Bit(gdTrueColorGetAlpha(val));
if (im->saveAlphaFlag) {
*(p++) = alpha7BitTo8Bit(gdTrueColorGetAlpha(val));
}
}
}

Expand Down
39 changes: 28 additions & 11 deletions ext/gd/libgd/gd_webp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -107,6 +107,9 @@ void gdImageWebpCtx (gdImagePtr im, gdIOCtx * outfile, int quality)
uint8_t *p;
uint8_t *out;
size_t out_size;
uint8_t bpp;
size_t (*encode)(const uint8_t*, int, int, int, float, uint8_t**);
size_t (*encode_lossless)(const uint8_t*, int, int, int, uint8_t**);

if (im == NULL) {
return;
Expand All @@ -121,15 +124,25 @@ void gdImageWebpCtx (gdImagePtr im, gdIOCtx * outfile, int quality)
quality = 80;
}

if (overflow2(gdImageSX(im), 4)) {
if (im->saveAlphaFlag) {
bpp = 4;
encode = WebPEncodeRGBA;
encode_lossless = WebPEncodeLosslessRGBA;
} else {
bpp = 3;
encode = WebPEncodeRGB;
encode_lossless = WebPEncodeLosslessRGB;
}

if (overflow2(gdImageSX(im), bpp)) {
return;
}

if (overflow2(gdImageSX(im) * 4, gdImageSY(im))) {
if (overflow2(gdImageSX(im) * bpp, gdImageSY(im))) {
return;
}

argb = (uint8_t *)gdMalloc(gdImageSX(im) * 4 * gdImageSY(im));
argb = (uint8_t *)gdMalloc(gdImageSX(im) * bpp * gdImageSY(im));
if (!argb) {
return;
}
Expand All @@ -139,23 +152,27 @@ void gdImageWebpCtx (gdImagePtr im, gdIOCtx * outfile, int quality)
register int c;
register char a;
c = im->tpixels[y][x];
a = gdTrueColorGetAlpha(c);
if (a == 127) {
a = 0;
} else {
a = 255 - ((a << 1) + (a >> 6));
if (bpp == 4) {
a = gdTrueColorGetAlpha(c);
if (a == 127) {
a = 0;
} else {
a = 255 - ((a << 1) + (a >> 6));
}
}
*(p++) = gdTrueColorGetRed(c);
*(p++) = gdTrueColorGetGreen(c);
*(p++) = gdTrueColorGetBlue(c);
*(p++) = a;
if (bpp == 4) {
*(p++) = a;
}
}
}

if (quality >= gdWebpLossless) {
out_size = WebPEncodeLosslessRGBA(argb, gdImageSX(im), gdImageSY(im), gdImageSX(im) * 4, &out);
out_size = encode_lossless(argb, gdImageSX(im), gdImageSY(im), gdImageSX(im) * bpp, &out);
} else {
out_size = WebPEncodeRGBA(argb, gdImageSX(im), gdImageSY(im), gdImageSX(im) * 4, quality, &out);
out_size = encode(argb, gdImageSX(im), gdImageSY(im), gdImageSX(im) * bpp, quality, &out);
}

if (out_size == 0) {
Expand Down
50 changes: 50 additions & 0 deletions ext/gd/tests/imagesavealpha_avif.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,50 @@
--TEST--
Testing imagesavealpha() with AVIF
--EXTENSIONS--
gd
--SKIPIF--
<?php
$support = gd_info();
if (!isset($support['AVIF Support']) || $support['AVIF Support'] === false) {
die("skip AVIF support not available");
}
?>
--FILE--
<?php
$filename = __DIR__ . "/imagesavealpha_avif.avif";
$im = imagecreatetruecolor(8, 8);
imagealphablending($im, false);
imagefilledrectangle($im, 0, 0, 7, 7, 0x7f000000);

echo "without alpha\n";
imagesavealpha($im, false);
imageavif($im, $filename, 100); // lossless
$im1 = imagecreatefromavif($filename);
checkColors($im1, 0x000000);
imagedestroy($im1);

echo "with alpha\n";
imagesavealpha($im, true);
imageavif($im, $filename, 100); // lossless
$im1 = imagecreatefromavif($filename);
checkColors($im1, 0x7f000000);
imagedestroy($im1);

function checkColors(GdImage $im, int $expected) {
for ($i = 0; $i < 8; $i++) {
for ($j = 0; $j < 8; $j++) {
$actual = imagecolorat($im, $i, $j);
if ($actual !== $expected) {
echo "($i, $j) is $actual, but $expected expected\n";
}
}
}
}
?>
--CLEAN--
<?php
@unlink(__DIR__ . "/imagesavealpha_avif.avif");
?>
--EXPECT--
without alpha
with alpha
50 changes: 50 additions & 0 deletions ext/gd/tests/imagesavealpha_png.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,50 @@
--TEST--
Testing imagesavealpha() with PNG
--EXTENSIONS--
gd
--SKIPIF--
<?php
$support = gd_info();
if (!isset($support['PNG Support']) || $support['PNG Support'] === false) {
die("skip PNG support not available");
}
?>
--FILE--
<?php
$filename = __DIR__ . "/imagesavealpha_png.png";
$im = imagecreatetruecolor(8, 8);
imagealphablending($im, false);
imagefilledrectangle($im, 0, 0, 7, 7, 0x7f000000);

echo "without alpha\n";
imagesavealpha($im, false);
imagepng($im, $filename);
$im1 = imagecreatefrompng($filename);
checkColors($im1, 0x000000);
imagedestroy($im1);

echo "with alpha\n";
imagesavealpha($im, true);
imagepng($im, $filename);
$im1 = imagecreatefrompng($filename);
checkColors($im1, 0x7f000000);
imagedestroy($im1);

function checkColors(GdImage $im, int $expected) {
for ($i = 0; $i < 8; $i++) {
for ($j = 0; $j < 8; $j++) {
$actual = imagecolorat($im, $i, $j);
if ($actual !== $expected) {
echo "($i, $j) is $actual, but $expected expected\n";
}
}
}
}
?>
--CLEAN--
<?php
@unlink(__DIR__ . "/imagesavealpha_png.png");
?>
--EXPECT--
without alpha
with alpha
50 changes: 50 additions & 0 deletions ext/gd/tests/imagesavealpha_webp.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,50 @@
--TEST--
Testing imagesavealpha() with WebP
--EXTENSIONS--
gd
--SKIPIF--
<?php
$support = gd_info();
if (!isset($support['WebP Support']) || $support['WebP Support'] === false) {
die("skip WebP support not available");
}
?>
--FILE--
<?php
$filename = __DIR__ . "/imagesavealpha_webp.webp";
$im = imagecreatetruecolor(8, 8);
imagealphablending($im, false);
imagefilledrectangle($im, 0, 0, 7, 7, 0x7f000000);

echo "without alpha\n";
imagesavealpha($im, false);
imagewebp($im, $filename, 101); // lossless
$im1 = imagecreatefromwebp($filename);
checkColors($im1, 0x000000);
imagedestroy($im1);

echo "with alpha\n";
imagesavealpha($im, true);
imagewebp($im, $filename, 101); // lossless
$im1 = imagecreatefromwebp($filename);
checkColors($im1, 0x7f000000);
imagedestroy($im1);

function checkColors(GdImage $im, int $expected) {
for ($i = 0; $i < 8; $i++) {
for ($j = 0; $j < 8; $j++) {
$actual = imagecolorat($im, $i, $j);
if ($actual !== $expected) {
echo "($i, $j) is $actual, but $expected expected\n";
}
}
}
}
?>
--CLEAN--
<?php
@unlink(__DIR__ . "/imagesavealpha_webp.webp");
?>
--EXPECT--
without alpha
with alpha