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Lossless conversion for webp
Propagating lossless conversion from libgd to our bundled gd. Changing "quantization" to "quality" as in libgd. Adding test. IMG_WEBP_LOSSLESS is only defined, if lossless WebP encoding is supported by the libgd used. Closes GH-7348.
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‎UPGRADING‎

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Original file line numberDiff line numberDiff line change
@@ -562,6 +562,11 @@ PHP 8.1 UPGRADE NOTES
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9. Other Changes to Extensions
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========================================
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- GD:
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imagewebp() can do lossless WebP encoding by passing IMG_WEBP_LOSSLESS as
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quality. This constant is only defined, if a libgd is used which supports
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lossless WebP encoding.
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565570
- MySQLi:
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. The mysqli_stmt::next_result() and mysqli::fetch_all() methods are now
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available when linking against libmysqlclient.

‎ext/gd/config.m4‎

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@@ -92,7 +92,7 @@ AC_DEFUN([PHP_GD_AVIF],[
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AC_DEFUN([PHP_GD_WEBP],[
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if test "$PHP_WEBP" != "no"; then
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PKG_CHECK_MODULES([WEBP], [libwebp])
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PKG_CHECK_MODULES([WEBP], [libwebp >= 0.2.0])
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PHP_EVAL_LIBLINE($WEBP_LIBS, GD_SHARED_LIBADD)
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PHP_EVAL_INCLINE($WEBP_CFLAGS)
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AC_DEFINE(HAVE_LIBWEBP, 1, [ ])

‎ext/gd/gd.c‎

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Original file line numberDiff line numberDiff line change
@@ -378,6 +378,11 @@ PHP_MINIT_FUNCTION(gd)
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REGISTER_LONG_CONSTANT("IMG_BMP", PHP_IMG_BMP, CONST_CS | CONST_PERSISTENT);
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REGISTER_LONG_CONSTANT("IMG_TGA", PHP_IMG_TGA, CONST_CS | CONST_PERSISTENT);
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381+
#ifdef gdWebpLossless
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/* constant for webp encoding */
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REGISTER_LONG_CONSTANT("IMG_WEBP_LOSSLESS", gdWebpLossless, CONST_CS | CONST_PERSISTENT);
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#endif
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/* special colours for gd */
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REGISTER_LONG_CONSTANT("IMG_COLOR_TILED", gdTiled, CONST_CS | CONST_PERSISTENT);
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REGISTER_LONG_CONSTANT("IMG_COLOR_STYLED", gdStyled, CONST_CS | CONST_PERSISTENT);

‎ext/gd/libgd/gd.h‎

Lines changed: 14 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -619,7 +619,20 @@ void *gdImageWBMPPtr(gdImagePtr im, int *size, int fg);
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void gdImageJpeg(gdImagePtr im, FILE *out, int quality);
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void gdImageJpegCtx(gdImagePtr im, gdIOCtx *out, int quality);
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622-
void gdImageWebpCtx (gdImagePtr im, gdIOCtx * outfile, int quantization);
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/**
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* Group: WebP
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*
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* Constant: gdWebpLossless
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*
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* Lossless quality threshold. When image quality is greater than or equal to
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* <gdWebpLossless>, the image will be written in the lossless WebP format.
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*
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* See also:
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* - <gdImageWebpCtx>
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*/
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#define gdWebpLossless 101
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void gdImageWebpCtx (gdImagePtr im, gdIOCtx * outfile, int quality);
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/* Best to free this memory with gdFree(), not free() */
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void *gdImageJpegPtr(gdImagePtr im, int *size, int quality);

‎ext/gd/libgd/gd_webp.c‎

Lines changed: 14 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -100,7 +100,7 @@ gdImagePtr gdImageCreateFromWebpCtx (gdIOCtx * infile)
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return im;
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}
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void gdImageWebpCtx (gdImagePtr im, gdIOCtx * outfile, int quantization)
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void gdImageWebpCtx (gdImagePtr im, gdIOCtx * outfile, int quality)
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{
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uint8_t *argb;
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int x, y;
@@ -117,8 +117,8 @@ void gdImageWebpCtx (gdImagePtr im, gdIOCtx * outfile, int quantization)
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return;
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}
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120-
if (quantization == -1) {
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quantization = 80;
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if (quality == -1) {
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quality = 80;
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}
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if (overflow2(gdImageSX(im), 4)) {
@@ -151,7 +151,13 @@ void gdImageWebpCtx (gdImagePtr im, gdIOCtx * outfile, int quantization)
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*(p++) = a;
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}
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}
154-
out_size = WebPEncodeRGBA(argb, gdImageSX(im), gdImageSY(im), gdImageSX(im) * 4, quantization, &out);
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if (quality >= gdWebpLossless) {
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out_size = WebPEncodeLosslessRGBA(argb, gdImageSX(im), gdImageSY(im), gdImageSX(im) * 4, &out);
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} else {
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out_size = WebPEncodeRGBA(argb, gdImageSX(im), gdImageSY(im), gdImageSX(im) * 4, quality, &out);
159+
}
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if (out_size == 0) {
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zend_error(E_ERROR, "gd-webp encoding failed");
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goto freeargb;
@@ -163,10 +169,10 @@ void gdImageWebpCtx (gdImagePtr im, gdIOCtx * outfile, int quantization)
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gdFree(argb);
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}
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166-
void gdImageWebpEx (gdImagePtr im, FILE * outFile, int quantization)
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void gdImageWebpEx (gdImagePtr im, FILE * outFile, int quality)
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{
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gdIOCtx *out = gdNewFileCtx(outFile);
169-
gdImageWebpCtx(im, out, quantization);
175+
gdImageWebpCtx(im, out, quality);
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out->gd_free(out);
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}
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@@ -188,11 +194,11 @@ void * gdImageWebpPtr (gdImagePtr im, int *size)
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return rv;
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}
190196

191-
void * gdImageWebpPtrEx (gdImagePtr im, int *size, int quantization)
197+
void * gdImageWebpPtrEx (gdImagePtr im, int *size, int quality)
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{
193199
void *rv;
194200
gdIOCtx *out = gdNewDynamicCtx(2048, NULL);
195-
gdImageWebpCtx(im, out, quantization);
201+
gdImageWebpCtx(im, out, quality);
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rv = gdDPExtractData(out, size);
197203
out->gd_free(out);
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return rv;

‎ext/gd/tests/webp_basic.phpt‎

Lines changed: 9 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -29,11 +29,19 @@ imagewebp($im1, $filename);
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$im2 = imagecreatefromwebp($filename);
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imagewebp($im2, $filename);
32+
echo 'Is lossy conversion close enough? ';
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var_dump(calc_image_dissimilarity($im1, $im2) < 10e5);
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35+
imagewebp($im1, $filename, IMG_WEBP_LOSSLESS);
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$im_lossless = imagecreatefromwebp($filename);
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echo 'Does lossless conversion work? ';
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var_dump(calc_image_dissimilarity($im1, $im_lossless) == 0);
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?>
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--CLEAN--
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<?php
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@unlink(__DIR__ . '/webp_basic.webp');
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?>
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--EXPECT--
39-
bool(true)
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Is lossy conversion close enough? bool(true)
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Does lossless conversion work? bool(true)

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