[gtk/image-loading: 6/24] Add code to load and save pngs
- From: Benjamin Otte <otte src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [gtk/image-loading: 6/24] Add code to load and save pngs
- Date: Tue, 14 Sep 2021 12:57:06 +0000 (UTC)
commit 7bfaddec4d775c02baa6ec804e16a6bb90137f05
Author: Matthias Clasen <mclasen redhat com>
Date: Fri Sep 10 12:44:43 2021 -0400
Add code to load and save pngs
Using libpng instead of the lowest-common-denominator
gdk-pixbuf loader. This will allow us to load >8bit data,
and apply gamma and color correction in the future.
For now, this still just provides RGBA8 data.
As a consequence, we are now linking against libpng.
gdk/loaders/gdkpng.c | 447 ++++++++++++++++++++++++++++++++++++++++++++
gdk/loaders/gdkpngprivate.h | 31 +++
gdk/meson.build | 4 +-
meson.build | 15 ++
subprojects/libpng.wrap | 12 ++
5 files changed, 508 insertions(+), 1 deletion(-)
---
diff --git a/gdk/loaders/gdkpng.c b/gdk/loaders/gdkpng.c
new file mode 100644
index 0000000000..097616232e
--- /dev/null
+++ b/gdk/loaders/gdkpng.c
@@ -0,0 +1,447 @@
+/* GDK - The GIMP Drawing Kit
+ * Copyright (C) 2021 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include "gdkpngprivate.h"
+
+#include "gdktexture.h"
+#include "gdktextureprivate.h"
+#include "gdkmemorytextureprivate.h"
+#include "gsk/ngl/fp16private.h"
+#include <png.h>
+#include <stdio.h>
+
+/* The main difference between the png load/save code here and
+ * gdk-pixbuf is that we can support loading 16-bit data in the
+ * future, and we can extract gamma and colorspace information
+ * to produce linear, color-corrected data.
+ */
+
+/* {{{ Callbacks */
+
+/* No sigsetjmp on Windows */
+#ifndef HAVE_SIGSETJMP
+#define sigjmp_buf jmp_buf
+#define sigsetjmp(jb, x) setjmp(jb)
+#define siglongjmp longjmp
+#endif
+
+typedef struct
+{
+ guchar *data;
+ gsize size;
+ gsize position;
+} png_io;
+
+
+static void
+png_read_func (png_structp png,
+ png_bytep data,
+ png_size_t size)
+{
+ png_io *io;
+
+ io = png_get_io_ptr (png);
+
+ if (io->position + size > io->size)
+ png_error (png, "Read past EOF");
+
+ memcpy (data, io->data + io->position, size);
+ io->position += size;
+}
+
+static void
+png_write_func (png_structp png,
+ png_bytep data,
+ png_size_t size)
+{
+ png_io *io;
+
+ io = png_get_io_ptr (png);
+
+ if (io->position > io->size ||
+ io->size - io->position < size)
+ {
+ io->size = io->position + size;
+ io->data = g_realloc (io->data, io->size);
+ }
+
+ memcpy (io->data + io->position, data, size);
+ io->position += size;
+}
+
+static void
+png_flush_func (png_structp png)
+{
+}
+
+static png_voidp
+png_malloc_callback (png_structp o,
+ png_size_t size)
+{
+ return g_try_malloc (size);
+}
+
+static void
+png_free_callback (png_structp o,
+ png_voidp x)
+{
+ g_free (x);
+}
+
+static void
+png_simple_error_callback (png_structp png,
+ png_const_charp error_msg)
+{
+ GError **error = png_get_error_ptr (png);
+
+ if (error && !*error)
+ g_set_error (error,
+ GDK_TEXTURE_ERROR, GDK_TEXTURE_ERROR_CORRUPT_IMAGE,
+ "Error reading png (%s)", error_msg);
+
+ longjmp (png_jmpbuf (png), 1);
+}
+
+static void
+png_simple_warning_callback (png_structp png,
+ png_const_charp error_msg)
+{
+}
+
+/* }}} */
+/* {{{ Format conversion */
+
+static void
+unpremultiply (guchar *data,
+ int width,
+ int height,
+ int stride)
+{
+ gsize x, y;
+
+ for (y = 0; y < height; y++)
+ {
+ for (x = 0; x < width; x++)
+ {
+ guchar *b = &data[x * 4];
+ guint32 pixel;
+ guchar alpha;
+
+ memcpy (&pixel, b, sizeof (guint32));
+ alpha = (pixel & 0xff000000) >> 24;
+ if (alpha == 0)
+ {
+ b[0] = 0;
+ b[1] = 0;
+ b[2] = 0;
+ b[3] = 0;
+ }
+ else
+ {
+ b[0] = (((pixel & 0x00ff0000) >> 16) * 255 + alpha / 2) / alpha;
+ b[1] = (((pixel & 0x0000ff00) >> 8) * 255 + alpha / 2) / alpha;
+ b[2] = (((pixel & 0x000000ff) >> 0) * 255 + alpha / 2) / alpha;
+ b[3] = alpha;
+ }
+ }
+ data += stride;
+ }
+}
+
+static inline int
+multiply_alpha (int alpha, int color)
+{
+ int temp = (alpha * color) + 0x80;
+ return ((temp + (temp >> 8)) >> 8);
+}
+
+static void
+premultiply_data (png_structp png,
+ png_row_infop row_info,
+ png_bytep data)
+{
+ unsigned int i;
+
+ for (i = 0; i < row_info->rowbytes; i += 4)
+ {
+ uint8_t *base = &data[i];
+ uint8_t alpha = base[3];
+ uint32_t p;
+
+ if (alpha == 0)
+ {
+ p = 0;
+ }
+ else
+ {
+ uint8_t red = base[0];
+ uint8_t green = base[1];
+ uint8_t blue = base[2];
+
+ if (alpha != 0xff)
+ {
+ red = multiply_alpha (alpha, red);
+ green = multiply_alpha (alpha, green);
+ blue = multiply_alpha (alpha, blue);
+ }
+ p = ((uint32_t)alpha << 24) | (red << 16) | (green << 8) | (blue << 0);
+ }
+ memcpy (base, &p, sizeof (uint32_t));
+ }
+}
+
+static void
+convert_bytes_to_data (png_structp png,
+ png_row_infop row_info,
+ png_bytep data)
+{
+ unsigned int i;
+
+ for (i = 0; i < row_info->rowbytes; i += 4)
+ {
+ uint8_t *base = &data[i];
+ uint8_t red = base[0];
+ uint8_t green = base[1];
+ uint8_t blue = base[2];
+ uint32_t pixel;
+
+ pixel = (0xffu << 24) | (red << 16) | (green << 8) | (blue << 0);
+ memcpy (base, &pixel, sizeof (uint32_t));
+ }
+}
+
+/* }}} */
+/* {{{ Public API */
+
+GdkTexture *
+gdk_load_png (GBytes *bytes,
+ GError **error)
+{
+ png_io io;
+ png_struct *png = NULL;
+ png_info *info;
+ guint width, height;
+ int depth, color_type;
+ int interlace, stride;
+ GdkMemoryFormat format;
+ guchar *buffer = NULL;
+ guchar **row_pointers = NULL;
+ GBytes *out_bytes;
+ GdkTexture *texture;
+
+ io.data = (guchar *)g_bytes_get_data (bytes, &io.size);
+ io.position = 0;
+
+ png = png_create_read_struct_2 (PNG_LIBPNG_VER_STRING,
+ error,
+ png_simple_error_callback,
+ png_simple_warning_callback,
+ NULL,
+ png_malloc_callback,
+ png_free_callback);
+ if (png == NULL)
+ {
+ g_set_error (error,
+ GDK_TEXTURE_ERROR, GDK_TEXTURE_ERROR_INSUFFICIENT_MEMORY,
+ "Failed to parse png image");
+ return NULL;
+ }
+
+ info = png_create_info_struct (png);
+ if (info == NULL)
+ {
+ png_destroy_read_struct (&png, NULL, NULL);
+ g_set_error (error,
+ GDK_TEXTURE_ERROR, GDK_TEXTURE_ERROR_INSUFFICIENT_MEMORY,
+ "Failed to parse png image");
+ return NULL;
+ }
+
+ png_set_read_fn (png, &io, png_read_func);
+
+ if (sigsetjmp (png_jmpbuf (png), 1))
+ {
+ g_free (buffer);
+ g_free (row_pointers);
+ png_destroy_read_struct (&png, &info, NULL);
+ return NULL;
+ }
+
+ png_read_info (png, info);
+
+ png_get_IHDR (png, info,
+ &width, &height, &depth,
+ &color_type, &interlace, NULL, NULL);
+
+ if (color_type == PNG_COLOR_TYPE_PALETTE)
+ png_set_palette_to_rgb (png);
+
+ if (color_type == PNG_COLOR_TYPE_GRAY)
+ png_set_expand_gray_1_2_4_to_8 (png);
+
+ if (png_get_valid (png, info, PNG_INFO_tRNS))
+ png_set_tRNS_to_alpha (png);
+
+ if (depth < 8)
+ png_set_packing (png);
+
+ if (color_type == PNG_COLOR_TYPE_GRAY ||
+ color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ png_set_gray_to_rgb (png);
+
+ if (interlace != PNG_INTERLACE_NONE)
+ png_set_interlace_handling (png);
+
+ png_set_filler (png, 0xff, PNG_FILLER_AFTER);
+
+ png_read_update_info (png, info);
+ png_get_IHDR (png, info,
+ &width, &height, &depth,
+ &color_type, &interlace, NULL, NULL);
+ if ((depth != 8) ||
+ !(color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_RGB_ALPHA))
+ {
+ png_destroy_read_struct (&png, &info, NULL);
+ g_set_error (error,
+ GDK_TEXTURE_ERROR, GDK_TEXTURE_ERROR_UNSUPPORTED,
+ "Failed to parse png image");
+ return NULL;
+ }
+
+ switch (color_type)
+ {
+ case PNG_COLOR_TYPE_RGB_ALPHA:
+ format = GDK_MEMORY_DEFAULT;
+ png_set_read_user_transform_fn (png, premultiply_data);
+ break;
+ case PNG_COLOR_TYPE_RGB:
+ format = GDK_MEMORY_DEFAULT;
+ png_set_read_user_transform_fn (png, convert_bytes_to_data);
+ break;
+ default:
+ g_assert_not_reached ();
+ }
+
+ stride = width * gdk_memory_format_bytes_per_pixel (format);
+ if (stride % 4)
+ stride += 4 - stride % 4;
+
+ buffer = g_try_malloc_n (height, stride);
+ row_pointers = g_try_malloc_n (height, sizeof (char *));
+
+ if (!buffer || !row_pointers)
+ {
+ g_free (buffer);
+ g_free (row_pointers);
+ png_destroy_read_struct (&png, &info, NULL);
+ g_set_error_literal (error,
+ GDK_TEXTURE_ERROR, GDK_TEXTURE_ERROR_INSUFFICIENT_MEMORY,
+ "Not enough memory to load png");
+ return NULL;
+ }
+
+ for (int i = 0; i < height; i++)
+ row_pointers[i] = &buffer[i * stride];
+
+ png_read_image (png, row_pointers);
+ png_read_end (png, info);
+
+ out_bytes = g_bytes_new_take (buffer, height * stride);
+ texture = gdk_memory_texture_new (width, height,
+ format,
+ out_bytes, stride);
+ g_bytes_unref (out_bytes);
+
+ g_free (row_pointers);
+ png_destroy_read_struct (&png, &info, NULL);
+
+ return texture;
+}
+
+GBytes *
+gdk_save_png (GdkTexture *texture)
+{
+ png_struct *png = NULL;
+ png_info *info;
+ png_io io;
+ guint width, height;
+ int stride;
+ guchar *data = NULL;
+ guchar *row;
+ int y;
+
+ width = gdk_texture_get_width (texture);
+ height = gdk_texture_get_height (texture);
+
+ stride = width * 4;
+ data = g_malloc_n (stride, height);
+ gdk_texture_download (texture, data, stride);
+ unpremultiply (data, width, height, stride);
+
+ png = png_create_write_struct_2 (PNG_LIBPNG_VER_STRING, NULL,
+ png_simple_error_callback,
+ png_simple_warning_callback,
+ NULL,
+ png_malloc_callback,
+ png_free_callback);
+ if (!png)
+ return NULL;
+
+ info = png_create_info_struct (png);
+ if (!info)
+ {
+ png_destroy_read_struct (&png, NULL, NULL);
+ return NULL;
+ }
+
+ if (sigsetjmp (png_jmpbuf (png), 1))
+ {
+ png_destroy_read_struct (&png, &info, NULL);
+ return NULL;
+ }
+
+ io.data = NULL;
+ io.size = 0;
+ io.position = 0;
+
+ png_set_write_fn (png, &io, png_write_func, png_flush_func);
+
+ png_set_IHDR (png, info, width, height, 8,
+ PNG_COLOR_TYPE_RGB_ALPHA,
+ PNG_INTERLACE_NONE,
+ PNG_COMPRESSION_TYPE_BASE,
+ PNG_FILTER_TYPE_BASE);
+
+ png_write_info (png, info);
+ png_set_packing (png);
+
+ for (y = 0, row = data; y < height; y++, row += stride)
+ png_write_rows (png, &row, 1);
+
+ png_write_end (png, info);
+
+ png_destroy_write_struct (&png, &info);
+
+ return g_bytes_new_take (io.data, io.size);
+}
+
+/* }}} */
+
+/* vim:set foldmethod=marker expandtab: */
diff --git a/gdk/loaders/gdkpngprivate.h b/gdk/loaders/gdkpngprivate.h
new file mode 100644
index 0000000000..ca824579a2
--- /dev/null
+++ b/gdk/loaders/gdkpngprivate.h
@@ -0,0 +1,31 @@
+/* GDK - The GIMP Drawing Kit
+ * Copyright (C) 2021 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __GDK_PNG_PRIVATE_H__
+#define __GDK_PNG_PRIVATE_H__
+
+#include "gdktexture.h"
+#include <gio/gio.h>
+
+#define PNG_SIGNATURE "\x89PNG"
+
+GdkTexture *gdk_load_png (GBytes *bytes,
+ GError **error);
+
+GBytes *gdk_save_png (GdkTexture *texture);
+
+#endif
diff --git a/gdk/meson.build b/gdk/meson.build
index ccc1738eab..092537257f 100644
--- a/gdk/meson.build
+++ b/gdk/meson.build
@@ -51,6 +51,7 @@ gdk_public_sources = files([
'gdktoplevelsize.c',
'gdktoplevel.c',
'gdkdragsurface.c',
+ 'loaders/gdkpng.c',
])
gdk_public_headers = files([
@@ -201,6 +202,7 @@ gdk_deps = [
platform_gio_dep,
pangocairo_dep,
vulkan_dep,
+ png_dep,
]
if profiler_enabled
@@ -257,7 +259,7 @@ endif
libgdk = static_library('gdk',
sources: [gdk_sources, gdk_backends_gen_headers, gdkconfig],
dependencies: gdk_deps + [libgtk_css_dep],
- link_with: [libgtk_css, ],
+ link_with: [libgtk_css],
include_directories: [confinc, gdkx11_inc, wlinc],
c_args: libgdk_c_args + common_cflags,
link_whole: gdk_backends,
diff --git a/meson.build b/meson.build
index 070aa6a80d..c4da5f02e7 100644
--- a/meson.build
+++ b/meson.build
@@ -207,6 +207,17 @@ foreach func : check_functions
endif
endforeach
+# We use links() because sigsetjmp() is often a macro hidden behind other macros
+cdata.set('HAVE_SIGSETJMP',
+ cc.links('''#define _POSIX_SOURCE
+ #include <setjmp.h>
+ int main (void) {
+ sigjmp_buf env;
+ sigsetjmp (env, 0);
+ return 0;
+ }''', name: 'sigsetjmp'),
+)
+
# Check for __uint128_t (gcc) by checking for 128-bit division
uint128_t_src = '''int main() {
static __uint128_t v1 = 100;
@@ -389,6 +400,10 @@ pangocairo_dep = dependency('pangocairo', version: pango_req,
pixbuf_dep = dependency('gdk-pixbuf-2.0', version: gdk_pixbuf_req,
fallback : ['gdk-pixbuf', 'gdkpixbuf_dep'],
default_options: ['png=enabled', 'jpeg=enabled', 'builtin_loaders=png,jpeg',
'man=false'])
+png_dep = dependency('libpng',
+ fallback: ['libpng', 'libpng_dep'],
+ required: true)
+
epoxy_dep = dependency('epoxy', version: epoxy_req,
fallback: ['libepoxy', 'libepoxy_dep'])
harfbuzz_dep = dependency('harfbuzz', version: '>= 2.1.0', required: false,
diff --git a/subprojects/libpng.wrap b/subprojects/libpng.wrap
new file mode 100644
index 0000000000..9d6c6b3078
--- /dev/null
+++ b/subprojects/libpng.wrap
@@ -0,0 +1,12 @@
+[wrap-file]
+directory = libpng-1.6.37
+source_url = https://github.com/glennrp/libpng/archive/v1.6.37.tar.gz
+source_filename = libpng-1.6.37.tar.gz
+source_hash = ca74a0dace179a8422187671aee97dd3892b53e168627145271cad5b5ac81307
+patch_url = https://wrapdb.mesonbuild.com/v2/libpng_1.6.37-3/get_patch
+patch_filename = libpng-1.6.37-3-wrap.zip
+patch_hash = 6c9f32fd9150b3a96ab89be52af664e32207e10aa9f5fb9aa015989ee2dd7100
+
+[provide]
+libpng = libpng_dep
+
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