Adds SDL3_image port

src/settings.js

@@ -1624,6 +1624,11 @@ var SDL2_IMAGE_FORMATS = [];
 // [link]
 var SDL2_MIXER_FORMATS = ["ogg"];
 
+// Formats to support in SDL3_image. Valid values: bmp, gif, lbm, pcx, png, pnm,
+// tga, webp, xcf, xpm, xv
+// [link]
+var SDL3_IMAGE_FORMATS = [];
+
 // 1 = use sqlite3 from emscripten-ports
 // Alternate syntax: --use-port=sqlite3
 // [compile+link]

test/browser/test_sdl3_image.c

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2025 The Emscripten Authors.  All rights reserved.
+ * Emscripten is available under two separate licenses, the MIT license and the
+ * University of Illinois/NCSA Open Source License.  Both these licenses can be
+ * found in the LICENSE file.
+ */
+
+#include <stdio.h>
+#include <SDL3/SDL.h>
+#include <SDL3_image/SDL_image.h>
+#include <assert.h>
+#include <emscripten.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#ifndef BITSPERPIXEL
+#define BITSPERPIXEL 32
+#endif
+
+int testImage(SDL_Renderer* renderer, const char* fileName) {
+  SDL_Surface *image = IMG_Load(fileName);
+  if (!image)
+  {
+     printf("IMG_Load: %s\n", SDL_GetError());
+     return 0;
+  }
+  assert(SDL_GetPixelFormatDetails(image->format)->bits_per_pixel == BITSPERPIXEL);
+  assert(SDL_GetPixelFormatDetails(image->format)->bytes_per_pixel == BITSPERPIXEL / 8);
+  assert(image->pitch == BITSPERPIXEL / 8 * image->w);
+  int result = image->w;
+
+#ifndef NO_PRELOADED
+  int w, h;
+  char *data = emscripten_get_preloaded_image_data(fileName, &w, &h);
+
+  assert(data);
+  assert(w == image->w);
+  assert(h == image->h);
+#endif
+
+  SDL_Texture *tex = SDL_CreateTextureFromSurface(renderer, image);
+
+  SDL_RenderTexture(renderer, tex, NULL, NULL);
+
+  SDL_DestroyTexture(tex);
+
+  SDL_DestroySurface(image);
+
+#ifndef NO_PRELOADED
+  free(data);
+#endif
+
+  return result;
+}
+
+int main() {
+  SDL_Init(SDL_INIT_VIDEO);
+
+  SDL_Window *window;
+  SDL_Renderer *renderer;
+
+  SDL_CreateWindowAndRenderer("Test Window", 600, 450, 0, &window, &renderer);
+
+  int result = 0;
+
+  result = testImage(renderer, SCREENSHOT_DIRNAME "/" SCREENSHOT_BASENAME); // absolute path
+  assert(result != 0);
+
+  chdir(SCREENSHOT_DIRNAME);
+  result = testImage(renderer, "./" SCREENSHOT_BASENAME); // relative path
+  assert(result != 0);
+
+  SDL_RenderPresent(renderer);
+
+  printf("you should see an image.\n");
+
+  return result;
+}

test/test_browser.py

@@ -2992,6 +2992,48 @@ def test_sdl2_image_formats(self):
       '--use-port=sdl2', '--use-port=sdl2_image:formats=jpg',
     ])
 
+  @requires_graphics_hardware
+  @also_with_wasm2js
+  def test_sdl3_image(self):
+    # Same test as for SDL2, but with SDL3.
+    shutil.copy(test_file('screenshot.jpg'), '.')
+
+    for dest, dirname, basename in [('screenshot.jpg', '/', 'screenshot.jpg'),
+                                    ('screenshot.jpg@/assets/screenshot.jpg', '/assets', 'screenshot.jpg')]:
+      self.btest_exit('test_sdl3_image.c', 600, cflags=[
+        '-O2',
+        '--preload-file', dest,
+        '-DSCREENSHOT_DIRNAME="' + dirname + '"',
+        '-DSCREENSHOT_BASENAME="' + basename + '"',
+        '-sUSE_SDL=3', '-sUSE_SDL_IMAGE=3', '--use-preload-plugins',
+      ])
+
+  @requires_graphics_hardware
+  def test_sdl3_image_jpeg(self):
+    shutil.copy(test_file('screenshot.jpg'), 'screenshot.jpeg')
+    self.btest_exit('test_sdl3_image.c', 600, cflags=[
+      '--preload-file', 'screenshot.jpeg',
+      '-DSCREENSHOT_DIRNAME="/"', '-DSCREENSHOT_BASENAME="screenshot.jpeg"',
+      '-sUSE_SDL=3', '-sUSE_SDL_IMAGE=3', '--use-preload-plugins',
+    ])
+
+  @also_with_wasmfs
+  @requires_graphics_hardware
+  @with_all_sjlj
+  def test_sdl3_image_formats(self):
+    shutil.copy(test_file('screenshot.png'), '.')
+    shutil.copy(test_file('screenshot.jpg'), '.')
+    self.btest_exit('test_sdl3_image.c', 512, cflags=[
+      '--preload-file', 'screenshot.png',
+      '-DSCREENSHOT_DIRNAME="/"', '-DSCREENSHOT_BASENAME="screenshot.png"', '-DNO_PRELOADED',
+      '-sUSE_SDL=3', '-sUSE_SDL_IMAGE=3', '-sSDL3_IMAGE_FORMATS=png',
+    ])
+    self.btest_exit('test_sdl3_image.c', 600, cflags=[
+      '--preload-file', 'screenshot.jpg',
+      '-DSCREENSHOT_DIRNAME="/"', '-DSCREENSHOT_BASENAME="screenshot.jpg"', '-DBITSPERPIXEL=24', '-DNO_PRELOADED',
+      '--use-port=sdl3', '--use-port=sdl3_image:formats=jpg',
+    ])
+
   def test_sdl2_key(self):
     self.btest_exit('test_sdl2_key.c', 37182145, cflags=['-sUSE_SDL=2', '--pre-js', test_file('browser/fake_events.js')])
 

tools/ports/sdl3_image.py

@@ -0,0 +1,136 @@
+# Copyright 2025 The Emscripten Authors.  All rights reserved.
+# Emscripten is available under two separate licenses, the MIT license and the
+# University of Illinois/NCSA Open Source License.  Both these licenses can be
+# found in the LICENSE file.
+
+import os
+
+from typing import Dict, Set
+
+TAG = 'release-3.2.4'
+HASH = '102b8ea30506a1aa0a23196d807e5cdf1ff9efcbcf9db2518a3fffef82f94bda96891129c24a8008a4ec374c9dfc39d5321cf7e573f3e3b10e85b2cfbbc1ad9b'
+
+deps = ['sdl3']
+variants = {
+  'sdl3_image-jpg':    {'SDL3_IMAGE_FORMATS': ["jpg"]},
+  'sdl3_image-png':    {'SDL3_IMAGE_FORMATS': ["png"]},
+  'sdl3_image-jpg-mt': {'SDL3_IMAGE_FORMATS': ["jpg"], 'PTHREADS': 1},
+  'sdl3_image-png-mt': {'SDL3_IMAGE_FORMATS': ["png"], 'PTHREADS': 1},
+}
+
+OPTIONS = {
+  'formats': 'A comma separated list of formats (ex: --use-port=sdl3_image:formats=png,jpg)',
+}
+
+SUPPORTED_FORMATS = {'avif', 'bmp', 'gif', 'jpg', 'jxl', 'lbm', 'pcx', 'png',
+                     'pnm', 'qoi', 'svg', 'tga', 'tif', 'webp', 'xcf', 'xpm', 'xv'}
+
+# user options (from --use-port)
+opts: Dict[str, Set] = {
+  'formats': set(),
+}
+
+
+def needed(settings):
+  return settings.USE_SDL_IMAGE == 3
+
+
+def get_formats(settings):
+  return opts['formats'].union(settings.SDL3_IMAGE_FORMATS)
+
+
+def get_lib_name(settings):
+  formats = '-'.join(sorted(get_formats(settings)))
+
+  libname = 'libSDL3_image'
+  if formats != '':
+    libname += '-' + formats
+  if settings.PTHREADS:
+    libname += '-mt'
+  if settings.SUPPORT_LONGJMP == 'wasm':
+    libname += '-wasm-sjlj'
+  return libname + '.a'
+
+
+def get(ports, settings, shared):
+  ports.fetch_project('sdl3_image', f'https://github.com/libsdl-org/SDL_image/archive/{TAG}.zip', sha512hash=HASH)
+  libname = get_lib_name(settings)
+
+  def create(final):
+    src_root = ports.get_dir('sdl3_image', 'SDL_image-' + TAG)
+    ports.install_header_dir(os.path.join(src_root, 'include'), target='.')
+    srcs = [
+      "src/IMG.c",
+      "src/IMG_ImageIO.m",
+      "src/IMG_WIC.c",
+      "src/IMG_avif.c",
+      "src/IMG_bmp.c",
+      "src/IMG_gif.c",
+      "src/IMG_jpg.c",
+      "src/IMG_jxl.c",
+      "src/IMG_lbm.c",
+      "src/IMG_pcx.c",
+      "src/IMG_png.c",
+      "src/IMG_pnm.c",
+      "src/IMG_qoi.c",
+      "src/IMG_stb.c",
+      "src/IMG_svg.c",
+      "src/IMG_tga.c",
+      "src/IMG_tif.c",
+      "src/IMG_webp.c",
+      "src/IMG_xcf.c",
+      "src/IMG_xpm.c",
+      "src/IMG_xv.c",
+      "src/IMG_xxx.c",
+      ]
+
+    flags = ['-sUSE_SDL=3', '-Wno-format-security']
+
+    formats = get_formats(settings)
+
+    flags.extend(f'-DLOAD_{fmt.upper()}' for fmt in formats)
+
+    if 'png' in formats:
+      flags += ['-sUSE_LIBPNG']
+
+    if 'jpg' in formats:
+      flags += ['-sUSE_LIBJPEG']
+
+    if settings.PTHREADS:
+      flags += ['-pthread']
+
+    if settings.SUPPORT_LONGJMP == 'wasm':
+      flags.append('-sSUPPORT_LONGJMP=wasm')
+
+    ports.build_port(src_root, final, 'sdl3_image', flags=flags, srcs=srcs)
+
+  return [shared.cache.get_lib(libname, create, what='port')]
+
+
+def clear(ports, settings, shared):
+  shared.cache.erase_lib(get_lib_name(settings))
+
+
+def process_dependencies(settings):
+  settings.USE_SDL = 3
+  formats = get_formats(settings)
+  if 'png' in formats:
+    deps.append('libpng')
+    settings.USE_LIBPNG = 1
+  if 'jpg' in formats:
+    deps.append('libjpeg')
+    settings.USE_LIBJPEG = 1
+
+
+def handle_options(options, error_handler):
+  formats = options['formats'].split(',')
+  for format in formats:
+    format = format.lower().strip()
+    if format not in SUPPORTED_FORMATS:
+      error_handler(f'{format} is not a supported format')
+    else:
+      opts['formats'].add(format)
+
+
+def show():
+  return 'sdl3_image (-sUSE_SDL_IMAGE=3 or --use-port=sdl3_image; zlib license)'

tools/settings.py

@@ -53,6 +53,7 @@
     'USE_FREETYPE',
     'SDL2_MIXER_FORMATS',
     'SDL2_IMAGE_FORMATS',
+    'SDL3_IMAGE_FORMATS',
     'USE_SQLITE3',
 }