vwebp_sdl: simple viewer based on SDL

Uses WebPToSDL() generic function defined in vwebp_sdl.[ch].
This function is not included in the libextras library, because it
would bring in an SDL dependency. Probably too heavy for now.

WebPToSDL() is separate, because it will be called used by the javascript
version of libwebp (through emscripten build rules)

Change-Id: Ic85b36f8ce4784f46023656278f6480be6802834

Makefile.vc

@@ -344,7 +344,7 @@ all: ex
 OUT_EXAMPLES = $(DIRBIN)\cwebp.exe $(DIRBIN)\dwebp.exe
 EXTRA_EXAMPLES = $(DIRBIN)\vwebp.exe $(DIRBIN)\webpmux.exe \
                  $(DIRBIN)\img2webp.exe $(DIRBIN)\get_disto.exe \
-                 $(DIRBIN)\webp_quality.exe
+                 $(DIRBIN)\webp_quality.exe $(DIRBIN)\vwebp_sdl.exe \
 
 ex: $(OUT_LIBS) $(OUT_EXAMPLES)
 all: ex $(EXTRA_EXAMPLES)
@@ -366,6 +366,9 @@ $(DIRBIN)\gif2webp.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS) $(LIBWEBPMUX)
 $(DIRBIN)\gif2webp.exe: $(LIBWEBP)
 $(DIRBIN)\vwebp.exe: $(DIROBJ)\examples\vwebp.obj $(EX_UTIL_OBJS)
 $(DIRBIN)\vwebp.exe: $(IMAGEIO_UTIL_OBJS) $(LIBWEBPDEMUX) $(LIBWEBP)
+$(DIRBIN)\vwebp_sdl.exe: $(DIROBJ)\examples\vwebp_sdl.obj
+$(DIRBIN)\vwebp_sdl.exe: $(DIROBJ)\examples\webp_to_sdl.obj
+$(DIRBIN)\vwebp_sdl.exe: $(IMAGEIO_UTIL_OBJS) $(LIBWEBP)
 $(DIRBIN)\webpmux.exe: $(DIROBJ)\examples\webpmux.obj $(LIBWEBPMUX)
 $(DIRBIN)\webpmux.exe: $(EX_UTIL_OBJS) $(IMAGEIO_UTIL_OBJS) $(LIBWEBP)
 $(DIRBIN)\img2webp.exe: $(DIROBJ)\examples\img2webp.obj $(LIBWEBPMUX)

configure.ac

@@ -428,6 +428,44 @@ AS_IF([test "x$enable_gl" != "xno"], [
 ])
 AM_CONDITIONAL([BUILD_VWEBP], [test "$build_vwebp" = "yes"])
 
+dnl === check for SDL support ===
+
+AC_ARG_ENABLE([sdl],
+              AS_HELP_STRING([--disable-sdl],
+                             [Disable detection of SDL support
+                              @<:@default=auto@:>@]))
+AS_IF([test "x$enable_sdl" != "xno"], [
+  CLEAR_LIBVARS([SDL])
+  WITHLIB_OPTION([sdl], [SDL])
+
+  $sdl_header = "no";
+  LIBCHECK_PROLOGUE([SDL])
+  AC_CHECK_HEADER([SDL/SDL.h], [sdl_header="SDL_SDL.h"],
+                  [AC_CHECK_HEADER([SDL.h], [sdl_header="SDL.h"],
+                  [AC_MSG_WARN(SDL library not available - no sdl.h)])])
+  if test x"$sdl_header" != "xno" ; then
+    AC_CHECK_LIB(SDL, SDL_Init,
+                 [SDL_LIBS="-lSDL"
+                  SDL_INCLUDES="-DWEBP_HAVE_SDL"
+                  AC_DEFINE(WEBP_HAVE_SDL, [1],
+                            [Set to 1 if SDL library is installed])
+                  sdl_support=yes
+                 ],
+                 AC_MSG_WARN(Optional SDL library not found),
+                 [$MATH_LIBS]),
+    if test x"$sdl_header" == "xSDL.h" ; then
+      SDL_INCLUDES="$SDL_INCLUDES -DWEBP_HAVE_JUST_SDL_H"
+    fi
+  fi
+  LIBCHECK_EPILOGUE([SDL])
+
+  if test "$sdl_support" = "yes" ; then
+    build_vwebp_sdl=yes
+  fi
+])
+
+AM_CONDITIONAL([BUILD_VWEBP_SDL], [test "$build_vwebp_sdl" = "yes"])
+
 dnl === check for PNG support ===
 
 AC_ARG_ENABLE([png], AS_HELP_STRING([--disable-png],
@@ -718,4 +756,6 @@ gif2webp    : ${build_gif2webp-no}
 img2webp    : ${build_img2webp-no}
 webpmux     : ${enable_libwebpmux-no}
 vwebp       : ${build_vwebp-no}
+SDL support : ${sdl_support-no}
+vwebp_sdl   : ${build_vwebp_sdl-no}
 ])

extras/Makefile.am

@@ -11,10 +11,14 @@ libwebpextras_la_CPPFLAGS = $(AM_CPPFLAGS)
 libwebpextras_la_LDFLAGS = -lm
 libwebpextras_la_LIBADD = ../src/libwebp.la
 
-noinst_PROGRAMS = get_disto webp_quality
+noinst_PROGRAMS =
+noinst_PROGRAMS += get_disto webp_quality
+if BUILD_VWEBP_SDL
+  noinst_PROGRAMS += vwebp_sdl
+endif
 
-get_disto_SOURCES = get_disto.c
-get_disto_CPPFLAGS  = $(AM_CPPFLAGS)
+get_disto_SOURCES  = get_disto.c
+get_disto_CPPFLAGS = $(AM_CPPFLAGS)
 get_disto_LDADD = ../imageio/libimageio_util.la ../imageio/libimagedec.la
 get_disto_LDADD += ../src/libwebp.la
 get_disto_LDADD += $(PNG_LIBS) $(JPEG_LIBS) $(TIFF_LIBS)
@@ -24,3 +28,9 @@ webp_quality_CPPFLAGS = $(AM_CPPFLAGS) $(USE_EXPERIMENTAL_CODE)
 webp_quality_LDADD  = ../imageio/libimageio_util.la
 webp_quality_LDADD += ./libwebpextras.la
 webp_quality_LDADD += ../src/libwebp.la
+
+vwebp_sdl_SOURCES  = vwebp_sdl.c webp_to_sdl.c webp_to_sdl.h
+vwebp_sdl_CPPFLAGS = $(AM_CPPFLAGS) $(SDL_INCLUDES)
+vwebp_sdl_LDADD = ../imageio/libimageio_util.la
+vwebp_sdl_LDADD += ../src/libwebp.la
+vwebp_sdl_LDADD += $(SDL_LIBS)

extras/vwebp_sdl.c

@@ -0,0 +1,96 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// Simple SDL-based WebP file viewer.
+// Does not support animation, just static images.
+//
+// Press 'q' to exit.
+//
+// Author: James Zern (jzern@google.com)
+
+#include <stdio.h>
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#if defined(WEBP_HAVE_SDL)
+
+#include "webp_to_sdl.h"
+#include "webp/decode.h"
+#include "../imageio/imageio_util.h"
+
+#if defined(WEBP_HAVE_JUST_SDL_H)
+#include <SDL.h>
+#else
+#include <SDL/SDL.h>
+#endif
+
+static void ProcessEvents(void) {
+  int done = 0;
+  SDL_Event event;
+  while (!done && SDL_WaitEvent(&event)) {
+    switch (event.type) {
+      case SDL_KEYUP:
+        switch (event.key.keysym.sym) {
+          case SDLK_q: done = 1; break;
+          default: break;
+        }
+        break;
+      default: break;
+    }
+  }
+}
+
+int main(int argc, char* argv[]) {
+  int c;
+  int ok = 0;
+  for (c = 1; c < argc; ++c) {
+    const char* file = NULL;
+    const uint8_t* webp = NULL;
+    size_t webp_size = 0;
+    if (!strcmp(argv[c], "-h")) {
+      printf("Usage: %s [-h] image.webp [more_files.webp...]\n", argv[0]);
+      return 0;
+    } else {
+      file = argv[c];
+    }
+    if (file == NULL) continue;
+    if (!ImgIoUtilReadFile(file, &webp, &webp_size)) {
+      fprintf(stderr, "Error opening file: %s\n", file);
+      goto Error;
+    }
+    if (webp_size != (size_t)(int)webp_size) {
+      fprintf(stderr, "File too large.\n");
+      goto Error;
+    }
+    ok = WebpToSDL((const char*)webp, (int)webp_size);
+    free((void*)webp);
+    if (!ok) {
+      fprintf(stderr, "Error decoding file %s\n", file);
+      goto Error;
+    }
+    ProcessEvents();
+  }
+  ok = 1;
+
+ Error:
+  SDL_Quit();
+  return ok ? 0 : 1;
+}
+
+#else  // !WEBP_HAVE_SDL
+
+int main(int argc, const char *argv[]) {
+  fprintf(stderr, "SDL support not enabled in %s.\n", argv[0]);
+  (void)argc;
+  return 0;
+}
+
+#endif

extras/webp_to_sdl.c

@@ -0,0 +1,105 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Simple WebP-to-SDL wrapper. Useful for emscripten.
+//
+// Author: James Zern (jzern@google.com)
+
+#ifdef HAVE_CONFIG_H
+#include "webp/config.h"
+#endif
+
+#if defined(WEBP_HAVE_SDL)
+
+#include "webp_to_sdl.h"
+
+#include <stdio.h>
+#include "webp/decode.h"
+
+#if defined(WEBP_HAVE_JUST_SDL_H)
+#include <SDL.h>
+#else
+#include <SDL/SDL.h>
+#endif
+
+int WebpToSDL(const char* data, unsigned int data_size) {
+  int ok = 0;
+  VP8StatusCode status;
+  WebPDecoderConfig config;
+  WebPBitstreamFeatures* const input = &config.input;
+  WebPDecBuffer* const output = &config.output;
+  SDL_Surface* screen = NULL;
+  SDL_Surface* surface = NULL;
+
+  if (!WebPInitDecoderConfig(&config)) {
+    fprintf(stderr, "Library version mismatch!\n");
+    return 1;
+  }
+
+  SDL_Init(SDL_INIT_VIDEO);
+
+  status = WebPGetFeatures((uint8_t*)data, (size_t)data_size, &config.input);
+  if (status != VP8_STATUS_OK) goto Error;
+
+  screen = SDL_SetVideoMode(input->width, input->height, 32, SDL_SWSURFACE);
+  if (screen == NULL) {
+    fprintf(stderr, "Unable to set video mode (32bpp %dx%d)!\n",
+            input->width, input->height);
+    goto Error;
+  }
+
+  surface = SDL_CreateRGBSurface(SDL_SWSURFACE,
+                                 input->width, input->height, 32,
+                                 0x000000ffu,   // R mask
+                                 0x0000ff00u,   // G mask
+                                 0x00ff0000u,   // B mask
+                                 0xff000000u);  // A mask
+  if (surface == NULL) {
+    fprintf(stderr, "Unable to create %dx%d RGBA surface!\n",
+            input->width, input->height);
+    goto Error;
+  }
+  if (SDL_MUSTLOCK(surface)) SDL_LockSurface(surface);
+
+#if SDL_BYTEORDER == SDL_BIG_ENDIAN
+  output->colorspace = MODE_BGRA;
+#else
+  output->colorspace = MODE_RGBA;
+#endif
+  output->width  = surface->w;
+  output->height = surface->h;
+  output->u.RGBA.rgba   = surface->pixels;
+  output->u.RGBA.stride = surface->pitch;
+  output->u.RGBA.size   = surface->pitch * surface->h;
+  output->is_external_memory = 1;
+
+  status = WebPDecode((const uint8_t*)data, (size_t)data_size, &config);
+  if (status != VP8_STATUS_OK) {
+    fprintf(stderr, "Error decoding image (%d)\n", status);
+    goto Error;
+  }
+
+  if (SDL_MUSTLOCK(surface)) SDL_UnlockSurface(surface);
+  if (SDL_FillRect(screen, &screen->clip_rect, 0xffffffff) ||
+      SDL_BlitSurface(surface, NULL, screen, NULL) ||
+      SDL_Flip(screen)) {
+    goto Error;
+  }
+
+  ok = 1;
+
+ Error:
+  SDL_FreeSurface(surface);
+  SDL_FreeSurface(screen);
+  return ok;
+}
+
+//------------------------------------------------------------------------------
+
+#endif  // WEBP_HAVE_SDL

extras/webp_to_sdl.h

@@ -0,0 +1,22 @@
+// Copyright 2017 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+//  Simple WebP-to-SDL wrapper. Useful for emscripten.
+//
+// Author: James Zern (jzern@google.com)
+
+#ifndef WEBP_EXTRAS_WEBP_TO_SDL_H_
+#define WEBP_EXTRAS_WEBP_TO_SDL_H_
+
+// Exports the method WebpToSDL(const char* data, int data_size) which decodes
+// a WebP bitstream into an RGBA SDL surface.
+// Return false on failure.
+extern int WebpToSDL(const char* data, unsigned int data_size);
+
+#endif  // WEBP_EXTRAS_WEBP_TO_SDL_H_

makefile.unix

@@ -329,7 +329,7 @@ EXTRA_LIB = extras/libwebpextras.a
 OUT_EXAMPLES = examples/cwebp examples/dwebp
 EXTRA_EXAMPLES = examples/gif2webp examples/vwebp examples/webpmux \
                  examples/anim_diff examples/img2webp
-OTHER_EXAMPLES = extras/get_disto extras/webp_quality
+OTHER_EXAMPLES = extras/get_disto extras/webp_quality extras/vwebp_sdl
 
 OUTPUT = $(OUT_LIBS) $(OUT_EXAMPLES)
 ifeq ($(MAKECMDGOALS),clean)
@@ -420,6 +420,13 @@ extras/webp_quality: extras/webp_quality.o
 extras/webp_quality: imageio/libimageio_util.a
 extras/webp_quality: $(EXTRA_LIB) src/libwebp.a
 
+extras/vwebp_sdl: extras/vwebp_sdl.o
+extras/vwebp_sdl: extras/webp_to_sdl.o
+extras/vwebp_sdl: imageio/libimageio_util.a
+extras/vwebp_sdl: src/libwebp.a
+extras/vwebp_sdl: EXTRA_FLAGS += -DWEBP_HAVE_SDL
+extras/vwebp_sdl: -lSDL
+
 $(OUT_EXAMPLES) $(EXTRA_EXAMPLES) $(OTHER_EXAMPLES):
 	$(CC) -o $@ $^ $(LDFLAGS)