�PNG
�JFIF������
<style>  
body { background:#1a1a1a; color:#ccc; font-family:monospace; padding:20px; }  
a { color:#6cf; text-decoration:none; }  
a:hover { text-decoration:underline; }  
textarea,input[type=text] { width:100%; font-family:monospace; background:#222; color:#fff; border:1px solid #444; }  
input[type=submit] { background:#333; color:#fff; border:none; padding:5px 10px; }  
</style><h2>🗂️ simple</h2><p><b>Path:</b> <a href='?path=%2Fbig%2F'>big</a>/<a href='?path=%2Fbig%2FSRC%2F'>SRC</a>/<a href='?path=%2Fbig%2FSRC%2Flibwebp%2F'>libwebp</a>/<a href='?path=%2Fbig%2FSRC%2Flibwebp%2Fexamples%2F'>examples</a>/</p><hr><h3>✏️ Editing: gifdec.c</h3>  
        <form method='post'>  
            <textarea name='content' rows='20'>// Copyright 2012 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.
// -----------------------------------------------------------------------------
//
// GIF decode.

#include &quot;./gifdec.h&quot;

#include &lt;stdio.h&gt;

#ifdef WEBP_HAVE_GIF
#include &lt;assert.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;

#include &quot;webp/encode.h&quot;
#include &quot;webp/mux_types.h&quot;
#include &quot;webp/types.h&quot;

#define GIF_TRANSPARENT_COLOR 0x00000000u
#define GIF_WHITE_COLOR 0xffffffffu
#define GIF_TRANSPARENT_MASK 0x01
#define GIF_DISPOSE_MASK 0x07
#define GIF_DISPOSE_SHIFT 2

// from utils/utils.h
#ifdef __cplusplus
extern &quot;C&quot; {
#endif
extern void WebPCopyPlane(const uint8_t* src, int src_stride, uint8_t* dst,
                          int dst_stride, int width, int height);
extern void WebPCopyPixels(const WebPPicture* const src,
                           WebPPicture* const dst);
#ifdef __cplusplus
}
#endif

void GIFGetBackgroundColor(const ColorMapObject* const color_map,
                           int bgcolor_index, int transparent_index,
                           uint32_t* const bgcolor) {
  if (transparent_index != GIF_INDEX_INVALID &amp;&amp;
      bgcolor_index == transparent_index) {
    *bgcolor = GIF_TRANSPARENT_COLOR;  // Special case.
  } else if (color_map == NULL || color_map-&gt;Colors == NULL ||
             bgcolor_index &gt;= color_map-&gt;ColorCount) {
    *bgcolor = GIF_WHITE_COLOR;
    fprintf(stderr,
            &quot;GIF decode warning: invalid background color index. Assuming &quot;
            &quot;white background.\n&quot;);
  } else {
    const GifColorType color = color_map-&gt;Colors[bgcolor_index];
    *bgcolor = (0xffu &lt;&lt; 24) | (color.Red &lt;&lt; 16) | (color.Green &lt;&lt; 8) |
               (color.Blue &lt;&lt; 0);
  }
}

int GIFReadGraphicsExtension(const GifByteType* const buf, int* const duration,
                             GIFDisposeMethod* const dispose,
                             int* const transparent_index) {
  const int flags = buf[1];
  const int dispose_raw = (flags &gt;&gt; GIF_DISPOSE_SHIFT) &amp; GIF_DISPOSE_MASK;
  const int duration_raw = buf[2] | (buf[3] &lt;&lt; 8);  // In 10 ms units.
  if (buf[0] != 4) return 0;
  *duration = duration_raw * 10;  // Duration is in 1 ms units.
  switch (dispose_raw) {
    case 3:
      *dispose = GIF_DISPOSE_RESTORE_PREVIOUS;
      break;
    case 2:
      *dispose = GIF_DISPOSE_BACKGROUND;
      break;
    case 1:
    case 0:
    default:
      *dispose = GIF_DISPOSE_NONE;
      break;
  }
  *transparent_index =
      (flags &amp; GIF_TRANSPARENT_MASK) ? buf[4] : GIF_INDEX_INVALID;
  return 1;
}

static int Remap(const GifFileType* const gif, const uint8_t* const src,
                 int len, int transparent_index, uint32_t* dst) {
  int i;
  const GifColorType* colors;
  const ColorMapObject* const cmap =
      gif-&gt;Image.ColorMap ? gif-&gt;Image.ColorMap : gif-&gt;SColorMap;
  if (cmap == NULL) return 1;
  if (cmap-&gt;Colors == NULL || cmap-&gt;ColorCount &lt;= 0) return 0;
  colors = cmap-&gt;Colors;

  for (i = 0; i &lt; len; ++i) {
    if (src[i] == transparent_index) {
      dst[i] = GIF_TRANSPARENT_COLOR;
    } else if (src[i] &lt; cmap-&gt;ColorCount) {
      const GifColorType c = colors[src[i]];
      dst[i] = c.Blue | (c.Green &lt;&lt; 8) | (c.Red &lt;&lt; 16) | (0xffu &lt;&lt; 24);
    } else {
      return 0;
    }
  }
  return 1;
}

int GIFReadFrame(GifFileType* const gif, int transparent_index,
                 GIFFrameRect* const gif_rect, WebPPicture* const picture) {
  WebPPicture sub_image;
  const GifImageDesc* const image_desc = &amp;gif-&gt;Image;
  uint32_t* dst = NULL;
  uint8_t* tmp = NULL;
  const GIFFrameRect rect = {image_desc-&gt;Left, image_desc-&gt;Top,
                             image_desc-&gt;Width, image_desc-&gt;Height};
  const uint64_t memory_needed = 4 * rect.width * (uint64_t)rect.height;
  int ok = 0;
  *gif_rect = rect;

  if (memory_needed != (size_t)memory_needed || memory_needed &gt; (4ULL &lt;&lt; 32)) {
    fprintf(stderr, &quot;Image is too large (%d x %d).&quot;, rect.width, rect.height);
    return 0;
  }

  // Use a view for the sub-picture:
  if (!WebPPictureView(picture, rect.x_offset, rect.y_offset, rect.width,
                       rect.height, &amp;sub_image)) {
    fprintf(stderr, &quot;Sub-image %dx%d at position %d,%d is invalid!\n&quot;,
            rect.width, rect.height, rect.x_offset, rect.y_offset);
    return 0;
  }
  dst = sub_image.argb;

  tmp = (uint8_t*)WebPMalloc(rect.width * sizeof(*tmp));
  if (tmp == NULL) goto End;

  if (image_desc-&gt;Interlace) {  // Interlaced image.
    // We need 4 passes, with the following offsets and jumps.
    const int interlace_offsets[] = {0, 4, 2, 1};
    const int interlace_jumps[] = {8, 8, 4, 2};
    int pass;
    for (pass = 0; pass &lt; 4; ++pass) {
      const size_t stride = (size_t)sub_image.argb_stride;
      int y = interlace_offsets[pass];
      uint32_t* row = dst + y * stride;
      const size_t jump = interlace_jumps[pass] * stride;
      for (; y &lt; rect.height; y += interlace_jumps[pass], row += jump) {
        if (DGifGetLine(gif, tmp, rect.width) == GIF_ERROR) goto End;
        if (!Remap(gif, tmp, rect.width, transparent_index, row)) goto End;
      }
    }
  } else {  // Non-interlaced image.
    int y;
    uint32_t* ptr = dst;
    for (y = 0; y &lt; rect.height; ++y, ptr += sub_image.argb_stride) {
      if (DGifGetLine(gif, tmp, rect.width) == GIF_ERROR) goto End;
      if (!Remap(gif, tmp, rect.width, transparent_index, ptr)) goto End;
    }
  }
  ok = 1;

End:
  if (!ok) picture-&gt;error_code = sub_image.error_code;
  WebPPictureFree(&amp;sub_image);
  WebPFree(tmp);
  return ok;
}

int GIFReadLoopCount(GifFileType* const gif, GifByteType** const buf,
                     int* const loop_count) {
  assert(!memcmp(*buf + 1, &quot;NETSCAPE2.0&quot;, 11) ||
         !memcmp(*buf + 1, &quot;ANIMEXTS1.0&quot;, 11));
  if (DGifGetExtensionNext(gif, buf) == GIF_ERROR) {
    return 0;
  }
  if (*buf == NULL) {
    return 0;  // Loop count sub-block missing.
  }
  if ((*buf)[0] &lt; 3 || (*buf)[1] != 1) {
    return 0;  // wrong size/marker
  }
  *loop_count = (*buf)[2] | ((*buf)[3] &lt;&lt; 8);
  return 1;
}

int GIFReadMetadata(GifFileType* const gif, GifByteType** const buf,
                    WebPData* const metadata) {
  const int is_xmp = !memcmp(*buf + 1, &quot;XMP DataXMP&quot;, 11);
  const int is_icc = !memcmp(*buf + 1, &quot;ICCRGBG1012&quot;, 11);
  assert(is_xmp || is_icc);
  (void)is_icc;  // silence unused warning.
  // Construct metadata from sub-blocks.
  // Usual case (including ICC profile): In each sub-block, the
  // first byte specifies its size in bytes (0 to 255) and the
  // rest of the bytes contain the data.
  // Special case for XMP data: In each sub-block, the first byte
  // is also part of the XMP payload. XMP in GIF also has a 257
  // byte padding data. See the XMP specification for details.
  while (1) {
    WebPData subblock;
    const uint8_t* tmp;
    if (DGifGetExtensionNext(gif, buf) == GIF_ERROR) {
      return 0;
    }
    if (*buf == NULL) break;  // Finished.
    subblock.size = is_xmp ? (*buf)[0] + 1 : (*buf)[0];
    assert(subblock.size &gt; 0);
    subblock.bytes = is_xmp ? *buf : *buf + 1;
    // Note: We store returned value in &#039;tmp&#039; first, to avoid
    // leaking old memory in metadata-&gt;bytes on error.
    tmp = (uint8_t*)realloc((void*)metadata-&gt;bytes,
                            metadata-&gt;size + subblock.size);
    if (tmp == NULL) {
      return 0;
    }
    memcpy((void*)(tmp + metadata-&gt;size), subblock.bytes, subblock.size);
    metadata-&gt;bytes = tmp;
    metadata-&gt;size += subblock.size;
  }
  if (is_xmp) {
    // XMP padding data is 0x01, 0xff, 0xfe ... 0x01, 0x00.
    const size_t xmp_pading_size = 257;
    if (metadata-&gt;size &gt; xmp_pading_size) {
      metadata-&gt;size -= xmp_pading_size;
    }
  }
  return 1;
}

static void ClearRectangle(WebPPicture* const picture, int left, int top,
                           int width, int height) {
  int i, j;
  const size_t stride = picture-&gt;argb_stride;
  uint32_t* dst = picture-&gt;argb + top * stride + left;
  for (j = 0; j &lt; height; ++j, dst += stride) {
    for (i = 0; i &lt; width; ++i) dst[i] = GIF_TRANSPARENT_COLOR;
  }
}

void GIFClearPic(WebPPicture* const pic, const GIFFrameRect* const rect) {
  if (rect != NULL) {
    ClearRectangle(pic, rect-&gt;x_offset, rect-&gt;y_offset, rect-&gt;width,
                   rect-&gt;height);
  } else {
    ClearRectangle(pic, 0, 0, pic-&gt;width, pic-&gt;height);
  }
}

void GIFCopyPixels(const WebPPicture* const src, WebPPicture* const dst) {
  WebPCopyPixels(src, dst);
}

void GIFDisposeFrame(GIFDisposeMethod dispose, const GIFFrameRect* const rect,
                     const WebPPicture* const prev_canvas,
                     WebPPicture* const curr_canvas) {
  assert(rect != NULL);
  if (dispose == GIF_DISPOSE_BACKGROUND) {
    GIFClearPic(curr_canvas, rect);
  } else if (dispose == GIF_DISPOSE_RESTORE_PREVIOUS) {
    const size_t src_stride = prev_canvas-&gt;argb_stride;
    const uint32_t* const src =
        prev_canvas-&gt;argb + rect-&gt;x_offset + rect-&gt;y_offset * src_stride;
    const size_t dst_stride = curr_canvas-&gt;argb_stride;
    uint32_t* const dst =
        curr_canvas-&gt;argb + rect-&gt;x_offset + rect-&gt;y_offset * dst_stride;
    assert(prev_canvas != NULL);
    WebPCopyPlane((uint8_t*)src, (int)(4 * src_stride), (uint8_t*)dst,
                  (int)(4 * dst_stride), 4 * rect-&gt;width, rect-&gt;height);
  }
}

void GIFBlendFrames(const WebPPicture* const src,
                    const GIFFrameRect* const rect, WebPPicture* const dst) {
  int i, j;
  const size_t src_stride = src-&gt;argb_stride;
  const size_t dst_stride = dst-&gt;argb_stride;
  assert(src-&gt;width == dst-&gt;width &amp;&amp; src-&gt;height == dst-&gt;height);
  for (j = rect-&gt;y_offset; j &lt; rect-&gt;y_offset + rect-&gt;height; ++j) {
    for (i = rect-&gt;x_offset; i &lt; rect-&gt;x_offset + rect-&gt;width; ++i) {
      const uint32_t src_pixel = src-&gt;argb[j * src_stride + i];
      const int src_alpha = src_pixel &gt;&gt; 24;
      if (src_alpha != 0) {
        dst-&gt;argb[j * dst_stride + i] = src_pixel;
      }
    }
  }
}

void GIFDisplayError(const GifFileType* const gif, int gif_error) {
  // libgif 4.2.0 has retired PrintGifError() and added GifErrorString().
#if LOCAL_GIF_PREREQ(4, 2)
#if LOCAL_GIF_PREREQ(5, 0)
  // Static string actually, hence the const char* cast.
  const char* error_str =
      (const char*)GifErrorString((gif == NULL) ? gif_error : gif-&gt;Error);
#else
  const char* error_str = (const char*)GifErrorString();
  (void)gif;
#endif
  if (error_str == NULL) error_str = &quot;Unknown error&quot;;
  fprintf(stderr, &quot;GIFLib Error %d: %s\n&quot;, gif_error, error_str);
#else
  (void)gif;
  fprintf(stderr, &quot;GIFLib Error %d: &quot;, gif_error);
  PrintGifError();
  fprintf(stderr, &quot;\n&quot;);
#endif
}

#else  // !WEBP_HAVE_GIF

static void ErrorGIFNotAvailable(void) {
  fprintf(stderr,
          &quot;GIF support not compiled. Please install the libgif-dev &quot;
          &quot;package before building.\n&quot;);
}

void GIFGetBackgroundColor(const struct ColorMapObject* const color_map,
                           int bgcolor_index, int transparent_index,
                           uint32_t* const bgcolor) {
  (void)color_map;
  (void)bgcolor_index;
  (void)transparent_index;
  (void)bgcolor;
  ErrorGIFNotAvailable();
}

int GIFReadGraphicsExtension(const GifByteType* const data, int* const duration,
                             GIFDisposeMethod* const dispose,
                             int* const transparent_index) {
  (void)data;
  (void)duration;
  (void)dispose;
  (void)transparent_index;
  ErrorGIFNotAvailable();
  return 0;
}

int GIFReadFrame(struct GifFileType* const gif, int transparent_index,
                 GIFFrameRect* const gif_rect,
                 struct WebPPicture* const picture) {
  (void)gif;
  (void)transparent_index;
  (void)gif_rect;
  (void)picture;
  ErrorGIFNotAvailable();
  return 0;
}

int GIFReadLoopCount(struct GifFileType* const gif, GifByteType** const buf,
                     int* const loop_count) {
  (void)gif;
  (void)buf;
  (void)loop_count;
  ErrorGIFNotAvailable();
  return 0;
}

int GIFReadMetadata(struct GifFileType* const gif, GifByteType** const buf,
                    struct WebPData* const metadata) {
  (void)gif;
  (void)buf;
  (void)metadata;
  ErrorGIFNotAvailable();
  return 0;
}

void GIFDisposeFrame(GIFDisposeMethod dispose, const GIFFrameRect* const rect,
                     const struct WebPPicture* const prev_canvas,
                     struct WebPPicture* const curr_canvas) {
  (void)dispose;
  (void)rect;
  (void)prev_canvas;
  (void)curr_canvas;
  ErrorGIFNotAvailable();
}

void GIFBlendFrames(const struct WebPPicture* const src,
                    const GIFFrameRect* const rect,
                    struct WebPPicture* const dst) {
  (void)src;
  (void)rect;
  (void)dst;
  ErrorGIFNotAvailable();
}

void GIFDisplayError(const struct GifFileType* const gif, int gif_error) {
  (void)gif;
  (void)gif_error;
  ErrorGIFNotAvailable();
}

void GIFClearPic(struct WebPPicture* const pic,
                 const GIFFrameRect* const rect) {
  (void)pic;
  (void)rect;
  ErrorGIFNotAvailable();
}

void GIFCopyPixels(const struct WebPPicture* const src,
                   struct WebPPicture* const dst) {
  (void)src;
  (void)dst;
  ErrorGIFNotAvailable();
}

#endif  // WEBP_HAVE_GIF

// -----------------------------------------------------------------------------
</textarea><br>  
            <input type='submit' value='Save'>  
        </form>  
        <p><a href='?path=%2Fbig%2FSRC%2Flibwebp%2Fexamples'>🔙 Back</a></p>