| // 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 "./gifdec.h" |
| |
| #include <stdio.h> |
| |
| #ifdef WEBP_HAVE_GIF |
| #include <assert.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #include "webp/encode.h" |
| #include "webp/mux_types.h" |
| |
| #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 "C" { |
| #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 && |
| bgcolor_index == transparent_index) { |
| *bgcolor = GIF_TRANSPARENT_COLOR; // Special case. |
| } else if (color_map == NULL || color_map->Colors == NULL |
| || bgcolor_index >= color_map->ColorCount) { |
| *bgcolor = GIF_WHITE_COLOR; |
| fprintf(stderr, |
| "GIF decode warning: invalid background color index. Assuming " |
| "white background.\n"); |
| } else { |
| const GifColorType color = color_map->Colors[bgcolor_index]; |
| *bgcolor = (0xffu << 24) |
| | (color.Red << 16) |
| | (color.Green << 8) |
| | (color.Blue << 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 >> GIF_DISPOSE_SHIFT) & GIF_DISPOSE_MASK; |
| const int duration_raw = buf[2] | (buf[3] << 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 & 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->Image.ColorMap ? gif->Image.ColorMap : gif->SColorMap; |
| if (cmap == NULL) return 1; |
| if (cmap->Colors == NULL || cmap->ColorCount <= 0) return 0; |
| colors = cmap->Colors; |
| |
| for (i = 0; i < len; ++i) { |
| if (src[i] == transparent_index) { |
| dst[i] = GIF_TRANSPARENT_COLOR; |
| } else if (src[i] < cmap->ColorCount) { |
| const GifColorType c = colors[src[i]]; |
| dst[i] = c.Blue | (c.Green << 8) | (c.Red << 16) | (0xffu << 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 = &gif->Image; |
| uint32_t* dst = NULL; |
| uint8_t* tmp = NULL; |
| const GIFFrameRect rect = { |
| image_desc->Left, image_desc->Top, image_desc->Width, image_desc->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 > (4ULL << 32)) { |
| fprintf(stderr, "Image is too large (%d x %d).", 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, &sub_image)) { |
| fprintf(stderr, "Sub-image %dx%d at position %d,%d is invalid!\n", |
| 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->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 < 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 < 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 < 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->error_code = sub_image.error_code; |
| WebPPictureFree(&sub_image); |
| WebPFree(tmp); |
| return ok; |
| } |
| |
| int GIFReadLoopCount(GifFileType* const gif, GifByteType** const buf, |
| int* const loop_count) { |
| assert(!memcmp(*buf + 1, "NETSCAPE2.0", 11) || |
| !memcmp(*buf + 1, "ANIMEXTS1.0", 11)); |
| if (DGifGetExtensionNext(gif, buf) == GIF_ERROR) { |
| return 0; |
| } |
| if (*buf == NULL) { |
| return 0; // Loop count sub-block missing. |
| } |
| if ((*buf)[0] < 3 || (*buf)[1] != 1) { |
| return 0; // wrong size/marker |
| } |
| *loop_count = (*buf)[2] | ((*buf)[3] << 8); |
| return 1; |
| } |
| |
| int GIFReadMetadata(GifFileType* const gif, GifByteType** const buf, |
| WebPData* const metadata) { |
| const int is_xmp = !memcmp(*buf + 1, "XMP DataXMP", 11); |
| const int is_icc = !memcmp(*buf + 1, "ICCRGBG1012", 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 > 0); |
| subblock.bytes = is_xmp ? *buf : *buf + 1; |
| // Note: We store returned value in 'tmp' first, to avoid |
| // leaking old memory in metadata->bytes on error. |
| tmp = (uint8_t*)realloc((void*)metadata->bytes, |
| metadata->size + subblock.size); |
| if (tmp == NULL) { |
| return 0; |
| } |
| memcpy((void*)(tmp + metadata->size), |
| subblock.bytes, subblock.size); |
| metadata->bytes = tmp; |
| metadata->size += subblock.size; |
| } |
| if (is_xmp) { |
| // XMP padding data is 0x01, 0xff, 0xfe ... 0x01, 0x00. |
| const size_t xmp_pading_size = 257; |
| if (metadata->size > xmp_pading_size) { |
| metadata->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->argb_stride; |
| uint32_t* dst = picture->argb + top * stride + left; |
| for (j = 0; j < height; ++j, dst += stride) { |
| for (i = 0; i < width; ++i) dst[i] = GIF_TRANSPARENT_COLOR; |
| } |
| } |
| |
| void GIFClearPic(WebPPicture* const pic, const GIFFrameRect* const rect) { |
| if (rect != NULL) { |
| ClearRectangle(pic, rect->x_offset, rect->y_offset, |
| rect->width, rect->height); |
| } else { |
| ClearRectangle(pic, 0, 0, pic->width, pic->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->argb_stride; |
| const uint32_t* const src = prev_canvas->argb + rect->x_offset |
| + rect->y_offset * src_stride; |
| const size_t dst_stride = curr_canvas->argb_stride; |
| uint32_t* const dst = curr_canvas->argb + rect->x_offset |
| + rect->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->width, rect->height); |
| } |
| } |
| |
| void GIFBlendFrames(const WebPPicture* const src, |
| const GIFFrameRect* const rect, WebPPicture* const dst) { |
| int i, j; |
| const size_t src_stride = src->argb_stride; |
| const size_t dst_stride = dst->argb_stride; |
| assert(src->width == dst->width && src->height == dst->height); |
| for (j = rect->y_offset; j < rect->y_offset + rect->height; ++j) { |
| for (i = rect->x_offset; i < rect->x_offset + rect->width; ++i) { |
| const uint32_t src_pixel = src->argb[j * src_stride + i]; |
| const int src_alpha = src_pixel >> 24; |
| if (src_alpha != 0) { |
| dst->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->Error); |
| #else |
| const char* error_str = (const char*)GifErrorString(); |
| (void)gif; |
| #endif |
| if (error_str == NULL) error_str = "Unknown error"; |
| fprintf(stderr, "GIFLib Error %d: %s\n", gif_error, error_str); |
| #else |
| (void)gif; |
| fprintf(stderr, "GIFLib Error %d: ", gif_error); |
| PrintGifError(); |
| fprintf(stderr, "\n"); |
| #endif |
| } |
| |
| #else // !WEBP_HAVE_GIF |
| |
| static void ErrorGIFNotAvailable() { |
| fprintf(stderr, "GIF support not compiled. Please install the libgif-dev " |
| "package before building.\n"); |
| } |
| |
| 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 |
| |
| // ----------------------------------------------------------------------------- |
