| // Copyright 2015 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. |
| // ----------------------------------------------------------------------------- |
| // |
| // Utilities for animated images |
| |
| #include "./anim_util.h" |
| |
| #include <assert.h> |
| #include <math.h> |
| #include <stdio.h> |
| #include <string.h> |
| |
| #if defined(WEBP_HAVE_GIF) |
| #include <gif_lib.h> |
| #endif |
| #include "webp/format_constants.h" |
| #include "webp/decode.h" |
| #include "webp/demux.h" |
| #include "../imageio/imageio_util.h" |
| |
| #if defined(_MSC_VER) && _MSC_VER < 1900 |
| #define snprintf _snprintf |
| #endif |
| |
| static const int kNumChannels = 4; |
| |
| // ----------------------------------------------------------------------------- |
| // Common utilities. |
| |
| #if defined(WEBP_HAVE_GIF) |
| // Returns true if the frame covers the full canvas. |
| static int IsFullFrame(int width, int height, |
| int canvas_width, int canvas_height) { |
| return (width == canvas_width && height == canvas_height); |
| } |
| #endif // WEBP_HAVE_GIF |
| |
| static int CheckSizeForOverflow(uint64_t size) { |
| return (size == (size_t)size); |
| } |
| |
| static int AllocateFrames(AnimatedImage* const image, uint32_t num_frames) { |
| uint32_t i; |
| uint8_t* mem = NULL; |
| DecodedFrame* frames = NULL; |
| const uint64_t rgba_size = |
| (uint64_t)image->canvas_width * kNumChannels * image->canvas_height; |
| const uint64_t total_size = (uint64_t)num_frames * rgba_size * sizeof(*mem); |
| const uint64_t total_frame_size = (uint64_t)num_frames * sizeof(*frames); |
| if (!CheckSizeForOverflow(total_size) || |
| !CheckSizeForOverflow(total_frame_size)) { |
| return 0; |
| } |
| mem = (uint8_t*)malloc((size_t)total_size); |
| frames = (DecodedFrame*)malloc((size_t)total_frame_size); |
| |
| if (mem == NULL || frames == NULL) { |
| free(mem); |
| free(frames); |
| return 0; |
| } |
| free(image->raw_mem); |
| image->num_frames = num_frames; |
| image->frames = frames; |
| for (i = 0; i < num_frames; ++i) { |
| frames[i].rgba = mem + i * rgba_size; |
| frames[i].duration = 0; |
| frames[i].is_key_frame = 0; |
| } |
| image->raw_mem = mem; |
| return 1; |
| } |
| |
| void ClearAnimatedImage(AnimatedImage* const image) { |
| if (image != NULL) { |
| free(image->raw_mem); |
| free(image->frames); |
| image->num_frames = 0; |
| image->frames = NULL; |
| image->raw_mem = NULL; |
| } |
| } |
| |
| #if defined(WEBP_HAVE_GIF) |
| // Clear the canvas to transparent. |
| static void ZeroFillCanvas(uint8_t* rgba, |
| uint32_t canvas_width, uint32_t canvas_height) { |
| memset(rgba, 0, canvas_width * kNumChannels * canvas_height); |
| } |
| |
| // Clear given frame rectangle to transparent. |
| static void ZeroFillFrameRect(uint8_t* rgba, int rgba_stride, int x_offset, |
| int y_offset, int width, int height) { |
| int j; |
| assert(width * kNumChannels <= rgba_stride); |
| rgba += y_offset * rgba_stride + x_offset * kNumChannels; |
| for (j = 0; j < height; ++j) { |
| memset(rgba, 0, width * kNumChannels); |
| rgba += rgba_stride; |
| } |
| } |
| |
| // Copy width * height pixels from 'src' to 'dst'. |
| static void CopyCanvas(const uint8_t* src, uint8_t* dst, |
| uint32_t width, uint32_t height) { |
| assert(src != NULL && dst != NULL); |
| memcpy(dst, src, width * kNumChannels * height); |
| } |
| |
| // Copy pixels in the given rectangle from 'src' to 'dst' honoring the 'stride'. |
| static void CopyFrameRectangle(const uint8_t* src, uint8_t* dst, int stride, |
| int x_offset, int y_offset, |
| int width, int height) { |
| int j; |
| const int width_in_bytes = width * kNumChannels; |
| const size_t offset = y_offset * stride + x_offset * kNumChannels; |
| assert(width_in_bytes <= stride); |
| src += offset; |
| dst += offset; |
| for (j = 0; j < height; ++j) { |
| memcpy(dst, src, width_in_bytes); |
| src += stride; |
| dst += stride; |
| } |
| } |
| #endif // WEBP_HAVE_GIF |
| |
| // Canonicalize all transparent pixels to transparent black to aid comparison. |
| static void CleanupTransparentPixels(uint32_t* rgba, |
| uint32_t width, uint32_t height) { |
| const uint32_t* const rgba_end = rgba + width * height; |
| while (rgba < rgba_end) { |
| const uint8_t alpha = (*rgba >> 24) & 0xff; |
| if (alpha == 0) { |
| *rgba = 0; |
| } |
| ++rgba; |
| } |
| } |
| |
| // Dump frame to a PAM file. Returns true on success. |
| static int DumpFrame(const char filename[], const char dump_folder[], |
| uint32_t frame_num, const uint8_t rgba[], |
| int canvas_width, int canvas_height) { |
| int ok = 0; |
| size_t max_len; |
| int y; |
| const char* base_name = NULL; |
| char* file_name = NULL; |
| FILE* f = NULL; |
| const char* row; |
| |
| if (dump_folder == NULL) dump_folder = "."; |
| |
| base_name = strrchr(filename, '/'); |
| base_name = (base_name == NULL) ? filename : base_name + 1; |
| max_len = strlen(dump_folder) + 1 + strlen(base_name) |
| + strlen("_frame_") + strlen(".pam") + 8; |
| file_name = (char*)malloc(max_len * sizeof(*file_name)); |
| if (file_name == NULL) goto End; |
| |
| if (snprintf(file_name, max_len, "%s/%s_frame_%d.pam", |
| dump_folder, base_name, frame_num) < 0) { |
| fprintf(stderr, "Error while generating file name\n"); |
| goto End; |
| } |
| |
| f = fopen(file_name, "wb"); |
| if (f == NULL) { |
| fprintf(stderr, "Error opening file for writing: %s\n", file_name); |
| ok = 0; |
| goto End; |
| } |
| if (fprintf(f, "P7\nWIDTH %d\nHEIGHT %d\n" |
| "DEPTH 4\nMAXVAL 255\nTUPLTYPE RGB_ALPHA\nENDHDR\n", |
| canvas_width, canvas_height) < 0) { |
| fprintf(stderr, "Write error for file %s\n", file_name); |
| goto End; |
| } |
| row = (const char*)rgba; |
| for (y = 0; y < canvas_height; ++y) { |
| if (fwrite(row, canvas_width * kNumChannels, 1, f) != 1) { |
| fprintf(stderr, "Error writing to file: %s\n", file_name); |
| goto End; |
| } |
| row += canvas_width * kNumChannels; |
| } |
| ok = 1; |
| End: |
| if (f != NULL) fclose(f); |
| free(file_name); |
| return ok; |
| } |
| |
| // ----------------------------------------------------------------------------- |
| // WebP Decoding. |
| |
| // Returns true if this is a valid WebP bitstream. |
| static int IsWebP(const WebPData* const webp_data) { |
| return (WebPGetInfo(webp_data->bytes, webp_data->size, NULL, NULL) != 0); |
| } |
| |
| // Read animated WebP bitstream 'webp_data' into 'AnimatedImage' struct. |
| static int ReadAnimatedWebP(const char filename[], |
| const WebPData* const webp_data, |
| AnimatedImage* const image, int dump_frames, |
| const char dump_folder[]) { |
| int ok = 0; |
| int dump_ok = 1; |
| uint32_t frame_index = 0; |
| int prev_frame_timestamp = 0; |
| WebPAnimDecoder* dec; |
| WebPAnimInfo anim_info; |
| |
| memset(image, 0, sizeof(*image)); |
| |
| dec = WebPAnimDecoderNew(webp_data, NULL); |
| if (dec == NULL) { |
| fprintf(stderr, "Error parsing image: %s\n", filename); |
| goto End; |
| } |
| |
| if (!WebPAnimDecoderGetInfo(dec, &anim_info)) { |
| fprintf(stderr, "Error getting global info about the animation\n"); |
| goto End; |
| } |
| |
| // Animation properties. |
| image->canvas_width = anim_info.canvas_width; |
| image->canvas_height = anim_info.canvas_height; |
| image->loop_count = anim_info.loop_count; |
| image->bgcolor = anim_info.bgcolor; |
| |
| // Allocate frames. |
| if (!AllocateFrames(image, anim_info.frame_count)) return 0; |
| |
| // Decode frames. |
| while (WebPAnimDecoderHasMoreFrames(dec)) { |
| DecodedFrame* curr_frame; |
| uint8_t* curr_rgba; |
| uint8_t* frame_rgba; |
| int timestamp; |
| |
| if (!WebPAnimDecoderGetNext(dec, &frame_rgba, ×tamp)) { |
| fprintf(stderr, "Error decoding frame #%u\n", frame_index); |
| goto End; |
| } |
| assert(frame_index < anim_info.frame_count); |
| curr_frame = &image->frames[frame_index]; |
| curr_rgba = curr_frame->rgba; |
| curr_frame->duration = timestamp - prev_frame_timestamp; |
| curr_frame->is_key_frame = 0; // Unused. |
| memcpy(curr_rgba, frame_rgba, |
| image->canvas_width * kNumChannels * image->canvas_height); |
| |
| // Needed only because we may want to compare with GIF later. |
| CleanupTransparentPixels((uint32_t*)curr_rgba, |
| image->canvas_width, image->canvas_height); |
| |
| if (dump_frames && dump_ok) { |
| dump_ok = DumpFrame(filename, dump_folder, frame_index, curr_rgba, |
| image->canvas_width, image->canvas_height); |
| if (!dump_ok) { // Print error once, but continue decode loop. |
| fprintf(stderr, "Error dumping frames to %s\n", dump_folder); |
| } |
| } |
| |
| ++frame_index; |
| prev_frame_timestamp = timestamp; |
| } |
| ok = dump_ok; |
| |
| End: |
| WebPAnimDecoderDelete(dec); |
| return ok; |
| } |
| |
| // ----------------------------------------------------------------------------- |
| // GIF Decoding. |
| |
| #if defined(WEBP_HAVE_GIF) |
| |
| // Returns true if this is a valid GIF bitstream. |
| static int IsGIF(const WebPData* const data) { |
| return data->size > GIF_STAMP_LEN && |
| (!memcmp(GIF_STAMP, data->bytes, GIF_STAMP_LEN) || |
| !memcmp(GIF87_STAMP, data->bytes, GIF_STAMP_LEN) || |
| !memcmp(GIF89_STAMP, data->bytes, GIF_STAMP_LEN)); |
| } |
| |
| // GIFLIB_MAJOR is only defined in libgif >= 4.2.0. |
| #if defined(GIFLIB_MAJOR) && defined(GIFLIB_MINOR) |
| # define LOCAL_GIF_VERSION ((GIFLIB_MAJOR << 8) | GIFLIB_MINOR) |
| # define LOCAL_GIF_PREREQ(maj, min) \ |
| (LOCAL_GIF_VERSION >= (((maj) << 8) | (min))) |
| #else |
| # define LOCAL_GIF_VERSION 0 |
| # define LOCAL_GIF_PREREQ(maj, min) 0 |
| #endif |
| |
| #if !LOCAL_GIF_PREREQ(5, 0) |
| |
| // Added in v5.0 |
| typedef struct { |
| int DisposalMode; |
| #define DISPOSAL_UNSPECIFIED 0 // No disposal specified |
| #define DISPOSE_DO_NOT 1 // Leave image in place |
| #define DISPOSE_BACKGROUND 2 // Set area to background color |
| #define DISPOSE_PREVIOUS 3 // Restore to previous content |
| int UserInputFlag; // User confirmation required before disposal |
| int DelayTime; // Pre-display delay in 0.01sec units |
| int TransparentColor; // Palette index for transparency, -1 if none |
| #define NO_TRANSPARENT_COLOR -1 |
| } GraphicsControlBlock; |
| |
| static int DGifExtensionToGCB(const size_t GifExtensionLength, |
| const GifByteType* GifExtension, |
| GraphicsControlBlock* gcb) { |
| if (GifExtensionLength != 4) { |
| return GIF_ERROR; |
| } |
| gcb->DisposalMode = (GifExtension[0] >> 2) & 0x07; |
| gcb->UserInputFlag = (GifExtension[0] & 0x02) != 0; |
| gcb->DelayTime = GifExtension[1] | (GifExtension[2] << 8); |
| if (GifExtension[0] & 0x01) { |
| gcb->TransparentColor = (int)GifExtension[3]; |
| } else { |
| gcb->TransparentColor = NO_TRANSPARENT_COLOR; |
| } |
| return GIF_OK; |
| } |
| |
| static int DGifSavedExtensionToGCB(GifFileType* GifFile, int ImageIndex, |
| GraphicsControlBlock* gcb) { |
| int i; |
| if (ImageIndex < 0 || ImageIndex > GifFile->ImageCount - 1) { |
| return GIF_ERROR; |
| } |
| gcb->DisposalMode = DISPOSAL_UNSPECIFIED; |
| gcb->UserInputFlag = 0; |
| gcb->DelayTime = 0; |
| gcb->TransparentColor = NO_TRANSPARENT_COLOR; |
| |
| for (i = 0; i < GifFile->SavedImages[ImageIndex].ExtensionBlockCount; i++) { |
| ExtensionBlock* ep = &GifFile->SavedImages[ImageIndex].ExtensionBlocks[i]; |
| if (ep->Function == GRAPHICS_EXT_FUNC_CODE) { |
| return DGifExtensionToGCB( |
| ep->ByteCount, (const GifByteType*)ep->Bytes, gcb); |
| } |
| } |
| return GIF_ERROR; |
| } |
| |
| #define CONTINUE_EXT_FUNC_CODE 0x00 |
| |
| // Signature was changed in v5.0 |
| #define DGifOpenFileName(a, b) DGifOpenFileName(a) |
| |
| #endif // !LOCAL_GIF_PREREQ(5, 0) |
| |
| // Signature changed in v5.1 |
| #if !LOCAL_GIF_PREREQ(5, 1) |
| #define DGifCloseFile(a, b) DGifCloseFile(a) |
| #endif |
| |
| static 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) |
| const char* error_str = |
| GifErrorString((gif == NULL) ? gif_error : gif->Error); |
| #else |
| const char* error_str = 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 |
| } |
| |
| static int IsKeyFrameGIF(const GifImageDesc* prev_desc, int prev_dispose, |
| const DecodedFrame* const prev_frame, |
| int canvas_width, int canvas_height) { |
| if (prev_frame == NULL) return 1; |
| if (prev_dispose == DISPOSE_BACKGROUND) { |
| if (IsFullFrame(prev_desc->Width, prev_desc->Height, |
| canvas_width, canvas_height)) { |
| return 1; |
| } |
| if (prev_frame->is_key_frame) return 1; |
| } |
| return 0; |
| } |
| |
| static int GetTransparentIndexGIF(GifFileType* gif) { |
| GraphicsControlBlock first_gcb; |
| memset(&first_gcb, 0, sizeof(first_gcb)); |
| DGifSavedExtensionToGCB(gif, 0, &first_gcb); |
| return first_gcb.TransparentColor; |
| } |
| |
| static uint32_t GetBackgroundColorGIF(GifFileType* gif) { |
| const int transparent_index = GetTransparentIndexGIF(gif); |
| const ColorMapObject* const color_map = gif->SColorMap; |
| if (transparent_index != NO_TRANSPARENT_COLOR && |
| gif->SBackGroundColor == transparent_index) { |
| return 0x00000000; // Special case: transparent black. |
| } else if (color_map == NULL || color_map->Colors == NULL |
| || gif->SBackGroundColor >= color_map->ColorCount) { |
| return 0xffffffff; // Invalid: assume white. |
| } else { |
| const GifColorType color = color_map->Colors[gif->SBackGroundColor]; |
| return (0xff << 24) | |
| (color.Red << 16) | |
| (color.Green << 8) | |
| (color.Blue << 0); |
| } |
| } |
| |
| // Find appropriate app extension and get loop count from the next extension. |
| // We use Chrome's interpretation of the 'loop_count' semantics: |
| // if not present -> loop once |
| // if present and loop_count == 0, return 0 ('infinite'). |
| // if present and loop_count != 0, it's the number of *extra* loops |
| // so we need to return loop_count + 1 as total loop number. |
| static uint32_t GetLoopCountGIF(const GifFileType* const gif) { |
| int i; |
| for (i = 0; i < gif->ImageCount; ++i) { |
| const SavedImage* const image = &gif->SavedImages[i]; |
| int j; |
| for (j = 0; (j + 1) < image->ExtensionBlockCount; ++j) { |
| const ExtensionBlock* const eb1 = image->ExtensionBlocks + j; |
| const ExtensionBlock* const eb2 = image->ExtensionBlocks + j + 1; |
| const char* const signature = (const char*)eb1->Bytes; |
| const int signature_is_ok = |
| (eb1->Function == APPLICATION_EXT_FUNC_CODE) && |
| (eb1->ByteCount == 11) && |
| (!memcmp(signature, "NETSCAPE2.0", 11) || |
| !memcmp(signature, "ANIMEXTS1.0", 11)); |
| if (signature_is_ok && |
| eb2->Function == CONTINUE_EXT_FUNC_CODE && eb2->ByteCount >= 3 && |
| eb2->Bytes[0] == 1) { |
| const uint32_t extra_loop = ((uint32_t)(eb2->Bytes[2]) << 8) + |
| ((uint32_t)(eb2->Bytes[1]) << 0); |
| return (extra_loop > 0) ? extra_loop + 1 : 0; |
| } |
| } |
| } |
| return 1; // Default. |
| } |
| |
| // Get duration of 'n'th frame in milliseconds. |
| static int GetFrameDurationGIF(GifFileType* gif, int n) { |
| GraphicsControlBlock gcb; |
| memset(&gcb, 0, sizeof(gcb)); |
| DGifSavedExtensionToGCB(gif, n, &gcb); |
| return gcb.DelayTime * 10; |
| } |
| |
| // Returns true if frame 'target' completely covers 'covered'. |
| static int CoversFrameGIF(const GifImageDesc* const target, |
| const GifImageDesc* const covered) { |
| return target->Left <= covered->Left && |
| covered->Left + covered->Width <= target->Left + target->Width && |
| target->Top <= covered->Top && |
| covered->Top + covered->Height <= target->Top + target->Height; |
| } |
| |
| static void RemapPixelsGIF(const uint8_t* const src, |
| const ColorMapObject* const cmap, |
| int transparent_color, int len, uint8_t* dst) { |
| int i; |
| for (i = 0; i < len; ++i) { |
| if (src[i] != transparent_color) { |
| // If a pixel in the current frame is transparent, we don't modify it, so |
| // that we can see-through the corresponding pixel from an earlier frame. |
| const GifColorType c = cmap->Colors[src[i]]; |
| dst[4 * i + 0] = c.Red; |
| dst[4 * i + 1] = c.Green; |
| dst[4 * i + 2] = c.Blue; |
| dst[4 * i + 3] = 0xff; |
| } |
| } |
| } |
| |
| static int ReadFrameGIF(const SavedImage* const gif_image, |
| const ColorMapObject* cmap, int transparent_color, |
| int out_stride, uint8_t* const dst) { |
| const GifImageDesc* image_desc = &gif_image->ImageDesc; |
| const uint8_t* in; |
| uint8_t* out; |
| int j; |
| |
| if (image_desc->ColorMap) cmap = image_desc->ColorMap; |
| |
| if (cmap == NULL || cmap->ColorCount != (1 << cmap->BitsPerPixel)) { |
| fprintf(stderr, "Potentially corrupt color map.\n"); |
| return 0; |
| } |
| |
| in = (const uint8_t*)gif_image->RasterBits; |
| out = dst + image_desc->Top * out_stride + image_desc->Left * kNumChannels; |
| |
| for (j = 0; j < image_desc->Height; ++j) { |
| RemapPixelsGIF(in, cmap, transparent_color, image_desc->Width, out); |
| in += image_desc->Width; |
| out += out_stride; |
| } |
| return 1; |
| } |
| |
| // Read animated GIF bitstream from 'filename' into 'AnimatedImage' struct. |
| static int ReadAnimatedGIF(const char filename[], AnimatedImage* const image, |
| int dump_frames, const char dump_folder[]) { |
| uint32_t frame_count; |
| uint32_t canvas_width, canvas_height; |
| uint32_t i; |
| int gif_error; |
| GifFileType* gif; |
| |
| gif = DGifOpenFileName(filename, NULL); |
| if (gif == NULL) { |
| fprintf(stderr, "Could not read file: %s.\n", filename); |
| return 0; |
| } |
| |
| gif_error = DGifSlurp(gif); |
| if (gif_error != GIF_OK) { |
| fprintf(stderr, "Could not parse image: %s.\n", filename); |
| GIFDisplayError(gif, gif_error); |
| DGifCloseFile(gif, NULL); |
| return 0; |
| } |
| |
| // Animation properties. |
| image->canvas_width = (uint32_t)gif->SWidth; |
| image->canvas_height = (uint32_t)gif->SHeight; |
| if (image->canvas_width > MAX_CANVAS_SIZE || |
| image->canvas_height > MAX_CANVAS_SIZE) { |
| fprintf(stderr, "Invalid canvas dimension: %d x %d\n", |
| image->canvas_width, image->canvas_height); |
| DGifCloseFile(gif, NULL); |
| return 0; |
| } |
| image->loop_count = GetLoopCountGIF(gif); |
| image->bgcolor = GetBackgroundColorGIF(gif); |
| |
| frame_count = (uint32_t)gif->ImageCount; |
| if (frame_count == 0) { |
| DGifCloseFile(gif, NULL); |
| return 0; |
| } |
| |
| if (image->canvas_width == 0 || image->canvas_height == 0) { |
| image->canvas_width = gif->SavedImages[0].ImageDesc.Width; |
| image->canvas_height = gif->SavedImages[0].ImageDesc.Height; |
| gif->SavedImages[0].ImageDesc.Left = 0; |
| gif->SavedImages[0].ImageDesc.Top = 0; |
| if (image->canvas_width == 0 || image->canvas_height == 0) { |
| fprintf(stderr, "Invalid canvas size in GIF.\n"); |
| DGifCloseFile(gif, NULL); |
| return 0; |
| } |
| } |
| // Allocate frames. |
| AllocateFrames(image, frame_count); |
| |
| canvas_width = image->canvas_width; |
| canvas_height = image->canvas_height; |
| |
| // Decode and reconstruct frames. |
| for (i = 0; i < frame_count; ++i) { |
| const int canvas_width_in_bytes = canvas_width * kNumChannels; |
| const SavedImage* const curr_gif_image = &gif->SavedImages[i]; |
| GraphicsControlBlock curr_gcb; |
| DecodedFrame* curr_frame; |
| uint8_t* curr_rgba; |
| |
| memset(&curr_gcb, 0, sizeof(curr_gcb)); |
| DGifSavedExtensionToGCB(gif, i, &curr_gcb); |
| |
| curr_frame = &image->frames[i]; |
| curr_rgba = curr_frame->rgba; |
| curr_frame->duration = GetFrameDurationGIF(gif, i); |
| // Force frames with a small or no duration to 100ms to be consistent |
| // with web browsers and other transcoding tools (like gif2webp itself). |
| if (curr_frame->duration <= 10) curr_frame->duration = 100; |
| |
| if (i == 0) { // Initialize as transparent. |
| curr_frame->is_key_frame = 1; |
| ZeroFillCanvas(curr_rgba, canvas_width, canvas_height); |
| } else { |
| DecodedFrame* const prev_frame = &image->frames[i - 1]; |
| const GifImageDesc* const prev_desc = &gif->SavedImages[i - 1].ImageDesc; |
| GraphicsControlBlock prev_gcb; |
| memset(&prev_gcb, 0, sizeof(prev_gcb)); |
| DGifSavedExtensionToGCB(gif, i - 1, &prev_gcb); |
| |
| curr_frame->is_key_frame = |
| IsKeyFrameGIF(prev_desc, prev_gcb.DisposalMode, prev_frame, |
| canvas_width, canvas_height); |
| |
| if (curr_frame->is_key_frame) { // Initialize as transparent. |
| ZeroFillCanvas(curr_rgba, canvas_width, canvas_height); |
| } else { |
| int prev_frame_disposed, curr_frame_opaque; |
| int prev_frame_completely_covered; |
| // Initialize with previous canvas. |
| uint8_t* const prev_rgba = image->frames[i - 1].rgba; |
| CopyCanvas(prev_rgba, curr_rgba, canvas_width, canvas_height); |
| |
| // Dispose previous frame rectangle. |
| prev_frame_disposed = |
| (prev_gcb.DisposalMode == DISPOSE_BACKGROUND || |
| prev_gcb.DisposalMode == DISPOSE_PREVIOUS); |
| curr_frame_opaque = |
| (curr_gcb.TransparentColor == NO_TRANSPARENT_COLOR); |
| prev_frame_completely_covered = |
| curr_frame_opaque && |
| CoversFrameGIF(&curr_gif_image->ImageDesc, prev_desc); |
| |
| if (prev_frame_disposed && !prev_frame_completely_covered) { |
| switch (prev_gcb.DisposalMode) { |
| case DISPOSE_BACKGROUND: { |
| ZeroFillFrameRect(curr_rgba, canvas_width_in_bytes, |
| prev_desc->Left, prev_desc->Top, |
| prev_desc->Width, prev_desc->Height); |
| break; |
| } |
| case DISPOSE_PREVIOUS: { |
| int src_frame_num = i - 2; |
| while (src_frame_num >= 0) { |
| GraphicsControlBlock src_frame_gcb; |
| memset(&src_frame_gcb, 0, sizeof(src_frame_gcb)); |
| DGifSavedExtensionToGCB(gif, src_frame_num, &src_frame_gcb); |
| if (src_frame_gcb.DisposalMode != DISPOSE_PREVIOUS) break; |
| --src_frame_num; |
| } |
| if (src_frame_num >= 0) { |
| // Restore pixels inside previous frame rectangle to |
| // corresponding pixels in source canvas. |
| uint8_t* const src_frame_rgba = |
| image->frames[src_frame_num].rgba; |
| CopyFrameRectangle(src_frame_rgba, curr_rgba, |
| canvas_width_in_bytes, |
| prev_desc->Left, prev_desc->Top, |
| prev_desc->Width, prev_desc->Height); |
| } else { |
| // Source canvas doesn't exist. So clear previous frame |
| // rectangle to background. |
| ZeroFillFrameRect(curr_rgba, canvas_width_in_bytes, |
| prev_desc->Left, prev_desc->Top, |
| prev_desc->Width, prev_desc->Height); |
| } |
| break; |
| } |
| default: |
| break; // Nothing to do. |
| } |
| } |
| } |
| } |
| |
| // Decode current frame. |
| if (!ReadFrameGIF(curr_gif_image, gif->SColorMap, curr_gcb.TransparentColor, |
| canvas_width_in_bytes, curr_rgba)) { |
| DGifCloseFile(gif, NULL); |
| return 0; |
| } |
| |
| if (dump_frames) { |
| if (!DumpFrame(filename, dump_folder, i, curr_rgba, |
| canvas_width, canvas_height)) { |
| DGifCloseFile(gif, NULL); |
| return 0; |
| } |
| } |
| } |
| DGifCloseFile(gif, NULL); |
| return 1; |
| } |
| |
| #else |
| |
| static int IsGIF(const WebPData* const data) { |
| (void)data; |
| return 0; |
| } |
| |
| static int ReadAnimatedGIF(const char filename[], AnimatedImage* const image, |
| int dump_frames, const char dump_folder[]) { |
| (void)filename; |
| (void)image; |
| (void)dump_frames; |
| (void)dump_folder; |
| fprintf(stderr, "GIF support not compiled. Please install the libgif-dev " |
| "package before building.\n"); |
| return 0; |
| } |
| |
| #endif // WEBP_HAVE_GIF |
| |
| // ----------------------------------------------------------------------------- |
| |
| int ReadAnimatedImage(const char filename[], AnimatedImage* const image, |
| int dump_frames, const char dump_folder[]) { |
| int ok = 0; |
| WebPData webp_data; |
| |
| WebPDataInit(&webp_data); |
| memset(image, 0, sizeof(*image)); |
| |
| if (!ImgIoUtilReadFile(filename, &webp_data.bytes, &webp_data.size)) { |
| fprintf(stderr, "Error reading file: %s\n", filename); |
| return 0; |
| } |
| |
| if (IsWebP(&webp_data)) { |
| ok = ReadAnimatedWebP(filename, &webp_data, image, dump_frames, |
| dump_folder); |
| } else if (IsGIF(&webp_data)) { |
| ok = ReadAnimatedGIF(filename, image, dump_frames, dump_folder); |
| } else { |
| fprintf(stderr, |
| "Unknown file type: %s. Supported file types are WebP and GIF\n", |
| filename); |
| ok = 0; |
| } |
| if (!ok) ClearAnimatedImage(image); |
| WebPDataClear(&webp_data); |
| return ok; |
| } |
| |
| static void Accumulate(double v1, double v2, double* const max_diff, |
| double* const sse) { |
| const double diff = fabs(v1 - v2); |
| if (diff > *max_diff) *max_diff = diff; |
| *sse += diff * diff; |
| } |
| |
| void GetDiffAndPSNR(const uint8_t rgba1[], const uint8_t rgba2[], |
| uint32_t width, uint32_t height, int premultiply, |
| int* const max_diff, double* const psnr) { |
| const uint32_t stride = width * kNumChannels; |
| const int kAlphaChannel = kNumChannels - 1; |
| double f_max_diff = 0.; |
| double sse = 0.; |
| uint32_t x, y; |
| for (y = 0; y < height; ++y) { |
| for (x = 0; x < stride; x += kNumChannels) { |
| int k; |
| const size_t offset = (size_t)y * stride + x; |
| const int alpha1 = rgba1[offset + kAlphaChannel]; |
| const int alpha2 = rgba2[offset + kAlphaChannel]; |
| Accumulate(alpha1, alpha2, &f_max_diff, &sse); |
| if (!premultiply) { |
| for (k = 0; k < kAlphaChannel; ++k) { |
| Accumulate(rgba1[offset + k], rgba2[offset + k], &f_max_diff, &sse); |
| } |
| } else { |
| // premultiply R/G/B channels with alpha value |
| for (k = 0; k < kAlphaChannel; ++k) { |
| Accumulate(rgba1[offset + k] * alpha1 / 255., |
| rgba2[offset + k] * alpha2 / 255., |
| &f_max_diff, &sse); |
| } |
| } |
| } |
| } |
| *max_diff = (int)f_max_diff; |
| if (*max_diff == 0) { |
| *psnr = 99.; // PSNR when images are identical. |
| } else { |
| sse /= stride * height; |
| *psnr = 4.3429448 * log(255. * 255. / sse); |
| } |
| } |
| |
| void GetAnimatedImageVersions(int* const decoder_version, |
| int* const demux_version) { |
| *decoder_version = WebPGetDecoderVersion(); |
| *demux_version = WebPGetDemuxVersion(); |
| } |
