diff options
Diffstat (limited to 'media/libjxl/src/lib/extras/dec/gif.cc')
| -rw-r--r-- | media/libjxl/src/lib/extras/dec/gif.cc | 414 |
1 files changed, 414 insertions, 0 deletions
diff --git a/media/libjxl/src/lib/extras/dec/gif.cc b/media/libjxl/src/lib/extras/dec/gif.cc new file mode 100644 index 0000000000..5167bf5fa0 --- /dev/null +++ b/media/libjxl/src/lib/extras/dec/gif.cc @@ -0,0 +1,414 @@ +// Copyright (c) the JPEG XL Project Authors. All rights reserved. +// +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +#include "lib/extras/dec/gif.h" + +#include <gif_lib.h> +#include <string.h> + +#include <memory> +#include <utility> +#include <vector> + +#include "jxl/codestream_header.h" +#include "lib/jxl/base/compiler_specific.h" +#include "lib/jxl/sanitizers.h" + +namespace jxl { +namespace extras { + +namespace { + +struct ReadState { + Span<const uint8_t> bytes; +}; + +struct DGifCloser { + void operator()(GifFileType* const ptr) const { DGifCloseFile(ptr, nullptr); } +}; +using GifUniquePtr = std::unique_ptr<GifFileType, DGifCloser>; + +struct PackedRgba { + uint8_t r, g, b, a; +}; + +struct PackedRgb { + uint8_t r, g, b; +}; + +// Gif does not support partial transparency, so this considers any nonzero +// alpha channel value as opaque. +bool AllOpaque(const PackedImage& color) { + for (size_t y = 0; y < color.ysize; ++y) { + const PackedRgba* const JXL_RESTRICT row = + static_cast<const PackedRgba*>(color.pixels()) + y * color.xsize; + for (size_t x = 0; x < color.xsize; ++x) { + if (row[x].a == 0) { + return false; + } + } + } + return true; +} + +void ensure_have_alpha(PackedFrame* frame) { + if (!frame->extra_channels.empty()) return; + const JxlPixelFormat alpha_format{ + /*num_channels=*/1u, + /*data_type=*/JXL_TYPE_UINT8, + /*endianness=*/JXL_NATIVE_ENDIAN, + /*align=*/0, + }; + frame->extra_channels.emplace_back(frame->color.xsize, frame->color.ysize, + alpha_format); + // We need to set opaque-by-default. + std::fill_n(static_cast<uint8_t*>(frame->extra_channels[0].pixels()), + frame->color.xsize * frame->color.ysize, 255u); +} + +} // namespace + +Status DecodeImageGIF(Span<const uint8_t> bytes, const ColorHints& color_hints, + const SizeConstraints& constraints, + PackedPixelFile* ppf) { + int error = GIF_OK; + ReadState state = {bytes}; + const auto ReadFromSpan = [](GifFileType* const gif, GifByteType* const bytes, + int n) { + ReadState* const state = reinterpret_cast<ReadState*>(gif->UserData); + // giflib API requires the input size `n` to be signed int. + if (static_cast<size_t>(n) > state->bytes.size()) { + n = state->bytes.size(); + } + memcpy(bytes, state->bytes.data(), n); + state->bytes.remove_prefix(n); + return n; + }; + GifUniquePtr gif(DGifOpen(&state, ReadFromSpan, &error)); + if (gif == nullptr) { + if (error == D_GIF_ERR_NOT_GIF_FILE) { + // Not an error. + return false; + } else { + return JXL_FAILURE("Failed to read GIF: %s", GifErrorString(error)); + } + } + error = DGifSlurp(gif.get()); + if (error != GIF_OK) { + return JXL_FAILURE("Failed to read GIF: %s", GifErrorString(gif->Error)); + } + + msan::UnpoisonMemory(gif.get(), sizeof(*gif)); + if (gif->SColorMap) { + msan::UnpoisonMemory(gif->SColorMap, sizeof(*gif->SColorMap)); + msan::UnpoisonMemory( + gif->SColorMap->Colors, + sizeof(*gif->SColorMap->Colors) * gif->SColorMap->ColorCount); + } + msan::UnpoisonMemory(gif->SavedImages, + sizeof(*gif->SavedImages) * gif->ImageCount); + + JXL_RETURN_IF_ERROR( + VerifyDimensions<uint32_t>(&constraints, gif->SWidth, gif->SHeight)); + uint64_t total_pixel_count = + static_cast<uint64_t>(gif->SWidth) * gif->SHeight; + for (int i = 0; i < gif->ImageCount; ++i) { + const SavedImage& image = gif->SavedImages[i]; + uint32_t w = image.ImageDesc.Width; + uint32_t h = image.ImageDesc.Height; + JXL_RETURN_IF_ERROR(VerifyDimensions<uint32_t>(&constraints, w, h)); + uint64_t pixel_count = static_cast<uint64_t>(w) * h; + if (total_pixel_count + pixel_count < total_pixel_count) { + return JXL_FAILURE("Image too big"); + } + total_pixel_count += pixel_count; + if (total_pixel_count > constraints.dec_max_pixels) { + return JXL_FAILURE("Image too big"); + } + } + + if (!gif->SColorMap) { + for (int i = 0; i < gif->ImageCount; ++i) { + if (!gif->SavedImages[i].ImageDesc.ColorMap) { + return JXL_FAILURE("Missing GIF color map"); + } + } + } + + if (gif->ImageCount > 1) { + ppf->info.have_animation = true; + // Delays in GIF are specified in 100ths of a second. + ppf->info.animation.tps_numerator = 100; + ppf->info.animation.tps_denominator = 1; + } + + ppf->frames.clear(); + ppf->frames.reserve(gif->ImageCount); + + ppf->info.xsize = gif->SWidth; + ppf->info.ysize = gif->SHeight; + ppf->info.bits_per_sample = 8; + ppf->info.exponent_bits_per_sample = 0; + // alpha_bits is later set to 8 if we find a frame with transparent pixels. + ppf->info.alpha_bits = 0; + ppf->info.alpha_exponent_bits = 0; + JXL_RETURN_IF_ERROR(ApplyColorHints(color_hints, /*color_already_set=*/false, + /*is_gray=*/false, ppf)); + + ppf->info.num_color_channels = 3; + + // Pixel format for the 'canvas' onto which we paint + // the (potentially individually cropped) GIF frames + // of an animation. + const JxlPixelFormat canvas_format{ + /*num_channels=*/4u, + /*data_type=*/JXL_TYPE_UINT8, + /*endianness=*/JXL_NATIVE_ENDIAN, + /*align=*/0, + }; + + // Pixel format for the JXL PackedFrame that goes into the + // PackedPixelFile. Here, we use 3 color channels, and provide + // the alpha channel as an extra_channel wherever it is used. + const JxlPixelFormat packed_frame_format{ + /*num_channels=*/3u, + /*data_type=*/JXL_TYPE_UINT8, + /*endianness=*/JXL_NATIVE_ENDIAN, + /*align=*/0, + }; + + GifColorType background_color; + if (gif->SColorMap == nullptr || + gif->SBackGroundColor >= gif->SColorMap->ColorCount) { + background_color = {0, 0, 0}; + } else { + background_color = gif->SColorMap->Colors[gif->SBackGroundColor]; + } + const PackedRgba background_rgba{background_color.Red, background_color.Green, + background_color.Blue, 0}; + PackedFrame canvas(gif->SWidth, gif->SHeight, canvas_format); + std::fill_n(static_cast<PackedRgba*>(canvas.color.pixels()), + canvas.color.xsize * canvas.color.ysize, background_rgba); + Rect canvas_rect{0, 0, canvas.color.xsize, canvas.color.ysize}; + + Rect previous_rect_if_restore_to_background; + + bool replace = true; + bool last_base_was_none = true; + for (int i = 0; i < gif->ImageCount; ++i) { + const SavedImage& image = gif->SavedImages[i]; + msan::UnpoisonMemory(image.RasterBits, sizeof(*image.RasterBits) * + image.ImageDesc.Width * + image.ImageDesc.Height); + const Rect image_rect(image.ImageDesc.Left, image.ImageDesc.Top, + image.ImageDesc.Width, image.ImageDesc.Height); + + Rect total_rect; + if (previous_rect_if_restore_to_background.xsize() != 0 || + previous_rect_if_restore_to_background.ysize() != 0) { + const size_t xbegin = std::min( + image_rect.x0(), previous_rect_if_restore_to_background.x0()); + const size_t ybegin = std::min( + image_rect.y0(), previous_rect_if_restore_to_background.y0()); + const size_t xend = + std::max(image_rect.x0() + image_rect.xsize(), + previous_rect_if_restore_to_background.x0() + + previous_rect_if_restore_to_background.xsize()); + const size_t yend = + std::max(image_rect.y0() + image_rect.ysize(), + previous_rect_if_restore_to_background.y0() + + previous_rect_if_restore_to_background.ysize()); + total_rect = Rect(xbegin, ybegin, xend - xbegin, yend - ybegin); + previous_rect_if_restore_to_background = Rect(); + replace = true; + } else { + total_rect = image_rect; + replace = false; + } + if (!image_rect.IsInside(canvas_rect)) { + return JXL_FAILURE("GIF frame extends outside of the canvas"); + } + + // Allocates the frame buffer. + ppf->frames.emplace_back(total_rect.xsize(), total_rect.ysize(), + packed_frame_format); + PackedFrame* frame = &ppf->frames.back(); + + // We cannot tell right from the start whether there will be a + // need for an alpha channel. This is discovered only as soon as + // we see a transparent pixel. We hence initialize alpha lazily. + auto set_pixel_alpha = [&frame](size_t x, size_t y, uint8_t a) { + // If we do not have an alpha-channel and a==255 (fully opaque), + // we can skip setting this pixel-value and rely on + // "no alpha channel = no transparency". + if (a == 255 && !frame->extra_channels.empty()) return; + ensure_have_alpha(frame); + static_cast<uint8_t*>( + frame->extra_channels[0].pixels())[y * frame->color.xsize + x] = a; + }; + + const ColorMapObject* const color_map = + image.ImageDesc.ColorMap ? image.ImageDesc.ColorMap : gif->SColorMap; + JXL_CHECK(color_map); + msan::UnpoisonMemory(color_map, sizeof(*color_map)); + msan::UnpoisonMemory(color_map->Colors, + sizeof(*color_map->Colors) * color_map->ColorCount); + GraphicsControlBlock gcb; + DGifSavedExtensionToGCB(gif.get(), i, &gcb); + msan::UnpoisonMemory(&gcb, sizeof(gcb)); + bool is_full_size = total_rect.x0() == 0 && total_rect.y0() == 0 && + total_rect.xsize() == canvas.color.xsize && + total_rect.ysize() == canvas.color.ysize; + if (ppf->info.have_animation) { + frame->frame_info.duration = gcb.DelayTime; + frame->frame_info.layer_info.have_crop = static_cast<int>(!is_full_size); + frame->frame_info.layer_info.crop_x0 = total_rect.x0(); + frame->frame_info.layer_info.crop_y0 = total_rect.y0(); + frame->frame_info.layer_info.xsize = frame->color.xsize; + frame->frame_info.layer_info.ysize = frame->color.ysize; + if (last_base_was_none) { + replace = true; + } + frame->frame_info.layer_info.blend_info.blendmode = + replace ? JXL_BLEND_REPLACE : JXL_BLEND_BLEND; + // We always only reference at most the last frame + frame->frame_info.layer_info.blend_info.source = + last_base_was_none ? 0u : 1u; + frame->frame_info.layer_info.blend_info.clamp = 1; + frame->frame_info.layer_info.blend_info.alpha = 0; + // TODO(veluca): this could in principle be implemented. + if (last_base_was_none && + (total_rect.x0() != 0 || total_rect.y0() != 0 || + total_rect.xsize() != canvas.color.xsize || + total_rect.ysize() != canvas.color.ysize || !replace)) { + return JXL_FAILURE( + "GIF with dispose-to-0 is not supported for non-full or " + "blended frames"); + } + switch (gcb.DisposalMode) { + case DISPOSE_DO_NOT: + case DISPOSE_BACKGROUND: + frame->frame_info.layer_info.save_as_reference = 1u; + last_base_was_none = false; + break; + case DISPOSE_PREVIOUS: + frame->frame_info.layer_info.save_as_reference = 0u; + break; + default: + frame->frame_info.layer_info.save_as_reference = 0u; + last_base_was_none = true; + } + } + + // Update the canvas by creating a copy first. + PackedImage new_canvas_image(canvas.color.xsize, canvas.color.ysize, + canvas.color.format); + memcpy(new_canvas_image.pixels(), canvas.color.pixels(), + new_canvas_image.pixels_size); + for (size_t y = 0, byte_index = 0; y < image_rect.ysize(); ++y) { + // Assumes format.align == 0. row points to the beginning of the y row in + // the image_rect. + PackedRgba* row = static_cast<PackedRgba*>(new_canvas_image.pixels()) + + (y + image_rect.y0()) * new_canvas_image.xsize + + image_rect.x0(); + for (size_t x = 0; x < image_rect.xsize(); ++x, ++byte_index) { + const GifByteType byte = image.RasterBits[byte_index]; + if (byte >= color_map->ColorCount) { + return JXL_FAILURE("GIF color is out of bounds"); + } + + if (byte == gcb.TransparentColor) continue; + GifColorType color = color_map->Colors[byte]; + row[x].r = color.Red; + row[x].g = color.Green; + row[x].b = color.Blue; + row[x].a = 255; + } + } + const PackedImage& sub_frame_image = frame->color; + if (replace) { + // Copy from the new canvas image to the subframe + for (size_t y = 0; y < total_rect.ysize(); ++y) { + const PackedRgba* row_in = + static_cast<const PackedRgba*>(new_canvas_image.pixels()) + + (y + total_rect.y0()) * new_canvas_image.xsize + total_rect.x0(); + PackedRgb* row_out = static_cast<PackedRgb*>(sub_frame_image.pixels()) + + y * sub_frame_image.xsize; + for (size_t x = 0; x < sub_frame_image.xsize; ++x) { + row_out[x].r = row_in[x].r; + row_out[x].g = row_in[x].g; + row_out[x].b = row_in[x].b; + set_pixel_alpha(x, y, row_in[x].a); + } + } + } else { + for (size_t y = 0, byte_index = 0; y < image_rect.ysize(); ++y) { + // Assumes format.align == 0 + PackedRgb* row = static_cast<PackedRgb*>(sub_frame_image.pixels()) + + y * sub_frame_image.xsize; + for (size_t x = 0; x < image_rect.xsize(); ++x, ++byte_index) { + const GifByteType byte = image.RasterBits[byte_index]; + if (byte > color_map->ColorCount) { + return JXL_FAILURE("GIF color is out of bounds"); + } + if (byte == gcb.TransparentColor) { + row[x].r = 0; + row[x].g = 0; + row[x].b = 0; + set_pixel_alpha(x, y, 0); + continue; + } + GifColorType color = color_map->Colors[byte]; + row[x].r = color.Red; + row[x].g = color.Green; + row[x].b = color.Blue; + set_pixel_alpha(x, y, 255); + } + } + } + + if (!frame->extra_channels.empty()) { + ppf->info.alpha_bits = 8; + } + + switch (gcb.DisposalMode) { + case DISPOSE_DO_NOT: + canvas.color = std::move(new_canvas_image); + break; + + case DISPOSE_BACKGROUND: + std::fill_n(static_cast<PackedRgba*>(canvas.color.pixels()), + canvas.color.xsize * canvas.color.ysize, background_rgba); + previous_rect_if_restore_to_background = image_rect; + break; + + case DISPOSE_PREVIOUS: + break; + + case DISPOSAL_UNSPECIFIED: + default: + std::fill_n(static_cast<PackedRgba*>(canvas.color.pixels()), + canvas.color.xsize * canvas.color.ysize, background_rgba); + } + } + // Finally, if any frame has an alpha-channel, every frame will need + // to have an alpha-channel. + bool seen_alpha = false; + for (const PackedFrame& frame : ppf->frames) { + if (!frame.extra_channels.empty()) { + seen_alpha = true; + break; + } + } + if (seen_alpha) { + for (PackedFrame& frame : ppf->frames) { + ensure_have_alpha(&frame); + } + } + return true; +} + +} // namespace extras +} // namespace jxl |