зеркало из https://github.com/mozilla/gecko-dev.git
Bug 1247152 (Part 2) - Remove even more code from the GIF decoder. r=edwin
This commit is contained in:
Seth Fowler
Родитель
875464424a
Коммит
3978c77cb6
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@ -29,7 +29,6 @@ typedef enum {
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gif_global_colormap,
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gif_image_start,
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gif_image_header,
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gif_image_header_continue,
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gif_image_colormap,
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gif_lzw_start,
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gif_lzw,
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@ -70,10 +69,6 @@ typedef struct gif_struct {
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int64_t pixels_remaining; // Pixels remaining to be output.
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// Parameters for image frame currently being decoded
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unsigned x_offset, y_offset; // With respect to "screen" origin
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unsigned height, width;
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unsigned clamped_height; // Size of the frame rectangle clamped to the
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unsigned clamped_width; // global logical size after x_ and y_offset.
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int tpixel; // Index of transparent pixel
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int32_t disposal_method; // Restore to background, leave in place, etc.
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uint32_t* local_colormap; // Per-image colormap
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@ -83,15 +78,14 @@ typedef struct gif_struct {
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// Global (multi-image) state
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int version; // Either 89 for GIF89 or 87 for GIF87
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unsigned screen_width; // Logical screen width & height
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unsigned screen_height;
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int32_t screen_width; // Logical screen width & height
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int32_t screen_height;
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uint32_t global_colormap_depth; // Depth of global colormap array
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int images_decoded; // Counts images for multi-part GIFs
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int loop_count; // Netscape specific extension block to control
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// the number of animation loops a GIF
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// renders.
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bool interlaced; // TRUE, if scanlines arrive interlaced order
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bool is_transparent; // TRUE, if tpixel is valid
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uint16_t prefix[MAX_BITS]; // LZW decoding tables
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@ -185,21 +185,20 @@ nsGIFDecoder2::ClampToImageRect(const IntRect& aRect)
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//******************************************************************************
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nsresult
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nsGIFDecoder2::BeginImageFrame(uint16_t aDepth)
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nsGIFDecoder2::BeginImageFrame(const IntRect& aFrameRect,
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uint16_t aDepth,
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bool aIsInterlaced)
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{
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MOZ_ASSERT(HasSize());
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IntRect frameRect(mGIFStruct.x_offset, mGIFStruct.y_offset,
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mGIFStruct.width, mGIFStruct.height);
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bool hasTransparency = CheckForTransparency(frameRect);
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bool hasTransparency = CheckForTransparency(aFrameRect);
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gfx::SurfaceFormat format = hasTransparency ? SurfaceFormat::B8G8R8A8
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: SurfaceFormat::B8G8R8X8;
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// Make sure there's no animation if we're downscaling.
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MOZ_ASSERT_IF(mDownscaler, !GetImageMetadata().HasAnimation());
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SurfacePipeFlags pipeFlags = mGIFStruct.interlaced
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SurfacePipeFlags pipeFlags = aIsInterlaced
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? SurfacePipeFlags::DEINTERLACE
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: SurfacePipeFlags();
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@ -210,7 +209,7 @@ nsGIFDecoder2::BeginImageFrame(uint16_t aDepth)
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IntSize targetSize = mDownscaler ? mDownscaler->TargetSize()
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: GetSize();
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IntRect targetFrameRect = mDownscaler ? IntRect(IntPoint(), targetSize)
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: frameRect;
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: aFrameRect;
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// The first frame may be displayed progressively.
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pipeFlags |= SurfacePipeFlags::PROGRESSIVE_DISPLAY;
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@ -226,7 +225,7 @@ nsGIFDecoder2::BeginImageFrame(uint16_t aDepth)
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MOZ_ASSERT(!mDownscaler);
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pipe =
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SurfacePipeFactory::CreatePalettedSurfacePipe(this, mGIFStruct.images_decoded,
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GetSize(), frameRect, format,
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GetSize(), aFrameRect, format,
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aDepth, pipeFlags);
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}
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@ -249,26 +248,10 @@ nsGIFDecoder2::EndImageFrame()
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Opacity opacity = Opacity::SOME_TRANSPARENCY;
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// First flush all pending image data
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if (!mGIFStruct.images_decoded) {
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if (mGIFStruct.images_decoded == 0) {
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// Only need to flush first frame
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FlushImageData();
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// If the first frame is smaller in height than the entire image, send an
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// invalidation for the area it does not have data for.
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// This will clear the remaining bits of the placeholder. (Bug 37589)
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const uint32_t realFrameHeight = mGIFStruct.height + mGIFStruct.y_offset;
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if (realFrameHeight < mGIFStruct.screen_height) {
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if (mDownscaler) {
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IntRect targetRect = IntRect(IntPoint(), mDownscaler->TargetSize());
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PostInvalidation(IntRect(IntPoint(), GetSize()), Some(targetRect));
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} else {
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nsIntRect r(0, realFrameHeight,
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mGIFStruct.screen_width,
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mGIFStruct.screen_height - realFrameHeight);
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PostInvalidation(r);
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}
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}
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// The first frame was preallocated with alpha; if it wasn't transparent, we
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// should fix that. We can also mark it opaque unconditionally if we didn't
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// actually see any transparent pixels - this test is only valid for the
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@ -872,25 +855,26 @@ nsGIFDecoder2::WriteInternal(const char* aBuffer, uint32_t aCount)
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}
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}
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IntRect frameRect;
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// Get image offsets, with respect to the screen origin
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mGIFStruct.x_offset = GETINT16(q);
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mGIFStruct.y_offset = GETINT16(q + 2);
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frameRect.x = GETINT16(q);
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frameRect.y = GETINT16(q + 2);
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// Get image width and height.
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mGIFStruct.width = GETINT16(q + 4);
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mGIFStruct.height = GETINT16(q + 6);
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frameRect.width = GETINT16(q + 4);
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frameRect.height = GETINT16(q + 6);
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if (!mGIFStruct.images_decoded) {
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// Work around broken GIF files where the logical screen
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// size has weird width or height. We assume that GIF87a
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// files don't contain animations.
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if ((mGIFStruct.screen_height < mGIFStruct.height) ||
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(mGIFStruct.screen_width < mGIFStruct.width) ||
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if ((mGIFStruct.screen_height < frameRect.height) ||
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(mGIFStruct.screen_width < frameRect.width) ||
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(mGIFStruct.version == 87)) {
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mGIFStruct.screen_height = mGIFStruct.height;
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mGIFStruct.screen_width = mGIFStruct.width;
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mGIFStruct.x_offset = 0;
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mGIFStruct.y_offset = 0;
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mGIFStruct.screen_height = frameRect.height;
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mGIFStruct.screen_width = frameRect.width;
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frameRect.MoveTo(0, 0);
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}
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// Create the image container with the right size.
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BeginGIF();
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@ -902,38 +886,21 @@ nsGIFDecoder2::WriteInternal(const char* aBuffer, uint32_t aCount)
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// If we were doing a metadata decode, we're done.
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if (IsMetadataDecode()) {
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IntRect frameRect(mGIFStruct.x_offset, mGIFStruct.y_offset,
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mGIFStruct.width, mGIFStruct.height);
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CheckForTransparency(frameRect);
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return;
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}
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}
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// Work around more broken GIF files that have zero image width or height
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if (!mGIFStruct.height || !mGIFStruct.width) {
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mGIFStruct.height = mGIFStruct.screen_height;
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mGIFStruct.width = mGIFStruct.screen_width;
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if (!mGIFStruct.height || !mGIFStruct.width) {
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if (!frameRect.height || !frameRect.width) {
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frameRect.height = mGIFStruct.screen_height;
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frameRect.width = mGIFStruct.screen_width;
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if (!frameRect.height || !frameRect.width) {
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mGIFStruct.state = gif_error;
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break;
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}
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}
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// Hack around GIFs with frame rects outside the given screen bounds.
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IntRect clampedRect =
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ClampToImageRect(IntRect(mGIFStruct.x_offset, mGIFStruct.y_offset,
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mGIFStruct.width, mGIFStruct.height));
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if (clampedRect.IsEmpty()) {
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// XXX Bug 1227546 - Maybe we should treat this as valid?
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mGIFStruct.state = gif_error;
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break;
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}
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mGIFStruct.clamped_width = clampedRect.width;
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mGIFStruct.clamped_height = clampedRect.height;
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MOZ_ASSERT(mGIFStruct.clamped_width <= mGIFStruct.width);
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MOZ_ASSERT(mGIFStruct.clamped_height <= mGIFStruct.height);
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// Depth of colors is determined by colormap
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// (q[8] & 0x80) indicates local colormap
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// bits per pixel is (q[8]&0x07 + 1) when local colormap is set
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@ -945,17 +912,18 @@ nsGIFDecoder2::WriteInternal(const char* aBuffer, uint32_t aCount)
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while (mGIFStruct.tpixel >= (1 << realDepth) && (realDepth < 8)) {
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realDepth++;
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}
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// Mask to limit the color values within the colormap
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mColorMask = 0xFF >> (8 - realDepth);
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if (NS_FAILED(BeginImageFrame(realDepth))) {
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// Determine if this frame is interlaced or not.
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const bool isInterlaced = q[8] & 0x40;
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if (NS_FAILED(BeginImageFrame(frameRect, realDepth, isInterlaced))) {
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mGIFStruct.state = gif_error;
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return;
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}
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MOZ_FALLTHROUGH; // to continue decoding header.
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}
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case gif_image_header_continue: {
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// While decoders can reuse frames, we unconditionally increment
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// mGIFStruct.images_decoded when we're done with a frame, so we both can
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// and need to zero out the colormap and image data after every new frame.
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@ -964,37 +932,9 @@ nsGIFDecoder2::WriteInternal(const char* aBuffer, uint32_t aCount)
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memset(mColormap, 0, mColormapSize);
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}
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if (!mGIFStruct.images_decoded) {
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// Send a onetime invalidation for the first frame if it has a y-axis
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// offset. Otherwise, the area may never be refreshed and the
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// placeholder will remain on the screen. (Bug 37589)
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if (mGIFStruct.y_offset > 0) {
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if (mDownscaler) {
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IntRect targetRect = IntRect(IntPoint(), mDownscaler->TargetSize());
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PostInvalidation(IntRect(IntPoint(), GetSize()), Some(targetRect));
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} else {
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nsIntRect r(0, 0, mGIFStruct.screen_width, mGIFStruct.y_offset);
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PostInvalidation(r);
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}
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}
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}
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mGIFStruct.interlaced = bool(q[8] & 0x40);
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// Clear state from last image
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mGIFStruct.pixels_remaining = mGIFStruct.width * mGIFStruct.height;
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mGIFStruct.pixels_remaining = frameRect.width * frameRect.height;
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// Depth of colors is determined by colormap
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// (q[8] & 0x80) indicates local colormap
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// bits per pixel is (q[8]&0x07 + 1) when local colormap is set
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uint32_t depth = mGIFStruct.global_colormap_depth;
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if (q[8] & 0x80) {
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depth = (q[8]&0x07) + 1;
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}
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uint32_t realDepth = depth;
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while (mGIFStruct.tpixel >= (1 << realDepth) && (realDepth < 8)) {
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realDepth++;
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}
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// has a local colormap?
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if (q[8] & 0x80) {
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mGIFStruct.local_colormap_size = 1 << depth;
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@ -33,11 +33,25 @@ private:
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// Decoders should only be instantiated via DecoderFactory.
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explicit nsGIFDecoder2(RasterImage* aImage);
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// These functions will be called when the decoder has a decoded row,
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// frame size information, etc.
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/// Called when we begin decoding the image.
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void BeginGIF();
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nsresult BeginImageFrame(uint16_t aDepth);
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/**
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* Called when we begin decoding a frame.
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*
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* @param aFrameRect The region of the image that contains data. The region
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* outside this rect is transparent.
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* @param aDepth The palette depth of this frame.
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* @param aIsInterlaced If true, this frame is an interlaced frame.
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*/
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nsresult BeginImageFrame(const gfx::IntRect& aFrameRect,
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uint16_t aDepth,
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bool aIsInterlaced);
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/// Called when we finish decoding a frame.
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void EndImageFrame();
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/// Called when we finish decoding the entire image.
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void FlushImageData();
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nsresult GifWrite(const uint8_t* buf, uint32_t numbytes);
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