diff options
Diffstat (limited to 'Userland/Libraries/LibGfx/JPEGLoader.cpp')
| -rw-r--r-- | Userland/Libraries/LibGfx/JPEGLoader.cpp | 29 |
1 files changed, 26 insertions, 3 deletions
diff --git a/Userland/Libraries/LibGfx/JPEGLoader.cpp b/Userland/Libraries/LibGfx/JPEGLoader.cpp index c6557d0cd6..5fab0ca8ba 100644 --- a/Userland/Libraries/LibGfx/JPEGLoader.cpp +++ b/Userland/Libraries/LibGfx/JPEGLoader.cpp @@ -363,6 +363,31 @@ static ErrorOr<void> build_macroblocks(JPEGLoadingContext& context, Vector<Macro return {}; } +static bool is_dct_based(StartOfFrame::FrameType frame_type) +{ + return frame_type == StartOfFrame::FrameType::Baseline_DCT + || frame_type == StartOfFrame::FrameType::Extended_Sequential_DCT + || frame_type == StartOfFrame::FrameType::Progressive_DCT + || frame_type == StartOfFrame::FrameType::Differential_Sequential_DCT + || frame_type == StartOfFrame::FrameType::Differential_Progressive_DCT + || frame_type == StartOfFrame::FrameType::Progressive_DCT_Arithmetic + || frame_type == StartOfFrame::FrameType::Differential_Sequential_DCT_Arithmetic + || frame_type == StartOfFrame::FrameType::Differential_Progressive_DCT_Arithmetic; +} + +static void reset_decoder(JPEGLoadingContext& context) +{ + // E.2.4 Control procedure for decoding a restart interval + if (is_dct_based(context.frame.type)) { + context.previous_dc_values[0] = 0; + context.previous_dc_values[1] = 0; + context.previous_dc_values[2] = 0; + return; + } + + VERIFY_NOT_REACHED(); +} + static ErrorOr<void> decode_huffman_stream(JPEGLoadingContext& context, Vector<Macroblock>& macroblocks) { if constexpr (JPEG_DEBUG) { @@ -385,9 +410,7 @@ static ErrorOr<void> decode_huffman_stream(JPEGLoadingContext& context, Vector<M u32 i = vcursor * context.mblock_meta.hpadded_count + hcursor; if (context.dc_restart_interval > 0) { if (i != 0 && i % (context.dc_restart_interval * context.vsample_factor * context.hsample_factor) == 0) { - context.previous_dc_values[0] = 0; - context.previous_dc_values[1] = 0; - context.previous_dc_values[2] = 0; + reset_decoder(context); // Restart markers are stored in byte boundaries. Advance the huffman stream cursor to // the 0th bit of the next byte. |