diff options
Diffstat (limited to 'Userland/Libraries/LibGfx/JPEGLoader.cpp')
| -rw-r--r-- | Userland/Libraries/LibGfx/JPEGLoader.cpp | 73 |
1 files changed, 43 insertions, 30 deletions
diff --git a/Userland/Libraries/LibGfx/JPEGLoader.cpp b/Userland/Libraries/LibGfx/JPEGLoader.cpp index 7b62a80311..ee3e67f897 100644 --- a/Userland/Libraries/LibGfx/JPEGLoader.cpp +++ b/Userland/Libraries/LibGfx/JPEGLoader.cpp @@ -124,13 +124,23 @@ struct MacroblockMeta { u32 vpadded_count { 0 }; }; -struct ComponentSpec { - u8 id { 0 }; - u8 hsample_factor { 1 }; // Horizontal sampling factor. - u8 vsample_factor { 1 }; // Vertical sampling factor. - u8 ac_destination_id { 0 }; - u8 dc_destination_id { 0 }; - u8 qtable_id { 0 }; // Quantization table id. +// In the JPEG format, components are defined first at the frame level, then +// referenced in each scan and aggregated with scan-specific information. The +// two following structs mimic this hierarchy. + +struct Component { + // B.2.2 - Frame header syntax + u8 id { 0 }; // Ci, Component identifier + u8 hsample_factor { 1 }; // Hi, Horizontal sampling factor + u8 vsample_factor { 1 }; // Vi, Vertical sampling factor + u8 qtable_id { 0 }; // Tqi, Quantization table destination selector +}; + +struct ScanComponent { + // B.2.3 - Scan header syntax + Component& component; + u8 dc_destination_id { 0 }; // Tdj, DC entropy coding table destination selector + u8 ac_destination_id { 0 }; // Taj, AC entropy coding table destination selector }; struct StartOfFrame { @@ -179,6 +189,7 @@ struct ICCMultiChunkState { struct Scan { // B.2.3 - Scan header syntax + Vector<ScanComponent, 3> components; u8 spectral_selection_start {}; u8 spectral_selection_end {}; @@ -205,7 +216,7 @@ struct JPEGLoadingContext { Scan current_scan; - Vector<ComponentSpec, 3> components; + Vector<Component, 3> components; RefPtr<Gfx::Bitmap> bitmap; u16 dc_restart_interval { 0 }; HashMap<u8, HuffmanTableSpec> dc_tables; @@ -283,9 +294,9 @@ static inline i32* get_component(Macroblock& block, unsigned component) } } -static ErrorOr<void> add_dc(JPEGLoadingContext& context, Macroblock& macroblock, ComponentSpec const& component, unsigned component_index) +static ErrorOr<void> add_dc(JPEGLoadingContext& context, Macroblock& macroblock, ScanComponent const& scan_component, unsigned component_index) { - auto& dc_table = context.dc_tables.find(component.dc_destination_id)->value; + auto& dc_table = context.dc_tables.find(scan_component.dc_destination_id)->value; // For DC coefficients, symbol encodes the length of the coefficient. auto dc_length = TRY(get_next_symbol(context.huffman_stream, dc_table)); @@ -308,9 +319,9 @@ static ErrorOr<void> add_dc(JPEGLoadingContext& context, Macroblock& macroblock, return {}; } -static ErrorOr<void> add_ac(JPEGLoadingContext& context, Macroblock& macroblock, ComponentSpec const& component, unsigned component_index) +static ErrorOr<void> add_ac(JPEGLoadingContext& context, Macroblock& macroblock, ScanComponent const& scan_component, unsigned component_index) { - auto& ac_table = context.ac_tables.find(component.ac_destination_id)->value; + auto& ac_table = context.ac_tables.find(scan_component.ac_destination_id)->value; auto* select_component = get_component(macroblock, component_index); // Compute the AC coefficients. @@ -370,22 +381,22 @@ static ErrorOr<void> add_ac(JPEGLoadingContext& context, Macroblock& macroblock, */ static ErrorOr<void> build_macroblocks(JPEGLoadingContext& context, Vector<Macroblock>& macroblocks, u32 hcursor, u32 vcursor) { - for (unsigned component_i = 0; component_i < context.components.size(); component_i++) { - auto& component = context.components[component_i]; + for (unsigned component_i = 0; component_i < context.current_scan.components.size(); component_i++) { + auto& scan_component = context.current_scan.components[component_i]; - if (component.dc_destination_id >= context.dc_tables.size()) + if (scan_component.dc_destination_id >= context.dc_tables.size()) return Error::from_string_literal("DC destination ID is greater than number of DC tables"); - if (component.ac_destination_id >= context.ac_tables.size()) + if (scan_component.ac_destination_id >= context.ac_tables.size()) return Error::from_string_literal("AC destination ID is greater than number of AC tables"); - for (u8 vfactor_i = 0; vfactor_i < component.vsample_factor; vfactor_i++) { - for (u8 hfactor_i = 0; hfactor_i < component.hsample_factor; hfactor_i++) { + for (u8 vfactor_i = 0; vfactor_i < scan_component.component.vsample_factor; vfactor_i++) { + for (u8 hfactor_i = 0; hfactor_i < scan_component.component.hsample_factor; hfactor_i++) { u32 mb_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hfactor_i + hcursor); Macroblock& block = macroblocks[mb_index]; if (context.current_scan.spectral_selection_start == 0) - TRY(add_dc(context, block, component, component_i)); - TRY(add_ac(context, block, component, component_i)); + TRY(add_dc(context, block, scan_component, component_i)); + TRY(add_ac(context, block, scan_component, component_i)); } } } @@ -552,6 +563,8 @@ static ErrorOr<void> read_start_of_scan(AK::SeekableStream& stream, JPEGLoadingC return Error::from_string_literal("Unsupported number of components"); } + Scan current_scan; + for (auto& component : context.components) { u8 component_id = TRY(stream.read_value<u8>()); @@ -562,25 +575,25 @@ static ErrorOr<void> read_start_of_scan(AK::SeekableStream& stream, JPEGLoadingC u8 table_ids = TRY(stream.read_value<u8>()); - component.dc_destination_id = table_ids >> 4; - component.ac_destination_id = table_ids & 0x0F; + ScanComponent scan_component { component, static_cast<u8>(table_ids >> 4), static_cast<u8>(table_ids & 0x0F) }; if (context.dc_tables.size() != context.ac_tables.size()) { dbgln_if(JPEG_DEBUG, "{}: DC & AC table count mismatch!", TRY(stream.tell())); return Error::from_string_literal("DC & AC table count mismatch"); } - if (!context.dc_tables.contains(component.dc_destination_id)) { - dbgln_if(JPEG_DEBUG, "DC table (id: {}) does not exist!", component.dc_destination_id); + if (!context.dc_tables.contains(scan_component.dc_destination_id)) { + dbgln_if(JPEG_DEBUG, "DC table (id: {}) does not exist!", scan_component.dc_destination_id); return Error::from_string_literal("DC table does not exist"); } - if (!context.ac_tables.contains(component.ac_destination_id)) { - dbgln_if(JPEG_DEBUG, "AC table (id: {}) does not exist!", component.ac_destination_id); + if (!context.ac_tables.contains(scan_component.ac_destination_id)) { + dbgln_if(JPEG_DEBUG, "AC table (id: {}) does not exist!", scan_component.ac_destination_id); return Error::from_string_literal("AC table does not exist"); } + + current_scan.components.append(scan_component); } - Scan current_scan; current_scan.spectral_selection_start = TRY(stream.read_value<u8>()); current_scan.spectral_selection_end = TRY(stream.read_value<u8>()); @@ -596,7 +609,7 @@ static ErrorOr<void> read_start_of_scan(AK::SeekableStream& stream, JPEGLoadingC return Error::from_string_literal("Spectral selection is not [0,63] or successive approximation is not null"); } - context.current_scan = current_scan; + context.current_scan = move(current_scan); return {}; } @@ -754,7 +767,7 @@ static ErrorOr<void> read_app_marker(SeekableStream& stream, JPEGLoadingContext& return stream.discard(bytes_to_read); } -static inline bool validate_luma_and_modify_context(ComponentSpec const& luma, JPEGLoadingContext& context) +static inline bool validate_luma_and_modify_context(Component const& luma, JPEGLoadingContext& context) { if ((luma.hsample_factor == 1 || luma.hsample_factor == 2) && (luma.vsample_factor == 1 || luma.vsample_factor == 2)) { context.mblock_meta.hpadded_count += luma.hsample_factor == 1 ? 0 : context.mblock_meta.hcount % 2; @@ -822,7 +835,7 @@ static ErrorOr<void> read_start_of_frame(AK::SeekableStream& stream, JPEGLoading } for (u8 i = 0; i < component_count; i++) { - ComponentSpec component; + Component component; component.id = TRY(stream.read_value<u8>()); u8 subsample_factors = TRY(stream.read_value<u8>()); |