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LibGfx/JPEG: Make JPEGLoadingContext::current_scan optional

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This allows us to construct a context without calling `Scan`'s
constructor.
This commit is contained in:
Lucas CHOLLET 2023-06-01 22:41:28 -04:00 • committed by Andreas Kling
parent df63e14da7
commit 9a317267de
1 changed files with 12 additions and 12 deletions
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24
Userland/Libraries/LibGfx/ImageFormats/JPEGLoader.cpp
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@ -515,7 +515,7 @@ struct JPEGLoadingContext {
u8 hsample_factor { 0 };
u8 vsample_factor { 0 };
Scan current_scan;
Optional<Scan> current_scan {};
Vector<Component, 4> components;
RefPtr<Gfx::Bitmap> bitmap;
@ -568,12 +568,12 @@ static ErrorOr<void> add_dc(JPEGLoadingContext& context, Macroblock& macroblock,
}
auto& dc_table = maybe_table.value();
auto& scan = context.current_scan;
auto& scan = *context.current_scan;
auto* select_component = get_component(macroblock, scan_component.component.index);
auto& coefficient = select_component[0];
if (context.current_scan.successive_approximation_high > 0) {
if (scan.successive_approximation_high > 0) {
TRY(refine_coefficient(scan, coefficient));
return {};
}
@ -644,7 +644,7 @@ static ErrorOr<void> add_ac(JPEGLoadingContext& context, Macroblock& macroblock,
auto& ac_table = maybe_table.value();
auto* select_component = get_component(macroblock, scan_component.component.index);
auto& scan = context.current_scan;
auto& scan = *context.current_scan;
// Compute the AC coefficients.
@ -755,12 +755,12 @@ static ErrorOr<void> add_ac(JPEGLoadingContext& context, Macroblock& macroblock,
*/
static ErrorOr<void> build_macroblocks(JPEGLoadingContext& context, Vector<Macroblock>& macroblocks, u32 hcursor, u32 vcursor)
{
for (auto const& scan_component : context.current_scan.components) {
for (auto const& scan_component : context.current_scan->components) {
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++) {
// A.2.3 - Interleaved order
u32 macroblock_index = (vcursor + vfactor_i) * context.mblock_meta.hpadded_count + (hfactor_i + hcursor);
if (!context.current_scan.are_components_interleaved()) {
if (!context.current_scan->are_components_interleaved()) {
macroblock_index = vcursor * context.mblock_meta.hpadded_count + (hfactor_i + (hcursor * scan_component.component.vsample_factor) + (vfactor_i * scan_component.component.hsample_factor));
// A.2.4 Completion of partial MCU
@ -777,14 +777,14 @@ static ErrorOr<void> build_macroblocks(JPEGLoadingContext& context, Vector<Macro
Macroblock& block = macroblocks[macroblock_index];
if (context.current_scan.spectral_selection_start == 0)
if (context.current_scan->spectral_selection_start == 0)
TRY(add_dc(context, block, scan_component));
if (context.current_scan.spectral_selection_end != 0)
if (context.current_scan->spectral_selection_end != 0)
TRY(add_ac(context, block, scan_component));
// G.1.2.2 - Progressive encoding of AC coefficients with Huffman coding
if (context.current_scan.end_of_bands_run_count > 0) {
--context.current_scan.end_of_bands_run_count;
if (context.current_scan->end_of_bands_run_count > 0) {
--context.current_scan->end_of_bands_run_count;
continue;
}
}
@ -809,7 +809,7 @@ static bool is_dct_based(StartOfFrame::FrameType frame_type)
static void reset_decoder(JPEGLoadingContext& context)
{
// G.1.2.2 - Progressive encoding of AC coefficients with Huffman coding
context.current_scan.end_of_bands_run_count = 0;
context.current_scan->end_of_bands_run_count = 0;
// E.2.4 Control procedure for decoding a restart interval
if (is_dct_based(context.frame.type)) {
@ -826,7 +826,7 @@ static ErrorOr<void> decode_huffman_stream(JPEGLoadingContext& context, Vector<M
for (u32 hcursor = 0; hcursor < context.mblock_meta.hcount; hcursor += context.hsample_factor) {
u32 i = vcursor * context.mblock_meta.hpadded_count + hcursor;
auto& huffman_stream = context.current_scan.huffman_stream;
auto& huffman_stream = context.current_scan->huffman_stream;
if (context.dc_restart_interval > 0) {
if (i != 0 && i % (context.dc_restart_interval * context.vsample_factor * context.hsample_factor) == 0) {