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LibGfx/JBIG2: Support custom adaptive template pixels in refinement

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The implementation is very similar to #23831.

I created the test exactly like in #23713, except that I replaced the
last four lines in the ini file with:

```
-txt -Param -rATX1 10
-txt -Param -rATY1 -1
-txt -Param -rATX2 4
-txt -Param -rATY2 15
```
This commit is contained in:
Nico Weber 2024-04-04 13:23:12 -07:00 committed by Andreas Kling
parent 154d0bb458
commit 2d4964b945
3 changed files with 17 additions and 11 deletions
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1
Tests/LibGfx/TestImageDecoder.cpp
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@ -365,6 +365,7 @@ TEST_CASE(test_jbig2_decode)
TEST_INPUT("jbig2/bitmap-template3-customat-tpgdon.jbig2"sv),
TEST_INPUT("jbig2/bitmap-symbol.jbig2"sv),
TEST_INPUT("jbig2/bitmap-symbol-textrefine.jbig2"sv),
TEST_INPUT("jbig2/bitmap-symbol-textrefine-customat.jbig2"sv),
TEST_INPUT("jbig2/bitmap-symbol-symbolrefine.jbig2"sv),
TEST_INPUT("jbig2/bitmap-symbol-textbottomleft.jbig2"sv),
TEST_INPUT("jbig2/bitmap-symbol-textbottomlefttranspose.jbig2"sv),

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Tests/LibGfx/test-inputs/jbig2/bitmap-symbol-textrefine-customat.jbig2 Normal file
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27
Userland/Libraries/LibGfx/ImageFormats/JBIG2Loader.cpp
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@ -1112,9 +1112,8 @@ static ErrorOr<NonnullOwnPtr<BitBuffer>> generic_refinement_region_decoding_proc
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Cannot decode typical prediction in generic refinement regions yet");
if (inputs.gr_template == 0) {
if (inputs.adaptive_template_pixels[0].x != -1 || inputs.adaptive_template_pixels[0].y != -1
|| inputs.adaptive_template_pixels[1].x != -1 || inputs.adaptive_template_pixels[1].y != -1)
return Error::from_string_literal("JBIG2ImageDecoderPlugin: Cannot handle custom adaptive pixels in refinement regions yet");
TRY(check_valid_adaptive_template_pixel(inputs.adaptive_template_pixels[0]));
// inputs.adaptive_template_pixels[1] is allowed to contain any value.
}
// GRTEMPLATE 1 never uses adaptive pixels.
@ -1126,22 +1125,28 @@ static ErrorOr<NonnullOwnPtr<BitBuffer>> generic_refinement_region_decoding_proc
};
// Figure 12 – 13-pixel refinement template showing the AT pixels at their nominal locations
constexpr auto compute_context_0 = [](BitBuffer const& reference, int reference_x, int reference_y, BitBuffer const& buffer, int x, int y) -> u16 {
constexpr auto compute_context_0 = [](ReadonlySpan<AdaptiveTemplatePixel> adaptive_pixels, BitBuffer const& reference, int reference_x, int reference_y, BitBuffer const& buffer, int x, int y) -> u16 {
u16 result = 0;
for (int dy = -1; dy <= 1; ++dy)
for (int dx = -1; dx <= 1; ++dx)
result = (result << 1) | (u16)get_pixel(reference, reference_x + dx, reference_y + dy);
for (int dy = -1; dy <= 1; ++dy) {
for (int dx = -1; dx <= 1; ++dx) {
if (dy == -1 && dx == -1)
result = (result << 1) | (u16)get_pixel(reference, reference_x + adaptive_pixels[1].x, reference_y + adaptive_pixels[1].y);
else
result = (result << 1) | (u16)get_pixel(reference, reference_x + dx, reference_y + dy);
}
}
for (int i = 0; i < 3; ++i)
result = (result << 1) | (u16)get_pixel(buffer, x - 1 + i, y - 1);
result = (result << 1) | (u16)get_pixel(buffer, x + adaptive_pixels[0].x, y + adaptive_pixels[0].y);
for (int i = 0; i < 2; ++i)
result = (result << 1) | (u16)get_pixel(buffer, x + i, y - 1);
result = (result << 1) | (u16)get_pixel(buffer, x - 1, y);
return result;
};
// Figure 13 – 10-pixel refinement template
constexpr auto compute_context_1 = [](BitBuffer const& reference, int reference_x, int reference_y, BitBuffer const& buffer, int x, int y) -> u16 {
constexpr auto compute_context_1 = [](ReadonlySpan<AdaptiveTemplatePixel>, BitBuffer const& reference, int reference_x, int reference_y, BitBuffer const& buffer, int x, int y) -> u16 {
u16 result = 0;
for (int dy = -1; dy <= 1; ++dy) {
@ -1165,7 +1170,7 @@ static ErrorOr<NonnullOwnPtr<BitBuffer>> generic_refinement_region_decoding_proc
auto result = TRY(BitBuffer::create(inputs.region_width, inputs.region_height));
for (size_t y = 0; y < result->height(); ++y) {
for (size_t x = 0; x < result->width(); ++x) {
u16 context = compute_context(*inputs.reference_bitmap, x - inputs.reference_x_offset, y - inputs.reference_y_offset, *result, x, y);
u16 context = compute_context(inputs.adaptive_template_pixels, *inputs.reference_bitmap, x - inputs.reference_x_offset, y - inputs.reference_y_offset, *result, x, y);
bool bit = decoder.get_next_bit(contexts[context]);
result->set_bit(x, y, bit);
}