LibGfx/PNG: Read the cICP chunk

LadybirdBrowser · Feb 12, 2025 · a144481 · a144481
1 parent cffc867
commit a144481
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Showing 10 changed files with 94 additions and 6 deletions.
diff --git a/Libraries/LibGfx/ImageFormats/PNGLoader.cpp b/Libraries/LibGfx/ImageFormats/PNGLoader.cpp
@@ -30,6 +30,7 @@ struct PNGLoadingContext {
     u32 frame_count { 0 };
     u32 loop_count { 0 };
     Vector<ImageFrameDescriptor> frame_descriptors;
+    Optional<Media::CodingIndependentCodePoints> cicp;
     Optional<ByteBuffer> icc_profile;
     OwnPtr<ExifMetadata> exif_metadata;
 
@@ -111,6 +112,11 @@ ErrorOr<ImageFrameDescriptor> PNGImageDecoderPlugin::frame(size_t index, Optiona
     return m_context->frame_descriptors[index];
 }
 
+ErrorOr<Optional<Media::CodingIndependentCodePoints>> PNGImageDecoderPlugin::cicp()
+{
+    return m_context->cicp;
+}
+
 ErrorOr<Optional<ReadonlyBytes>> PNGImageDecoderPlugin::icc_data()
 {
     if (m_context->icc_profile.has_value())
@@ -187,12 +193,24 @@ ErrorOr<void> PNGImageDecoderPlugin::initialize()
     png_set_filler(m_context->png_ptr, 0xFF, PNG_FILLER_AFTER);
     png_set_bgr(m_context->png_ptr);
 
-    char* profile_name = nullptr;
-    int compression_type = 0;
-    u8* profile_data = nullptr;
-    u32 profile_len = 0;
-    if (png_get_iCCP(m_context->png_ptr, m_context->info_ptr, &profile_name, &compression_type, &profile_data, &profile_len))
-        m_context->icc_profile = TRY(ByteBuffer::copy(profile_data, profile_len));
+    png_byte color_primaries { 0 };
+    png_byte transfer_function { 0 };
+    png_byte matrix_coefficients { 0 };
+    png_byte video_full_range_flag { 0 };
+    if (png_get_cICP(m_context->png_ptr, m_context->info_ptr, &color_primaries, &transfer_function, &matrix_coefficients, &video_full_range_flag)) {
+        Media::ColorPrimaries cp { color_primaries };
+        Media::TransferCharacteristics tc { transfer_function };
+        Media::MatrixCoefficients mc { matrix_coefficients };
+        Media::VideoFullRangeFlag rf { video_full_range_flag };
+        m_context->cicp = Media::CodingIndependentCodePoints { cp, tc, mc, rf };
+    } else {
+        char* profile_name = nullptr;
+        int compression_type = 0;
+        u8* profile_data = nullptr;
+        u32 profile_len = 0;
+        if (png_get_iCCP(m_context->png_ptr, m_context->info_ptr, &profile_name, &compression_type, &profile_data, &profile_len))
+            m_context->icc_profile = TRY(ByteBuffer::copy(profile_data, profile_len));
+    }
 
     u8* exif_data = nullptr;
     u32 exif_length = 0;

diff --git a/Libraries/LibGfx/ImageFormats/PNGLoader.h b/Libraries/LibGfx/ImageFormats/PNGLoader.h
@@ -27,6 +27,7 @@ class PNGImageDecoderPlugin final : public ImageDecoderPlugin {
     virtual size_t first_animated_frame_index() override;
     virtual ErrorOr<ImageFrameDescriptor> frame(size_t index, Optional<IntSize> ideal_size = {}) override;
     virtual Optional<Metadata const&> metadata() override;
+    virtual ErrorOr<Optional<Media::CodingIndependentCodePoints>> cicp() override;
     virtual ErrorOr<Optional<ReadonlyBytes>> icc_data() override;
 
 private:

diff --git a/Tests/LibWeb/Ref/expected/wpt-import/png/apng/apng-lime-rectangle-ref.html b/Tests/LibWeb/Ref/expected/wpt-import/png/apng/apng-lime-rectangle-ref.html
@@ -0,0 +1,8 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>PNG Third Edition: animated PNG</title>
+<link rel="author" title="Chris Lilley" href="mailto:[email protected]">
+<body>
+    <p>Test passes if you see a lime green rectangle, and no red.</p>
+    <div class="test"><img src="support/lime.png" alt=""></div>
+</body>
diff --git a/Tests/LibWeb/Ref/expected/wpt-import/png/apng/support/lime.png b/Tests/LibWeb/Ref/expected/wpt-import/png/apng/support/lime.png
diff --git a/Tests/LibWeb/Ref/expected/wpt-import/png/cICP-wins-ref.html b/Tests/LibWeb/Ref/expected/wpt-import/png/cICP-wins-ref.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<html>
+<meta charset="utf-8">
+<title>PNG Third Edition: Coding Independent Code Points</title>
+<link rel="author" title="Chris Lilley" href="mailto:[email protected]">
+<style>
+    .test {
+        width: 128px;
+        height: 64px;
+        background-color: green;
+    }
+</style>
+<body>
+    <p>Test passes if you see a green rectangle, and no red.</p>
+    <div class="test"><img src="support/srgb_green.png" alt=""></div>
+</body>
+</html>
diff --git a/Tests/LibWeb/Ref/expected/wpt-import/png/support/srgb_green.png b/Tests/LibWeb/Ref/expected/wpt-import/png/support/srgb_green.png
diff --git a/Tests/LibWeb/Ref/input/wpt-import/png/apng/fDAT-inherits-cICP.html b/Tests/LibWeb/Ref/input/wpt-import/png/apng/fDAT-inherits-cICP.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<html class="reftest-wait">
+<meta charset="utf-8">
+<title>PNG Third Edition: animated PNG, fdAT inherits colorspace from cICP</title>
+<link rel="author" title="Chris Lilley" href="mailto:[email protected]">
+<link rel="help" href="https://www.w3.org/TR/png-3/#apng-frame-based-animation">
+<link rel="help" href="https://www.w3.org/TR/png-3/#structure">
+<link rel="help" href="https://www.w3.org/TR/png-3/#fdAT-chunk">
+<link rel="help" href="https://www.w3.org/TR/png-3/#cICP-chunk">
+<link rel="match" href="../../../../expected/wpt-import/png/apng/apng-lime-rectangle-ref.html">
+<meta name="assert" content="Each frame inherits every property specified by any critical or ancillary chunks before the first IDAT chunk in the file">
+<script>
+    const el = document.querySelector(".reftest-wait");
+    setTimeout(() => {
+        el.classList.remove('reftest-wait');
+        }, 2100);
+</script>
+<body>
+    <p>Test passes if you see a lime green rectangle, and no red.</p>
+    <!-- sRGB lime =  color(display-p3 0.4584 0.9853 0.2983) -->
+    <div class="test"><img src="support/062.png" alt=""></div>
+</body>
diff --git a/Tests/LibWeb/Ref/input/wpt-import/png/apng/support/062.png b/Tests/LibWeb/Ref/input/wpt-import/png/apng/support/062.png
diff --git a/Tests/LibWeb/Ref/input/wpt-import/png/cICP-wins.html b/Tests/LibWeb/Ref/input/wpt-import/png/cICP-wins.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<html>
+<meta charset="utf-8">
+<title>PNG Third Edition: Coding Independent Code Points</title>
+<link rel="author" title="Chris Lilley" href="mailto:[email protected]">
+<link rel="help" href="https://www.w3.org/TR/png-3/#11iCCP">
+<link rel="help" href="https://www.w3.org/TR/png-3/#cICP-chunk">
+
+<link rel="match" href="../../../expected/wpt-import/png/cICP-wins-ref.html">
+<meta name="assert" content="When the cICP chunk is present, decoders that recognize it SHALL ignore iCCP">
+<style>
+    .test {
+        width: 128px;
+        height: 64px;
+        background-color: red;
+    }
+</style>
+<body>
+    <p>Test passes if you see a green rectangle, and no red.</p>
+    <div class="test"><img src="support/cICP-and-iCCP.png" alt=""></div>
+</body>
+</html>
diff --git a/Tests/LibWeb/Ref/input/wpt-import/png/support/cICP-and-iCCP.png b/Tests/LibWeb/Ref/input/wpt-import/png/support/cICP-and-iCCP.png