LibGfx/WebPWriter: Add a toggle for disabling individual transforms

Author: https://github.com/nico
Commit: 533b29dde7
Pull-request: https://github.com/SerenityOS/serenity/pull/24483
Reviewed-by: https://github.com/gmta ✅

Tests/LibGfx/TestImageWriter.cpp

@@ -213,7 +213,9 @@ TEST_CASE(test_webp_icc)
     auto sRGB_icc_data = MUST(Gfx::ICC::encode(sRGB_icc_profile));
 
     auto rgba_bitmap = TRY_OR_FAIL(create_test_rgba_bitmap());
-    auto encoded_rgba_bitmap = TRY_OR_FAIL((encode_bitmap<Gfx::WebPWriter>(rgba_bitmap, Gfx::WebPEncoderOptions { .icc_data = sRGB_icc_data })));
+    Gfx::WebPEncoderOptions options;
+    options.icc_data = sRGB_icc_data;
+    auto encoded_rgba_bitmap = TRY_OR_FAIL((encode_bitmap<Gfx::WebPWriter>(rgba_bitmap, options)));
 
     auto decoded_rgba_plugin = TRY_OR_FAIL(Gfx::WebPImageDecoderPlugin::create(encoded_rgba_bitmap));
     expect_bitmaps_equal(*TRY_OR_FAIL(expect_single_frame_of_size(*decoded_rgba_plugin, rgba_bitmap->size())), rgba_bitmap);

Userland/Libraries/LibGfx/ImageFormats/WebPWriter.cpp

@@ -14,7 +14,6 @@
 #include <LibGfx/ImageFormats/AnimationWriter.h>
 #include <LibGfx/ImageFormats/WebPShared.h>
 #include <LibGfx/ImageFormats/WebPWriter.h>
-#include <LibGfx/ImageFormats/WebPWriterLossless.h>
 
 namespace Gfx {
 
@@ -183,7 +182,7 @@ ErrorOr<void> WebPWriter::encode(Stream& stream, Bitmap const& bitmap, Options c
 {
     // The chunk headers need to know their size, so we either need a SeekableStream or need to buffer the data. We're doing the latter.
     bool is_fully_opaque;
-    auto vp8l_data_bytes = TRY(compress_VP8L_image_data(bitmap, is_fully_opaque));
+    auto vp8l_data_bytes = TRY(compress_VP8L_image_data(bitmap, options.vp8l_options, is_fully_opaque));
     bool alpha_is_used_hint = !is_fully_opaque;
     dbgln_if(WEBP_DEBUG, "Writing WebP of size {} with alpha hint: {}", bitmap.size(), alpha_is_used_hint);
 
@@ -216,10 +215,11 @@ ErrorOr<void> WebPWriter::encode(Stream& stream, Bitmap const& bitmap, Options c
 
 class WebPAnimationWriter : public AnimationWriter {
 public:
-    WebPAnimationWriter(SeekableStream& stream, IntSize dimensions, u8 original_vp8x_flags)
+    WebPAnimationWriter(SeekableStream& stream, IntSize dimensions, u8 original_vp8x_flags, VP8LEncoderOptions vp8l_options)
         : m_stream(stream)
         , m_dimensions(dimensions)
         , m_vp8x_flags(original_vp8x_flags)
+        , m_vp8l_options(vp8l_options)
     {
     }
 
@@ -232,6 +232,7 @@ private:
     SeekableStream& m_stream;
     IntSize m_dimensions;
     u8 m_vp8x_flags { 0 };
+    VP8LEncoderOptions m_vp8l_options;
 };
 
 static ErrorOr<void> align_to_two(SeekableStream& stream)
@@ -307,7 +308,7 @@ ErrorOr<void> WebPAnimationWriter::add_frame(Bitmap& bitmap, int duration_ms, In
     // compress the frame data directly to the stream, and then go back and update the two sizes.
     // That's pretty messy though, and the compressed image data is smaller than the uncompressed bitmap passed in. So we'll buffer it.
     bool is_fully_opaque;
-    auto vp8l_data_bytes = TRY(compress_VP8L_image_data(bitmap, is_fully_opaque));
+    auto vp8l_data_bytes = TRY(compress_VP8L_image_data(bitmap, m_vp8l_options, is_fully_opaque));
 
     ANMFChunkHeader chunk;
     chunk.frame_x = static_cast<u32>(at.x());
@@ -387,7 +388,7 @@ ErrorOr<NonnullOwnPtr<AnimationWriter>> WebPWriter::start_encoding_animation(See
 
     TRY(write_ANIM_chunk(stream, { .background_color = background_color.value(), .loop_count = static_cast<u16>(loop_count) }));
 
-    auto writer = make<WebPAnimationWriter>(stream, dimensions, vp8x_flags_from_header(vp8x_header));
+    auto writer = make<WebPAnimationWriter>(stream, dimensions, vp8x_flags_from_header(vp8x_header), options.vp8l_options);
     TRY(writer->update_size_in_header());
     return writer;
 }

Userland/Libraries/LibGfx/ImageFormats/WebPWriter.h

@@ -9,6 +9,7 @@
 #include <AK/Error.h>
 #include <LibGfx/Color.h>
 #include <LibGfx/Forward.h>
+#include <LibGfx/ImageFormats/WebPWriterLossless.h>
 #include <LibGfx/Point.h>
 
 namespace Gfx {
@@ -16,6 +17,7 @@ namespace Gfx {
 class AnimationWriter;
 
 struct WebPEncoderOptions {
+    VP8LEncoderOptions vp8l_options;
     Optional<ReadonlyBytes> icc_data;
 };
 

Userland/Libraries/LibGfx/ImageFormats/WebPWriterLossless.cpp

@@ -411,13 +411,14 @@ static ErrorOr<NonnullRefPtr<Bitmap>> maybe_write_color_indexing_transform(Littl
     return new_bitmap;
 }
 
-static ErrorOr<void> write_VP8L_image_data(Stream& stream, NonnullRefPtr<Bitmap> bitmap, IsOpaque& is_fully_opaque)
+static ErrorOr<void> write_VP8L_image_data(Stream& stream, NonnullRefPtr<Bitmap> bitmap, VP8LEncoderOptions const& options, IsOpaque& is_fully_opaque)
 {
     LittleEndianOutputBitStream bit_stream { MaybeOwned<Stream>(stream) };
 
     // image-stream  = optional-transform spatially-coded-image
     // optional-transform   =  (%b1 transform optional-transform) / %b0
-    bitmap = TRY(maybe_write_color_indexing_transform(bit_stream, bitmap, is_fully_opaque));
+    if (options.allowed_transforms & (1u << COLOR_INDEXING_TRANSFORM))
+        bitmap = TRY(maybe_write_color_indexing_transform(bit_stream, bitmap, is_fully_opaque));
     TRY(bit_stream.write_bits(0u, 1u)); // No further transforms for now.
 
     TRY(write_VP8L_coded_image(ImageKind::SpatiallyCoded, bit_stream, *bitmap, is_fully_opaque));
@@ -429,11 +430,11 @@ static ErrorOr<void> write_VP8L_image_data(Stream& stream, NonnullRefPtr<Bitmap>
     return {};
 }
 
-ErrorOr<ByteBuffer> compress_VP8L_image_data(Bitmap const& bitmap, bool& is_fully_opaque)
+ErrorOr<ByteBuffer> compress_VP8L_image_data(Bitmap const& bitmap, VP8LEncoderOptions const& options, bool& is_fully_opaque)
 {
     AllocatingMemoryStream vp8l_data_stream;
     IsOpaque is_opaque_struct;
-    TRY(write_VP8L_image_data(vp8l_data_stream, bitmap, is_opaque_struct));
+    TRY(write_VP8L_image_data(vp8l_data_stream, bitmap, options, is_opaque_struct));
     VERIFY(is_opaque_struct.is_opacity_known);
     is_fully_opaque = is_opaque_struct.is_fully_opaque;
     return vp8l_data_stream.read_until_eof();

Userland/Libraries/LibGfx/ImageFormats/WebPWriterLossless.h

@@ -11,6 +11,11 @@
 
 namespace Gfx {
 
-ErrorOr<ByteBuffer> compress_VP8L_image_data(Bitmap const&, bool& is_fully_opaque);
+struct VP8LEncoderOptions {
+    // For each TransformType, set bit `1 << transform_type` if that transform type is allowed.
+    unsigned allowed_transforms { 0xf };
+};
+
+ErrorOr<ByteBuffer> compress_VP8L_image_data(Bitmap const&, VP8LEncoderOptions const&, bool& is_fully_opaque);
 
 }