mirrors/ladybird
0
0
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2025-07-29 04:09:13 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 9

LibWeb/Canvas: Support globalCompositionOperation

Browse source 
Canvas now supports compositing and various blending modes via the
`globalCompositeOperation` attribute.
This commit is contained in:
Glenn Skrzypczak 2025-01-28 18:19:30 +01:00 • committed by Sam Atkins
commit 8575bddfe6
Notes: github-actions[bot] 2025-02-05 11:28:07 +00:00
16 changed files with 283 additions and 32 deletions
Download patch file Download diff file Expand all files Collapse all files

8
Libraries/LibGfx/ImageFormats/PNGLoader.cpp
View file

@ -283,12 +283,11 @@ ErrorOr<size_t> PNGLoadingContext::read_frames(png_structp png_ptr, png_infop in
switch (blend_op) {
case PNG_BLEND_OP_SOURCE:
// All color components of the frame, including alpha, overwrite the current contents of the frame's output buffer region.
painter->clear_rect(frame_rect, Gfx::Color::Transparent);
painter->draw_bitmap(frame_rect, Gfx::ImmutableBitmap::create(*decoded_frame_bitmap), decoded_frame_bitmap->rect(), Gfx::ScalingMode::NearestNeighbor, {}, 1.0f);
painter->draw_bitmap(frame_rect, Gfx::ImmutableBitmap::create(*decoded_frame_bitmap), decoded_frame_bitmap->rect(), Gfx::ScalingMode::NearestNeighbor, {}, 1.0f, Gfx::CompositingAndBlendingOperator::Copy);
break;
case PNG_BLEND_OP_OVER:
// The frame should be composited onto the output buffer based on its alpha, using a simple OVER operation as described in the "Alpha Channel Processing" section of the PNG specification.
painter->draw_bitmap(frame_rect, Gfx::ImmutableBitmap::create(*decoded_frame_bitmap), decoded_frame_bitmap->rect(), ScalingMode::NearestNeighbor, {}, 1.0f);
painter->draw_bitmap(frame_rect, Gfx::ImmutableBitmap::create(*decoded_frame_bitmap), decoded_frame_bitmap->rect(), ScalingMode::NearestNeighbor, {}, 1.0f, Gfx::CompositingAndBlendingOperator::SourceOver);
break;
default:
VERIFY_NOT_REACHED();
@ -306,8 +305,7 @@ ErrorOr<size_t> PNGLoadingContext::read_frames(png_structp png_ptr, png_infop in
break;
case PNG_DISPOSE_OP_PREVIOUS:
// The frame's region of the output buffer is to be reverted to the previous contents before rendering the next frame.
painter->clear_rect(frame_rect, Gfx::Color::Transparent);
painter->draw_bitmap(frame_rect, Gfx::ImmutableBitmap::create(*prev_output_buffer), IntRect { x, y, width, height }, Gfx::ScalingMode::NearestNeighbor, {}, 1.0f);
painter->draw_bitmap(frame_rect, Gfx::ImmutableBitmap::create(*prev_output_buffer), IntRect { x, y, width, height }, Gfx::ScalingMode::NearestNeighbor, {}, 1.0f, Gfx::CompositingAndBlendingOperator::Copy);
break;
default:
VERIFY_NOT_REACHED();