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b193fe658d
We use instances of `Gfx::Bitmap` to move pixel data all the way from raw image bytes up to the Skia renderer. A vital piece of information for correct blending of bitmaps is the alpha type, i.e. are we dealing with premultiplied or unpremultiplied color values? Premultiplied means that the RGB colors have been multiplied with the associated alpha value, i.e. RGB(255, 255, 255) with an alpha of 2% is stored as RGBA(5, 5, 5, 2%). Unpremultiplied means that the original RGB colors are stored, regardless of the alpha value. I.e. RGB(255, 255, 255) with an alpha of 2% is stored as RGBA(255, 255, 255, 2%). It is important to know how the color data is stored in a `Gfx::Bitmap`, because correct blending depends on knowing the alpha type: premultiplied blending uses `S + (1 - A) * D`, while unpremultiplied blending uses `A * S + (1 - A) * D`. This adds the alpha type information to `Gfx::Bitmap` across the board. It isn't used anywhere yet.
32 lines
884 B
C++
32 lines
884 B
C++
/*
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* Copyright (c) 2024, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <LibGfx/Bitmap.h>
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#include <LibWeb/Painting/BackingStore.h>
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namespace Web::Painting {
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BitmapBackingStore::BitmapBackingStore(RefPtr<Gfx::Bitmap> bitmap)
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: m_bitmap(move(bitmap))
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{
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}
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#ifdef AK_OS_MACOS
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IOSurfaceBackingStore::IOSurfaceBackingStore(Core::IOSurfaceHandle&& iosurface_handle)
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: m_iosurface_handle(move(iosurface_handle))
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{
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auto bytes_per_row = m_iosurface_handle.bytes_per_row();
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auto bitmap = Gfx::Bitmap::create_wrapper(Gfx::BitmapFormat::BGRA8888, Gfx::AlphaType::Premultiplied, size(), bytes_per_row, m_iosurface_handle.data());
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m_bitmap_wrapper = bitmap.release_value();
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}
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Gfx::IntSize IOSurfaceBackingStore::size() const
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{
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return { m_iosurface_handle.width(), m_iosurface_handle.height() };
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}
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#endif
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};
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