92d9b6edb8
This adds CanvasPathClipper and ScopedCanvasPathClip. These allow clipping the canvas by some arbitrary path. This initial implementation is fairly naive, with a good few allocations, though this can probably be improved in future.
46 lines
1.8 KiB
C++
46 lines
1.8 KiB
C++
/*
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* Copyright (c) 2023, MacDue <macdue@dueutil.tech>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <LibGfx/AntiAliasingPainter.h>
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#include <LibWeb/HTML/Canvas/CanvasPathClipper.h>
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namespace Web::HTML {
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// FIXME: This pretty naive, we should be able to cut down the allocations here
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// (especially for the paint style which is a bit sad).
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ErrorOr<CanvasPathClipper> CanvasPathClipper::create(Gfx::Painter& painter, CanvasClip const& canvas_clip)
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{
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auto bounding_box = enclosing_int_rect(canvas_clip.path.bounding_box());
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Gfx::IntRect actual_save_rect {};
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auto maybe_bitmap = painter.get_region_bitmap(bounding_box, Gfx::BitmapFormat::BGRA8888, actual_save_rect);
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RefPtr<Gfx::Bitmap> saved_clip_region;
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if (!maybe_bitmap.is_error()) {
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saved_clip_region = maybe_bitmap.release_value();
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} else if (actual_save_rect.is_empty()) {
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// This is okay, no need to report an error.
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} else {
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return maybe_bitmap.release_error();
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}
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painter.save();
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painter.add_clip_rect(bounding_box);
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return CanvasPathClipper(move(saved_clip_region), bounding_box, canvas_clip);
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}
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ErrorOr<void> CanvasPathClipper::apply_clip(Gfx::Painter& painter)
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{
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painter.restore();
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if (!m_saved_clip_region)
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return {};
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Gfx::IntRect actual_save_rect {};
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auto clip_area = TRY(painter.get_region_bitmap(m_bounding_box, Gfx::BitmapFormat::BGRA8888, actual_save_rect));
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painter.blit(actual_save_rect.location(), *m_saved_clip_region, m_saved_clip_region->rect(), 1.0f, false);
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Gfx::AntiAliasingPainter aa_painter { painter };
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auto fill_offset = m_bounding_box.location() - actual_save_rect.location();
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aa_painter.fill_path(m_canvas_clip.path, TRY(Gfx::BitmapPaintStyle::create(clip_area, fill_offset)), m_canvas_clip.winding_rule);
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return {};
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}
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}
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