e9001da8d6
Implement setLineDash() and getLineDash() in CanvasPathDrawingStyles, which write/read from the CanvasState object. This doesn't implement the actual drawing of a dashed line, but at least sites using the Chart.js library no longer fail with an exception. Unfortunately the Painter classes don't support dashed/dotted lines based on segments yet.
65 lines
2.3 KiB
C++
65 lines
2.3 KiB
C++
/*
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* Copyright (c) 2022, Sam Atkins <atkinssj@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <LibWeb/HTML/Canvas/CanvasState.h>
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namespace Web::HTML {
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// https://html.spec.whatwg.org/multipage/canvas.html#canvaspathdrawingstyles
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template<typename IncludingClass>
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class CanvasPathDrawingStyles {
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public:
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~CanvasPathDrawingStyles() = default;
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// https://html.spec.whatwg.org/multipage/canvas.html#dom-context-2d-linewidth
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void set_line_width(float line_width)
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{
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// On setting, zero, negative, infinite, and NaN values must be ignored, leaving the value unchanged;
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if (line_width <= 0 || !isfinite(line_width))
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return;
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// other values must change the current value to the new value.
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my_drawing_state().line_width = line_width;
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}
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float line_width() const
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{
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// On getting, it must return the current value.
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return my_drawing_state().line_width;
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}
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// https://html.spec.whatwg.org/multipage/canvas.html#dom-context-2d-setlinedash
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void set_line_dash(Vector<double> segments)
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{
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// 1. If any value in segments is not finite (e.g. an Infinity or a NaN value), or if any value is negative (less than zero), then return (without throwing an exception; user agents could show a message on a developer console, though, as that would be helpful for debugging).
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for (auto const& segment : segments) {
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if (!isfinite(segment) || segment < 0)
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return;
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}
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// 2. If the number of elements in segments is odd, then let segments be the concatenation of two copies of segments.
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if (segments.size() % 2 == 1)
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segments.extend(segments);
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// 3. Let the object's dash list be segments.
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my_drawing_state().dash_list = segments;
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}
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// https://html.spec.whatwg.org/multipage/canvas.html#dom-context-2d-getlinedash
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Vector<double> get_line_dash()
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{
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return my_drawing_state().dash_list;
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}
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protected:
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CanvasPathDrawingStyles() = default;
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private:
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CanvasState::DrawingState& my_drawing_state() { return reinterpret_cast<IncludingClass&>(*this).drawing_state(); }
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CanvasState::DrawingState const& my_drawing_state() const { return reinterpret_cast<IncludingClass const&>(*this).drawing_state(); }
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};
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}
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