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LibWeb: Extract CanvasTransform class from CRC2D

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The implementation of this got a little funky, because it has to access
methods from CanvasState.
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Sam Atkins 2022-08-12 14:48:11 +01:00 • committed by Andreas Kling
parent 08e6071ebb
commit aa87b9699e
5 changed files with 101 additions and 69 deletions
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84
Userland/Libraries/LibWeb/HTML/Canvas/CanvasTransform.h Normal file
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/*
* Copyright (c) 2020-2022, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021-2022, Linus Groh <linusg@serenityos.org>
* Copyright (c) 2022, Sam Atkins <atkinssj@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Debug.h>
#include <LibWeb/HTML/Canvas/CanvasState.h>
namespace Web::HTML {
// https://html.spec.whatwg.org/multipage/canvas.html#canvastransform
template<typename IncludingClass>
class CanvasTransform {
public:
~CanvasTransform() = default;
void scale(float sx, float sy)
{
dbgln_if(CANVAS_RENDERING_CONTEXT_2D_DEBUG, "CanvasTransform::scale({}, {})", sx, sy);
my_drawing_state().transform.scale(sx, sy);
}
void translate(float tx, float ty)
{
dbgln_if(CANVAS_RENDERING_CONTEXT_2D_DEBUG, "CanvasTransform::translate({}, {})", tx, ty);
my_drawing_state().transform.translate(tx, ty);
}
void rotate(float radians)
{
dbgln_if(CANVAS_RENDERING_CONTEXT_2D_DEBUG, "CanvasTransform::rotate({})", radians);
my_drawing_state().transform.rotate_radians(radians);
}
// https://html.spec.whatwg.org/multipage/canvas.html#dom-context-2d-transform
void transform(double a, double b, double c, double d, double e, double f)
{
// 1. If any of the arguments are infinite or NaN, then return.
if (!isfinite(a) || !isfinite(b) || !isfinite(c) || !isfinite(d) || !isfinite(e) || !isfinite(f))
return;
// 2. Replace the current transformation matrix with the result of multiplying the current transformation matrix with the matrix described by:
// a c e
// b d f
// 0 0 1
my_drawing_state().transform.multiply({ static_cast<float>(a), static_cast<float>(b), static_cast<float>(c), static_cast<float>(d), static_cast<float>(e), static_cast<float>(f) });
}
// https://html.spec.whatwg.org/multipage/canvas.html#dom-context-2d-settransform
void set_transform(double a, double b, double c, double d, double e, double f)
{
// 1. If any of the arguments are infinite or NaN, then return.
if (!isfinite(a) || !isfinite(b) || !isfinite(c) || !isfinite(d) || !isfinite(e) || !isfinite(f))
return;
// 2. Reset the current transformation matrix to the identity matrix.
my_drawing_state().transform = {};
// 3. Invoke the transform(a, b, c, d, e, f) method with the same arguments.
transform(a, b, c, d, e, f);
}
// https://html.spec.whatwg.org/multipage/canvas.html#dom-context-2d-resettransform
void reset_transform()
{
// The resetTransform() method, when invoked, must reset the current transformation matrix to the identity matrix.
my_drawing_state().transform = {};
}
protected:
CanvasTransform() = default;
private:
CanvasState::DrawingState& my_drawing_state() { return reinterpret_cast<IncludingClass&>(*this).drawing_state(); }
CanvasState::DrawingState const& my_drawing_state() const { return reinterpret_cast<IncludingClass const&>(*this).drawing_state(); }
};
}