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			120 lines
		
	
	
	
		
			3.8 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			120 lines
		
	
	
	
		
			3.8 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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|  * All rights reserved.
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|  *
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|  * Redistribution and use in source and binary forms, with or without
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|  * modification, are permitted provided that the following conditions are met:
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|  *
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|  * 1. Redistributions of source code must retain the above copyright notice, this
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|  *    list of conditions and the following disclaimer.
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|  *
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|  * 2. Redistributions in binary form must reproduce the above copyright notice,
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|  *    this list of conditions and the following disclaimer in the documentation
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|  *    and/or other materials provided with the distribution.
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|  *
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|  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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|  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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|  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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|  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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|  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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|  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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|  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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|  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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|  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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|  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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|  */
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| 
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| #include <AK/Checked.h>
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| #include <LibGfx/Bitmap.h>
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| #include <LibWeb/CSS/StyleResolver.h>
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| #include <LibWeb/DOM/CanvasRenderingContext2D.h>
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| #include <LibWeb/DOM/Document.h>
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| #include <LibWeb/DOM/HTMLCanvasElement.h>
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| #include <LibWeb/Layout/LayoutCanvas.h>
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| 
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| namespace Web {
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| 
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| static constexpr auto max_canvas_area = 16384 * 16384;
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| 
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| HTMLCanvasElement::HTMLCanvasElement(Document& document, const FlyString& tag_name)
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|     : HTMLElement(document, tag_name)
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| {
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| }
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| 
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| HTMLCanvasElement::~HTMLCanvasElement()
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| {
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| }
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| 
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| int HTMLCanvasElement::requested_width() const
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| {
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|     bool ok = false;
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|     unsigned width = attribute("width").to_int(ok);
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|     if (ok)
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|         return width;
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| 
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|     return 300;
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| }
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| 
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| int HTMLCanvasElement::requested_height() const
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| {
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|     bool ok = false;
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|     unsigned height = attribute("height").to_int(ok);
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|     if (ok)
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|         return height;
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| 
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|     return 150;
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| }
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| 
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| RefPtr<LayoutNode> HTMLCanvasElement::create_layout_node(const StyleProperties* parent_style) const
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| {
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|     auto style = document().style_resolver().resolve_style(*this, parent_style);
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|     auto display = style->string_or_fallback(CSS::PropertyID::Display, "inline");
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|     if (display == "none")
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|         return nullptr;
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|     return adopt(*new LayoutCanvas(*this, move(style)));
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| }
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| 
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| CanvasRenderingContext2D* HTMLCanvasElement::get_context(String type)
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| {
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|     ASSERT(type == "2d");
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|     if (!m_context)
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|         m_context = CanvasRenderingContext2D::create(*this);
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|     return m_context;
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| }
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| 
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| static Gfx::Size bitmap_size_for_canvas(const HTMLCanvasElement& canvas)
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| {
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|     int width = canvas.requested_width();
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|     int height = canvas.requested_height();
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|     if (width < 0 || height < 0) {
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|         dbg() << "Refusing to create canvas with negative size";
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|         return {};
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|     }
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| 
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|     Checked<size_t> area = width;
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|     area *= height;
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| 
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|     if (area.has_overflow()) {
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|         dbg() << "Refusing to create " << width << "x" << height << " canvas (overflow)";
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|         return {};
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|     }
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|     if (area.value() > max_canvas_area) {
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|         dbg() << "Refusing to create " << width << "x" << height << " canvas (exceeds maximum size)";
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|         return {};
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|     }
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|     return { width, height };
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| }
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| 
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| bool HTMLCanvasElement::create_bitmap()
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| {
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|     auto size = bitmap_size_for_canvas(*this);
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|     if (size.is_empty()) {
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|         m_bitmap = nullptr;
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|         return false;
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|     }
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|     if (!m_bitmap || m_bitmap->size() != size)
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|         m_bitmap = Gfx::Bitmap::create(Gfx::BitmapFormat::RGBA32, size);
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|     return m_bitmap;
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| }
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| 
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| }
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