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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Base64.h>
#include <AK/Checked.h>
#include <LibGfx/Bitmap.h>
#include <LibGfx/PNGWriter.h>
#include <LibWeb/CSS/StyleComputer.h>
#include <LibWeb/DOM/Document.h>
#include <LibWeb/HTML/CanvasRenderingContext2D.h>
#include <LibWeb/HTML/HTMLCanvasElement.h>
#include <LibWeb/Layout/CanvasBox.h>
namespace Web::HTML {
static constexpr auto max_canvas_area = 16384 * 16384;
HTMLCanvasElement::HTMLCanvasElement(DOM::Document& document, DOM::QualifiedName qualified_name)
: HTMLElement(document, move(qualified_name))
{
}
HTMLCanvasElement::~HTMLCanvasElement() = default;
unsigned HTMLCanvasElement::width() const
{
return attribute(HTML::AttributeNames::width).to_uint().value_or(300);
}
unsigned HTMLCanvasElement::height() const
{
return attribute(HTML::AttributeNames::height).to_uint().value_or(150);
}
void HTMLCanvasElement::set_width(unsigned value)
{
set_attribute(HTML::AttributeNames::width, String::number(value));
m_bitmap = nullptr;
if (m_context)
m_context->reset_to_default_state();
}
void HTMLCanvasElement::set_height(unsigned value)
{
set_attribute(HTML::AttributeNames::height, String::number(value));
m_bitmap = nullptr;
if (m_context)
m_context->reset_to_default_state();
}
RefPtr<Layout::Node> HTMLCanvasElement::create_layout_node(NonnullRefPtr<CSS::StyleProperties> style)
{
return adopt_ref(*new Layout::CanvasBox(document(), *this, move(style)));
}
CanvasRenderingContext2D* HTMLCanvasElement::get_context(String type)
{
if (type != "2d")
return nullptr;
if (!m_context)
m_context = CanvasRenderingContext2D::create(*this);
return m_context;
}
static Gfx::IntSize bitmap_size_for_canvas(HTMLCanvasElement const& canvas)
{
auto width = canvas.width();
auto height = canvas.height();
Checked<size_t> area = width;
area *= height;
if (area.has_overflow()) {
dbgln("Refusing to create {}x{} canvas (overflow)", width, height);
return {};
}
if (area.value() > max_canvas_area) {
dbgln("Refusing to create {}x{} canvas (exceeds maximum size)", width, height);
return {};
}
return Gfx::IntSize(width, height);
}
bool HTMLCanvasElement::create_bitmap()
{
auto size = bitmap_size_for_canvas(*this);
if (size.is_empty()) {
m_bitmap = nullptr;
return false;
}
if (!m_bitmap || m_bitmap->size() != size) {
auto bitmap_or_error = Gfx::Bitmap::try_create(Gfx::BitmapFormat::BGRA8888, size);
if (bitmap_or_error.is_error())
return false;
m_bitmap = bitmap_or_error.release_value_but_fixme_should_propagate_errors();
}
return m_bitmap;
}
String HTMLCanvasElement::to_data_url(String const& type, [[maybe_unused]] Optional<double> quality) const
{
if (!m_bitmap)
return {};
if (type != "image/png")
return {};
auto encoded_bitmap = Gfx::PNGWriter::encode(*m_bitmap);
return AK::URL::create_with_data(type, encode_base64(encoded_bitmap), true).to_string();
}
}
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