ladybird/Libraries/LibWeb/DOM/HTMLPathElement.h

/*
 * Copyright (c) 2020, Matthew Olsson <matthewcolsson@gmail.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include <LibGfx/Bitmap.h>
#include <LibWeb/DOM/HTMLElement.h>
#include <LibWeb/DOM/SvgContext.h>

namespace Web {

enum class PathInstructionType {
    Move,
    ClosePath,
    Line,
    HorizontalLine,
    VerticalLine,
    Curve,
    SmoothCurve,
    QuadraticBezierCurve,
    SmoothQuadraticBezierCurve,
    EllipticalArc,
    Invalid,
};

struct PathInstruction {
    PathInstructionType type;
    bool absolute;
    Vector<float> data;
};

class PathDataParser final {
public:
    PathDataParser(const String& source);
    ~PathDataParser() = default;

    Vector<PathInstruction> parse();

private:
    void parse_drawto();

    void parse_moveto();
    void parse_closepath();
    void parse_lineto();
    void parse_horizontal_lineto();
    void parse_vertical_lineto();
    void parse_curveto();
    void parse_smooth_curveto();
    void parse_quadratic_bezier_curveto();
    void parse_smooth_quadratic_bezier_curveto();
    void parse_elliptical_arc();

    float parse_coordinate();
    Vector<float> parse_coordinate_pair();
    Vector<float> parse_coordinate_sequence();
    Vector<Vector<float>> parse_coordinate_pair_sequence();
    Vector<float> parse_coordinate_pair_double();
    Vector<float> parse_coordinate_pair_triplet();
    Vector<float> parse_elliptical_arg_argument();
    void parse_whitespace(bool must_match_once = false);
    void parse_comma_whitespace();
    float parse_fractional_constant();
    float parse_number();
    float parse_flag();

    bool match_whitespace() const;
    bool match_comma_whitespace() const;
    bool match_number() const;
    bool match(char c) const { return !done() && ch() == c; }

    bool done() const { return m_cursor >= m_source.length(); }
    char ch() const { return m_source[m_cursor]; }
    char consume() { return m_source[m_cursor++]; }

    String m_source;
    size_t m_cursor { 0 };
    Vector<PathInstruction> m_instructions;
};

class HTMLPathElement final
    : public HTMLElement
    , public SvgGraphicElement {
public:
    HTMLPathElement(Document&, const FlyString& tag_name);
    virtual ~HTMLPathElement() override = default;

    virtual void parse_attribute(const FlyString& name, const String& value) override;
    virtual void paint(const SvgPaintingContext&, Gfx::Painter& painter) override;

private:
    Vector<PathInstruction> m_instructions;
};

template<>
inline bool is<HTMLPathElement>(const Node& node)
{
    return is<Element>(node) && to<Element>(node).tag_name() == HTML::TagNames::path;
}

}