third_party/WebKit/Source/core/css/CSSToLengthConversionData.h

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#ifndef CSSToLengthConversionData_h
#define CSSToLengthConversionData_h

#include "core/CoreExport.h"
#include "core/css/CSSPrimitiveValue.h"
#include "platform/geometry/DoubleSize.h"
#include "wtf/Allocator.h"
#include "wtf/Assertions.h"
#include "wtf/MathExtras.h"
#include <limits>

namespace blink {

class ComputedStyle;
class LayoutView;
class Font;

class CORE_EXPORT CSSToLengthConversionData {
    DISALLOW_NEW();
public:

    class FontSizes {
        DISALLOW_NEW();
    public:
        FontSizes() : m_em(0), m_rem(0), m_font(nullptr) { }
        FontSizes(float em, float rem, const Font*);
        FontSizes(const ComputedStyle*, const ComputedStyle* rootStyle);

        float em() const { return m_em; }
        float rem() const { return m_rem; }
        float ex() const;
        float ch() const;
    private:
        float m_em;
        float m_rem;
        const Font* m_font;
    };

    class ViewportSize {
        DISALLOW_NEW();
    public:
        ViewportSize() { }
        ViewportSize(double width, double height) : m_size(width, height) { }
        explicit ViewportSize(const LayoutView*);

        double width() const { return m_size.width(); }
        double height() const { return m_size.height(); }
    private:
        DoubleSize m_size;
    };

    CSSToLengthConversionData() { }
    CSSToLengthConversionData(const ComputedStyle*, const FontSizes&, const ViewportSize&, float zoom);
    CSSToLengthConversionData(const ComputedStyle* currStyle, const ComputedStyle* rootStyle, const LayoutView*, float zoom);

    float zoom() const { return m_zoom; }

    float emFontSize() const { return m_fontSizes.em(); }
    float remFontSize() const;
    float exFontSize() const { return m_fontSizes.ex(); }
    float chFontSize() const { return m_fontSizes.ch(); }

    // Accessing these marks the style as having viewport units
    double viewportWidthPercent() const;
    double viewportHeightPercent() const;
    double viewportMinPercent() const;
    double viewportMaxPercent() const;

    void setFontSizes(const FontSizes& fontSizes) { m_fontSizes = fontSizes; }
    void setZoom(float zoom)
    {
        ASSERT(std::isfinite(zoom) && zoom > 0);
        m_zoom = zoom;
    }

    CSSToLengthConversionData copyWithAdjustedZoom(float newZoom) const
    {
        return CSSToLengthConversionData(m_style, m_fontSizes, m_viewportSize, newZoom);
    }

    double zoomedComputedPixels(double value, CSSPrimitiveValue::UnitType) const;

private:
    const ComputedStyle* m_style;
    FontSizes m_fontSizes;
    ViewportSize m_viewportSize;
    float m_zoom;
};

} // namespace blink

#endif