chromium/src/third_party/blink/renderer/core/css/css_to_length_conversion_data.h

/*
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 * in the documentation and/or other materials provided with the
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 * this software without specific prior written permission.
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#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_CSS_CSS_TO_LENGTH_CONVERSION_DATA_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_CSS_CSS_TO_LENGTH_CONVERSION_DATA_H_

#include <limits>
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/css/css_primitive_value.h"
#include "third_party/blink/renderer/platform/geometry/double_size.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/assertions.h"
#include "third_party/blink/renderer/platform/wtf/math_extras.h"

namespace blink {

class ComputedStyle;
class LayoutView;
class Font;

class CORE_EXPORT CSSToLengthConversionData {
  STACK_ALLOCATED();

 public:
  class CORE_EXPORT FontSizes {
    DISALLOW_NEW();

   public:
    FontSizes() : em_(0), rem_(0), font_(nullptr), zoom_(1) {}
    FontSizes(float em, float rem, const Font*, float zoom);
    FontSizes(const ComputedStyle*, const ComputedStyle* root_style);

    float Em() const { return em_; }
    float Rem() const { return rem_; }
    float Zoom() const;
    float Ex() const;
    float Ch() const;

   private:
    float em_;
    float rem_;
    const Font* font_;
    float zoom_;
  };

  class CORE_EXPORT ViewportSize {
    DISALLOW_NEW();

   public:
    ViewportSize() = default;
    ViewportSize(double width, double height) : size_(width, height) {}
    explicit ViewportSize(const LayoutView*);

    double Width() const { return size_.Width(); }
    double Height() const { return size_.Height(); }

   private:
    DoubleSize size_;
  };

  CSSToLengthConversionData() : style_(nullptr), zoom_(1) {}
  CSSToLengthConversionData(const ComputedStyle*,
                            const FontSizes&,
                            const ViewportSize&,
                            float zoom);
  CSSToLengthConversionData(const ComputedStyle* curr_style,
                            const ComputedStyle* root_style,
                            const LayoutView*,
                            float zoom);

  float Zoom() const { return zoom_; }

  float EmFontSize() const;
  float RemFontSize() const;
  float ExFontSize() const;
  float ChFontSize() const;
  float FontSizeZoom() const { return font_sizes_.Zoom(); }

  // 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& font_sizes) { font_sizes_ = font_sizes; }
  void SetZoom(float zoom) {
    DCHECK(std::isfinite(zoom));
    DCHECK_GT(zoom, 0);
    zoom_ = zoom;
  }

  CSSToLengthConversionData CopyWithAdjustedZoom(float new_zoom) const {
    return CSSToLengthConversionData(style_, font_sizes_, viewport_size_,
                                     new_zoom);
  }

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

 private:
  const ComputedStyle* style_;
  FontSizes font_sizes_;
  ViewportSize viewport_size_;
  float zoom_;
};

}  // namespace blink

#endif