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

   1 /*
   2  * Copyright (C) 2013 Google Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
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   9  * notice, this list of conditions and the following disclaimer.
  10  *     * Redistributions in binary form must reproduce the above
  11  * copyright notice, this list of conditions and the following disclaimer
  12  * in the documentation and/or other materials provided with the
  13  * distribution.
  14  *     * Neither the name of Google Inc. nor the names of its
  15  * contributors may be used to endorse or promote products derived from
  16  * this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #ifndef CSSToLengthConversionData_h
  32 #define CSSToLengthConversionData_h
  33
  34 #include "core/CoreExport.h"
  35 #include "wtf/Allocator.h"
  36 #include "wtf/Assertions.h"
  37 #include "wtf/MathExtras.h"
  38 #include <limits>
  39
  40 namespace blink {
  41
  42 class ComputedStyle;
  43 class LayoutView;
  44 class Font;
  45
  46 class CORE_EXPORT CSSToLengthConversionData {
  47     DISALLOW_ALLOCATION();
  48 public:
  49
  50     class FontSizes {
  51         DISALLOW_ALLOCATION();
  52     public:
  53         FontSizes() : m_em(0), m_rem(0), m_font(nullptr) { }
  54         FontSizes(float em, float rem, const Font*);
  55         FontSizes(const ComputedStyle*, const ComputedStyle* rootStyle);
  56
  57         float em() const { return m_em; }
  58         float rem() const { return m_rem; }
  59         float ex() const;
  60         float ch() const;
  61     private:
  62         float m_em;
  63         float m_rem;
  64         const Font* m_font;
  65     };
  66
  67     class ViewportSize {
  68         DISALLOW_ALLOCATION();
  69     public:
  70         ViewportSize() : m_width(0), m_height(0) { }
  71         ViewportSize(double width, double height) : m_width(width), m_height(height) { }
  72         explicit ViewportSize(const LayoutView*);
  73
  74         double width() const { return m_width; }
  75         double height() const { return m_height; }
  76     private:
  77         double m_width;
  78         double m_height;
  79     };
  80
  81     CSSToLengthConversionData() { }
  82     CSSToLengthConversionData(const ComputedStyle*, const FontSizes&, const ViewportSize&, float zoom);
  83     CSSToLengthConversionData(const ComputedStyle* currStyle, const ComputedStyle* rootStyle, const LayoutView*, float zoom);
  84
  85     float zoom() const { return m_zoom; }
  86
  87     float emFontSize() const { return m_fontSizes.em(); }
  88     float remFontSize() const;
  89     float exFontSize() const { return m_fontSizes.ex(); }
  90     float chFontSize() const { return m_fontSizes.ch(); }
  91
  92     // Accessing these marks the style as having viewport units
  93     double viewportWidthPercent() const;
  94     double viewportHeightPercent() const;
  95     double viewportMinPercent() const;
  96     double viewportMaxPercent() const;
  97
  98     void setFontSizes(const FontSizes& fontSizes) { m_fontSizes = fontSizes; }
  99     void setZoom(float zoom)
 100     {
 101         ASSERT(std::isfinite(zoom) && zoom > 0);
 102         m_zoom = zoom;
 103     }
 104
 105     CSSToLengthConversionData copyWithAdjustedZoom(float newZoom) const
 106     {
 107         return CSSToLengthConversionData(m_style, m_fontSizes, m_viewportSize, newZoom);
 108     }
 109
 110 private:
 111     const ComputedStyle* m_style;
 112     FontSizes m_fontSizes;
 113     ViewportSize m_viewportSize;
 114     float m_zoom;
 115 };
 116
 117 } // namespace blink
 118
 119 #endif