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

   1 /*
   2  * Copyright (C) 2013 Google Inc. All rights reserved.
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  16  * this software without specific prior written permission.
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  30
  31 #include "config.h"
  32 #include "core/css/CSSToLengthConversionData.h"
  33
  34 #include "core/layout/LayoutView.h"
  35 #include "core/style/ComputedStyle.h"
  36
  37 namespace blink {
  38
  39 CSSToLengthConversionData::FontSizes::FontSizes(float em, float rem, const Font* font)
  40     : m_em(em)
  41     , m_rem(rem)
  42     , m_font(font)
  43 {
  44     // FIXME: Improve RAII of StyleResolverState to use const Font&.
  45     ASSERT(m_font);
  46 }
  47
  48 CSSToLengthConversionData::FontSizes::FontSizes(const ComputedStyle* style, const ComputedStyle* rootStyle)
  49     : FontSizes(style->computedFontSize(), rootStyle ? rootStyle->computedFontSize() : 1.0f, &style->font())
  50 {
  51 }
  52
  53 float CSSToLengthConversionData::FontSizes::ex() const
  54 {
  55     ASSERT(m_font);
  56     // FIXME: We have a bug right now where the zoom will be applied twice to EX units.
  57     // We really need to compute EX using fontMetrics for the original specifiedSize and not use
  58     // our actual constructed layoutObject font.
  59     if (!m_font->fontMetrics().hasXHeight())
  60         return m_em / 2.0f;
  61     return m_font->fontMetrics().xHeight();
  62 }
  63
  64 float CSSToLengthConversionData::FontSizes::ch() const
  65 {
  66     ASSERT(m_font);
  67     return m_font->fontMetrics().zeroWidth();
  68 }
  69
  70 CSSToLengthConversionData::ViewportSize::ViewportSize(const LayoutView* layoutView)
  71     : m_width(layoutView ? layoutView->layoutViewportWidth() : 0)
  72     , m_height(layoutView ? layoutView->layoutViewportHeight() : 0)
  73 {
  74 }
  75
  76 CSSToLengthConversionData::CSSToLengthConversionData(const ComputedStyle* style, const FontSizes& fontSizes, const ViewportSize& viewportSize, float zoom)
  77     : m_style(style)
  78     , m_fontSizes(fontSizes)
  79     , m_viewportSize(viewportSize)
  80     , m_zoom(clampTo<float>(zoom, std::numeric_limits<float>::denorm_min()))
  81 {
  82     ASSERT(m_style);
  83 }
  84
  85 CSSToLengthConversionData::CSSToLengthConversionData(const ComputedStyle* style, const ComputedStyle* rootStyle, const LayoutView* layoutView, float zoom)
  86     : CSSToLengthConversionData(style, FontSizes(style, rootStyle), ViewportSize(layoutView), zoom)
  87 {
  88 }
  89
  90 double CSSToLengthConversionData::viewportWidthPercent() const
  91 {
  92     m_style->setHasViewportUnits();
  93     return m_viewportSize.width() / 100;
  94 }
  95 double CSSToLengthConversionData::viewportHeightPercent() const
  96 {
  97     m_style->setHasViewportUnits();
  98     return m_viewportSize.height() / 100;
  99 }
 100 double CSSToLengthConversionData::viewportMinPercent() const
 101 {
 102     m_style->setHasViewportUnits();
 103     return std::min(m_viewportSize.width(), m_viewportSize.height()) / 100;
 104 }
 105 double CSSToLengthConversionData::viewportMaxPercent() const
 106 {
 107     m_style->setHasViewportUnits();
 108     return std::max(m_viewportSize.width(), m_viewportSize.height()) / 100;
 109 }
 110
 111 float CSSToLengthConversionData::remFontSize() const
 112 {
 113     m_style->setHasRemUnits();
 114     return m_fontSizes.rem();
 115 }
 116
 117 } // namespace blink