Adding support of viewport units to SVG

third_party/WebKit/Source/core/svg/SVGLengthContext.cpp

Index: third_party/WebKit/Source/core/svg/SVGLengthContext.cpp
diff --git a/third_party/WebKit/Source/core/svg/SVGLengthContext.cpp b/third_party/WebKit/Source/core/svg/SVGLengthContext.cpp
index f553158421f727b1c1c0d0772fdae44da33a1052..81404c2aab8f1c9e8d327086c74c3bf38444bd3c 100644
--- a/third_party/WebKit/Source/core/svg/SVGLengthContext.cpp
+++ b/third_party/WebKit/Source/core/svg/SVGLengthContext.cpp
@@ -26,6 +26,7 @@
 #include "core/css/CSSHelper.h"
 #include "core/css/CSSPrimitiveValue.h"
 #include "core/dom/NodeComputedStyle.h"
+#include "core/frame/FrameView.h"
 #include "core/layout/LayoutObject.h"
 #include "core/style/ComputedStyle.h"
 #include "core/svg/SVGSVGElement.h"
@@ -226,6 +227,12 @@ float SVGLengthContext::convertValueToUserUnits(float value, SVGLengthMode mode,
     case CSSPrimitiveValue::UnitType::Chs:
         userUnits = convertValueFromCHSToUserUnits(value);
         break;
+    case CSSPrimitiveValue::UnitType::ViewportWidth:
+    case CSSPrimitiveValue::UnitType::ViewportHeight:
+    case CSSPrimitiveValue::UnitType::ViewportMin:
+    case CSSPrimitiveValue::UnitType::ViewportMax:
+        userUnits = convertValueFromViewportUnitsToUserUnits(fromUnit, value);
+        break;
     default:
         ASSERT_NOT_REACHED();
         break;
@@ -273,6 +280,11 @@ float SVGLengthContext::convertValueFromUserUnits(float value, SVGLengthMode mod
         return value / cssPixelsPerPoint;
     case CSSPrimitiveValue::UnitType::Picas:
         return value / cssPixelsPerPica;
+    case CSSPrimitiveValue::UnitType::ViewportWidth:
+    case CSSPrimitiveValue::UnitType::ViewportHeight:
+    case CSSPrimitiveValue::UnitType::ViewportMin:
+    case CSSPrimitiveValue::UnitType::ViewportMax:
+        return convertValueFromUserUnitsToViewportUnits(toUnit, value);
     default:
         break;
     }
@@ -329,6 +341,94 @@ float SVGLengthContext::convertValueFromEXSToUserUnits(float value) const
     return value * ceilf(style->fontMetrics().xHeight() / style->effectiveZoom());
 }
 
+static inline float viewportLengthPercent(const float widthOrHeight)
+{
+    return widthOrHeight / 100;
+}
+
+static inline float viewportMinPercent(const FloatSize& viewportSize)
+{
+    return std::min(viewportSize.width(), viewportSize.height()) / 100;
+}
+
+static inline float viewportMaxPercent(const FloatSize& viewportSize)
+{
+    return std::max(viewportSize.width(), viewportSize.height()) / 100;
+}
+
+
+float SVGLengthContext::convertValueFromUserUnitsToViewportUnits(CSSPrimitiveValue::UnitType toUnit, float value) const
+{
+    if (!m_context)
+        return 0;
+
+    const ComputedStyle* style = computedStyleForLengthResolving(m_context);
+    if (!style)
+        return 0;
+
+    const Document& document = m_context->document();
+    FrameView* view = document.view();
+    if (!view)
+        return 0;
+
+    FloatSize viewportSize(view->width(), view->height());
+
+    switch (toUnit) {

[fs, 2016/01/04 19:40:05]

I think this would be slightly if it was using same approach as dimensionForMode
- i.e have a helper that returns either the viewport width/height/min/man and
then apply that to |value| as needed. Should get rid of the duplication between
the "From" and "To" cases.

[Shanmuga Pandi, 2016/01/05 10:04:49]

Done.

+    case CSSPrimitiveValue::UnitType::ViewportWidth:
+        return value / viewportLengthPercent(viewportSize.width()) / style->effectiveZoom();
+
+    case CSSPrimitiveValue::UnitType::ViewportHeight:
+        return value / viewportLengthPercent(viewportSize.height()) / style->effectiveZoom();
+
+    case CSSPrimitiveValue::UnitType::ViewportMin:
+        return value / viewportMinPercent(viewportSize) / style->effectiveZoom();
+
+    case CSSPrimitiveValue::UnitType::ViewportMax:
+        return value / viewportMaxPercent(viewportSize) / style->effectiveZoom();
+    default:
+        break;
+    }
+
+    ASSERT_NOT_REACHED();
+    return 0;
+}
+
+float SVGLengthContext::convertValueFromViewportUnitsToUserUnits(CSSPrimitiveValue::UnitType fromUnit, float value) const
+{
+    if (!m_context)
+        return 0;
+
+    const ComputedStyle* style = computedStyleForLengthResolving(m_context);
+    if (!style)
+        return 0;
+
+    const Document& document = m_context->document();
+    FrameView* view = document.view();
+    if (!view)
+        return 0;
+
+    FloatSize viewportSize(view->width(), view->height());
+
+    switch (fromUnit) {
+    case CSSPrimitiveValue::UnitType::ViewportWidth:
+        return value * viewportLengthPercent(viewportSize.width()) / style->effectiveZoom();
+
+    case CSSPrimitiveValue::UnitType::ViewportHeight:
+        return value * viewportLengthPercent(viewportSize.height()) / style->effectiveZoom();
+
+    case CSSPrimitiveValue::UnitType::ViewportMin:
+        return value * viewportMinPercent(viewportSize) / style->effectiveZoom();
+
+    case CSSPrimitiveValue::UnitType::ViewportMax:
+        return value * viewportMaxPercent(viewportSize) / style->effectiveZoom();
+    default:
+        break;
+    }
+
+    ASSERT_NOT_REACHED();
+    return 0;
+}
+
 bool SVGLengthContext::determineViewport(FloatSize& viewportSize) const
 {
     if (!m_context)