Less magic numbers in converting CSS lengths of cm/mm/pc/pt types.

Source/core/svg/SVGLengthContext.cpp

 /*
  * Copyright (C) 2004, 2005, 2006 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 93 matching lines @@
         return value;
     case LengthTypePX:
         return value;
     case LengthTypePercentage:
         return convertValueFromPercentageToUserUnits(value / 100, mode, exceptionState);
     case LengthTypeEMS:
         return convertValueFromEMSToUserUnits(value, exceptionState);
     case LengthTypeEXS:
         return convertValueFromEXSToUserUnits(value, exceptionState);
     case LengthTypeCM:
-        return value * cssPixelsPerInch / 2.54f;
+        return value * cssPixelsPerCentimeter;
     case LengthTypeMM:
-        return value * cssPixelsPerInch / 25.4f;
+        return value * cssPixelsPerMillimeter;
     case LengthTypeIN:
         return value * cssPixelsPerInch;
     case LengthTypePT:
-        return value * cssPixelsPerInch / 72;
+        return value * cssPixelsPerPoint;
     case LengthTypePC:
-        return value * cssPixelsPerInch / 6;
+        return value * cssPixelsPerPica;
     }
 
     ASSERT_NOT_REACHED();
     return 0;
 }
 
 float SVGLengthContext::convertValueFromUserUnits(float value, SVGLengthMode mode, SVGLengthType toUnit, ExceptionState& exceptionState) const
 {
     switch (toUnit) {
     case LengthTypeUnknown:
         exceptionState.throwUninformativeAndGenericDOMException(NotSupportedError);
         return 0;
     case LengthTypeNumber:
         return value;
     case LengthTypePercentage:
         return convertValueFromUserUnitsToPercentage(value * 100, mode, exceptionState);
     case LengthTypeEMS:
         return convertValueFromUserUnitsToEMS(value, exceptionState);
     case LengthTypeEXS:
         return convertValueFromUserUnitsToEXS(value, exceptionState);
     case LengthTypePX:
         return value;
     case LengthTypeCM:
-        return value * 2.54f / cssPixelsPerInch;
+        return value / cssPixelsPerCentimeter;
     case LengthTypeMM:
-        return value * 25.4f / cssPixelsPerInch;
+        return value / cssPixelsPerMillimeter;
     case LengthTypeIN:
         return value / cssPixelsPerInch;
     case LengthTypePT:
-        return value * 72 / cssPixelsPerInch;
+        return value / cssPixelsPerPoint;
     case LengthTypePC:
-        return value * 6 / cssPixelsPerInch;
+        return value / cssPixelsPerPica;
     }
 
     ASSERT_NOT_REACHED();
     return 0;
 }
 
 float SVGLengthContext::convertValueFromUserUnitsToPercentage(float value, SVGLengthMode mode, ExceptionState& exceptionState) const
 {
     FloatSize viewportSize;
     if (!determineViewport(viewportSize)) {
@@ skipping 136 matching lines @@
 
     const SVGSVGElement* svg = static_cast<const SVGSVGElement*>(viewportElement);
     viewportSize = svg->currentViewBoxRect().size();
     if (viewportSize.isEmpty())
         viewportSize = svg->currentViewportSize();
 
     return true;
 }
 
 }