ui/gfx/shadow_value.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_GFX_SHADOW_VALUE_H_
   6 #define UI_GFX_SHADOW_VALUE_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "third_party/skia/include/core/SkColor.h"
  12 #include "ui/base/ui_export.h"
  13 #include "ui/gfx/point.h"
  14
  15 namespace gfx {
  16
  17 class Insets;
  18
  19 class ShadowValue;
  20 typedef std::vector<ShadowValue> ShadowValues;
  21
  22 // ShadowValue encapsulates parameters needed to define a shadow, including the
  23 // shadow's offset, blur amount and color.
  24 class UI_EXPORT ShadowValue {
  25  public:
  26   ShadowValue();
  27   ShadowValue(const gfx::Point& offset, double blur, SkColor color);
  28   ~ShadowValue();
  29
  30   int x() const { return offset_.x(); }
  31   int y() const { return offset_.y(); }
  32   const gfx::Point& offset() const { return offset_; }
  33   double blur() const { return blur_; }
  34   SkColor color() const { return color_; }
  35
  36   ShadowValue Scale(float scale) const;
  37
  38   std::string ToString() const;
  39
  40   // Gets margin space needed for shadows. Note that values in returned Insets
  41   // are negative because shadow margins are outside a boundary.
  42   static Insets GetMargin(const ShadowValues& shadows);
  43
  44  private:
  45   gfx::Point offset_;
  46
  47   // Blur amount of the shadow in pixels. If underlying implementation supports
  48   // (e.g. Skia), it can have fraction part such as 0.5 pixel. The value
  49   // defines a range from full shadow color at the start point inside the
  50   // shadow to fully transparent at the end point outside it. The range is
  51   // perpendicular to and centered on the shadow edge. For example, a blur
  52   // amount of 4.0 means to have a blurry shadow edge of 4 pixels that
  53   // transitions from full shadow color to fully transparent and with 2 pixels
  54   // inside the shadow and 2 pixels goes beyond the edge.
  55   double blur_;
  56
  57   SkColor color_;
  58 };
  59
  60 }  // namespace gfx
  61
  62 #endif  // UI_GFX_SHADOW_VALUE_H_