ui/base/layout.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_BASE_LAYOUT_H_
   6 #define UI_BASE_LAYOUT_H_
   7
   8 #include <vector>
   9
  10 #include "build/build_config.h"
  11 #include "ui/base/ui_base_export.h"
  12 #include "ui/gfx/native_widget_types.h"
  13
  14 namespace ui {
  15
  16 // Supported UI scale factors for the platform. This is used as an index
  17 // into the array |kScaleFactorScales| which maps the enum value to a float.
  18 // SCALE_FACTOR_NONE is used for density independent resources such as
  19 // string, html/js files or an image that can be used for any scale factors
  20 // (such as wallpapers).
  21 enum ScaleFactor : int {
  22   SCALE_FACTOR_NONE = 0,
  23   SCALE_FACTOR_100P,
  24   SCALE_FACTOR_125P,
  25   SCALE_FACTOR_133P,
  26   SCALE_FACTOR_140P,
  27   SCALE_FACTOR_150P,
  28   SCALE_FACTOR_180P,
  29   SCALE_FACTOR_200P,
  30   SCALE_FACTOR_250P,
  31   SCALE_FACTOR_300P,
  32
  33   NUM_SCALE_FACTORS  // This always appears last.
  34 };
  35
  36 // Changes the value of GetSupportedScaleFactors() to |scale_factors|.
  37 // Use ScopedSetSupportedScaleFactors for unit tests as not to affect the
  38 // state of other tests.
  39 UI_BASE_EXPORT void SetSupportedScaleFactors(
  40     const std::vector<ScaleFactor>& scale_factors);
  41
  42 // Returns a vector with the scale factors which are supported by this
  43 // platform, in ascending order.
  44 UI_BASE_EXPORT const std::vector<ScaleFactor>& GetSupportedScaleFactors();
  45
  46 // Returns the supported ScaleFactor which most closely matches |scale|.
  47 // Converting from float to ScaleFactor is inefficient and should be done as
  48 // little as possible.
  49 UI_BASE_EXPORT ScaleFactor GetSupportedScaleFactor(float image_scale);
  50
  51 // Returns the ScaleFactor used by |view|.
  52 UI_BASE_EXPORT float GetScaleFactorForNativeView(gfx::NativeView view);
  53
  54 // Returns the image scale for the scale factor passed in.
  55 UI_BASE_EXPORT float GetScaleForScaleFactor(ScaleFactor scale_factor);
  56
  57 namespace test {
  58 // Class which changes the value of GetSupportedScaleFactors() to
  59 // |new_scale_factors| for the duration of its lifetime.
  60 class UI_BASE_EXPORT ScopedSetSupportedScaleFactors {
  61  public:
  62   explicit ScopedSetSupportedScaleFactors(
  63       const std::vector<ui::ScaleFactor>& new_scale_factors);
  64   ~ScopedSetSupportedScaleFactors();
  65
  66  private:
  67   std::vector<ui::ScaleFactor>* original_scale_factors_;
  68
  69   DISALLOW_COPY_AND_ASSIGN(ScopedSetSupportedScaleFactors);
  70 };
  71
  72 }  // namespace test
  73
  74 }  // namespace ui
  75
  76 #endif  // UI_BASE_LAYOUT_H_