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_export.h"
  12 #include "ui/gfx/native_widget_types.h"
  13
  14 namespace ui {
  15
  16 enum DisplayLayout {
  17   // The typical layout for e.g. Windows, Mac and Linux.
  18   LAYOUT_DESKTOP,
  19
  20   // Layout optimized for touch.  Used e.g. for Windows 8 Metro mode.
  21   LAYOUT_TOUCH,
  22 };
  23
  24 // Returns the display layout that should be used.  This could be used
  25 // e.g. to tweak hard-coded padding that's layout specific, or choose
  26 // the .pak file of theme resources to load.
  27 // WARNING: this is deprecated and will be nuked as soon as aura is the default
  28 // on windows.
  29 UI_EXPORT DisplayLayout GetDisplayLayout();
  30
  31 // Supported UI scale factors for the platform. This is used as an index
  32 // into the array |kScaleFactorScales| which maps the enum value to a float.
  33 // SCALE_FACTOR_NONE is used for density independent resources such as
  34 // string, html/js files or an image that can be used for any scale factors
  35 // (such as wallpapers).
  36 enum ScaleFactor {
  37   SCALE_FACTOR_NONE = 0,
  38   SCALE_FACTOR_100P,
  39   SCALE_FACTOR_133P,
  40   SCALE_FACTOR_140P,
  41   SCALE_FACTOR_150P,
  42   SCALE_FACTOR_180P,
  43   SCALE_FACTOR_200P,
  44
  45   NUM_SCALE_FACTORS  // This always appears last.
  46 };
  47
  48 // Returns the float scale value for |scale_factor|.
  49 UI_EXPORT float GetScaleFactorScale(ScaleFactor scale_factor);
  50
  51 // Returns the supported ScaleFactor which most closely matches |scale|.
  52 // Converting from float to ScaleFactor is inefficient and should be done as
  53 // little as possible.
  54 // TODO(oshima): Make ScaleFactor a class and remove this.
  55 UI_EXPORT ScaleFactor GetScaleFactorFromScale(float scale);
  56
  57 // Returns the ScaleFactor used by |view|.
  58 UI_EXPORT ScaleFactor GetScaleFactorForNativeView(gfx::NativeView view);
  59
  60 // Returns the maximum device scale factor supported by this platform.
  61 UI_EXPORT ScaleFactor GetMaxScaleFactor();
  62
  63 // Returns a vector with the scale factors which are supported by this
  64 // platform, in ascending order.
  65 UI_EXPORT std::vector<ScaleFactor> GetSupportedScaleFactors();
  66
  67 // Returns true if |scale_factor| is supported by this platform.
  68 UI_EXPORT bool IsScaleFactorSupported(ScaleFactor scale_factor);
  69
  70 namespace test {
  71
  72 // Changes the value of GetSupportedScaleFactors() to |scale_factors|.
  73 // Use ScopedSetSupportedScaleFactors for unit tests as not to affect the
  74 // state of other tests.
  75 UI_EXPORT void SetSupportedScaleFactors(
  76     const std::vector<ScaleFactor>& scale_factors);
  77
  78 // Class which changes the value of GetSupportedScaleFactors() to
  79 // |new_scale_factors| for the duration of its lifetime.
  80 class UI_EXPORT ScopedSetSupportedScaleFactors {
  81  public:
  82   explicit ScopedSetSupportedScaleFactors(
  83       const std::vector<ui::ScaleFactor>& new_scale_factors);
  84   ~ScopedSetSupportedScaleFactors();
  85
  86  private:
  87   const std::vector<ui::ScaleFactor> original_scale_factors_;
  88
  89   DISALLOW_COPY_AND_ASSIGN(ScopedSetSupportedScaleFactors);
  90 };
  91
  92 }  // namespace test
  93
  94 }  // namespace ui
  95
  96 #endif  // UI_BASE_LAYOUT_H_