ui/gfx/win/dpi.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_DPI_WIN_H_
   6 #define UI_GFX_DPI_WIN_H_
   7
   8 #include "ui/gfx/gfx_export.h"
   9 #include "ui/gfx/point.h"
  10 #include "ui/gfx/rect.h"
  11 #include "ui/gfx/size.h"
  12
  13 namespace gfx {
  14
  15 // Initialization of the scale factor that should be applied for rendering
  16 // in this process. Must be called before attempts to call any of the getter
  17 // methods below in this file, e.g. in the early toolkit/resource bundle setup.
  18 // This can be called multiple times during various tests, but subsequent calls
  19 // have no effect.
  20 GFX_EXPORT void InitDeviceScaleFactor(float scale);
  21
  22 GFX_EXPORT Size GetDPI();
  23
  24 // Gets the scale factor of the display. For example, if the display DPI is
  25 // 96 then the scale factor is 1.0.
  26 GFX_EXPORT float GetDPIScale();
  27
  28 namespace win {
  29
  30 GFX_EXPORT Point ScreenToDIPPoint(const Point& pixel_point);
  31
  32 GFX_EXPORT Point DIPToScreenPoint(const Point& dip_point);
  33
  34 // WARNING: there is no right way to scale sizes and rects. The implementation
  35 // of these strives to maintain a constant size by scaling the size independent
  36 // of the origin. An alternative is to get the enclosing rect, which is the
  37 // right way for some situations. Understand which you need before blindly
  38 // assuming this is the right way.
  39 GFX_EXPORT Rect ScreenToDIPRect(const Rect& pixel_bounds);
  40 GFX_EXPORT Rect DIPToScreenRect(const Rect& dip_bounds);
  41 GFX_EXPORT Size ScreenToDIPSize(const Size& size_in_pixels);
  42 GFX_EXPORT Size DIPToScreenSize(const Size& dip_size);
  43
  44 // Win32's GetSystemMetrics uses pixel measures. This function calls
  45 // GetSystemMetrics for the given |metric|, then converts the result to DIP.
  46 GFX_EXPORT int GetSystemMetricsInDIP(int metric);
  47
  48 }  // namespace win
  49 }  // namespace gfx
  50
  51 #endif  // UI_GFX_DPI_WIN_H_