Fix high-DPI on Windows to make use of DIP scaling in WebKit.

BUG=149881


Review URL: https://chromiumcodereview.appspot.com/11953054

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@179899 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 69 insertions, 0 deletions

diff --git a/ui/base/win/dpi.cc b/ui/base/win/dpi.cc
index 9c56af0..ecfb3e7 100644
--- a/ui/base/win/dpi.cc
+++ b/ui/base/win/dpi.cc
@@ -7,12 +7,26 @@
 #include <windows.h>
 
 #include "base/win/scoped_hdc.h"
+#include "ui/gfx/display.h"
+#include "ui/gfx/point_conversions.h"
+#include "ui/gfx/rect_conversions.h"
+#include "ui/gfx/size_conversions.h"
 
 namespace {
 
 int kDefaultDPIX = 96;
 int kDefaultDPIY = 96;
 
+
+float GetDeviceScaleFactorImpl() {
+#if defined(ENABLE_HIDPI)
+  return gfx::Display::HasForceDeviceScaleFactor() ?
+      gfx::Display::GetForcedDeviceScaleFactor() : ui::GetDPIScale();
+#else
+  return 1.0f;
+#endif
+}
+
 }  // namespace
 
 namespace ui {
@@ -53,4 +67,39 @@ void EnableHighDPISupport() {
     set_process_dpi_aware_func();
 }
 
+namespace win {
+
+float GetDeviceScaleFactor() {
+  static const float device_scale_factor = GetDeviceScaleFactorImpl();
+  return device_scale_factor;
+}
+
+gfx::Point ScreenToDIPPoint(const gfx::Point& pixel_point) {
+  return gfx::ToFlooredPoint(
+      gfx::ScalePoint(pixel_point, 1.0f / GetDeviceScaleFactor()));
+}
+
+gfx::Rect ScreenToDIPRect(const gfx::Rect& pixel_bounds) {
+  // TODO(kevers): Switch to non-deprecated method for float to int conversions.
+  return gfx::ToFlooredRectDeprecated(
+      gfx::ScaleRect(pixel_bounds, 1.0f / GetDeviceScaleFactor()));
+}
+
+gfx::Rect DIPToScreenRect(const gfx::Rect& dip_bounds) {
+  // TODO(kevers): Switch to non-deprecated method for float to int conversions.
+  return gfx::ToFlooredRectDeprecated(
+      gfx::ScaleRect(dip_bounds, GetDeviceScaleFactor()));
+}
+
+gfx::Size ScreenToDIPSize(const gfx::Size& size_in_pixels) {
+  return gfx::ToFlooredSize(
+      gfx::ScaleSize(size_in_pixels, 1.0f / GetDeviceScaleFactor()));
+}
+
+gfx::Size DIPToScreenSize(const gfx::Size& dip_size) {
+  return gfx::ToFlooredSize(gfx::ScaleSize(dip_size, GetDeviceScaleFactor()));
+}
+
+}  // namespace win
+
 }  // namespace ui
diff --git a/ui/base/win/dpi.h b/ui/base/win/dpi.h
index 930922a..99252c7 100644
--- a/ui/base/win/dpi.h
+++ b/ui/base/win/dpi.h
@@ -5,6 +5,8 @@
 #ifndef UI_BASE_WIN_DPI_H_
 #define UI_BASE_WIN_DPI_H_
 
+#include "ui/gfx/point.h"
+#include "ui/gfx/rect.h"
 #include "ui/gfx/size.h"
 #include "ui/base/ui_export.h"
 
@@ -20,6 +22,24 @@ UI_EXPORT bool IsInHighDPIMode();
 
 UI_EXPORT void EnableHighDPISupport();
 
+// TODO(kevers|girard):  Move above methods into win namespace.
+
+namespace win {
+
+UI_EXPORT float GetDeviceScaleFactor();
+
+UI_EXPORT gfx::Point ScreenToDIPPoint(const gfx::Point& pixel_point);
+
+UI_EXPORT gfx::Rect ScreenToDIPRect(const gfx::Rect& pixel_bounds);
+
+UI_EXPORT gfx::Rect DIPToScreenRect(const gfx::Rect& dip_bounds);
+
+UI_EXPORT gfx::Size ScreenToDIPSize(const gfx::Size& size_in_pixels);
+
+UI_EXPORT gfx::Size DIPToScreenSize(const gfx::Size& dip_size);
+
+}  // namespace win
+
 }  // namespace ui
 
 #endif  // UI_BASE_WIN_DPI_H_