ui/base/layout.cc

   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 #include "ui/base/layout.h"
   6
   7 #include <algorithm>
   8 #include <cmath>
   9 #include <limits>
  10
  11 #include "base/basictypes.h"
  12 #include "base/command_line.h"
  13 #include "base/logging.h"
  14 #include "build/build_config.h"
  15 #include "ui/base/touch/touch_device.h"
  16 #include "ui/base/ui_base_switches.h"
  17 #include "ui/gfx/display.h"
  18 #include "ui/gfx/image/image_skia.h"
  19 #include "ui/gfx/screen.h"
  20
  21 #if defined(OS_WIN)
  22 #include "base/win/metro.h"
  23 #include "ui/gfx/win/dpi.h"
  24 #include <Windows.h>
  25 #endif  // defined(OS_WIN)
  26
  27 namespace ui {
  28
  29 namespace {
  30
  31 std::vector<ScaleFactor>* g_supported_scale_factors = NULL;
  32
  33 const float kScaleFactorScales[] = {1.0f, 1.0f, 1.25f, 1.33f, 1.4f, 1.5f, 1.8f,
  34                                     2.0f, 2.5f, 3.0f};
  35 static_assert(NUM_SCALE_FACTORS == arraysize(kScaleFactorScales),
  36               "kScaleFactorScales has incorrect size");
  37
  38 }  // namespace
  39
  40 void SetSupportedScaleFactors(
  41     const std::vector<ui::ScaleFactor>& scale_factors) {
  42   if (g_supported_scale_factors != NULL)
  43     delete g_supported_scale_factors;
  44
  45   g_supported_scale_factors = new std::vector<ScaleFactor>(scale_factors);
  46   std::sort(g_supported_scale_factors->begin(),
  47             g_supported_scale_factors->end(),
  48             [](ScaleFactor lhs, ScaleFactor rhs) {
  49     return GetScaleForScaleFactor(lhs) < GetScaleForScaleFactor(rhs);
  50   });
  51
  52   // Set ImageSkia's supported scales.
  53   std::vector<float> scales;
  54   for (std::vector<ScaleFactor>::const_iterator it =
  55           g_supported_scale_factors->begin();
  56        it != g_supported_scale_factors->end(); ++it) {
  57     scales.push_back(kScaleFactorScales[*it]);
  58   }
  59   gfx::ImageSkia::SetSupportedScales(scales);
  60 }
  61
  62 const std::vector<ScaleFactor>& GetSupportedScaleFactors() {
  63   DCHECK(g_supported_scale_factors != NULL);
  64   return *g_supported_scale_factors;
  65 }
  66
  67 ScaleFactor GetSupportedScaleFactor(float scale) {
  68   DCHECK(g_supported_scale_factors != NULL);
  69   ScaleFactor closest_match = SCALE_FACTOR_100P;
  70   float smallest_diff =  std::numeric_limits<float>::max();
  71   for (size_t i = 0; i < g_supported_scale_factors->size(); ++i) {
  72     ScaleFactor scale_factor = (*g_supported_scale_factors)[i];
  73     float diff = std::abs(kScaleFactorScales[scale_factor] - scale);
  74     if (diff < smallest_diff) {
  75       closest_match = scale_factor;
  76       smallest_diff = diff;
  77     }
  78   }
  79   DCHECK_NE(closest_match, SCALE_FACTOR_NONE);
  80   return closest_match;
  81 }
  82
  83 float GetImageScale(ScaleFactor scale_factor) {
  84 #if defined(OS_WIN)
  85   return gfx::GetDPIScale();
  86 #else
  87   return GetScaleForScaleFactor(scale_factor);
  88 #endif
  89 }
  90
  91 float GetScaleForScaleFactor(ScaleFactor scale_factor) {
  92   return kScaleFactorScales[scale_factor];
  93 }
  94
  95 namespace test {
  96
  97 ScopedSetSupportedScaleFactors::ScopedSetSupportedScaleFactors(
  98     const std::vector<ui::ScaleFactor>& new_scale_factors) {
  99   if (g_supported_scale_factors) {
 100     original_scale_factors_ =
 101         new std::vector<ScaleFactor>(*g_supported_scale_factors);
 102   } else {
 103     original_scale_factors_ = NULL;
 104   }
 105   SetSupportedScaleFactors(new_scale_factors);
 106 }
 107
 108 ScopedSetSupportedScaleFactors::~ScopedSetSupportedScaleFactors() {
 109   if (original_scale_factors_) {
 110     SetSupportedScaleFactors(*original_scale_factors_);
 111     delete original_scale_factors_;
 112   } else {
 113     delete g_supported_scale_factors;
 114     g_supported_scale_factors = NULL;
 115   }
 116 }
 117
 118 }  // namespace test
 119
 120 #if !defined(OS_MACOSX)
 121 float GetScaleFactorForNativeView(gfx::NativeView view) {
 122   gfx::Screen* screen = gfx::Screen::GetScreenFor(view);
 123   gfx::Display display = screen->GetDisplayNearestWindow(view);
 124   return display.device_scale_factor();
 125 }
 126 #endif  // !defined(OS_MACOSX)
 127
 128 }  // namespace ui