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 bool ScaleFactorComparator(const ScaleFactor& lhs, const ScaleFactor& rhs){
  32   return GetScaleForScaleFactor(lhs) < GetScaleForScaleFactor(rhs);
  33 }
  34
  35 std::vector<ScaleFactor>* g_supported_scale_factors = NULL;
  36
  37 const float kScaleFactorScales[] = {1.0f, 1.0f, 1.25f, 1.33f, 1.4f, 1.5f, 1.8f,
  38                                     2.0f, 2.5f, 3.0f};
  39 COMPILE_ASSERT(NUM_SCALE_FACTORS == arraysize(kScaleFactorScales),
  40                kScaleFactorScales_incorrect_size);
  41
  42 }  // namespace
  43
  44 void SetSupportedScaleFactors(
  45     const std::vector<ui::ScaleFactor>& scale_factors) {
  46   if (g_supported_scale_factors != NULL)
  47     delete g_supported_scale_factors;
  48
  49   g_supported_scale_factors = new std::vector<ScaleFactor>(scale_factors);
  50   std::sort(g_supported_scale_factors->begin(),
  51             g_supported_scale_factors->end(),
  52             ScaleFactorComparator);
  53
  54   // Set ImageSkia's supported scales.
  55   std::vector<float> scales;
  56   for (std::vector<ScaleFactor>::const_iterator it =
  57           g_supported_scale_factors->begin();
  58        it != g_supported_scale_factors->end(); ++it) {
  59     scales.push_back(kScaleFactorScales[*it]);
  60   }
  61   gfx::ImageSkia::SetSupportedScales(scales);
  62 }
  63
  64 const std::vector<ScaleFactor>& GetSupportedScaleFactors() {
  65   DCHECK(g_supported_scale_factors != NULL);
  66   return *g_supported_scale_factors;
  67 }
  68
  69 ScaleFactor GetSupportedScaleFactor(float scale) {
  70   DCHECK(g_supported_scale_factors != NULL);
  71   ScaleFactor closest_match = SCALE_FACTOR_100P;
  72   float smallest_diff =  std::numeric_limits<float>::max();
  73   for (size_t i = 0; i < g_supported_scale_factors->size(); ++i) {
  74     ScaleFactor scale_factor = (*g_supported_scale_factors)[i];
  75     float diff = std::abs(kScaleFactorScales[scale_factor] - scale);
  76     if (diff < smallest_diff) {
  77       closest_match = scale_factor;
  78       smallest_diff = diff;
  79     }
  80   }
  81   DCHECK_NE(closest_match, SCALE_FACTOR_NONE);
  82   return closest_match;
  83 }
  84
  85 float GetImageScale(ScaleFactor scale_factor) {
  86 #if defined(OS_WIN)
  87   if (gfx::IsHighDPIEnabled())
  88     return gfx::GetDPIScale();
  89 #endif
  90   return GetScaleForScaleFactor(scale_factor);
  91 }
  92
  93 float GetScaleForScaleFactor(ScaleFactor scale_factor) {
  94   return kScaleFactorScales[scale_factor];
  95 }
  96
  97 namespace test {
  98
  99 ScopedSetSupportedScaleFactors::ScopedSetSupportedScaleFactors(
 100     const std::vector<ui::ScaleFactor>& new_scale_factors) {
 101   if (g_supported_scale_factors) {
 102     original_scale_factors_ =
 103         new std::vector<ScaleFactor>(*g_supported_scale_factors);
 104   } else {
 105     original_scale_factors_ = NULL;
 106   }
 107   SetSupportedScaleFactors(new_scale_factors);
 108 }
 109
 110 ScopedSetSupportedScaleFactors::~ScopedSetSupportedScaleFactors() {
 111   if (original_scale_factors_) {
 112     SetSupportedScaleFactors(*original_scale_factors_);
 113     delete original_scale_factors_;
 114   } else {
 115     delete g_supported_scale_factors;
 116     g_supported_scale_factors = NULL;
 117   }
 118 }
 119
 120 }  // namespace test
 121
 122 #if !defined(OS_MACOSX)
 123 float GetScaleFactorForNativeView(gfx::NativeView view) {
 124   gfx::Screen* screen = gfx::Screen::GetScreenFor(view);
 125   gfx::Display display = screen->GetDisplayNearestWindow(view);
 126   return display.device_scale_factor();
 127 }
 128 #endif  // !defined(OS_MACOSX)
 129
 130 }  // namespace ui