COMPLETED PREVIEW Migrate to Display Placement

ui/gfx/screen_win.cc

Index: ui/gfx/screen_win.cc
diff --git a/ui/gfx/screen_win.cc b/ui/gfx/screen_win.cc
index 32326a45f8afd88b150f283efb8e8079f60395f4..d68ee725c45b21cdb7e9ceab5617227309f32e54 100644
--- a/ui/gfx/screen_win.cc
+++ b/ui/gfx/screen_win.cc
@@ -9,6 +9,8 @@
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "ui/gfx/display.h"
+#include "ui/gfx/display_layout.h"
+#include "ui/gfx/display_layout_builder.h"
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/point_conversions.h"
 #include "ui/gfx/geometry/rect.h"
@@ -16,7 +18,7 @@
 #include "ui/gfx/geometry/vector2d.h"
 #include "ui/gfx/win/display_info.h"
 #include "ui/gfx/win/dpi.h"
-#include "ui/gfx/win/rect_util.h"
+#include "ui/gfx/win/scaling_util.h"
 #include "ui/gfx/win/screen_win_display.h"
 
 namespace {
@@ -24,21 +26,32 @@ namespace {
 gfx::ScreenWin* g_screen_win_instance = nullptr;
 
 std::vector<gfx::win::DisplayInfo>::const_iterator FindTouchingDisplayInfo(
-    const gfx::win::ScreenWinDisplay& screen_win_display,
+    const gfx::win::DisplayInfo& display_info,
     const std::vector<gfx::win::DisplayInfo>& display_infos) {
   auto end = display_infos.end();
   for (auto display_info_iter = display_infos.begin();
        display_info_iter != end;
        display_info_iter++) {
-    gfx::win::RectEdge edge =
-        gfx::win::FindTouchingRectEdge(screen_win_display.pixel_bounds(),
-                                       display_info_iter->screen_rect());
-    if (edge != gfx::win::RectEdge::NONE)
+    if (gfx::win::DisplayInfosTouch(display_info, *display_info_iter))
       return display_info_iter;
   }
   return end;
 }
 
+gfx::Display CreateDisplayFromDisplayInfo(
+    const gfx::win::DisplayInfo& display_info) {
+  gfx::Display display(display_info.id());
+  float scale_factor = display_info.device_scale_factor();
+  display.set_device_scale_factor(scale_factor);
+  display.set_work_area(
+      gfx::ScaleToEnclosingRect(display_info.screen_work_rect(),
+                                1.0f / scale_factor));
+  display.set_bounds(gfx::ScaleToEnclosingRect(display_info.screen_rect(),
+                     1.0f / scale_factor));
+  display.set_rotation(display_info.rotation());
+  return display;
+}
+
 // Windows historically has had a hard time handling displays of DPIs higher
 // than 96. Handling multiple DPI displays means we have to deal with Windows'
 // monitor physical coordinates and map into Chrome's DIP coordinates.
@@ -64,43 +77,62 @@ std::vector<gfx::win::DisplayInfo>::const_iterator FindTouchingDisplayInfo(
 // will take precedence.
 std::vector<gfx::win::ScreenWinDisplay> DisplayInfosToScreenWinDisplays(
     const std::vector<gfx::win::DisplayInfo>& display_infos) {
-  std::vector<gfx::win::DisplayInfo> display_infos_remaining = display_infos;
 
-  // Seed the primary display to layout all the other displays.
-  std::vector<gfx::win::ScreenWinDisplay> screen_win_displays;
-  for (auto current = display_infos_remaining.begin();
-       current != display_infos_remaining.end();
-       current++) {
-    if (current->screen_rect().origin().IsOrigin()) {
-      screen_win_displays.push_back(gfx::win::ScreenWinDisplay(*current));
-      display_infos_remaining.erase(current);
+  // DisplayLayout reasons over gfx::Displays and we need to add on pixel info
+  // after it finishes its layout. As a result, create a vector of displays now
+  // for mutation to maintain this gfx::Display - gfx::win::DisplayInfo
+  // correspondence to construct a ScreenWinDisplay.
+
+  // Stage 1: display_infos <--> displays
+  // Stage 2: Layout
+  // Stage 3: display_infos + displays -> ScreenWinDisplay
+
+  // Find and extract the primary display.
+  size_t primary_display_index = 0;
+  int64_t primary_display_id = 0;
+  const size_t num_displays = display_infos.size();
+  for (size_t i = 0; i < num_displays; ++i) {
+    if (display_infos[i].screen_rect().origin().IsOrigin()) {
+      primary_display_index = i;
       break;
     }
   }
 
-  // Scale touching display_infos relative to each other.
-  // If the DisplayInfo count doesn't change through one cycle of the loop, it
-  // either means we're done or we have non-touching DisplayInfos in the vector.
+  std::vector<gfx::win::DisplayInfo> display_infos_remaining = display_infos;
+  display_infos_remaining.erase(
+      display_infos_remaining.begin() + primary_display_id);
+  std::vector<gfx::win::DisplayInfo> rooted_display_infos;
+  rooted_display_infos.push_back(display_infos[primary_display_index]);
+  gfx::DisplayLayoutBuilder builder(display_infos[primary_display_id].id());
+
   size_t display_infos_at_cycle_start = 0;
   while ((display_infos_remaining.size() > 0) &&
          (display_infos_remaining.size() != display_infos_at_cycle_start)) {
     display_infos_at_cycle_start = display_infos_remaining.size();
-    for (const auto& screen_win_display : screen_win_displays) {
-      auto display_info = FindTouchingDisplayInfo(screen_win_display,
-                                                  display_infos_remaining);
-      if (display_info != display_infos_remaining.end()) {
-        screen_win_displays.push_back(
-            gfx::win::ScreenWinDisplay(screen_win_display, *display_info));
-        display_infos_remaining.erase(display_info);
+    for (const auto& rooted_display_info : rooted_display_infos) {
+      auto display_info_iter = FindTouchingDisplayInfo(rooted_display_info,
+                                                       display_infos_remaining);
+      if (display_info_iter != display_infos_remaining.end()) {
+        builder.AddDisplayPlacement(
+            gfx::win::CalculateDisplayPlacement(rooted_display_info,
+                                                *display_info_iter));
+        rooted_display_infos.push_back(*display_info_iter);
+        display_infos_remaining.erase(display_info_iter);
         break;
       }
     }
   }
 
-  // Under Windows DPI virtualization, not all display_infos touch, so scale
-  // the remaining display infos relative to the origin.
-  for (const auto& display_info : display_infos_remaining)
-    screen_win_displays.push_back(gfx::win::ScreenWinDisplay(display_info));
+  std::vector<gfx::Display> displays;
+  for (const auto& display_info : display_infos)
+    displays.push_back(CreateDisplayFromDisplayInfo(display_info));
+
+  scoped_ptr<gfx::DisplayLayout> layout(builder.Build());
+  layout->ApplyToDisplayList(&displays, nullptr, 0);
+
+  std::vector<gfx::win::ScreenWinDisplay> screen_win_displays;
+  for (size_t i = 0; i < num_displays; ++i)
+    screen_win_displays.emplace_back(displays[i], display_infos[i]);
 
   return screen_win_displays;
 }