exo: Fix cursor scaling for 1.25 DSF

components/exo/pointer.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/exo/pointer.h"
 
-#include <algorithm>
 #include <numeric>
+#include <tuple>
 #include <utility>
 
 #include "ash/public/cpp/shell_window_ids.h"
 #include "cc/output/copy_output_request.h"
 #include "cc/output/copy_output_result.h"
 #include "components/exo/pointer_delegate.h"
 #include "components/exo/pointer_stylus_delegate.h"
 #include "components/exo/surface.h"
 #include "components/exo/wm_helper.h"
 #include "ui/aura/client/cursor_client.h"
@@ skipping 246 matching lines @@
     UpdateCursor();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // WMHelper::DisplayConfigurationObserver overrides:
 
 void Pointer::OnDisplayConfigurationChanged() {
   UpdatePointerSurface(surface_);
 
   const auto& displays = display::Screen::GetScreen()->GetAllDisplays();
-  capture_scale_ = std::accumulate(
-      displays.begin(), displays.end(), 1.0f,
-      [](float scale, const display::Display& display) -> float {
+  using ScalePair = std::pair<float, float>;
+  std::tie(capture_scale_, capture_ratio_) = std::accumulate(

[reveman, 2017/06/19 22:20:39]

heh, cool; but I think you've crossed the line to where having simple for-loop
is easier to read :)

[Dominik Laskowski, 2017/06/20 15:52:35]

Yeah, even the original was pushing it. Done.

+      displays.begin(), displays.end(), ScalePair(1.0f, 1.0f),
+      [](const ScalePair& pair, const display::Display& display) -> ScalePair {
         const auto& info =
             WMHelper::GetInstance()->GetDisplayInfo(display.id());
-        return std::max(scale, info.device_scale_factor());
+        return info.device_scale_factor() > pair.first
+                   ? ScalePair(info.device_scale_factor(),
+                               info.GetDensityRatio())
+                   : pair;
       });
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // SurfaceDelegate overrides:
 
 void Pointer::OnSurfaceCommit() {
   surface_->CheckIfSurfaceHierarchyNeedsCommitToNewSurfaces();
   surface_->CommitSurfaceHierarchy();
 
@@ skipping 91 matching lines @@
   UpdateCursor();
 }
 
 void Pointer::UpdateCursor() {
   DCHECK(focus_);
 
   if (cursor_bitmap_.drawsNothing()) {
     cursor_ = ui::CursorType::kNone;
   } else {
     SkBitmap bitmap = cursor_bitmap_;
-    gfx::Point hotspot = gfx::ScaleToFlooredPoint(hotspot_, capture_scale_);
+    gfx::Point hotspot = gfx::ScaleToFlooredPoint(hotspot_, capture_ratio_);
 
     auto* helper = WMHelper::GetInstance();
     const display::Display& display = helper->GetCursorDisplay();
-    float scale = helper->GetDisplayInfo(display.id()).device_scale_factor() /
-                  capture_scale_;
+    float scale =
+        helper->GetDisplayInfo(display.id()).GetDensityRatio() / capture_ratio_;
 
     if (helper->GetCursorSet() == ui::CURSOR_SET_LARGE)
       scale *= kLargeCursorScale;
 
     ui::ScaleAndRotateCursorBitmapAndHotpoint(scale, display.rotation(),
                                               &bitmap, &hotspot);
 
     ui::PlatformCursor platform_cursor;
 #if defined(USE_OZONE)
     // TODO(reveman): Add interface for creating cursors from GpuMemoryBuffers
@@ skipping 17 matching lines @@
   if (!root_window)
     return;
 
   aura::client::CursorClient* cursor_client =
       aura::client::GetCursorClient(root_window);
   if (cursor_client)
     cursor_client->SetCursor(cursor_);
 }
 
 }  // namespace exo