Full-screen Magnifier: Support warping the cursor on the edge

ui/aura/root_window.cc

Index: ui/aura/root_window.cc
diff --git a/ui/aura/root_window.cc b/ui/aura/root_window.cc
index e6797dcd024fa26ceb2e6e6fe40a9336e38d2018..8f2f7bb68d0c362b70f1f7d49c3143a57dca74df 100644
--- a/ui/aura/root_window.cc
+++ b/ui/aura/root_window.cc
@@ -33,6 +33,8 @@
 #include "ui/gfx/monitor.h"
 #include "ui/gfx/screen.h"
 
+#include "ui/compositor/layer_type.h"
+
 using std::vector;
 
 namespace aura {
@@ -129,6 +131,7 @@ RootWindow::RootWindow(const gfx::Rect& initial_bounds)
       defer_draw_scheduling_(false),
       mouse_move_hold_count_(0),
       should_hold_mouse_moves_(false),
+      force_hide_cursor_(false),
       compositor_lock_(NULL),
       draw_on_compositor_unlock_(false),
       draw_trace_count_(0) {
@@ -166,7 +169,15 @@ void RootWindow::Init() {
   Window::Init(ui::LAYER_NOT_DRAWN);
   last_mouse_location_ =
       ui::ConvertPointToDIP(layer(), host_->QueryMouseLocation());
-  compositor()->SetRootLayer(layer());
+
+  magnification_layer_.reset(new ui::Layer(ui::LAYER_TEXTURED));

[piman, 2012/05/18 03:09:49]

Does this need to be LAYER_TEXTURED? Since it has no delegate, nothing is going
to paint the texture.
Also, since the rest of the layer tree is going to be drawn on top, this is just
going to draw black, just to be replaced by something else. Culling can help,
but we should just avoid doing this in the first place.

+  magnification_layer_->SetVisible(false);
+  magnification_layer_->SetFillsBoundsOpaquely(true);
+  magnification_layer_->Add(layer());
+  magnification_layer_->SetVisible(true);

[piman, 2012/05/18 03:09:49]

Is this layer needed at all? If it's just there to add a transform, can't we
just bake it into the root layer?

+
+  compositor()->SetRootLayer(magnification_layer_.get());
+
   SetBounds(
       ui::ConvertRectToDIP(layer(), gfx::Rect(host_->GetBounds().size())));
   Show();
@@ -212,7 +223,15 @@ void RootWindow::SetCursor(gfx::NativeCursor cursor) {
   host_->SetCursor(cursor);
 }
 
+void RootWindow::SetForceHideCursor(bool hide) {
+  force_hide_cursor_ = hide;
+  ShowCursor(!hide);

[piman, 2012/05/18 03:09:49]

This makes SetForceHideCursor and ShowCursor non-orthogonal which is a little
surprising.
If I do ShowCursor(false); SetForceHideCursor(false); then the cursor will be
shown.

How about we keep 2 states, (like we already have), force_hide_cursor_ (set by
SetForceHideCursor) and cursor_shown_ (set by ShowCursor), and call
host_->ShowCursor(cursor_shown_ && !force_hide_cursor_) when any of them
changes?

+}
+
 void RootWindow::ShowCursor(bool show) {
+  if (force_hide_cursor_ && show)
+    show = false;
+
   cursor_shown_ = show;
   host_->ShowCursor(show);
 }
@@ -311,6 +330,10 @@ bool RootWindow::DispatchScrollEvent(ScrollEvent* event) {
 
 bool RootWindow::DispatchTouchEvent(TouchEvent* event) {
   DispatchHeldMouseMove();
+
+  // Touch event should be transformed by magnifition transform matrix.
+  event->UpdateForRootTransform(magnification_layer()->transform());
+
   if (ui::IsDIPEnabled()) {
     float scale = ui::GetDeviceScaleFactor(layer());
     ui::Transform transform = layer()->transform();