2x Cursor support.

ui/aura/root_window_host_linux.cc

Index: ui/aura/root_window_host_linux.cc
diff --git a/ui/aura/root_window_host_linux.cc b/ui/aura/root_window_host_linux.cc
index 864ebb71a572996052e2f85661d793bb7da5fe9d..111236a4f0b93d29d2d0b68a29fc93b7bf4d1644 100644
--- a/ui/aura/root_window_host_linux.cc
+++ b/ui/aura/root_window_host_linux.cc
@@ -33,6 +33,7 @@
 #include "ui/compositor/layer.h"
 #include "ui/gfx/codec/png_codec.h"
 #include "ui/gfx/image/image.h"
+#include "ui/gfx/image/image_skia.h"
 
 using ui::X11AtomCache;
 using std::max;
@@ -296,13 +297,46 @@ bool ShouldSendCharEventForKeyboardCode(ui::KeyboardCode keycode) {
 // image resources.
 class RootWindowHostLinux::ImageCursors {
  public:
-  ImageCursors() {
-    LoadImageCursor(ui::kCursorNoDrop, IDR_AURA_CURSOR_NO_DROP);
-    LoadImageCursor(ui::kCursorCopy, IDR_AURA_CURSOR_COPY);
+  ImageCursors() : scale_factor_(0.0) {
+  }
+
+  void Reload(float scale_factor) {
+    if (scale_factor_ == scale_factor)
+      return;
+    scale_factor_ = scale_factor;
+    UnloadAll();
+    // The cursor's hot points are defined in chromeos's
+    // src/platforms/assets/cursors/*.cfg files.
+    LoadImageCursor(ui::kCursorNull, IDR_AURA_CURSOR_PTR, 9, 5);

[varunjain, 2012/05/22 20:12:01]

when I was trying to include all the new cursors, I noticed that most of the
cursor assets had empty boundaries and needed to be cropped to get rid of it (I
think I noted that here:
http://code.google.com/p/chromium/issues/detail?id=123655#c18 ). Do these hot
points take care of that? I had assigned that bug to kuscher to fix the assets.
Should we wait for the assets to be fixed instead of fixing the issue with hot
points?

[oshima, 2012/05/22 20:23:05]

Yes,
hot point is the right way to deal with it. Some cursor has hot point in the
middle
of the image (like move, double arrow) so you can't fix by cropping :)

[varunjain, 2012/05/22 20:32:21]

I did not mean we should not have hot points at all. Obviously hot points are
different for a lot of cursors. But seems to me that we should not be making
adjustments in the code based on bad assets.  For instance, IDR_AURA_CURSOR_PTR
is simply a left arrow cursor and should have hot point (0,0) but is right now
set at (9,5) because of the bad asset. I think this is fine too but would have
liked it if the asset was fixed instead. In any case, if we go with this then I
should probably update that bug so that no one wastes their time fixing the
assets :)

[oshima, 2012/05/22 20:46:06]

I don't think these are necessarily bad assets. Some cursor MAY have hot
point at 0,0 but that's just coincident and specific to the current image.
There is no guarantee that IDR_AURA_CURSOR_IPTR is always 0,0.

The right way is to embed this info in the cursor image so that designer can
specify
exactly where the hot spot should be without modifying the code.

I'm planning to look into similar issue for 9 patch (or 9 slice, whatever people
call it)
and will try to address this issue as well. (post 21, though)

+    LoadImageCursor(ui::kCursorPointer, IDR_AURA_CURSOR_PTR, 9, 5);
+    LoadImageCursor(ui::kCursorNoDrop, IDR_AURA_CURSOR_NO_DROP, 9, 5);
+    LoadImageCursor(ui::kCursorCopy, IDR_AURA_CURSOR_COPY, 9, 5);
+    LoadImageCursor(ui::kCursorHand, IDR_AURA_CURSOR_HAND, 9, 4);
+    LoadImageCursor(ui::kCursorMove, IDR_AURA_CURSOR_MOVE, 12, 12);
+    LoadImageCursor(ui::kCursorNorthEastResize,
+                    IDR_AURA_CURSOR_NORTH_EAST_RESIZE, 12, 11);
+    LoadImageCursor(ui::kCursorSouthWestResize,
+                    IDR_AURA_CURSOR_SOUTH_WEST_RESIZE, 12, 11);
+    LoadImageCursor(ui::kCursorSouthEastResize,
+                    IDR_AURA_CURSOR_SOUTH_EAST_RESIZE, 11, 11);
+    LoadImageCursor(ui::kCursorNorthWestResize,
+                    IDR_AURA_CURSOR_NORTH_WEST_RESIZE, 11, 11);
+    LoadImageCursor(ui::kCursorNorthResize,
+                    IDR_AURA_CURSOR_NORTH_RESIZE, 11, 10);
+    LoadImageCursor(ui::kCursorSouthResize,
+                    IDR_AURA_CURSOR_SOUTH_RESIZE, 11, 10);
+    LoadImageCursor(ui::kCursorEastResize, IDR_AURA_CURSOR_EAST_RESIZE, 11, 11);
+    LoadImageCursor(ui::kCursorWestResize, IDR_AURA_CURSOR_WEST_RESIZE, 11, 11);
+    LoadImageCursor(ui::kCursorIBeam, IDR_AURA_CURSOR_IBEAM, 12, 11);
+
     // TODO (varunjain): add more cursors once we have assets.
   }
 
   ~ImageCursors() {
+    UnloadAll();
+  }
+
+  void UnloadAll() {
     std::map<int, Cursor>::const_iterator it;
     for (it = cursors_.begin(); it != cursors_.end(); ++it)
       ui::UnrefCustomXCursor(it->second);
@@ -321,19 +355,32 @@ class RootWindowHostLinux::ImageCursors {
 
  private:
   // Creates an X Cursor from an image resource and puts it in the cursor map.
-  void LoadImageCursor(int id, int resource_id) {
-    const SkBitmap* bitmap =
-        ui::ResourceBundle::GetSharedInstance().GetImageNamed(
-            resource_id).ToSkBitmap();
-
-    XcursorImage* image = ui::SkBitmapToXcursorImage(bitmap, gfx::Point(0, 0));
-    cursors_[id] = ui::CreateReffedCustomXCursor(image);
+  void LoadImageCursor(int id, int resource_id, int hot_x, int hot_y) {
+    const gfx::ImageSkia* image =
+        ui::ResourceBundle::GetSharedInstance().GetImageSkiaNamed(resource_id);
+    float actual_scale = 0;
+    const SkBitmap& bitmap = image->GetBitmapForScale(scale_factor_,
+                                                      scale_factor_,
+                                                      &actual_scale);
+    // We never use scaled cursor, but the following DCHECK fails
+    // because the method above coputes the actual scale from the image

[varunjain, 2012/05/22 20:12:01]

computes

[oshima, 2012/05/22 20:23:05]

Fixed. thanks.

+    // size instead of obtaining from the resource data, and the some
+    // of cursors are indeed not 2x size of the 2x images.
+    // TODO(oshima): Fix this and enable the following DCHECK.
+    // DCHECK_EQ(actual_scale, scale_factor_);
+    XcursorImage* x_image =
+        ui::SkBitmapToXcursorImage(&bitmap, gfx::Point(0, 0));
+    x_image->xhot = hot_x * actual_scale;
+    x_image->yhot = hot_y * actual_scale;
+    cursors_[id] = ui::CreateReffedCustomXCursor(x_image);
     // |bitmap| is owned by the resource bundle. So we do not need to free it.
   }
 
   // A map to hold all image cursors. It maps the cursor ID to the X Cursor.
   std::map<int, Cursor> cursors_;
 
+  float scale_factor_;
+
   DISALLOW_COPY_AND_ASSIGN(ImageCursors);
 };
 
@@ -640,6 +687,8 @@ bool RootWindowHostLinux::Dispatch(const base::NativeEvent& event) {
 
 void RootWindowHostLinux::SetRootWindow(RootWindow* root_window) {
   root_window_ = root_window;
+  // The device scale factor is now accessible, so load cursors now.
+  image_cursors_->Reload(root_window_->layer()->device_scale_factor());
 }
 
 RootWindow* RootWindowHostLinux::GetRootWindow() {
@@ -872,6 +921,11 @@ void RootWindowHostLinux::PostNativeEvent(
   XSendEvent(xdisplay_, xwindow_, False, 0, &xevent);
 }
 
+void RootWindowHostLinux::OnDeviceScaleFactorChanged(
+    float device_scale_factor) {
+  image_cursors_->Reload(device_scale_factor);
+}
+
 bool RootWindowHostLinux::IsWindowManagerPresent() {
   // Per ICCCM 2.8, "Manager Selections", window managers should take ownership
   // of WM_Sn selections (where n is a screen number).
@@ -884,11 +938,9 @@ void RootWindowHostLinux::SetCursorInternal(gfx::NativeCursor cursor) {
   ::Cursor xcursor =
       image_cursors_->IsImageCursor(cursor) ?
       image_cursors_->ImageCursorFromNative(cursor) :
-      cursor == ui::kCursorNone ?
-      invisible_cursor_ :
-      cursor == ui::kCursorCustom ?
-      cursor.platform() :
-      ui::GetXCursor(CursorShapeFromNative(cursor));
+      (cursor == ui::kCursorNone ? invisible_cursor_ :
+       (cursor == ui::kCursorCustom ? cursor.platform() :
+        ui::GetXCursor(CursorShapeFromNative(cursor))));
   XDefineCursor(xdisplay_, xwindow_, xcursor);
 }