Support for Adaptive Handle Orientation

content/browser/android/composited_touch_handle_drawable.cc

 // Copyright 2014 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 "content/browser/android/composited_touch_handle_drawable.h"
 
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/layers/ui_resource_layer.h"
@@ skipping 83 matching lines @@
   DetachLayer();
 }
 
 void CompositedTouchHandleDrawable::SetEnabled(bool enabled) {
   layer_->SetIsDrawable(enabled);
   // Force a position update in case the disabled layer's properties are stale.
   if (enabled)
     UpdateLayerPosition();
 }
 
-void CompositedTouchHandleDrawable::SetOrientation(
-    ui::TouchHandleOrientation orientation) {
+void CompositedTouchHandleDrawable::SetLayout(
+    const gfx::PointF& position,
+    ui::TouchHandleOrientation orientation,
+    bool mirror_vertical,
+    bool mirror_horizontal) {
   DCHECK(layer_->parent());
+  focal_position_ = gfx::ScalePoint(position, dpi_scale_);
+
   orientation_ = orientation;
 
   const SkBitmap& bitmap = g_selection_resources.Get().GetBitmap(orientation);
+  const int bitmap_height = bitmap.height();
+  const int bitmap_width = bitmap.width();
+  int focal_offset_x = 0;
+  int focal_offset_y = mirror_vertical ? bitmap_height : 0;
+
   layer_->SetBitmap(bitmap);

[jdduke (slow), 2015/05/11 15:40:15]

Hmm, it looks like UIResourceLayer doesn't cache the bitmap reference, so I
think we should only perform this update when the orientation changes (might
have to cache the orientation).

[AviD, 2015/05/19 16:26:27]

Done.
We save orientation_ here, I have used that to check if orientation is changed.

-  layer_->SetBounds(gfx::Size(bitmap.width(), bitmap.height()));
+  layer_->SetBounds(gfx::Size(bitmap_width, bitmap_height));
+
+  // Invert about X and Y axis based on the mirror values
+  gfx::Transform transform;
+  float scale_x = mirror_horizontal ? -1.f : 1.f;
+  float scale_y = mirror_vertical ? -1.f : 1.f;
+
+  layer_->SetTransformOrigin(
+      gfx::Point3F(bitmap_width * 0.5f, bitmap_height * 0.5f, 0));
+  transform.Scale(scale_x, scale_y);
+  layer_->SetTransform(transform);
 
   switch (orientation_) {

[jdduke (slow), 2015/05/11 15:40:15]

Hmm, to save on code can you do:

focal_offset_x = 0;
switch (...) {
  ... focal_offset_x = ...
}
focal_offset_from_origin_ = gfx::Vector2df(focal_offset_x, focal_offset_y);

[AviD, 2015/05/19 16:26:27]

Done.

     case ui::TouchHandleOrientation::LEFT:
-      focal_offset_from_origin_ = gfx::Vector2dF(bitmap.width() * 0.75f, 0);
+      focal_offset_x =
+          mirror_horizontal ? bitmap_width * 0.25f : bitmap_width * 0.75f;
+      focal_offset_from_origin_ =
+          gfx::Vector2dF(focal_offset_x, focal_offset_y);
       break;
     case ui::TouchHandleOrientation::RIGHT:
-      focal_offset_from_origin_ = gfx::Vector2dF(bitmap.width() * 0.25f, 0);
+      focal_offset_x =
+          mirror_horizontal ? bitmap_width * 0.75f : bitmap_width * 0.25f;
+      focal_offset_from_origin_ =
+          gfx::Vector2dF(focal_offset_x, focal_offset_y);
       break;
     case ui::TouchHandleOrientation::CENTER:
-      focal_offset_from_origin_ = gfx::Vector2dF(bitmap.width() * 0.5f, 0);
+      focal_offset_x = bitmap_width * 0.5f;
+      focal_offset_from_origin_ =
+          gfx::Vector2dF(focal_offset_x, focal_offset_y);
       break;
     case ui::TouchHandleOrientation::UNDEFINED:
       NOTREACHED() << "Invalid touch handle orientation.";
       break;
   };
 
   UpdateLayerPosition();
 }
 
 void CompositedTouchHandleDrawable::SetAlpha(float alpha) {
   DCHECK(layer_->parent());
   alpha = std::max(0.f, std::min(1.f, alpha));
   bool hidden = alpha <= 0;
   layer_->SetOpacity(alpha);
   layer_->SetHideLayerAndSubtree(hidden);
 }
 
-void CompositedTouchHandleDrawable::SetFocus(const gfx::PointF& position) {
-  DCHECK(layer_->parent());
-  focal_position_ = gfx::ScalePoint(position, dpi_scale_);
-  UpdateLayerPosition();
-}
-
 gfx::RectF CompositedTouchHandleDrawable::GetVisibleBounds() const {
   return gfx::ScaleRect(gfx::RectF(layer_->position().x(),
                                    layer_->position().y(),
                                    layer_->bounds().width(),
                                    layer_->bounds().height()),
                         1.f / dpi_scale_);
 }
 
 void CompositedTouchHandleDrawable::DetachLayer() {
   layer_->RemoveFromParent();
 }
 
 void CompositedTouchHandleDrawable::UpdateLayerPosition() {
   layer_->SetPosition(focal_position_ - focal_offset_from_origin_);

[jdduke (slow), 2015/05/11 15:40:15]

Since this is only called in one place now, I'd be OK moving the logic up to
where it is called and removing this function.

[AviD, 2015/05/19 16:26:27]

It is currently being called from SetEnabled() too.

 }
 
 // static
 bool CompositedTouchHandleDrawable::RegisterHandleViewResources(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace content