[Android] Suppress overscroll for unscrollable axes in the browser

content/browser/android/overscroll_glow.cc

 // Copyright (c) 2013 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/overscroll_glow.h"
 
 #include "cc/layers/layer.h"
 #include "content/browser/android/edge_effect_base.h"
 #include "content/public/browser/android/compositor.h"
 
@@ skipping 59 matching lines @@
       return gfx::SizeF(window_size.height(), window_size.width());
     default:
       NOTREACHED() << "Invalid edge: " << edge;
       return gfx::SizeF();
   };
 }
 
 }  // namespace
 
 OverscrollGlow::OverscrollGlow(OverscrollGlowClient* client)
-    : client_(client), edge_offsets_(), initialized_(false) {
+    : client_(client),
+      edge_offsets_(),
+      initialized_(false),
+      allow_horizontal_overscroll_(true),
+      allow_vertical_overscroll_(true) {
   DCHECK(client);
 }
 
 OverscrollGlow::~OverscrollGlow() {
   Detach();
 }
 
 void OverscrollGlow::Reset() {
   if (!initialized_)
     return;
@@ skipping 18 matching lines @@
     if (!edge_effects_[i]->IsFinished())
       max_alpha = std::max(max_alpha, edge_effects_[i]->GetAlpha());
   }
   return std::min(max_alpha, 1.f);
 }
 
 bool OverscrollGlow::OnOverscrolled(base::TimeTicks current_time,
           const gfx::Vector2dF& accumulated_overscroll,
           gfx::Vector2dF overscroll_delta,
           gfx::Vector2dF velocity,
-          const gfx::Vector2dF& displacement) {
+          const gfx::Vector2dF& overscroll_location) {
   // The size of the glow determines the relative effect of the inputs; an
   // empty-sized effect is effectively disabled.
   if (viewport_size_.IsEmpty())
     return false;
 
+  if (!allow_horizontal_overscroll_) {
+    overscroll_delta.set_x(0);
+    velocity.set_x(0);
+  }
+  if (!allow_vertical_overscroll_) {
+    overscroll_delta.set_y(0);
+    velocity.set_y(0);
+  }
+
   // Ignore sufficiently small values that won't meaningfuly affect animation.
   overscroll_delta = ZeroSmallComponents(overscroll_delta);
   if (overscroll_delta.IsZero()) {
     if (initialized_)
       Release(current_time);
     return CheckNeedsAnimate();
   }
 
   if (!InitializeIfNecessary())
     return false;
 
   gfx::Vector2dF old_overscroll = accumulated_overscroll - overscroll_delta;
   bool x_overscroll_started =
       !IsApproxZero(overscroll_delta.x()) && IsApproxZero(old_overscroll.x());
   bool y_overscroll_started =
       !IsApproxZero(overscroll_delta.y()) && IsApproxZero(old_overscroll.y());
 
   velocity = ZeroSmallComponents(velocity);
   if (!velocity.IsZero())
     Absorb(current_time, velocity, x_overscroll_started, y_overscroll_started);
   else
-    Pull(current_time, overscroll_delta, displacement);
+    Pull(current_time, overscroll_delta, overscroll_location);
 
   return CheckNeedsAnimate();
 }
 
 bool OverscrollGlow::Animate(base::TimeTicks current_time,
                              cc::Layer* parent_layer) {
   DCHECK(parent_layer);
   if (!CheckNeedsAnimate())
     return false;
 
@@ skipping 16 matching lines @@
     const gfx::SizeF& content_size,
     const gfx::Vector2dF& content_scroll_offset) {
   viewport_size_ = viewport_size;
   edge_offsets_[OverscrollGlow::EDGE_TOP] = -content_scroll_offset.y();
   edge_offsets_[OverscrollGlow::EDGE_LEFT] = -content_scroll_offset.x();
   edge_offsets_[OverscrollGlow::EDGE_BOTTOM] = content_size.height() -
                                                content_scroll_offset.y() -
                                                viewport_size.height();
   edge_offsets_[OverscrollGlow::EDGE_RIGHT] =
       content_size.width() - content_scroll_offset.x() - viewport_size.width();
+
+  // Disallow overscroll on unscrollable axes, matching platform behavior.
+  allow_horizontal_overscroll_ =
+      std::ceil(viewport_size_.width()) < content_size.width();
+  allow_vertical_overscroll_ =
+      std::ceil(viewport_size_.height()) < content_size.height();

[tdresser, 2015/07/10 18:41:30]

We don't need an epsilon check here?

[jdduke (slow), 2015/07/10 19:12:50]

This is the logic we had before the check got moved to the renderer (see
https://codereview.chromium.org/230223006/diff/40001/content/browser/renderer...).
I can switch it to an epsilon check if you like.

 }
 
 bool OverscrollGlow::CheckNeedsAnimate() {
   if (!initialized_) {
     Detach();
     return false;
   }
 
   if (IsActive())
     return true;
@@ skipping 46 matching lines @@
   const float inv_width = 1.f / viewport_size_.width();
   const float inv_height = 1.f / viewport_size_.height();
 
   gfx::Vector2dF overscroll_pull =
       gfx::ScaleVector2d(overscroll_delta, inv_width, inv_height);
   const float edge_pull[EDGE_COUNT] = {
       min(overscroll_pull.y(), 0.f),  // Top
       min(overscroll_pull.x(), 0.f),  // Left
       max(overscroll_pull.y(), 0.f),  // Bottom
       max(overscroll_pull.x(), 0.f)   // Right
-  };
-
+  }

[tdresser, 2015/07/10 18:41:30]

Fix ;

[jdduke (slow), 2015/07/10 19:12:50]

Whoops, done.

+;
   gfx::Vector2dF displacement =
       gfx::ScaleVector2d(overscroll_location, inv_width, inv_height);
   displacement.set_x(max(0.f, min(1.f, displacement.x())));
   displacement.set_y(max(0.f, min(1.f, displacement.y())));
   const float edge_displacement[EDGE_COUNT] = {
       1.f - displacement.x(),  // Top
       displacement.y(),        // Left
       displacement.x(),        // Bottom
       1.f - displacement.y()   // Right
   };
@@ skipping 37 matching lines @@
   for (size_t i = 0; i < EDGE_COUNT; ++i)
     edge_effects_[i]->Release(current_time);
 }
 
 EdgeEffectBase* OverscrollGlow::GetOppositeEdge(int edge_index) {
   DCHECK(initialized_);
   return edge_effects_[(edge_index + 2) % EDGE_COUNT].get();
 }
 
 }  // namespace content