1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "content/renderer/webscrollbarbehavior_impl_gtkoraura.h"
6
7 #include "third_party/WebKit/public/platform/WebPoint.h"
8 #include "third_party/WebKit/public/platform/WebRect.h"
9
10 namespace content {
11
shouldCenterOnThumb(blink::WebScrollbarBehavior::Button mouseButton,bool shiftKeyPressed,bool altKeyPressed)12 bool WebScrollbarBehaviorImpl::shouldCenterOnThumb(
13 blink::WebScrollbarBehavior::Button mouseButton,
14 bool shiftKeyPressed,
15 bool altKeyPressed) {
16 #if (defined(OS_LINUX) && !defined(OS_CHROMEOS))
17 if (mouseButton == blink::WebScrollbarBehavior::ButtonMiddle)
18 return true;
19 #endif
20 return (mouseButton == blink::WebScrollbarBehavior::ButtonLeft) &&
21 shiftKeyPressed;
22 }
23
shouldSnapBackToDragOrigin(const blink::WebPoint & eventPoint,const blink::WebRect & scrollbarRect,bool isHorizontal)24 bool WebScrollbarBehaviorImpl::shouldSnapBackToDragOrigin(
25 const blink::WebPoint& eventPoint,
26 const blink::WebRect& scrollbarRect,
27 bool isHorizontal) {
28 // Constants used to figure the drag rect outside which we should snap the
29 // scrollbar thumb back to its origin. These calculations are based on
30 // observing the behavior of the MSVC8 main window scrollbar + some
31 // guessing/extrapolation.
32 static const int kOffEndMultiplier = 3;
33 static const int kOffSideMultiplier = 8;
34
35 // Find the rect within which we shouldn't snap, by expanding the track rect
36 // in both dimensions.
37 gfx::Rect noSnapRect(scrollbarRect);
38 const int thickness = isHorizontal ? noSnapRect.height() : noSnapRect.width();
39 noSnapRect.Inset(
40 (isHorizontal ? kOffEndMultiplier : kOffSideMultiplier) * -thickness,
41 (isHorizontal ? kOffSideMultiplier : kOffEndMultiplier) * -thickness);
42
43 // We should snap iff the event is outside our calculated rect.
44 return !noSnapRect.Contains(eventPoint);
45 }
46
47 } // namespace content
48