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// 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/renderer/webscrollbarbehavior_impl_gtkoraura.h"
#include "build/build_config.h"
#include "third_party/WebKit/public/platform/WebPoint.h"
#include "third_party/WebKit/public/platform/WebRect.h"
namespace content {
bool WebScrollbarBehaviorImpl::shouldCenterOnThumb(
blink::WebScrollbarBehavior::Button mouseButton,
bool shiftKeyPressed,
bool altKeyPressed) {
#if (defined(OS_LINUX) && !defined(OS_CHROMEOS))
if (mouseButton == blink::WebScrollbarBehavior::ButtonMiddle)
return true;
#endif
return (mouseButton == blink::WebScrollbarBehavior::ButtonLeft) &&
shiftKeyPressed;
}
bool WebScrollbarBehaviorImpl::shouldSnapBackToDragOrigin(
const blink::WebPoint& eventPoint,
const blink::WebRect& scrollbarRect,
bool isHorizontal) {
// Constants used to figure the drag rect outside which we should snap the
// scrollbar thumb back to its origin. These calculations are based on
// observing the behavior of the MSVC8 main window scrollbar + some
// guessing/extrapolation.
static const int kOffEndMultiplier = 3;
static const int kOffSideMultiplier = 8;
static const int kDefaultWinScrollbarThickness = 17;
// Find the rect within which we shouldn't snap, by expanding the track rect
// in both dimensions.
gfx::Rect noSnapRect(scrollbarRect);
int thickness = isHorizontal ? noSnapRect.height() : noSnapRect.width();
// Even if the platform's scrollbar is narrower than the default Windows one,
// we still want to provide at least as much slop area, since a slightly
// narrower scrollbar doesn't necessarily imply that users will drag
// straighter.
thickness = std::max(thickness, kDefaultWinScrollbarThickness);
noSnapRect.Inset(
(isHorizontal ? kOffEndMultiplier : kOffSideMultiplier) * -thickness,
(isHorizontal ? kOffSideMultiplier : kOffEndMultiplier) * -thickness);
// On most platforms, we should snap iff the event is outside our calculated
// rect. On Linux, however, we should not snap for events off the ends, but
// not the sides, of the rect.
#if (defined(OS_LINUX) && !defined(OS_CHROMEOS))
return isHorizontal ?
(eventPoint.y < noSnapRect.y() || eventPoint.y >= noSnapRect.bottom()) :
(eventPoint.x < noSnapRect.x() || eventPoint.x >= noSnapRect.right());
#else
return !noSnapRect.Contains(eventPoint);
#endif
}
} // namespace content
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