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// Copyright (c) 2012 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/disambiguation_popup_helper.h"
#include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebRect.h"
#include "ui/gfx/size_conversions.h"
using WebKit::WebRect;
using WebKit::WebVector;
namespace {
// The amount of padding to add to the disambiguation popup to show
// content around the possible elements, adding some context.
const int kDisambiguationPopupPadding = 8;
// Constants used for fitting the disambiguation popup inside the bounds of
// the view. Note that there are mirror constants in PopupZoomer.java.
const int kDisambiguationPopupBoundsMargin = 25;
// The smallest allowable touch target used for disambiguation popup.
// This value is used to determine the minimum amount we need to scale to
// make all targets touchable.
const int kDisambiguationPopupMinimumTouchSize = 40;
const float kDisambiguationPopupMaxScale = 5.0;
const float kDisambiguationPopupMinScale = 2.0;
// Compute the scaling factor to ensure the smallest touch candidate reaches
// a certain clickable size after zooming
float FindOptimalScaleFactor(const WebVector<WebRect>& target_rects) {
using std::min;
using std::max;
if (!target_rects.size()) // shall never reach
return kDisambiguationPopupMinScale;
int smallest_target = min(target_rects[0].width, target_rects[0].height);
for (size_t i = 1; i < target_rects.size(); i++) {
smallest_target = min(smallest_target, target_rects[i].width);
smallest_target = min(smallest_target, target_rects[i].height);
}
smallest_target = max(smallest_target, 1);
return min(kDisambiguationPopupMaxScale, max(kDisambiguationPopupMinScale,
static_cast<float>(kDisambiguationPopupMinimumTouchSize)
/ smallest_target));
}
void TrimEdges(int *e1, int *e2, int max_combined) {
if (*e1 + *e2 <= max_combined)
return;
if (std::min(*e1, *e2) * 2 >= max_combined)
*e1 = *e2 = max_combined / 2;
else if (*e1 > *e2)
*e1 = max_combined - *e2;
else
*e2 = max_combined - *e1;
}
// Ensure the disambiguation popup fits inside the screen,
// clip the edges farthest to the touch point if needed.
gfx::Rect CropZoomArea(const gfx::Rect& zoom_rect,
const gfx::Size& viewport_size,
const gfx::Point& touch_point,
float scale) {
gfx::Size max_size = viewport_size;
max_size.Enlarge(-2 * kDisambiguationPopupBoundsMargin,
-2 * kDisambiguationPopupBoundsMargin);
max_size = ToCeiledSize(ScaleSize(max_size, 1.0 / scale));
int left = touch_point.x() - zoom_rect.x();
int right = zoom_rect.right() - touch_point.x();
int top = touch_point.y() - zoom_rect.y();
int bottom = zoom_rect.bottom() - touch_point.y();
TrimEdges(&left, &right, max_size.width());
TrimEdges(&top, &bottom, max_size.height());
return gfx::Rect(touch_point.x() - left,
touch_point.y() - top,
left + right,
top + bottom);
}
} // unnamed namespace
namespace content {
float DisambiguationPopupHelper::ComputeZoomAreaAndScaleFactor(
const gfx::Rect& tap_rect,
const WebVector<WebRect>& target_rects,
const gfx::Size& viewport_size,
gfx::Rect* zoom_rect) {
*zoom_rect = tap_rect;
for (size_t i = 0; i < target_rects.size(); i++)
zoom_rect->Union(gfx::Rect(target_rects[i]));
zoom_rect->Inset(-kDisambiguationPopupPadding, -kDisambiguationPopupPadding);
zoom_rect->Intersect(gfx::Rect(viewport_size));
float scale = FindOptimalScaleFactor(target_rects);
*zoom_rect = CropZoomArea(
*zoom_rect, viewport_size, tap_rect.CenterPoint(), scale);
return scale;
}
} // namespace content
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