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1 // Copyright (c) 2012 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/disambiguation_popup_helper.h" | |
6 | |
7 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebRect.h" | |
8 #include "ui/gfx/size_conversions.h" | |
9 | |
10 using WebKit::WebRect; | |
11 using WebKit::WebVector; | |
12 | |
13 namespace { | |
14 | |
15 // The amount of padding to add to the disambiguation popup to show | |
16 // content around the possible elements, adding some context. | |
17 const int kDisambiguationPopupPadding = 8; | |
18 | |
19 // Constants used for fitting the disambiguation popup inside the bounds of | |
20 // the view. Note that there are mirror constants in PopupZoomer.java. | |
21 const int kDisambiguationPopupBoundsMargin = 25; | |
22 | |
23 // The smallest allowable touch target used for disambiguation popup. | |
24 // This value is used to determine the minimum amount we need to scale to | |
25 // make all targets touchable. | |
26 const int kDisambiguationPopupMinimumTouchSize = 40; | |
27 const float kDisambiguationPopupMaxScale = 5.0; | |
28 const float kDisambiguationPopupMinScale = 2.0; | |
29 | |
30 // Compute the scaling factor to ensure the smallest touch candidate reaches | |
31 // a certain clickable size after zooming | |
32 float FindOptimalScaleFactor(const WebVector<WebRect>& target_rects) { | |
33 using std::min; | |
34 using std::max; | |
35 if (!target_rects.size()) // shall never reach | |
36 return kDisambiguationPopupMinScale; | |
37 int smallest_target = min(target_rects[0].width, target_rects[0].height); | |
38 for (size_t i = 1; i < target_rects.size(); i++) { | |
39 smallest_target = min(smallest_target, target_rects[i].width); | |
40 smallest_target = min(smallest_target, target_rects[i].height); | |
41 } | |
42 smallest_target = max(smallest_target, 1); | |
43 return min(kDisambiguationPopupMaxScale, max(kDisambiguationPopupMinScale, | |
44 static_cast<float>(kDisambiguationPopupMinimumTouchSize) | |
45 / smallest_target)); | |
46 } | |
47 | |
48 void TrimEdges(int *e1, int *e2, int max_combined) { | |
49 if (*e1 + *e2 <= max_combined) | |
50 return; | |
51 | |
52 if (std::min(*e1, *e2) * 2 >= max_combined) | |
53 *e1 = *e2 = max_combined / 2; | |
54 else if (*e1 > *e2) | |
55 *e1 = max_combined - *e2; | |
56 else | |
57 *e2 = max_combined - *e1; | |
58 } | |
59 | |
60 // Ensure the disambiguation popup fits inside the screen, | |
61 // clip the edges farthest to the touch point if needed. | |
62 gfx::Rect CropZoomArea(const gfx::Rect& zoom_rect, | |
63 const gfx::Size& viewport_size, | |
64 const gfx::Point& touch_point, | |
65 float scale) { | |
66 gfx::Size max_size = viewport_size; | |
darin (slow to review)
2012/10/17 19:14:01
nit: indent by 2 spaces
trchen
2012/10/17 22:25:08
Done.
| |
67 max_size.Enlarge(-2 * kDisambiguationPopupBoundsMargin, | |
68 -2 * kDisambiguationPopupBoundsMargin); | |
69 max_size = ToCeiledSize(max_size.Scale(1.0 / scale)); | |
70 | |
71 int left = touch_point.x() - zoom_rect.x(); | |
72 int right = zoom_rect.right() - touch_point.x(); | |
73 int top = touch_point.y() - zoom_rect.y(); | |
74 int bottom = zoom_rect.bottom() - touch_point.y(); | |
75 TrimEdges(&left, &right, max_size.width()); | |
76 TrimEdges(&top, &bottom, max_size.height()); | |
77 | |
78 return gfx::Rect(touch_point.x() - left, | |
79 touch_point.y() - top, | |
80 left + right, | |
81 top + bottom); | |
82 } | |
83 | |
84 } // unnamed namespace | |
85 | |
86 namespace content { | |
87 | |
88 float DisambiguationPopupHelper::ComputeZoomAreaAndScaleFactor( | |
89 const gfx::Rect& tap_rect, | |
90 const WebVector<WebRect>& target_rects, | |
91 const gfx::Size& viewport_size, | |
92 gfx::Rect* zoom_rect) { | |
93 *zoom_rect = tap_rect; | |
94 for (size_t i = 0; i < target_rects.size(); i++) | |
95 *zoom_rect = zoom_rect->Union(gfx::Rect(target_rects[i])); | |
96 zoom_rect->Inset(-kDisambiguationPopupPadding, -kDisambiguationPopupPadding); | |
97 *zoom_rect = zoom_rect->Intersect(gfx::Rect(viewport_size)); | |
98 | |
99 float scale = FindOptimalScaleFactor(target_rects); | |
100 *zoom_rect = CropZoomArea( | |
101 *zoom_rect, viewport_size, tap_rect.CenterPoint(), scale); | |
102 | |
103 return scale; | |
104 } | |
105 | |
106 } // namespace content | |
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