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.
5 #include "chrome/browser/chromeos/ui/accessibility_focus_ring_controller.h"
7 #include "ash/display/display_controller.h"
9 #include "base/logging.h"
10 #include "chrome/browser/chromeos/ui/focus_ring_layer.h"
11 #include "ui/gfx/screen.h"
17 // The number of pixels the focus ring is outset from the object it outlines,
18 // which also determines the border radius of the rounded corners.
19 // TODO(dmazzoni): take display resolution into account.
20 const int kAccessibilityFocusRingMargin = 7;
22 // Time to transition between one location and the next.
23 const int kTransitionTimeMilliseconds = 300;
25 // A Region is an unordered collection of Rects that maintains its
26 // bounding box. Used in the middle of an algorithm that groups
27 // adjacent and overlapping rects.
29 explicit Region(gfx::Rect initial_rect) {
30 bounds = initial_rect;
31 rects.push_back(initial_rect);
34 std::vector<gfx::Rect> rects;
40 AccessibilityFocusRingController*
41 AccessibilityFocusRingController::GetInstance() {
42 return Singleton<AccessibilityFocusRingController>::get();
45 AccessibilityFocusRingController::AccessibilityFocusRingController()
49 AccessibilityFocusRingController::~AccessibilityFocusRingController() {
52 void AccessibilityFocusRingController::SetFocusRing(
53 const std::vector<gfx::Rect>& rects) {
58 void AccessibilityFocusRingController::Update() {
59 previous_rings_.swap(rings_);
61 RectsToRings(rects_, &rings_);
62 layers_.resize(rings_.size());
63 for (size_t i = 0; i < rings_.size(); ++i) {
65 layers_[i].reset(new AccessibilityFocusRingLayer(this));
68 // Focus rings other than the first one don't animate.
69 layers_[i]->Set(rings_[i]);
73 gfx::Rect bounds = rings_[0].GetBounds();
74 gfx::Display display =
75 gfx::Screen::GetNativeScreen()->GetDisplayMatching(bounds);
76 aura::Window* root_window = ash::Shell::GetInstance()->display_controller()
77 ->GetRootWindowForDisplayId(display.id());
78 ui::Compositor* compositor = root_window->layer()->GetCompositor();
79 if (!compositor || root_window != layers_[0]->root_window()) {
80 layers_[0]->Set(rings_[0]);
81 if (compositor_ && compositor_->HasAnimationObserver(this)) {
82 compositor_->RemoveAnimationObserver(this);
88 focus_change_time_ = base::TimeTicks::Now();
89 if (!compositor->HasAnimationObserver(this)) {
90 compositor_ = compositor;
91 compositor_->AddAnimationObserver(this);
96 void AccessibilityFocusRingController::RectsToRings(
97 const std::vector<gfx::Rect>& src_rects,
98 std::vector<AccessibilityFocusRing>* rings) const {
99 if (src_rects.empty())
102 // Give all of the rects a margin.
103 std::vector<gfx::Rect> rects;
104 rects.resize(src_rects.size());
105 for (size_t i = 0; i < src_rects.size(); ++i) {
106 rects[i] = src_rects[i];
107 rects[i].Inset(-GetMargin(), -GetMargin());
110 // Split the rects into contiguous regions.
111 std::vector<Region> regions;
112 regions.push_back(Region(rects[0]));
113 for (size_t i = 1; i < rects.size(); ++i) {
115 for (size_t j = 0; j < regions.size(); ++j) {
116 if (Intersects(rects[i], regions[j].bounds)) {
117 regions[j].rects.push_back(rects[i]);
118 regions[j].bounds.Union(rects[i]);
123 regions.push_back(Region(rects[i]));
127 // Keep merging regions that intersect.
128 // TODO(dmazzoni): reduce the worst-case complexity! This appears like
129 // it could be O(n^3), make sure it's not in practice.
133 for (size_t i = 0; i < regions.size() - 1 && !merged; ++i) {
134 for (size_t j = i + 1; j < regions.size() && !merged; ++j) {
135 if (Intersects(regions[i].bounds, regions[j].bounds)) {
136 regions[i].rects.insert(regions[i].rects.end(),
137 regions[j].rects.begin(),
138 regions[j].rects.end());
139 regions[i].bounds.Union(regions[j].bounds);
140 regions.erase(regions.begin() + j);
147 for (size_t i = 0; i < regions.size(); ++i) {
148 std::sort(regions[i].rects.begin(), regions[i].rects.end());
149 rings->push_back(RingFromSortedRects(regions[i].rects));
153 int AccessibilityFocusRingController::GetMargin() const {
154 return kAccessibilityFocusRingMargin;
157 // Given a vector of rects that all overlap, already sorted from top to bottom
158 // and left to right, split them into three shapes covering the top, middle,
159 // and bottom of a "paragraph shape".
165 // +---------------------+---+---+
167 // +--------+---------------+----+
169 // +--------+---------------+--+
171 // +---------+-----------------+
179 // +---------------------+-------+
185 // +---------+-------------------+
189 // When there's no clear "top" or "bottom" segment, split the overall rect
190 // evenly so that some of the area still fits into the "top" and "bottom"
192 void AccessibilityFocusRingController::SplitIntoParagraphShape(
193 const std::vector<gfx::Rect>& rects,
196 gfx::Rect* bottom) const {
197 size_t n = rects.size();
199 // Figure out how many rects belong in the top portion.
200 gfx::Rect top_rect = rects[0];
201 int top_middle = (top_rect.y() + top_rect.bottom()) / 2;
202 size_t top_count = 1;
203 while (top_count < n && rects[top_count].y() < top_middle) {
204 top_rect.Union(rects[top_count]);
205 top_middle = (top_rect.y() + top_rect.bottom()) / 2;
209 // Figure out how many rects belong in the bottom portion.
210 gfx::Rect bottom_rect = rects[n - 1];
211 int bottom_middle = (bottom_rect.y() + bottom_rect.bottom()) / 2;
212 size_t bottom_count = std::min(static_cast<size_t>(1), n - top_count);
213 while (bottom_count + top_count < n &&
214 rects[n - bottom_count - 1].bottom() > bottom_middle) {
215 bottom_rect.Union(rects[n - bottom_count - 1]);
216 bottom_middle = (bottom_rect.y() + bottom_rect.bottom()) / 2;
220 // Whatever's left goes to the middle rect, but if there's no middle or
221 // bottom rect, split the existing rects evenly to make one.
222 gfx::Rect middle_rect;
223 if (top_count + bottom_count < n) {
224 middle_rect = rects[top_count];
225 for (size_t i = top_count + 1; i < n - bottom_count; i++)
226 middle_rect.Union(rects[i]);
227 } else if (bottom_count > 0) {
228 gfx::Rect enclosing_rect = top_rect;
229 enclosing_rect.Union(bottom_rect);
230 int middle_top = (top_rect.y() + top_rect.bottom() * 2) / 3;
231 int middle_bottom = (bottom_rect.y() * 2 + bottom_rect.bottom()) / 3;
232 top_rect.set_height(middle_top - top_rect.y());
233 bottom_rect.set_height(bottom_rect.bottom() - middle_bottom);
234 bottom_rect.set_y(middle_bottom);
235 middle_rect = gfx::Rect(enclosing_rect.x(), middle_top,
236 enclosing_rect.width(), middle_bottom - middle_top);
238 int middle_top = (top_rect.y() * 2 + top_rect.bottom()) / 3;
239 int middle_bottom = (top_rect.y() + top_rect.bottom() * 2) / 3;
240 middle_rect = gfx::Rect(top_rect.x(), middle_top,
241 top_rect.width(), middle_bottom - middle_top);
242 bottom_rect = gfx::Rect(
243 top_rect.x(), middle_bottom,
244 top_rect.width(), top_rect.bottom() - middle_bottom);
245 top_rect.set_height(middle_top - top_rect.y());
248 if (middle_rect.y() > top_rect.bottom()) {
249 middle_rect.set_height(
250 middle_rect.height() + middle_rect.y() - top_rect.bottom());
251 middle_rect.set_y(top_rect.bottom());
254 if (middle_rect.bottom() < bottom_rect.y()) {
255 middle_rect.set_height(bottom_rect.y() - middle_rect.y());
259 *middle = middle_rect;
260 *bottom = bottom_rect;
263 AccessibilityFocusRing AccessibilityFocusRingController::RingFromSortedRects(
264 const std::vector<gfx::Rect>& rects) const {
265 if (rects.size() == 1)
266 return AccessibilityFocusRing::CreateWithRect(rects[0], GetMargin());
271 SplitIntoParagraphShape(rects, &top, &middle, &bottom);
273 return AccessibilityFocusRing::CreateWithParagraphShape(
274 top, middle, bottom, GetMargin());
277 bool AccessibilityFocusRingController::Intersects(
278 const gfx::Rect& r1, const gfx::Rect& r2) const {
279 int slop = GetMargin();
280 return (r2.x() <= r1.right() + slop &&
281 r2.right() >= r1.x() - slop &&
282 r2.y() <= r1.bottom() + slop &&
283 r2.bottom() >= r1.y() - slop);
286 void AccessibilityFocusRingController::OnDeviceScaleFactorChanged() {
290 void AccessibilityFocusRingController::OnAnimationStep(
291 base::TimeTicks timestamp) {
296 CHECK(!rings_.empty());
297 CHECK(!layers_.empty());
300 // It's quite possible for the first 1 or 2 animation frames to be
301 // for a timestamp that's earlier than the time we received the
302 // focus change, so we just treat those as a delta of zero.
303 if (timestamp < focus_change_time_)
304 timestamp = focus_change_time_;
306 base::TimeDelta delta = timestamp - focus_change_time_;
307 base::TimeDelta transition_time =
308 base::TimeDelta::FromMilliseconds(kTransitionTimeMilliseconds);
309 if (delta >= transition_time) {
310 layers_[0]->Set(rings_[0]);
311 compositor_->RemoveAnimationObserver(this);
316 double fraction = delta.InSecondsF() / transition_time.InSecondsF();
319 fraction = pow(fraction, 0.3);
321 layers_[0]->Set(AccessibilityFocusRing::Interpolate(
322 previous_rings_[0], rings_[0], fraction));
325 } // namespace chromeos