1// Copyright (c) 2010 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 "pdf/paint_manager.h"
6
7#include <algorithm>
8
9#include "base/logging.h"
10#include "ppapi/c/pp_errors.h"
11#include "ppapi/cpp/instance.h"
12#include "ppapi/cpp/module.h"
13
14PaintManager::PaintManager(pp::Instance* instance,
15                           Client* client,
16                           bool is_always_opaque)
17    : instance_(instance),
18      client_(client),
19      is_always_opaque_(is_always_opaque),
20      callback_factory_(NULL),
21      manual_callback_pending_(false),
22      flush_pending_(false),
23      has_pending_resize_(false),
24      graphics_need_to_be_bound_(false),
25      pending_device_scale_(1.0),
26      device_scale_(1.0),
27      in_paint_(false),
28      first_paint_(true),
29      view_size_changed_waiting_for_paint_(false) {
30  // Set the callback object outside of the initializer list to avoid a
31  // compiler warning about using "this" in an initializer list.
32  callback_factory_.Initialize(this);
33
34  // You can not use a NULL client pointer.
35  DCHECK(client);
36}
37
38PaintManager::~PaintManager() {
39}
40
41// static
42pp::Size PaintManager::GetNewContextSize(const pp::Size& current_context_size,
43                                         const pp::Size& plugin_size) {
44  // The amount of additional space in pixels to allocate to the right/bottom of
45  // the context.
46  const int kBufferSize = 50;
47
48  // Default to returning the same size.
49  pp::Size result = current_context_size;
50
51  // The minimum size of the plugin before resizing the context to ensure we
52  // aren't wasting too much memory. We deduct twice the kBufferSize from the
53  // current context size which gives a threshhold that is kBufferSize below
54  // the plugin size when the context size was last computed.
55  pp::Size min_size(
56      std::max(current_context_size.width() - 2 * kBufferSize, 0),
57      std::max(current_context_size.height() - 2 * kBufferSize, 0));
58
59  // If the plugin size is bigger than the current context size, we need to
60  // resize the context. If the plugin size is smaller than the current
61  // context size by a given threshhold then resize the context so that we
62  // aren't wasting too much memory.
63  if (plugin_size.width() > current_context_size.width() ||
64      plugin_size.height() > current_context_size.height() ||
65      plugin_size.width() < min_size.width() ||
66      plugin_size.height() < min_size.height()) {
67      // Create a larger context than needed so that if we only resize by a
68      // small margin, we don't need a new context.
69      result = pp::Size(plugin_size.width() + kBufferSize,
70                        plugin_size.height() + kBufferSize);
71  }
72
73  return result;
74}
75
76void PaintManager::Initialize(pp::Instance* instance,
77                              Client* client,
78                              bool is_always_opaque) {
79  DCHECK(!instance_ && !client_);  // Can't initialize twice.
80  instance_ = instance;
81  client_ = client;
82  is_always_opaque_ = is_always_opaque;
83}
84
85void PaintManager::SetSize(const pp::Size& new_size, float device_scale) {
86  if (GetEffectiveSize() == new_size &&
87      GetEffectiveDeviceScale() == device_scale)
88    return;
89
90  has_pending_resize_ = true;
91  pending_size_ = new_size;
92  pending_device_scale_ = device_scale;
93
94  view_size_changed_waiting_for_paint_ = true;
95
96  Invalidate();
97}
98
99void PaintManager::Invalidate() {
100  // You must call SetSize before using.
101  DCHECK(!graphics_.is_null() || has_pending_resize_);
102
103  EnsureCallbackPending();
104  aggregator_.InvalidateRect(pp::Rect(GetEffectiveSize()));
105}
106
107void PaintManager::InvalidateRect(const pp::Rect& rect) {
108  DCHECK(!in_paint_);
109
110  // You must call SetSize before using.
111  DCHECK(!graphics_.is_null() || has_pending_resize_);
112
113  // Clip the rect to the device area.
114  pp::Rect clipped_rect = rect.Intersect(pp::Rect(GetEffectiveSize()));
115  if (clipped_rect.IsEmpty())
116    return;  // Nothing to do.
117
118  EnsureCallbackPending();
119  aggregator_.InvalidateRect(clipped_rect);
120}
121
122void PaintManager::ScrollRect(const pp::Rect& clip_rect,
123                              const pp::Point& amount) {
124  DCHECK(!in_paint_);
125
126  // You must call SetSize before using.
127  DCHECK(!graphics_.is_null() || has_pending_resize_);
128
129  EnsureCallbackPending();
130
131  aggregator_.ScrollRect(clip_rect, amount);
132}
133
134pp::Size PaintManager::GetEffectiveSize() const {
135  return has_pending_resize_ ? pending_size_ : plugin_size_;
136}
137
138float PaintManager::GetEffectiveDeviceScale() const {
139  return has_pending_resize_ ? pending_device_scale_ : device_scale_;
140}
141
142void PaintManager::EnsureCallbackPending() {
143  // The best way for us to do the next update is to get a notification that
144  // a previous one has completed. So if we're already waiting for one, we
145  // don't have to do anything differently now.
146  if (flush_pending_)
147    return;
148
149  // If no flush is pending, we need to do a manual call to get back to the
150  // main thread. We may have one already pending, or we may need to schedule.
151  if (manual_callback_pending_)
152    return;
153
154  pp::Module::Get()->core()->CallOnMainThread(
155      0,
156      callback_factory_.NewCallback(&PaintManager::OnManualCallbackComplete),
157      0);
158  manual_callback_pending_ = true;
159}
160
161void PaintManager::DoPaint() {
162  in_paint_ = true;
163
164  std::vector<ReadyRect> ready;
165  std::vector<pp::Rect> pending;
166
167  DCHECK(aggregator_.HasPendingUpdate());
168
169  // Apply any pending resize. Setting the graphics to this class must happen
170  // before asking the plugin to paint in case it requests invalides or resizes.
171  // However, the bind must not happen until afterward since we don't want to
172  // have an unpainted device bound. The needs_binding flag tells us whether to
173  // do this later.
174  if (has_pending_resize_) {
175    plugin_size_ = pending_size_;
176    // Only create a new graphics context if the current context isn't big
177    // enough or if it is far too big. This avoids creating a new context if
178    // we only resize by a small amount.
179    pp::Size new_size = GetNewContextSize(graphics_.size(), pending_size_);
180    if (graphics_.size() != new_size) {
181      graphics_ = pp::Graphics2D(instance_, new_size, is_always_opaque_);
182      graphics_need_to_be_bound_ = true;
183
184      // Since we're binding a new one, all of the callbacks have been canceled.
185      manual_callback_pending_ = false;
186      flush_pending_ = false;
187      callback_factory_.CancelAll();
188    }
189
190    if (pending_device_scale_ != 1.0)
191      graphics_.SetScale(1.0 / pending_device_scale_);
192    device_scale_ = pending_device_scale_;
193
194    // This must be cleared before calling into the plugin since it may do
195    // additional invalidation or sizing operations.
196    has_pending_resize_ = false;
197    pending_size_ = pp::Size();
198  }
199
200  PaintAggregator::PaintUpdate update = aggregator_.GetPendingUpdate();
201  client_->OnPaint(update.paint_rects, &ready, &pending);
202
203  if (ready.empty() && pending.empty()) {
204    in_paint_ = false;
205    return;  // Nothing was painted, don't schedule a flush.
206  }
207
208  std::vector<PaintAggregator::ReadyRect> ready_now;
209  if (pending.empty()) {
210    std::vector<PaintAggregator::ReadyRect> temp_ready;
211    for (size_t i = 0; i < ready.size(); ++i)
212      temp_ready.push_back(ready[i]);
213    aggregator_.SetIntermediateResults(temp_ready, pending);
214    ready_now = aggregator_.GetReadyRects();
215    aggregator_.ClearPendingUpdate();
216
217    // Apply any scroll first.
218    if (update.has_scroll)
219      graphics_.Scroll(update.scroll_rect, update.scroll_delta);
220
221    view_size_changed_waiting_for_paint_ = false;
222  } else {
223    std::vector<PaintAggregator::ReadyRect> ready_later;
224    for (size_t i = 0; i < ready.size(); ++i) {
225      // Don't flush any part (i.e. scrollbars) if we're resizing the browser,
226      // as that'll lead to flashes.  Until we flush, the browser will use the
227      // previous image, but if we flush, it'll revert to using the blank image.
228      // We make an exception for the first paint since we want to show the
229      // default background color instead of the pepper default of black.
230      if (ready[i].flush_now &&
231          (!view_size_changed_waiting_for_paint_ || first_paint_)) {
232        ready_now.push_back(ready[i]);
233      } else {
234        ready_later.push_back(ready[i]);
235      }
236    }
237    // Take the rectangles, except the ones that need to be flushed right away,
238    // and save them so that everything is flushed at once.
239    aggregator_.SetIntermediateResults(ready_later, pending);
240
241    if (ready_now.empty()) {
242      in_paint_ = false;
243      EnsureCallbackPending();
244      return;
245    }
246  }
247
248  for (size_t i = 0; i < ready_now.size(); ++i) {
249    graphics_.PaintImageData(
250        ready_now[i].image_data, ready_now[i].offset, ready_now[i].rect);
251  }
252
253  int32_t result = graphics_.Flush(
254      callback_factory_.NewCallback(&PaintManager::OnFlushComplete));
255
256  // If you trigger this assertion, then your plugin has called Flush()
257  // manually. When using the PaintManager, you should not call Flush, it will
258  // handle that for you because it needs to know when it can do the next paint
259  // by implementing the flush callback.
260  //
261  // Another possible cause of this assertion is re-using devices. If you
262  // use one device, swap it with another, then swap it back, we won't know
263  // that we've already scheduled a Flush on the first device. It's best to not
264  // re-use devices in this way.
265  DCHECK(result != PP_ERROR_INPROGRESS);
266
267  if (result == PP_OK_COMPLETIONPENDING) {
268    flush_pending_ = true;
269  } else {
270    DCHECK(result == PP_OK);  // Catch all other errors in debug mode.
271  }
272
273  in_paint_ = false;
274  first_paint_ = false;
275
276  if (graphics_need_to_be_bound_) {
277    instance_->BindGraphics(graphics_);
278    graphics_need_to_be_bound_ = false;
279  }
280}
281
282void PaintManager::OnFlushComplete(int32_t) {
283  DCHECK(flush_pending_);
284  flush_pending_ = false;
285
286  // If more paints were enqueued while we were waiting for the flush to
287  // complete, execute them now.
288  if (aggregator_.HasPendingUpdate())
289    DoPaint();
290}
291
292void PaintManager::OnManualCallbackComplete(int32_t) {
293  DCHECK(manual_callback_pending_);
294  manual_callback_pending_ = false;
295
296  // Just because we have a manual callback doesn't mean there are actually any
297  // invalid regions. Even though we only schedule this callback when something
298  // is pending, a Flush callback could have come in before this callback was
299  // executed and that could have cleared the queue.
300  if (aggregator_.HasPendingUpdate())
301    DoPaint();
302}
303