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// Copyright (c) 2010 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 "pdf/paint_manager.h"
#include <stddef.h>
#include <stdint.h>
#include <algorithm>
#include "base/auto_reset.h"
#include "base/bind.h"
#include "base/callback.h"
#include "base/check.h"
#include "pdf/paint_ready_rect.h"
#include "pdf/ppapi_migration/callback.h"
#include "pdf/ppapi_migration/geometry_conversions.h"
#include "pdf/ppapi_migration/graphics.h"
#include "ppapi/cpp/completion_callback.h"
#include "ppapi/cpp/module.h"
#include "ui/gfx/geometry/point.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/geometry/size.h"
#include "ui/gfx/geometry/vector2d.h"
namespace chrome_pdf {
PaintManager::PaintManager(Client* client) : client_(client) {
PaintManager::~PaintManager() = default;
// static
gfx::Size PaintManager::GetNewContextSize(const gfx::Size& current_context_size,
const gfx::Size& plugin_size) {
// The amount of additional space in pixels to allocate to the right/bottom of
// the context.
constexpr int kBufferSize = 50;
// Default to returning the same size.
gfx::Size result = current_context_size;
// The minimum size of the plugin before resizing the context to ensure we
// aren't wasting too much memory. We deduct twice the kBufferSize from the
// current context size which gives a threshhold that is kBufferSize below
// the plugin size when the context size was last computed.
gfx::Size min_size(
std::max(current_context_size.width() - 2 * kBufferSize, 0),
std::max(current_context_size.height() - 2 * kBufferSize, 0));
// If the plugin size is bigger than the current context size, we need to
// resize the context. If the plugin size is smaller than the current
// context size by a given threshhold then resize the context so that we
// aren't wasting too much memory.
if (plugin_size.width() > current_context_size.width() ||
plugin_size.height() > current_context_size.height() ||
plugin_size.width() < min_size.width() ||
plugin_size.height() < min_size.height()) {
// Create a larger context than needed so that if we only resize by a
// small margin, we don't need a new context.
result = gfx::Size(plugin_size.width() + kBufferSize,
plugin_size.height() + kBufferSize);
return result;
void PaintManager::SetSize(const gfx::Size& new_size, float device_scale) {
if (GetEffectiveSize() == new_size &&
GetEffectiveDeviceScale() == device_scale) {
has_pending_resize_ = true;
pending_size_ = new_size;
pending_device_scale_ = device_scale;
view_size_changed_waiting_for_paint_ = true;
void PaintManager::SetTransform(float scale,
const gfx::Point& origin,
const gfx::Vector2d& translate,
bool schedule_flush) {
if (!graphics_)
graphics_->SetLayerTransform(scale, origin, translate);
if (!schedule_flush)
if (flush_pending_) {
flush_requested_ = true;
void PaintManager::ClearTransform() {
SetTransform(1.f, gfx::Point(), gfx::Vector2d(), false);
void PaintManager::Invalidate() {
if (!graphics_ && !has_pending_resize_)
void PaintManager::InvalidateRect(const gfx::Rect& rect) {
if (!graphics_ && !has_pending_resize_)
// Clip the rect to the device area.
gfx::Rect clipped_rect =
gfx::IntersectRects(rect, gfx::Rect(GetEffectiveSize()));
if (clipped_rect.IsEmpty())
return; // Nothing to do.
void PaintManager::ScrollRect(const gfx::Rect& clip_rect,
const gfx::Vector2d& amount) {
if (!graphics_ && !has_pending_resize_)
aggregator_.ScrollRect(clip_rect, amount);
gfx::Size PaintManager::GetEffectiveSize() const {
return has_pending_resize_ ? pending_size_ : plugin_size_;
float PaintManager::GetEffectiveDeviceScale() const {
return has_pending_resize_ ? pending_device_scale_ : device_scale_;
void PaintManager::EnsureCallbackPending() {
// The best way for us to do the next update is to get a notification that
// a previous one has completed. So if we're already waiting for one, we
// don't have to do anything differently now.
if (flush_pending_)
// If no flush is pending, we need to do a manual call to get back to the
// main thread. We may have one already pending, or we may need to schedule.
if (manual_callback_pending_)
&PaintManager::OnManualCallbackComplete, weak_factory_.GetWeakPtr())),
manual_callback_pending_ = true;
void PaintManager::DoPaint() {
base::AutoReset<bool> auto_reset_in_paint(&in_paint_, true);
std::vector<PaintReadyRect> ready_rects;
std::vector<gfx::Rect> pending_rects;
// Apply any pending resize. Setting the graphics to this class must happen
// before asking the plugin to paint in case it requests invalides or resizes.
// However, the bind must not happen until afterward since we don't want to
// have an unpainted device bound. The needs_binding flag tells us whether to
// do this later.
// Note that |has_pending_resize_| will always be set on the first DoPaint().
DCHECK(graphics_ || has_pending_resize_);
if (has_pending_resize_) {
plugin_size_ = pending_size_;
// Only create a new graphics context if the current context isn't big
// enough or if it is far too big. This avoids creating a new context if
// we only resize by a small amount.
gfx::Size old_size = graphics_ ? graphics_->size() : gfx::Size();
gfx::Size new_size = GetNewContextSize(old_size, pending_size_);
if (old_size != new_size || !graphics_) {
graphics_ = client_->CreatePaintGraphics(new_size);
graphics_need_to_be_bound_ = true;
// Since we're binding a new one, all of the callbacks have been canceled.
manual_callback_pending_ = false;
flush_pending_ = false;
if (pending_device_scale_ != 1.0)
graphics_->SetScale(1.0 / pending_device_scale_);
device_scale_ = pending_device_scale_;
// This must be cleared before calling into the plugin since it may do
// additional invalidation or sizing operations.
has_pending_resize_ = false;
pending_size_ = gfx::Size();
PaintAggregator::PaintUpdate update = aggregator_.GetPendingUpdate();
client_->OnPaint(update.paint_rects, &ready_rects, &pending_rects);
if (ready_rects.empty() && pending_rects.empty())
return; // Nothing was painted, don't schedule a flush.
std::vector<PaintReadyRect> ready_now;
if (pending_rects.empty()) {
aggregator_.SetIntermediateResults(ready_rects, pending_rects);
ready_now = aggregator_.GetReadyRects();
// Apply any scroll first.
if (update.has_scroll)
graphics_->Scroll(update.scroll_rect, update.scroll_delta);
view_size_changed_waiting_for_paint_ = false;
} else {
std::vector<PaintReadyRect> ready_later;
for (const auto& ready_rect : ready_rects) {
// Don't flush any part (i.e. scrollbars) if we're resizing the browser,
// as that'll lead to flashes. Until we flush, the browser will use the
// previous image, but if we flush, it'll revert to using the blank image.
// We make an exception for the first paint since we want to show the
// default background color instead of the pepper default of black.
if (ready_rect.flush_now() &&
(!view_size_changed_waiting_for_paint_ || first_paint_)) {
} else {
// Take the rectangles, except the ones that need to be flushed right away,
// and save them so that everything is flushed at once.
aggregator_.SetIntermediateResults(ready_later, pending_rects);
if (ready_now.empty()) {
for (const auto& ready_rect : ready_now) {
graphics_->PaintImage(ready_rect.image(), ready_rect.rect());
first_paint_ = false;
if (graphics_need_to_be_bound_) {
graphics_need_to_be_bound_ = false;
void PaintManager::Flush() {
flush_requested_ = false;
flush_pending_ = graphics_->Flush(base::BindOnce(
&PaintManager::OnFlushComplete, weak_factory_.GetWeakPtr()));
void PaintManager::OnFlushComplete(int32_t) {
flush_pending_ = false;
// If more paints were enqueued while we were waiting for the flush to
// complete, execute them now.
if (aggregator_.HasPendingUpdate())
// If there was another flush request while flushing we flush again.
if (flush_requested_) {
void PaintManager::OnManualCallbackComplete(int32_t) {
manual_callback_pending_ = false;
// Just because we have a manual callback doesn't mean there are actually any
// invalid regions. Even though we only schedule this callback when something
// is pending, a Flush callback could have come in before this callback was
// executed and that could have cleared the queue.
if (aggregator_.HasPendingUpdate())
} // namespace chrome_pdf