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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 <vector>
#include "pdf/paint_aggregator.h"
#include "ppapi/cpp/graphics_2d.h"
#include "ppapi/utility/completion_callback_factory.h"
namespace pp {
class Graphics2D;
class Instance;
class Point;
class Rect;
// Custom PaintManager for the PDF plugin. This is branched from the Pepper
// version. The difference is that this supports progressive rendering of dirty
// rects, where multiple calls to the rendering engine are needed. It also
// supports having higher-priority rects flushing right away, i.e. the
// scrollbars.
// The client's OnPaint
class PaintManager {
// Like PaintAggregator's version, but allows the plugin to tell us whether
// it should be flushed to the screen immediately or when the rest of the
// plugin viewport is ready.
struct ReadyRect {
pp::Point offset;
pp::Rect rect;
pp::ImageData image_data;
bool flush_now;
ReadyRect(const pp::Rect& r, const pp::ImageData& i, bool f)
: rect(r), image_data(i), flush_now(f) {}
operator PaintAggregator::ReadyRect() const {
PaintAggregator::ReadyRect rv;
rv.offset = offset;
rv.rect = rect;
rv.image_data = image_data;
return rv;
class Client {
// Paints the given invalid area of the plugin to the given graphics
// device. Returns true if anything was painted.
// You are given the list of rects to paint in |paint_rects|. You can
// combine painting into less rectangles if it's more efficient. When a
// rect is painted, information about that paint should be inserted into
// |ready|. Otherwise if a paint needs more work, add the rect to
// |pending|. If |pending| is not empty, your OnPaint function will get
// called again. Once OnPaint is called and it returns no pending rects,
// all the previously ready rects will be flushed on screen. The exception
// is for ready rects that have |flush_now| set to true. These will be
// flushed right away.
// Do not call Flush() on the graphics device, this will be done
// automatically if you return true from this function since the
// PaintManager needs to handle the callback.
// Calling Invalidate/Scroll is not allowed while inside an OnPaint
virtual void OnPaint(const std::vector<pp::Rect>& paint_rects,
std::vector<ReadyRect>* ready,
std::vector<pp::Rect>* pending) = 0;
// You shouldn't be doing deleting through this interface.
virtual ~Client() {}
// The instance is the plugin instance using this paint manager to do its
// painting. Painting will automatically go to this instance and you don't
// have to manually bind any device context (this is all handled by the
// paint manager).
// The Client is a non-owning pointer and must remain valid (normally the
// object implementing the Client interface will own the paint manager).
// The is_always_opaque flag will be passed to the device contexts that this
// class creates. Set this to true if your plugin always draws an opaque
// image to the device. This is used as a hint to the browser that it does
// not need to do alpha blending, which speeds up painting. If you generate
// non-opqaue pixels or aren't sure, set this to false for more general
// blending.
// If you set is_always_opaque, your alpha channel should always be set to
// 0xFF or there may be painting artifacts. Being opaque will allow the
// browser to do a memcpy rather than a blend to paint the plugin, and this
// means your alpha values will get set on the page backing store. If these
// values are incorrect, it could mess up future blending. If you aren't
// sure, it is always correct to specify that it it not opaque.
// You will need to call SetSize before this class will do anything. Normally
// you do this from the ViewChanged method of your plugin instance.
PaintManager(pp::Instance* instance, Client* client, bool is_always_opaque);
// Returns the size of the graphics context to allocate for a given plugin
// size. We may allocated a slightly larger buffer than required so that we
// don't have to resize the context when scrollbars appear/dissapear due to
// zooming (which can result in flickering).
static pp::Size GetNewContextSize(const pp::Size& current_context_size,
const pp::Size& plugin_size);
// You must call this function before using if you use the 0-arg constructor.
// See the constructor for what these arguments mean.
void Initialize(pp::Instance* instance, Client* client,
bool is_always_opaque);
// Sets the size of the plugin. If the size is the same as the previous call,
// this will be a NOP. If the size has changed, a new device will be
// allocated to the given size and a paint to that device will be scheduled.
// This is intended to be called from ViewChanged with the size of the
// plugin. Since it tracks the old size and only allocates when the size
// changes, you can always call this function without worrying about whether
// the size changed or ViewChanged is called for another reason (like the
// position changed).
void SetSize(const pp::Size& new_size, float new_device_scale);
// Invalidate the entire plugin.
void Invalidate();
// Invalidate the given rect.
void InvalidateRect(const pp::Rect& rect);
// The given rect should be scrolled by the given amounts.
void ScrollRect(const pp::Rect& clip_rect, const pp::Point& amount);
// Returns the size of the graphics context for the next paint operation.
// This is the pending size if a resize is pending (the plugin has called
// SetSize but we haven't actually painted it yet), or the current size of
// no resize is pending.
pp::Size GetEffectiveSize() const;
float GetEffectiveDeviceScale() const;
// Disallow copy and assign (these are unimplemented).
PaintManager(const PaintManager&);
PaintManager& operator=(const PaintManager&);
// Makes sure there is a callback that will trigger a paint at a later time.
// This will be either a Flush callback telling us we're allowed to generate
// more data, or, if there's no flush callback pending, a manual call back
// to the message loop via ExecuteOnMainThread.
void EnsureCallbackPending();
// Does the client paint and executes a Flush if necessary.
void DoPaint();
// Callback for asynchronous completion of Flush.
void OnFlushComplete(int32_t);
// Callback for manual scheduling of paints when there is no flush callback
// pending.
void OnManualCallbackComplete(int32_t);
pp::Instance* instance_;
// Non-owning pointer. See the constructor.
Client* client_;
bool is_always_opaque_;
pp::CompletionCallbackFactory<PaintManager> callback_factory_;
// This graphics device will be is_null() if no graphics has been manually
// set yet.
pp::Graphics2D graphics_;
PaintAggregator aggregator_;
// See comment for EnsureCallbackPending for more on how these work.
bool manual_callback_pending_;
bool flush_pending_;
// When we get a resize, we don't bind right away (see SetSize). The
// has_pending_resize_ tells us that we need to do a resize for the next
// paint operation. When true, the new size is in pending_size_.
bool has_pending_resize_;
bool graphics_need_to_be_bound_;
pp::Size pending_size_;
pp::Size plugin_size_;
float pending_device_scale_;
float device_scale_;
// True iff we're in the middle of a paint.
bool in_paint_;
// True if we haven't painted the plugin viewport yet.
bool first_paint_;
// True when the view size just changed and we're waiting for a paint.
bool view_size_changed_waiting_for_paint_;