blob: 5d2bb22ee152b09d83db5c2e02b19e7b8a5e7d4d [file] [log] [blame]
// 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 "ppapi/c/pp_input_event.h"
#include "ppapi/cpp/graphics_2d.h"
#include "ppapi/cpp/image_data.h"
#include "ppapi/cpp/instance.h"
#include "ppapi/cpp/module.h"
#include "ppapi/cpp/paint_manager.h"
#include "ppapi/cpp/size.h"
// Number of pixels to each side of the center of the square that we draw.
static const int kSquareRadius = 2;
// We identify our square by the center point. This computes the rect for the
// square given that point.
pp::Rect SquareForPoint(int x, int y) {
return PP_MakeRectFromXYWH(x - kSquareRadius, y - kSquareRadius,
kSquareRadius * 2 + 1, kSquareRadius * 2 + 1);
static void FillRect(pp::ImageData* image,
int left, int top, int width, int height,
uint32_t color) {
for (int y = std::max(0, top);
y < std::min(image->size().height() - 1, top + height);
y++) {
for (int x = std::max(0, left);
x < std::min(image->size().width() - 1, left + width);
*image->GetAddr32(pp::Point(x, y)) = color;
class MyInstance : public pp::Instance, public pp::PaintManager::Client {
MyInstance(PP_Instance instance)
: pp::Instance(instance),
last_y_(0) {
paint_manager_.Initialize(this, this, false);
virtual bool HandleEvent(const PP_InputEvent& event) {
switch (event.type) {
const PP_InputEvent_Mouse& mouse_event = event.u.mouse;
// Update the square on a mouse down.
if (mouse_event.button == PP_INPUTEVENT_MOUSEBUTTON_LEFT) {
return true;
const PP_InputEvent_Mouse& mouse_event = event.u.mouse;
// Update the square on a drag.
if (mouse_event.button == PP_INPUTEVENT_MOUSEBUTTON_LEFT) {
return true;
return false;
virtual void ViewChanged(const pp::Rect& position, const pp::Rect& clip) {
// PaintManager::Client implementation.
virtual bool OnPaint(pp::Graphics2D& device,
const std::vector<pp::Rect>& paint_rects,
const pp::Rect& paint_bounds) {
// Make an image just large enough to hold all dirty rects. We won't
// actually paint all of these pixels below, but rather just the dirty
// ones. Since image allocation can be somewhat heavyweight, we wouldn't
// want to allocate separate images in the case of multiple dirty rects.
pp::ImageData updated_image(PP_IMAGEDATAFORMAT_BGRA_PREMUL,
paint_bounds.size(), false);
// We could repaint everything inside the image we made above. For this
// example, that would probably be the easiest thing since updates are
// small and typically close to each other. However, for the purposes of
// demonstration, here we only actually paint the pixels that changed,
// which may be the entire update region, or could be multiple discontigous
// regions inside the update region.
// Note that the aggregator used by the paint manager won't give us
// multiple regions that overlap, so we don't have to worry about double
// painting in this code.
for (size_t i = 0; i < paint_rects.size(); i++) {
// Since our image is just the invalid region, we need to offset the
// areas we paint by that much. This is just a light blue background.
paint_rects[i].x() - paint_bounds.x(),
paint_rects[i].y() - paint_bounds.y(),
// Paint the square black. Because we're lazy, we do this outside of the
// loop above.
pp::Rect square = SquareForPoint(last_x_, last_y_);
square.x() - paint_bounds.x(),
square.y() - paint_bounds.y(),
return true;
void UpdateSquare(int x, int y) {
if (x == last_x_ && y == last_y_)
return; // Nothing changed.
// Invalidate the region around the old square which needs to be repainted
// because it's no longer there.
paint_manager_.InvalidateRect(SquareForPoint(last_x_, last_y_));
// Update the current position.
last_x_ = x;
last_y_ = y;
// Also invalidate the region around the new square.
paint_manager_.InvalidateRect(SquareForPoint(last_x_, last_y_));
pp::PaintManager paint_manager_;
int last_x_;
int last_y_;
class MyModule : public pp::Module {
virtual pp::Instance* CreateInstance(PP_Instance instance) {
return new MyInstance(instance);
namespace pp {
// Factory function for your specialization of the Module object.
Module* CreateModule() {
return new MyModule();
} // namespace pp