ppapi/examples/input/pointer_event_input.cc

   1 // Copyright (c) 2012 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 <algorithm>
   6
   7 #include "ppapi/c/pp_input_event.h"
   8 #include "ppapi/cpp/graphics_2d.h"
   9 #include "ppapi/cpp/image_data.h"
  10 #include "ppapi/cpp/input_event.h"
  11 #include "ppapi/cpp/instance.h"
  12 #include "ppapi/cpp/module.h"
  13 #include "ppapi/cpp/size.h"
  14 #include "ppapi/cpp/view.h"
  15 #include "ppapi/utility/graphics/paint_manager.h"
  16
  17 // Number of pixels to each side of the center of the square that we draw.
  18 static const int kSquareRadius = 2;
  19
  20 // We identify our square by the center point. This computes the rect for the
  21 // square given that point.
  22 pp::Rect SquareForPoint(int x, int y) {
  23   return PP_MakeRectFromXYWH(x - kSquareRadius, y - kSquareRadius,
  24                              kSquareRadius * 2 + 1, kSquareRadius * 2 + 1);
  25 }
  26
  27 static void FillRect(pp::ImageData* image,
  28                      int left, int top, int width, int height,
  29                      uint32_t color) {
  30   for (int y = std::max(0, top);
  31        y < std::min(image->size().height() - 1, top + height);
  32        y++) {
  33     for (int x = std::max(0, left);
  34          x < std::min(image->size().width() - 1, left + width);
  35          x++)
  36       *image->GetAddr32(pp::Point(x, y)) = color;
  37   }
  38 }
  39
  40 class MyInstance : public pp::Instance, public pp::PaintManager::Client {
  41  public:
  42   MyInstance(PP_Instance instance)
  43       : pp::Instance(instance),
  44         paint_manager_(),
  45         last_x_(0),
  46         last_y_(0) {
  47     paint_manager_.Initialize(this, this, false);
  48     RequestInputEvents(PP_INPUTEVENT_CLASS_MOUSE | PP_INPUTEVENT_CLASS_TOUCH);
  49   }
  50
  51   virtual bool HandleInputEvent(const pp::InputEvent& event) {
  52     switch (event.GetType()) {
  53       case PP_INPUTEVENT_TYPE_MOUSEDOWN: {
  54         pp::MouseInputEvent mouse_event(event);
  55         // Update the square on a mouse down.
  56         if (mouse_event.GetButton() == PP_INPUTEVENT_MOUSEBUTTON_LEFT) {
  57           UpdateSquare(static_cast<int>(mouse_event.GetPosition().x()),
  58                        static_cast<int>(mouse_event.GetPosition().y()));
  59         }
  60         return true;
  61       }
  62       case PP_INPUTEVENT_TYPE_MOUSEMOVE: {
  63         pp::MouseInputEvent mouse_event(event);
  64         // Update the square on a drag.
  65         if (mouse_event.GetButton() == PP_INPUTEVENT_MOUSEBUTTON_LEFT) {
  66           UpdateSquare(static_cast<int>(mouse_event.GetPosition().x()),
  67                        static_cast<int>(mouse_event.GetPosition().y()));
  68         }
  69         return true;
  70       }
  71
  72       case PP_INPUTEVENT_TYPE_TOUCHSTART: {
  73         pp::TouchInputEvent touch(event);
  74         // Update the square on a touch down.
  75         uint32_t count = touch.GetTouchCount(PP_TOUCHLIST_TYPE_CHANGEDTOUCHES);
  76         for (uint32_t i = 0; i < count; ++i) {
  77           pp::TouchPoint point = touch.GetTouchByIndex(
  78               PP_TOUCHLIST_TYPE_CHANGEDTOUCHES, i);
  79           UpdateSquare(static_cast<int>(point.position().x()),
  80                        static_cast<int>(point.position().y()));
  81         }
  82         return true;
  83       }
  84       case PP_INPUTEVENT_TYPE_TOUCHMOVE:
  85       case PP_INPUTEVENT_TYPE_TOUCHEND:
  86       case PP_INPUTEVENT_TYPE_TOUCHCANCEL:
  87         return true;
  88
  89       default:
  90         return false;
  91     }
  92   }
  93
  94   virtual void DidChangeView(const pp::View& view) {
  95     paint_manager_.SetSize(view.GetRect().size());
  96   }
  97
  98   // PaintManager::Client implementation.
  99   virtual bool OnPaint(pp::Graphics2D& graphics_2d,
 100                        const std::vector<pp::Rect>& paint_rects,
 101                        const pp::Rect& paint_bounds) {
 102     // Make an image just large enough to hold all dirty rects. We won't
 103     // actually paint all of these pixels below, but rather just the dirty
 104     // ones. Since image allocation can be somewhat heavyweight, we wouldn't
 105     // want to allocate separate images in the case of multiple dirty rects.
 106     pp::ImageData updated_image(this, PP_IMAGEDATAFORMAT_BGRA_PREMUL,
 107                                 paint_bounds.size(), false);
 108
 109     // We could repaint everything inside the image we made above. For this
 110     // example, that would probably be the easiest thing since updates are
 111     // small and typically close to each other. However, for the purposes of
 112     // demonstration, here we only actually paint the pixels that changed,
 113     // which may be the entire update region, or could be multiple discontigous
 114     // regions inside the update region.
 115     //
 116     // Note that the aggregator used by the paint manager won't give us
 117     // multiple regions that overlap, so we don't have to worry about double
 118     // painting in this code.
 119     for (size_t i = 0; i < paint_rects.size(); i++) {
 120       // Since our image is just the invalid region, we need to offset the
 121       // areas we paint by that much. This is just a light blue background.
 122       FillRect(&updated_image,
 123                paint_rects[i].x() - paint_bounds.x(),
 124                paint_rects[i].y() - paint_bounds.y(),
 125                paint_rects[i].width(),
 126                paint_rects[i].height(),
 127                0xFFAAAAFF);
 128     }
 129
 130     // Paint the square black. Because we're lazy, we do this outside of the
 131     // loop above.
 132     pp::Rect square = SquareForPoint(last_x_, last_y_);
 133     FillRect(&updated_image,
 134              square.x() - paint_bounds.x(),
 135              square.y() - paint_bounds.y(),
 136              square.width(),
 137              square.height(),
 138              0xFF000000);
 139
 140     graphics_2d.PaintImageData(updated_image, paint_bounds.point());
 141     return true;
 142   }
 143
 144  private:
 145   void UpdateSquare(int x, int y) {
 146     if (x == last_x_ && y == last_y_)
 147       return;  // Nothing changed.
 148
 149     // Invalidate the region around the old square which needs to be repainted
 150     // because it's no longer there.
 151     paint_manager_.InvalidateRect(SquareForPoint(last_x_, last_y_));
 152
 153     // Update the current position.
 154     last_x_ = x;
 155     last_y_ = y;
 156
 157     // Also invalidate the region around the new square.
 158     paint_manager_.InvalidateRect(SquareForPoint(last_x_, last_y_));
 159   }
 160
 161   pp::PaintManager paint_manager_;
 162
 163   int last_x_;
 164   int last_y_;
 165 };
 166
 167 class MyModule : public pp::Module {
 168  public:
 169   virtual pp::Instance* CreateInstance(PP_Instance instance) {
 170     return new MyInstance(instance);
 171   }
 172 };
 173
 174 namespace pp {
 175
 176 // Factory function for your specialization of the Module object.
 177 Module* CreateModule() {
 178   return new MyModule();
 179 }
 180
 181 }  // namespace pp