Mouse lock implementation, including the renderer side and the Windows version of the browser side.

ppapi/examples/mouse_lock/mouse_lock.cc

+// Copyright (c) 2011 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 <cmath>
+#include <stdarg.h>
+#include <stdio.h>
+
+#include "ppapi/c/dev/ppb_console_dev.h"
+#include "ppapi/c/ppb_input_event.h"
+#include "ppapi/cpp/completion_callback.h"
+#include "ppapi/cpp/dev/mouse_lock_dev.h"
+#include "ppapi/cpp/graphics_2d.h"
+#include "ppapi/cpp/image_data.h"
+#include "ppapi/cpp/input_event.h"
+#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/logging.h"
+#include "ppapi/cpp/module.h"
+#include "ppapi/cpp/rect.h"
+#include "ppapi/cpp/var.h"
+
+class MyInstance : public pp::Instance, public pp::MouseLock_Dev {
+ public:
+  explicit MyInstance(PP_Instance instance)
+      : pp::Instance(instance),
+        pp::MouseLock_Dev(this),
+        width_(0),
+        height_(0),
+        mouse_locked_(false),
+        pending_paint_(false),
+        waiting_for_flush_completion_(false),
+        callback_factory_(this),
+        console_(NULL) {
+  }
+  virtual ~MyInstance() {}
+
+  virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]) {
+    console_ = reinterpret_cast<const PPB_Console_Dev*>(
+        pp::Module::Get()->GetBrowserInterface(PPB_CONSOLE_DEV_INTERFACE));
+    if (!console_)
+      return false;
+
+    RequestInputEvents(PP_INPUTEVENT_CLASS_MOUSE |
+                       PP_INPUTEVENT_CLASS_KEYBOARD);
+    return true;
+  }
+
+  virtual bool HandleInputEvent(const pp::InputEvent& event) {
+    switch (event.GetType()) {
+      case PP_INPUTEVENT_TYPE_MOUSEDOWN: {
+        pp::MouseInputEvent mouse_event(event);
+        if (mouse_event.GetButton() == PP_INPUTEVENT_MOUSEBUTTON_LEFT &&
+            !mouse_locked_) {
+          LockMouse(
+              callback_factory_.NewRequiredCallback(&MyInstance::DidLockMouse));
+        } else if (mouse_event.GetButton() == PP_INPUTEVENT_MOUSEBUTTON_RIGHT &&
+                   mouse_locked_) {
+          UnlockMouse();
+        }
+        return true;
+      }
+      case PP_INPUTEVENT_TYPE_MOUSEMOVE: {
+        pp::MouseInputEvent mouse_event(event);
+        pp::Point movement = mouse_event.GetMovement();
+        static unsigned int i = 0;
+        Log(PP_LOGLEVEL_LOG, "[%d] movementX: %d; movementY: %d\n", i++,
+            movement.x(), movement.y());
+
+        if (mouse_locked_) {

[scheib, 2011/09/14 18:13:23]

I still think it's worth verifying that the movement graphically displays the
same when under mouse lock or not. There's no need for this conditional, right?

[yzshen1, 2011/09/19 20:48:41]

Done. I make the testing plugin also show mouse movement when the mouse is not
locked. (But it doesn't work currently because it depends on the change in
WebKit.)

+          mouse_movement_ = movement;
+          Paint();
+        }
+        return true;
+      }
+      case PP_INPUTEVENT_TYPE_KEYDOWN: {
+        pp::KeyboardInputEvent key_event(event);
+        // Lock the mouse when the Enter key is pressed.
+        if (!mouse_locked_ && key_event.GetKeyCode() == 13) {
+          LockMouse(
+              callback_factory_.NewRequiredCallback(&MyInstance::DidLockMouse));
+        }
+        return true;
+      }
+      default:
+        return false;
+    }
+  }
+
+  virtual void DidChangeView(const pp::Rect& position, const pp::Rect& clip) {
+    if (position.size().width() == width_ &&
+        position.size().height() == height_)
+      return;  // We don't care about the position, only the size.
+
+    width_ = position.size().width();
+    height_ = position.size().height();
+
+    device_context_ = pp::Graphics2D(this, pp::Size(width_, height_), false);
+    if (!BindGraphics(device_context_))
+      return;
+
+    Paint();
+  }
+
+  virtual void MouseLockLost() {
+    if (mouse_locked_) {
+      mouse_locked_ = false;
+      Paint();
+    } else {
+      PP_NOTREACHED();
+    }
+  }
+
+ private:
+  void DidLockMouse(int32_t result) {
+    mouse_locked_ = result == PP_OK;
+    mouse_movement_.set_x(0);
+    mouse_movement_.set_y(0);
+    Paint();
+  }
+
+  void DidFlush(int32_t result) {
+    waiting_for_flush_completion_ = false;
+    if (pending_paint_) {
+      pending_paint_ = false;
+      Paint();
+    }
+  }
+
+  void Paint() {
+    if (waiting_for_flush_completion_) {
+      pending_paint_ = true;
+      return;
+    }
+
+    pp::ImageData image = PaintImage(width_, height_);
+    if (!image.is_null()) {
+      device_context_.ReplaceContents(&image);
+      waiting_for_flush_completion_ = true;
+      device_context_.Flush(
+          callback_factory_.NewRequiredCallback(&MyInstance::DidFlush));
+    }
+  }
+
+  pp::ImageData PaintImage(int width, int height) {
+    pp::ImageData image(this, PP_IMAGEDATAFORMAT_BGRA_PREMUL,
+                        pp::Size(width, height), false);
+    if (image.is_null())
+      return image;
+
+    const static int kCenteralSpotRadius = 5;
+    const static uint32_t kBackgroundColor = 0xfff0f0f0;
+    const static uint32_t kForegroundColor = 0xfff08080;
+
+    int center_x = width / 2;
+    int center_y = height / 2;
+    pp::Point vertex(mouse_movement_.x() + center_x,
+                     mouse_movement_.y() + center_y);
+    pp::Point anchor_1;
+    pp::Point anchor_2;
+    enum {
+      LEFT = 0,
+      RIGHT = 1,
+      UP = 2,
+      DOWN = 3
+    } direction;
+    bool draw_needle = mouse_locked_ &&
+                       GetDistance(mouse_movement_.x(), mouse_movement_.y(),
+                                   0, 0) > kCenteralSpotRadius;
+    if (draw_needle) {
+      if (abs(mouse_movement_.x()) >= abs(mouse_movement_.y())) {
+         anchor_1.set_x(center_x);
+         anchor_1.set_y(center_y - kCenteralSpotRadius);
+         anchor_2.set_x(center_x);
+         anchor_2.set_y(center_y + kCenteralSpotRadius);
+         direction = (mouse_movement_.x() < 0) ? LEFT : RIGHT;
+         if (direction == LEFT)
+           anchor_1.swap(anchor_2);
+      } else {
+         anchor_1.set_x(center_x + kCenteralSpotRadius);
+         anchor_1.set_y(center_y);
+         anchor_2.set_x(center_x - kCenteralSpotRadius);
+         anchor_2.set_y(center_y);
+         direction = (mouse_movement_.y() < 0) ? UP : DOWN;
+         if (direction == UP)
+           anchor_1.swap(anchor_2);
+      }
+    }
+
+    for (int y = 0; y < image.size().height(); ++y) {
+      for (int x = 0; x < image.size().width(); ++x) {
+        if (mouse_locked_) {
+          if (GetDistance(x, y, center_x, center_y) < kCenteralSpotRadius) {
+            *image.GetAddr32(pp::Point(x, y)) = kForegroundColor;
+            continue;
+          }
+          if (draw_needle) {
+            bool within_bound_1 =
+                ((y - anchor_1.y()) * (vertex.x() - anchor_1.x())) >
+                ((vertex.y() - anchor_1.y()) * (x - anchor_1.x()));
+            bool within_bound_2 =
+                ((y - anchor_2.y()) * (vertex.x() - anchor_2.x())) <
+                ((vertex.y() - anchor_2.y()) * (x - anchor_2.x()));
+            bool within_bound_3 =
+                (direction == UP && y < center_y) ||
+                (direction == DOWN && y > center_y) ||
+                (direction == LEFT && x < center_x) ||
+                (direction == RIGHT && x > center_y);
+
+            if (within_bound_1 && within_bound_2 && within_bound_3) {
+              *image.GetAddr32(pp::Point(x, y)) = kForegroundColor;
+              continue;
+            }
+          }
+        }
+        *image.GetAddr32(pp::Point(x, y)) = kBackgroundColor;
+      }
+    }
+
+    return image;
+  }
+
+  double GetDistance(int point_1_x, int point_1_y,
+                     int point_2_x, int point_2_y) {
+    return sqrt(pow(static_cast<double>(point_1_x - point_2_x), 2) +
+                pow(static_cast<double>(point_1_y - point_2_y), 2));
+  }
+
+  void Log(PP_LogLevel_Dev level, const char* format, ...) {
+    va_list args;
+    va_start(args, format);
+    char buf[512];
+    vsnprintf(buf, sizeof(buf) - 1, format, args);
+    buf[sizeof(buf) - 1] = '\0';
+    va_end(args);
+
+    pp::Var value(buf);
+    console_->Log(pp_instance(), level, value.pp_var());
+  }
+
+  int width_;
+  int height_;
+
+  bool mouse_locked_;
+  // Only valid when the mouse is locked.
+  pp::Point mouse_movement_;
+
+  bool pending_paint_;
+  bool waiting_for_flush_completion_;
+
+  pp::CompletionCallbackFactory<MyInstance> callback_factory_;
+
+  const PPB_Console_Dev* console_;
+
+  pp::Graphics2D device_context_;
+};
+
+// This object is the global object representing this plugin library as long
+// as it is loaded.
+class MyModule : public pp::Module {
+ public:
+  MyModule() : pp::Module() {}
+  virtual ~MyModule() {}
+
+  // Override CreateInstance to create your customized Instance object.
+  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
+