1// Copyright (c) 2013 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 <math.h>
6#include <stdio.h>
7
8#include "ppapi/c/ppb_mouse_cursor.h"
9#include "ppapi/cpp/image_data.h"
10#include "ppapi/cpp/instance.h"
11#include "ppapi/cpp/module.h"
12#include "ppapi/cpp/mouse_cursor.h"
13#include "ppapi/cpp/size.h"
14#include "ppapi/cpp/var.h"
15#include "ppapi/utility/completion_callback_factory.h"
16
17#ifdef WIN32
18#undef PostMessage
19// Allow 'this' in initializer list
20#pragma warning(disable : 4355)
21#endif
22
23namespace {
24
25uint32_t MakeColor(float r, float g, float b, float a) {
26  // Since we're using premultiplied alpha
27  // (PP_IMAGEDATAFORMAT_BGRA_PREMUL), we have to multiply each
28  // color component by the alpha value.
29  uint8_t a8 = static_cast<uint8_t>(255 * a);
30  uint8_t r8 = static_cast<uint8_t>(255 * r * a);
31  uint8_t g8 = static_cast<uint8_t>(255 * g * a);
32  uint8_t b8 = static_cast<uint8_t>(255 * b * a);
33  return (a8 << 24) | (r8 << 16) | (g8 << 8) | b8;
34}
35
36}
37
38class MouseCursorInstance : public pp::Instance {
39 public:
40  explicit MouseCursorInstance(PP_Instance instance)
41      : pp::Instance(instance) {}
42
43  virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]) {
44    MakeCustomCursor();
45    return true;
46  }
47
48 private:
49  virtual void HandleMessage(const pp::Var& var_message) {
50    if (!var_message.is_number()) {
51      fprintf(stderr, "Unexpected message.\n");
52      return;
53    }
54
55    PP_MouseCursor_Type cursor =
56        static_cast<PP_MouseCursor_Type>(var_message.AsInt());
57    if (cursor == PP_MOUSECURSOR_TYPE_CUSTOM) {
58      pp::Point hot_spot(16, 16);
59      pp::MouseCursor::SetCursor(this, cursor, custom_cursor_, hot_spot);
60    } else {
61      pp::MouseCursor::SetCursor(this, cursor);
62    }
63  }
64
65  void MakeCustomCursor() {
66    pp::Size size(32, 32);
67    custom_cursor_ =
68        pp::ImageData(this, PP_IMAGEDATAFORMAT_BGRA_PREMUL, size, true);
69    DrawCircle(16, 16, 9, 14, 0.8f, 0.8f, 0);
70    DrawCircle(11, 12, 2, 3, 0, 0, 0);
71    DrawCircle(21, 12, 2, 3, 0, 0, 0);
72    DrawHorizontalLine(12, 20, 21, 0.5f, 0, 0, 1.0f);
73  }
74
75  void DrawCircle(int cx, int cy, float alpha_radius, float radius,
76                  float r, float g, float b) {
77    pp::Size size = custom_cursor_.size();
78    uint32_t* data = static_cast<uint32_t*>(custom_cursor_.data());
79    // It's less efficient to loop over the entire image this way, but the
80    // image is small, and this is simpler.
81    for (int y = 0; y < size.width(); ++y) {
82      for (int x = 0; x < size.width(); ++x) {
83        int dx = (x - cx);
84        int dy = (y - cy);
85        float dist = sqrtf(dx * dx + dy * dy);
86
87        if (dist < radius) {
88          float a;
89          if (dist > alpha_radius) {
90            a = 1.f - (dist - alpha_radius) / (radius - alpha_radius);
91          } else {
92            a = 1.f;
93          }
94
95          data[y * size.width() + x] = MakeColor(r, g, b, a);
96        }
97      }
98    }
99  }
100
101  void DrawHorizontalLine(int x1, int x2, int y,
102                          float r, float g, float b, float a) {
103    pp::Size size = custom_cursor_.size();
104    uint32_t* data = static_cast<uint32_t*>(custom_cursor_.data());
105    for (int x = x1; x <= x2; ++x) {
106      data[y * size.width() + x] = MakeColor(r, g, b, a);
107    }
108  }
109
110  pp::ImageData custom_cursor_;
111};
112
113class MouseCursorModule : public pp::Module {
114 public:
115  MouseCursorModule() : pp::Module() {}
116  virtual ~MouseCursorModule() {}
117
118  virtual pp::Instance* CreateInstance(PP_Instance instance) {
119    return new MouseCursorInstance(instance);
120  }
121};
122
123namespace pp {
124Module* CreateModule() { return new MouseCursorModule(); }
125}  // namespace pp
126