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Limit mouse move events to one every 17 ms
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1/*
2 * noVNC: HTML5 VNC client
412d9306 3 * Copyright (C) 2019 The noVNC Authors
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4 * Licensed under MPL 2.0 or any later version (see LICENSE.txt)
5 */
6
c1e2785f 7import * as Log from '../util/logging.js';
59ef2916 8import { isTouchDevice } from '../util/browser.js';
c1e2785f 9import { setCapture, stopEvent, getPointerEvent } from '../util/events.js';
c1e2785f 10
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11const WHEEL_STEP = 10; // Delta threshold for a mouse wheel step
12const WHEEL_STEP_TIMEOUT = 50; // ms
13const WHEEL_LINE_HEIGHT = 19;
44eb1fe5 14const MOUSE_MOVE_DELAY = 17; // Minimum wait (ms) between two mouse moves
28b004fd 15
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16export default class Mouse {
17 constructor(target) {
18 this._target = target || document;
19
20 this._doubleClickTimer = null;
21 this._lastTouchPos = null;
22
23 this._pos = null;
24 this._wheelStepXTimer = null;
25 this._wheelStepYTimer = null;
44eb1fe5 26 this._oldMouseMoveTime = 0;
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27 this._accumulatedWheelDeltaX = 0;
28 this._accumulatedWheelDeltaY = 0;
29
30 this._eventHandlers = {
31 'mousedown': this._handleMouseDown.bind(this),
32 'mouseup': this._handleMouseUp.bind(this),
33 'mousemove': this._handleMouseMove.bind(this),
34 'mousewheel': this._handleMouseWheel.bind(this),
35 'mousedisable': this._handleMouseDisable.bind(this)
36 };
c1e2785f 37
0e4808bf 38 // ===== PROPERTIES =====
747b4623 39
0e4808bf 40 this.touchButton = 1; // Button mask (1, 2, 4) for touch devices (0 means ignore clicks)
747b4623 41
0e4808bf 42 // ===== EVENT HANDLERS =====
747b4623 43
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44 this.onmousebutton = () => {}; // Handler for mouse button click/release
45 this.onmousemove = () => {}; // Handler for mouse movement
46 }
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47
48 // ===== PRIVATE METHODS =====
c1e2785f 49
0e4808bf 50 _resetDoubleClickTimer() {
c1e2785f 51 this._doubleClickTimer = null;
0e4808bf 52 }
c1e2785f 53
0e4808bf 54 _handleMouseButton(e, down) {
28b004fd 55 this._updateMousePosition(e);
2b5f94fa 56 let pos = this._pos;
c1e2785f 57
2b5f94fa 58 let bmask;
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59 if (e.touches || e.changedTouches) {
60 // Touch device
61
62 // When two touches occur within 500 ms of each other and are
63 // close enough together a double click is triggered.
64 if (down == 1) {
65 if (this._doubleClickTimer === null) {
66 this._lastTouchPos = pos;
67 } else {
68 clearTimeout(this._doubleClickTimer);
69
70 // When the distance between the two touches is small enough
71 // force the position of the latter touch to the position of
72 // the first.
73
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74 const xs = this._lastTouchPos.x - pos.x;
75 const ys = this._lastTouchPos.y - pos.y;
76 const d = Math.sqrt((xs * xs) + (ys * ys));
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77
78 // The goal is to trigger on a certain physical width, the
79 // devicePixelRatio brings us a bit closer but is not optimal.
2b5f94fa 80 const threshold = 20 * (window.devicePixelRatio || 1);
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81 if (d < threshold) {
82 pos = this._lastTouchPos;
83 }
84 }
85 this._doubleClickTimer = setTimeout(this._resetDoubleClickTimer.bind(this), 500);
86 }
747b4623 87 bmask = this.touchButton;
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88 // If bmask is set
89 } else if (e.which) {
90 /* everything except IE */
91 bmask = 1 << e.button;
92 } else {
93 /* IE including 9 */
94 bmask = (e.button & 0x1) + // Left
95 (e.button & 0x2) * 2 + // Right
96 (e.button & 0x4) / 2; // Middle
97 }
98
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99 Log.Debug("onmousebutton " + (down ? "down" : "up") +
100 ", x: " + pos.x + ", y: " + pos.y + ", bmask: " + bmask);
101 this.onmousebutton(pos.x, pos.y, down, bmask);
102
c1e2785f 103 stopEvent(e);
0e4808bf 104 }
c1e2785f 105
0e4808bf 106 _handleMouseDown(e) {
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107 // Touch events have implicit capture
108 if (e.type === "mousedown") {
109 setCapture(this._target);
110 }
111
112 this._handleMouseButton(e, 1);
0e4808bf 113 }
c1e2785f 114
0e4808bf 115 _handleMouseUp(e) {
c1e2785f 116 this._handleMouseButton(e, 0);
0e4808bf 117 }
c1e2785f 118
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119 // Mouse wheel events are sent in steps over VNC. This means that the VNC
120 // protocol can't handle a wheel event with specific distance or speed.
121 // Therefor, if we get a lot of small mouse wheel events we combine them.
0e4808bf 122 _generateWheelStepX() {
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123
124 if (this._accumulatedWheelDeltaX < 0) {
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125 this.onmousebutton(this._pos.x, this._pos.y, 1, 1 << 5);
126 this.onmousebutton(this._pos.x, this._pos.y, 0, 1 << 5);
28b004fd 127 } else if (this._accumulatedWheelDeltaX > 0) {
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128 this.onmousebutton(this._pos.x, this._pos.y, 1, 1 << 6);
129 this.onmousebutton(this._pos.x, this._pos.y, 0, 1 << 6);
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130 }
131
132 this._accumulatedWheelDeltaX = 0;
0e4808bf 133 }
28b004fd 134
0e4808bf 135 _generateWheelStepY() {
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136
137 if (this._accumulatedWheelDeltaY < 0) {
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138 this.onmousebutton(this._pos.x, this._pos.y, 1, 1 << 3);
139 this.onmousebutton(this._pos.x, this._pos.y, 0, 1 << 3);
28b004fd 140 } else if (this._accumulatedWheelDeltaY > 0) {
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141 this.onmousebutton(this._pos.x, this._pos.y, 1, 1 << 4);
142 this.onmousebutton(this._pos.x, this._pos.y, 0, 1 << 4);
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143 }
144
145 this._accumulatedWheelDeltaY = 0;
0e4808bf 146 }
28b004fd 147
0e4808bf 148 _resetWheelStepTimers() {
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149 window.clearTimeout(this._wheelStepXTimer);
150 window.clearTimeout(this._wheelStepYTimer);
151 this._wheelStepXTimer = null;
152 this._wheelStepYTimer = null;
0e4808bf 153 }
28b004fd 154
0e4808bf 155 _handleMouseWheel(e) {
28b004fd 156 this._resetWheelStepTimers();
c1e2785f 157
28b004fd 158 this._updateMousePosition(e);
c1e2785f 159
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160 let dX = e.deltaX;
161 let dY = e.deltaY;
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162
163 // Pixel units unless it's non-zero.
164 // Note that if deltamode is line or page won't matter since we aren't
165 // sending the mouse wheel delta to the server anyway.
166 // The difference between pixel and line can be important however since
167 // we have a threshold that can be smaller than the line height.
168 if (e.deltaMode !== 0) {
169 dX *= WHEEL_LINE_HEIGHT;
170 dY *= WHEEL_LINE_HEIGHT;
171 }
172
173 this._accumulatedWheelDeltaX += dX;
174 this._accumulatedWheelDeltaY += dY;
175
176 // Generate a mouse wheel step event when the accumulated delta
177 // for one of the axes is large enough.
178 // Small delta events that do not pass the threshold get sent
179 // after a timeout.
180 if (Math.abs(this._accumulatedWheelDeltaX) > WHEEL_STEP) {
181 this._generateWheelStepX();
182 } else {
183 this._wheelStepXTimer =
184 window.setTimeout(this._generateWheelStepX.bind(this),
185 WHEEL_STEP_TIMEOUT);
186 }
187 if (Math.abs(this._accumulatedWheelDeltaY) > WHEEL_STEP) {
188 this._generateWheelStepY();
189 } else {
190 this._wheelStepYTimer =
191 window.setTimeout(this._generateWheelStepY.bind(this),
192 WHEEL_STEP_TIMEOUT);
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193 }
194
195 stopEvent(e);
0e4808bf 196 }
c1e2785f 197
0e4808bf 198 _handleMouseMove(e) {
28b004fd 199 this._updateMousePosition(e);
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200
201 // Limit mouse move events to one every MOUSE_MOVE_DELAY ms
202 clearTimeout(this.mouseMoveTimer);
203 const newMouseMoveTime = Date.now();
204 if (newMouseMoveTime < this._oldMouseMoveTime + MOUSE_MOVE_DELAY) {
205 this.mouseMoveTimer = setTimeout(this.onmousemove.bind(this),
206 MOUSE_MOVE_DELAY,
207 this._pos.x, this._pos.y);
208 } else {
209 this.onmousemove(this._pos.x, this._pos.y);
210 }
211 this._oldMouseMoveTime = newMouseMoveTime;
212
c1e2785f 213 stopEvent(e);
0e4808bf 214 }
c1e2785f 215
0e4808bf 216 _handleMouseDisable(e) {
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217 /*
218 * Stop propagation if inside canvas area
219 * Note: This is only needed for the 'click' event as it fails
220 * to fire properly for the target element so we have
221 * to listen on the document element instead.
222 */
223 if (e.target == this._target) {
224 stopEvent(e);
225 }
0e4808bf 226 }
c1e2785f 227
28b004fd 228 // Update coordinates relative to target
0e4808bf 229 _updateMousePosition(e) {
c1e2785f 230 e = getPointerEvent(e);
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231 const bounds = this._target.getBoundingClientRect();
232 let x;
233 let y;
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234 // Clip to target bounds
235 if (e.clientX < bounds.left) {
236 x = 0;
237 } else if (e.clientX >= bounds.right) {
238 x = bounds.width - 1;
239 } else {
240 x = e.clientX - bounds.left;
241 }
242 if (e.clientY < bounds.top) {
243 y = 0;
244 } else if (e.clientY >= bounds.bottom) {
245 y = bounds.height - 1;
246 } else {
247 y = e.clientY - bounds.top;
248 }
942a3127 249 this._pos = {x: x, y: y};
0e4808bf 250 }
c1e2785f 251
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252 // ===== PUBLIC METHODS =====
253
0e4808bf 254 grab() {
c1e2785f 255 if (isTouchDevice) {
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256 this._target.addEventListener('touchstart', this._eventHandlers.mousedown);
257 this._target.addEventListener('touchend', this._eventHandlers.mouseup);
258 this._target.addEventListener('touchmove', this._eventHandlers.mousemove);
c1e2785f 259 }
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260 this._target.addEventListener('mousedown', this._eventHandlers.mousedown);
261 this._target.addEventListener('mouseup', this._eventHandlers.mouseup);
262 this._target.addEventListener('mousemove', this._eventHandlers.mousemove);
263 this._target.addEventListener('wheel', this._eventHandlers.mousewheel);
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264
265 /* Prevent middle-click pasting (see above for why we bind to document) */
266 document.addEventListener('click', this._eventHandlers.mousedisable);
267
268 /* preventDefault() on mousedown doesn't stop this event for some
269 reason so we have to explicitly block it */
9255e0fb 270 this._target.addEventListener('contextmenu', this._eventHandlers.mousedisable);
0e4808bf 271 }
c1e2785f 272
0e4808bf 273 ungrab() {
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274 this._resetWheelStepTimers();
275
c1e2785f 276 if (isTouchDevice) {
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277 this._target.removeEventListener('touchstart', this._eventHandlers.mousedown);
278 this._target.removeEventListener('touchend', this._eventHandlers.mouseup);
279 this._target.removeEventListener('touchmove', this._eventHandlers.mousemove);
c1e2785f 280 }
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281 this._target.removeEventListener('mousedown', this._eventHandlers.mousedown);
282 this._target.removeEventListener('mouseup', this._eventHandlers.mouseup);
283 this._target.removeEventListener('mousemove', this._eventHandlers.mousemove);
284 this._target.removeEventListener('wheel', this._eventHandlers.mousewheel);
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285
286 document.removeEventListener('click', this._eventHandlers.mousedisable);
287
9255e0fb 288 this._target.removeEventListener('contextmenu', this._eventHandlers.mousedisable);
c1e2785f 289 }
0e4808bf 290}