| 1 | /* |
| 2 | * noVNC: HTML5 VNC client |
| 3 | * Copyright (C) 2019 The noVNC Authors |
| 4 | * Licensed under MPL 2.0 or any later version (see LICENSE.txt) |
| 5 | */ |
| 6 | |
| 7 | import { supportsCursorURIs, isTouchDevice } from './browser.js'; |
| 8 | |
| 9 | const useFallback = !supportsCursorURIs || isTouchDevice; |
| 10 | |
| 11 | export default class Cursor { |
| 12 | constructor() { |
| 13 | this._target = null; |
| 14 | |
| 15 | this._canvas = document.createElement('canvas'); |
| 16 | |
| 17 | if (useFallback) { |
| 18 | this._canvas.style.position = 'fixed'; |
| 19 | this._canvas.style.zIndex = '65535'; |
| 20 | this._canvas.style.pointerEvents = 'none'; |
| 21 | // Safari on iOS can select the cursor image |
| 22 | // https://bugs.webkit.org/show_bug.cgi?id=249223 |
| 23 | this._canvas.style.userSelect = 'none'; |
| 24 | this._canvas.style.WebkitUserSelect = 'none'; |
| 25 | // Can't use "display" because of Firefox bug #1445997 |
| 26 | this._canvas.style.visibility = 'hidden'; |
| 27 | } |
| 28 | |
| 29 | this._position = { x: 0, y: 0 }; |
| 30 | this._hotSpot = { x: 0, y: 0 }; |
| 31 | |
| 32 | this._eventHandlers = { |
| 33 | 'mouseover': this._handleMouseOver.bind(this), |
| 34 | 'mouseleave': this._handleMouseLeave.bind(this), |
| 35 | 'mousemove': this._handleMouseMove.bind(this), |
| 36 | 'mouseup': this._handleMouseUp.bind(this), |
| 37 | }; |
| 38 | } |
| 39 | |
| 40 | attach(target) { |
| 41 | if (this._target) { |
| 42 | this.detach(); |
| 43 | } |
| 44 | |
| 45 | this._target = target; |
| 46 | |
| 47 | if (useFallback) { |
| 48 | document.body.appendChild(this._canvas); |
| 49 | |
| 50 | const options = { capture: true, passive: true }; |
| 51 | this._target.addEventListener('mouseover', this._eventHandlers.mouseover, options); |
| 52 | this._target.addEventListener('mouseleave', this._eventHandlers.mouseleave, options); |
| 53 | this._target.addEventListener('mousemove', this._eventHandlers.mousemove, options); |
| 54 | this._target.addEventListener('mouseup', this._eventHandlers.mouseup, options); |
| 55 | } |
| 56 | |
| 57 | this.clear(); |
| 58 | } |
| 59 | |
| 60 | detach() { |
| 61 | if (!this._target) { |
| 62 | return; |
| 63 | } |
| 64 | |
| 65 | if (useFallback) { |
| 66 | const options = { capture: true, passive: true }; |
| 67 | this._target.removeEventListener('mouseover', this._eventHandlers.mouseover, options); |
| 68 | this._target.removeEventListener('mouseleave', this._eventHandlers.mouseleave, options); |
| 69 | this._target.removeEventListener('mousemove', this._eventHandlers.mousemove, options); |
| 70 | this._target.removeEventListener('mouseup', this._eventHandlers.mouseup, options); |
| 71 | |
| 72 | if (document.contains(this._canvas)) { |
| 73 | document.body.removeChild(this._canvas); |
| 74 | } |
| 75 | } |
| 76 | |
| 77 | this._target = null; |
| 78 | } |
| 79 | |
| 80 | change(rgba, hotx, hoty, w, h) { |
| 81 | if ((w === 0) || (h === 0)) { |
| 82 | this.clear(); |
| 83 | return; |
| 84 | } |
| 85 | |
| 86 | this._position.x = this._position.x + this._hotSpot.x - hotx; |
| 87 | this._position.y = this._position.y + this._hotSpot.y - hoty; |
| 88 | this._hotSpot.x = hotx; |
| 89 | this._hotSpot.y = hoty; |
| 90 | |
| 91 | let ctx = this._canvas.getContext('2d'); |
| 92 | |
| 93 | this._canvas.width = w; |
| 94 | this._canvas.height = h; |
| 95 | |
| 96 | let img = new ImageData(new Uint8ClampedArray(rgba), w, h); |
| 97 | ctx.clearRect(0, 0, w, h); |
| 98 | ctx.putImageData(img, 0, 0); |
| 99 | |
| 100 | if (useFallback) { |
| 101 | this._updatePosition(); |
| 102 | } else { |
| 103 | let url = this._canvas.toDataURL(); |
| 104 | this._target.style.cursor = 'url(' + url + ')' + hotx + ' ' + hoty + ', default'; |
| 105 | } |
| 106 | } |
| 107 | |
| 108 | clear() { |
| 109 | this._target.style.cursor = 'none'; |
| 110 | this._canvas.width = 0; |
| 111 | this._canvas.height = 0; |
| 112 | this._position.x = this._position.x + this._hotSpot.x; |
| 113 | this._position.y = this._position.y + this._hotSpot.y; |
| 114 | this._hotSpot.x = 0; |
| 115 | this._hotSpot.y = 0; |
| 116 | } |
| 117 | |
| 118 | // Mouse events might be emulated, this allows |
| 119 | // moving the cursor in such cases |
| 120 | move(clientX, clientY) { |
| 121 | if (!useFallback) { |
| 122 | return; |
| 123 | } |
| 124 | // clientX/clientY are relative the _visual viewport_, |
| 125 | // but our position is relative the _layout viewport_, |
| 126 | // so try to compensate when we can |
| 127 | if (window.visualViewport) { |
| 128 | this._position.x = clientX + window.visualViewport.offsetLeft; |
| 129 | this._position.y = clientY + window.visualViewport.offsetTop; |
| 130 | } else { |
| 131 | this._position.x = clientX; |
| 132 | this._position.y = clientY; |
| 133 | } |
| 134 | this._updatePosition(); |
| 135 | let target = document.elementFromPoint(clientX, clientY); |
| 136 | this._updateVisibility(target); |
| 137 | } |
| 138 | |
| 139 | _handleMouseOver(event) { |
| 140 | // This event could be because we're entering the target, or |
| 141 | // moving around amongst its sub elements. Let the move handler |
| 142 | // sort things out. |
| 143 | this._handleMouseMove(event); |
| 144 | } |
| 145 | |
| 146 | _handleMouseLeave(event) { |
| 147 | // Check if we should show the cursor on the element we are leaving to |
| 148 | this._updateVisibility(event.relatedTarget); |
| 149 | } |
| 150 | |
| 151 | _handleMouseMove(event) { |
| 152 | this._updateVisibility(event.target); |
| 153 | |
| 154 | this._position.x = event.clientX - this._hotSpot.x; |
| 155 | this._position.y = event.clientY - this._hotSpot.y; |
| 156 | |
| 157 | this._updatePosition(); |
| 158 | } |
| 159 | |
| 160 | _handleMouseUp(event) { |
| 161 | // We might get this event because of a drag operation that |
| 162 | // moved outside of the target. Check what's under the cursor |
| 163 | // now and adjust visibility based on that. |
| 164 | let target = document.elementFromPoint(event.clientX, event.clientY); |
| 165 | this._updateVisibility(target); |
| 166 | |
| 167 | // Captures end with a mouseup but we can't know the event order of |
| 168 | // mouseup vs releaseCapture. |
| 169 | // |
| 170 | // In the cases when releaseCapture comes first, the code above is |
| 171 | // enough. |
| 172 | // |
| 173 | // In the cases when the mouseup comes first, we need wait for the |
| 174 | // browser to flush all events and then check again if the cursor |
| 175 | // should be visible. |
| 176 | if (this._captureIsActive()) { |
| 177 | window.setTimeout(() => { |
| 178 | // We might have detached at this point |
| 179 | if (!this._target) { |
| 180 | return; |
| 181 | } |
| 182 | // Refresh the target from elementFromPoint since queued events |
| 183 | // might have altered the DOM |
| 184 | target = document.elementFromPoint(event.clientX, |
| 185 | event.clientY); |
| 186 | this._updateVisibility(target); |
| 187 | }, 0); |
| 188 | } |
| 189 | } |
| 190 | |
| 191 | _showCursor() { |
| 192 | if (this._canvas.style.visibility === 'hidden') { |
| 193 | this._canvas.style.visibility = ''; |
| 194 | } |
| 195 | } |
| 196 | |
| 197 | _hideCursor() { |
| 198 | if (this._canvas.style.visibility !== 'hidden') { |
| 199 | this._canvas.style.visibility = 'hidden'; |
| 200 | } |
| 201 | } |
| 202 | |
| 203 | // Should we currently display the cursor? |
| 204 | // (i.e. are we over the target, or a child of the target without a |
| 205 | // different cursor set) |
| 206 | _shouldShowCursor(target) { |
| 207 | if (!target) { |
| 208 | return false; |
| 209 | } |
| 210 | // Easy case |
| 211 | if (target === this._target) { |
| 212 | return true; |
| 213 | } |
| 214 | // Other part of the DOM? |
| 215 | if (!this._target.contains(target)) { |
| 216 | return false; |
| 217 | } |
| 218 | // Has the child its own cursor? |
| 219 | // FIXME: How can we tell that a sub element has an |
| 220 | // explicit "cursor: none;"? |
| 221 | if (window.getComputedStyle(target).cursor !== 'none') { |
| 222 | return false; |
| 223 | } |
| 224 | return true; |
| 225 | } |
| 226 | |
| 227 | _updateVisibility(target) { |
| 228 | // When the cursor target has capture we want to show the cursor. |
| 229 | // So, if a capture is active - look at the captured element instead. |
| 230 | if (this._captureIsActive()) { |
| 231 | target = document.captureElement; |
| 232 | } |
| 233 | if (this._shouldShowCursor(target)) { |
| 234 | this._showCursor(); |
| 235 | } else { |
| 236 | this._hideCursor(); |
| 237 | } |
| 238 | } |
| 239 | |
| 240 | _updatePosition() { |
| 241 | this._canvas.style.left = this._position.x + "px"; |
| 242 | this._canvas.style.top = this._position.y + "px"; |
| 243 | } |
| 244 | |
| 245 | _captureIsActive() { |
| 246 | return document.captureElement && |
| 247 | document.documentElement.contains(document.captureElement); |
| 248 | } |
| 249 | } |