72 lines
2.1 KiB
JavaScript
72 lines
2.1 KiB
JavaScript
/**
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* Management class for Mouse events
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*/
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class MouseManager {
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constructor() {
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this._wheelTime = 0;
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}
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/**
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* Specify a rate limit for mouse wheel to gate repeated scrolling.
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* This is especially important for continuous scrolling mice which emit hundreds of events per second.
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* This designates a minimum number of milliseconds which must pass before another wheel event is handled
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* @type {number}
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*/
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static MOUSE_WHEEL_RATE_LIMIT = 50;
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/* -------------------------------------------- */
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/**
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* Begin listening to mouse events.
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* @internal
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*/
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_activateListeners() {
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window.addEventListener("wheel", this._onWheel.bind(this), {passive: false});
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}
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/* -------------------------------------------- */
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/**
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* Master mouse-wheel event handler
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* @param {WheelEvent} event The mouse wheel event
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* @private
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*/
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_onWheel(event) {
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// Prevent zooming the entire browser window
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if ( event.ctrlKey ) event.preventDefault();
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// Interpret shift+scroll as vertical scroll
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let dy = event.delta = event.deltaY;
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if ( event.shiftKey && (dy === 0) ) {
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dy = event.delta = event.deltaX;
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}
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if ( dy === 0 ) return;
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// Take no actions if the canvas is not hovered
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if ( !canvas.ready ) return;
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const hover = document.elementFromPoint(event.clientX, event.clientY);
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if ( !hover || (hover.id !== "board") ) return;
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event.preventDefault();
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// Identify scroll modifiers
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const isCtrl = event.ctrlKey || event.metaKey;
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const isShift = event.shiftKey;
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const layer = canvas.activeLayer;
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// Case 1 - rotate placeable objects
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if ( layer?.options?.rotatableObjects && (isCtrl || isShift) ) {
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const hasTarget = layer.options?.controllableObjects ? layer.controlled.length : !!layer.hover;
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if ( hasTarget ) {
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const t = Date.now();
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if ( (t - this._wheelTime) < this.constructor.MOUSE_WHEEL_RATE_LIMIT ) return;
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this._wheelTime = t;
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return layer._onMouseWheel(event);
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}
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}
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// Case 2 - zoom the canvas
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canvas._onMouseWheel(event);
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}
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}
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