55 lines
1.4 KiB
JavaScript
55 lines
1.4 KiB
JavaScript
import {
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EVENT_ZOOM,
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SCALE_POWER_MAX,
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SCALE_POWER_MIN,
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} from './config.js';
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import {div, sub} from './vector.js';
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export class Zoom {
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sim = undefined;
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nextZoom = undefined;
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constructor(sim) {
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this.sim = sim;
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}
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// velocity should be in Sim coordinate scale
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scheduleZoom({x, y}, factor, velocity) {
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this.nextZoom = {x, y, factor, velocity};
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}
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frame() {
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if (this.nextZoom) {
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this.zoom(this.nextZoom);
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this.nextZoom = undefined;
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}
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}
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// x, y should be in Sim coordinates
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// velocity should be in Sim coordinate scale
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zoom({x, y, factor, velocity}) {
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const {display} = this.sim;
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// x, y are the mouse coordinates, which should be the center of the new view frame
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// the new view origin should be x, y minus half the new view width and height
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// compute new scale
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// TODO: Lossy rescaling to expand zoom range
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let scalePower = display.scalePower + factor;
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scalePower = Math.max(scalePower, SCALE_POWER_MIN);
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scalePower = Math.min(scalePower, SCALE_POWER_MAX);
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display.scalePower = scalePower;
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// compute coordinates of new view frame
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display.viewOrigin = sub({x, y}, div({x: display.width, y: display.height}, 2));
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// TODO: If paused, set panning velocity on resume
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// if (this.sim.playing && velocity) {
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if (velocity) {
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this.sim.panning.setVelocity(velocity);
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}
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const e = new CustomEvent(EVENT_ZOOM);
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this.sim.div.dispatchEvent(e);
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}
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}
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