gravity/tool/zoom.js
2025-12-31 20:01:48 -06:00

76 lines
2.5 KiB
JavaScript

import { Tool } from '../tool.js';
import {
ZOOM_IN_FACTOR,
ZOOM_OUT_FACTOR,
WIDE_CLASSNAME,
TALL_CLASSNAME,
TOOL_INFO_CLASSNAME,
} from '../config.js';
export class Zoom extends Tool {
get displayScaleText() {
return `Scale: ${this.sim.getScaleDisplay()}`;
}
constructor(container) {
super(container);
const currentScale = document.createElement('button')
const zoomOut = document.createElement('button');
const zoomIn = document.createElement('button');
const zoomAll = document.createElement('button');
this.div.appendChild(currentScale);
this.div.appendChild(zoomOut);
this.div.appendChild(zoomIn);
this.div.appendChild(zoomAll);
currentScale.classList.add(WIDE_CLASSNAME);
currentScale.classList.add(TOOL_INFO_CLASSNAME);
zoomAll.classList.add(WIDE_CLASSNAME);
zoomAll.classList.add(TALL_CLASSNAME);
currentScale.innerHTML = this.displayScaleText;
zoomOut.innerHTML = 'Zoom<br>Out';
zoomIn.innerHTML = 'Zoom<br>In';
zoomAll.innerHTML = 'Zoom to Fit';
this.sim.onZoom(() => {
currentScale.innerHTML = this.displayScaleText;
});
zoomOut.addEventListener('click', () => {
// Aim at center of view
const x = this.sim.display.width * this.sim.display.scale / 2;
const y = this.sim.display.height * this.sim.display.scale / 2;
this.sim.scheduleZoom(this.sim.screenToSim(x, y), ZOOM_OUT_FACTOR);
});
zoomIn.addEventListener('click', () => {
// Aim at center of view
const x = this.sim.display.width * this.sim.display.scale / 2;
const y = this.sim.display.height * this.sim.display.scale / 2;
this.sim.scheduleZoom(this.sim.screenToSim(x, y), ZOOM_IN_FACTOR);
});
zoomAll.addEventListener('click', () => {
// Determine bounding box
const box = this.sim.system.boundingBox;
const x = (box.start.x + box.end.x) / 2;
const y = (box.start.y + box.end.y) / 2;
const widthRatio = Math.abs(box.start.x - box.end.x) / this.sim.display.width;
const heightRatio = Math.abs(box.start.y - box.end.y) / this.sim.display.height;
const ratio = Math.max(widthRatio, heightRatio) * 2.5;
const factor = Math.ceil(Math.log2(1 / ratio));
// Determine average momentum and set panning velocity to match
const { netMomentum, totalMass } = this.sim.system.computeSystemCenter();
const netVelocity = {
x: netMomentum.x / totalMass,
y: netMomentum.y / totalMass,
};
this.sim.scheduleZoom({x, y}, factor, netVelocity)
});
}
}