48 lines
1.1 KiB
JavaScript
48 lines
1.1 KiB
JavaScript
export class Viewport {
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constructor() {
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this.panX = 0;
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this.panY = 0;
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this.zoomLevel = 0;
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}
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get zoom() {
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return Math.pow(2, this.zoomLevel * 0.25);
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}
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panAround(x, y) {
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this.panX -= x / this.zoom;
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this.panY -= y / this.zoom;
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}
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zoomIn(delta) {
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this.zoomLevel += delta;
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this.zoomLevel = Math.max(-16, Math.min(20, this.zoomLevel));
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}
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getVisibleRect(windowSize) {
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let invZoom = 1 / this.zoom;
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let width = windowSize.width * invZoom;
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let height = windowSize.height * invZoom;
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return {
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x: this.panX - width / 2,
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y: this.panY - height / 2,
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width,
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height,
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};
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}
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toViewportSpace(x, y, windowSize) {
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return [
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(x - windowSize.width / 2) / this.zoom + this.panX,
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(y - windowSize.height / 2) / this.zoom + this.panY,
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];
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}
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toScreenSpace(x, y, windowSize) {
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return [
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(x - this.panX) * this.zoom + windowSize.width / 2,
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(y - this.panY) * this.zoom + windowSize.height / 2,
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];
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}
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}
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