33 lines
1.3 KiB
TypeScript
33 lines
1.3 KiB
TypeScript
import { describe, expect, it } from 'vitest';
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import { fitView, screenToImage, zoomAt, type View } from '../src/lib/view';
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describe('view transform', () => {
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it('maps screen to image coordinates', () => {
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const view: View = { scale: 2, offsetX: 10, offsetY: 20 };
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expect(screenToImage({ x: 30, y: 60 }, view)).toEqual({ x: 10, y: 20 });
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});
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it('keeps the point under the cursor fixed while zooming', () => {
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const view: View = { scale: 0.5, offsetX: 40, offsetY: -15 };
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const cursor = { x: 300, y: 200 };
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const before = screenToImage(cursor, view);
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const zoomed = zoomAt(view, cursor, 3);
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expect(zoomed.scale).toBeCloseTo(1.5);
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const after = screenToImage(cursor, zoomed);
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expect(after.x).toBeCloseTo(before.x);
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expect(after.y).toBeCloseTo(before.y);
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});
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it('clamps zoom', () => {
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expect(zoomAt({ scale: 10, offsetX: 0, offsetY: 0 }, { x: 0, y: 0 }, 100).scale).toBe(20);
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expect(zoomAt({ scale: 0.1, offsetX: 0, offsetY: 0 }, { x: 0, y: 0 }, 0.001).scale).toBe(0.05);
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});
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it('fits and centres the image in the viewport', () => {
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const view = fitView(2000, 1000, 1016, 1016, 8);
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expect(view.scale).toBeCloseTo(0.5);
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expect(view.offsetX).toBeCloseTo(8);
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expect(view.offsetY).toBeCloseTo(258);
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});
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});
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