feat: scaleToFit utility

web/src/lib/utils/layout-utils.spec.ts

@@ -0,0 +1,54 @@
+import { scaleToFit } from '$lib/utils/layout-utils';
+
+describe('scaleToFit', () => {
+  const tests = [
+    {
+      name: 'landscape image in square container',
+      dimensions: { width: 2000, height: 1000 },
+      container: { width: 500, height: 500 },
+      expected: { width: 500, height: 250 },
+    },
+    {
+      name: 'portrait image in square container',
+      dimensions: { width: 1000, height: 2000 },
+      container: { width: 500, height: 500 },
+      expected: { width: 250, height: 500 },
+    },
+    {
+      name: 'square image in square container',
+      dimensions: { width: 1000, height: 1000 },
+      container: { width: 500, height: 500 },
+      expected: { width: 500, height: 500 },
+    },
+    {
+      name: 'landscape image in landscape container',
+      dimensions: { width: 1600, height: 900 },
+      container: { width: 800, height: 600 },
+      expected: { width: 800, height: 450 },
+    },
+    {
+      name: 'portrait image in portrait container',
+      dimensions: { width: 900, height: 1600 },
+      container: { width: 600, height: 800 },
+      expected: { width: 450, height: 800 },
+    },
+    {
+      name: 'image matches container exactly',
+      dimensions: { width: 500, height: 300 },
+      container: { width: 500, height: 300 },
+      expected: { width: 500, height: 300 },
+    },
+    {
+      name: 'image smaller than container scales up',
+      dimensions: { width: 100, height: 50 },
+      container: { width: 400, height: 400 },
+      expected: { width: 400, height: 200 },
+    },
+  ];
+
+  for (const { name, dimensions, container, expected } of tests) {
+    it(`should handle ${name}`, () => {
+      expect(scaleToFit(dimensions, container)).toEqual(expected);
+    });
+  }
+});

web/src/lib/utils/layout-utils.ts

@@ -129,3 +129,19 @@ export type CommonPosition = {
   width: number;
   height: number;
 };
+
+// Scales dimensions to fit within a container (like object-fit: contain)
+export const scaleToFit = (
+  dimensions: { width: number; height: number },
+  container: { width: number; height: number },
+) => {
+  const scaleX = container.width / dimensions.width;
+  const scaleY = container.height / dimensions.height;
+
+  const scale = Math.min(scaleX, scaleY);
+
+  return {
+    width: dimensions.width * scale,
+    height: dimensions.height * scale,
+  };
+};