fix: round fractional height values in resolveDimensions

src/lib/api-validation.ts

@@ -53,6 +53,7 @@ export function resolveDimensions(
   height?: number
 ): DimensionResolution {
   if (width !== undefined) width = Math.round(width);
+  if (height !== undefined) height = Math.round(height);
 
   if (width !== undefined && (width < OG_MIN_WIDTH || width > OG_MAX_WIDTH)) {
     return {

tests/api/og.test.ts

@@ -191,6 +191,19 @@ describe('resolveDimensions', () => {
     });
   });
 
+  it('rounds a fractional height to a whole number', () => {
+    expect(resolveDimensions(undefined, 315.6)).toEqual({
+      success: true,
+      width: 602,
+      height: 316,
+    });
+    expect(resolveDimensions(undefined, 175.2)).toEqual({
+      success: true,
+      width: 333,
+      height: 175,
+    });
+  });
+
   it('derives width when only height is supplied', () => {
     expect(resolveDimensions(undefined, 315)).toEqual({
       success: true,
@@ -225,6 +238,11 @@ describe('resolveDimensions', () => {
       width: 2400,
       height: 1260,
     });
+    expect(resolveDimensions(600.4, 315.2)).toEqual({
+      success: true,
+      width: 600,
+      height: 315,
+    });
   });
 
   it('rejects mismatched aspect ratios when both dimensions are supplied', () => {
@@ -558,15 +576,15 @@ describe('OG API dimension resolution and scaling', () => {
     );
   });
 
-  it('scales down to 601 when height is fractional', async () => {
+  it('scales down to a whole-number width when height is fractional', async () => {
     const { renderToPng } = await import('@/lib/og-engine');
     vi.mocked(renderToPng).mockClear();
 
     const res = await GET(makeContext(`${BASE}?template=blog-minimal-dark&title=Hi&height=315.5`));
     expect(res.status).toBe(200);
     expect(renderToPng).toHaveBeenCalledWith(
       expect.anything(),
-      { width: 1200, height: 630, scaleDown: 601 }
+      { width: 1200, height: 630, scaleDown: 602 }
     );
   });