From 2aaf5a2dc501ab38ebb1882fc546eca3fd5e9454 Mon Sep 17 00:00:00 2001
From: Tofandel <adrien.foulon@tukan.hu>
Date: Thu, 30 Oct 2025 16:09:52 +0100
Subject: [PATCH] Fix clamping for different fit than cover and don't clamp
 SVGs by default

---
 src/handlers/handlers.ts    | 17 +++++++++----
 src/handlers/utils.ts       | 24 +++++++++++++++----
 src/ipx.ts                  |  3 ++-
 test.mjs                    |  2 +-
 test/handlers/utils.test.ts | 48 +++++++++++++++++++++++++++++++------
 5 files changed, 76 insertions(+), 18 deletions(-)

diff --git a/src/handlers/handlers.ts b/src/handlers/handlers.ts
index 6935dc1c..5773aae0 100644
--- a/src/handlers/handlers.ts
+++ b/src/handlers/handlers.ts
@@ -94,11 +94,18 @@ export const resize: Handler = {
       height = width;
     }
     // sharp's `withoutEnlargement` doesn't respect the requested aspect ratio, so we need to do it ourselves
-    if (!context.enlarge) {
-      const clamped = clampDimensionsPreservingAspectRatio(context.meta, {
-        width,
-        height,
-      });
+    // By default don't clamp svgs unless explicitly desired with enlarge=false
+    if (
+      context.meta?.type === "svg" ? context.enlarge === false : !context.enlarge
+    ) {
+      const clamped = clampDimensionsPreservingAspectRatio(
+        context.fit,
+        context.meta,
+        {
+          width,
+          height,
+        },
+      );
       width = clamped.width;
       height = clamped.height;
     }
diff --git a/src/handlers/utils.ts b/src/handlers/utils.ts
index 2e2211dd..0ce8bba3 100644
--- a/src/handlers/utils.ts
+++ b/src/handlers/utils.ts
@@ -35,18 +35,34 @@ export function applyHandler(
 }
 
 export function clampDimensionsPreservingAspectRatio(
+  fit: HandlerContext["fit"],
   sourceDimensions: ImageMeta,
   desiredDimensions: { width: number; height: number },
 ) {
   const desiredAspectRatio = desiredDimensions.width / desiredDimensions.height;
+  const sourceAspectRatio = sourceDimensions.width / sourceDimensions.height;
   let { width, height } = desiredDimensions;
   if (sourceDimensions.width && width > sourceDimensions.width) {
-    width = sourceDimensions.width;
-    height = Math.round(sourceDimensions.width / desiredAspectRatio);
+    if (
+      ["contain", "fill", "inside"].includes(fit) &&
+      sourceAspectRatio < desiredAspectRatio
+    ) {
+      width = Math.round(height * desiredAspectRatio);
+    } else {
+      width = sourceDimensions.width;
+      height = Math.round(sourceDimensions.width / desiredAspectRatio);
+    }
   }
   if (sourceDimensions.height && height > sourceDimensions.height) {
-    height = sourceDimensions.height;
-    width = Math.round(sourceDimensions.height * desiredAspectRatio);
+    if (
+      ["contain", "fill", "inside"].includes(fit) &&
+      sourceAspectRatio > desiredAspectRatio
+    ) {
+      height = Math.round(width / desiredAspectRatio);
+    } else {
+      height = sourceDimensions.height;
+      width = Math.round(sourceDimensions.height * desiredAspectRatio);
+    }
   }
 
   return { width, height };
diff --git a/src/ipx.ts b/src/ipx.ts
index 617d68d3..9efbeeed 100644
--- a/src/ipx.ts
+++ b/src/ipx.ts
@@ -287,6 +287,7 @@ export function createIPX(userOptions: IPXOptions): IPX {
       if (mFormat === "jpg") {
         mFormat = "jpeg";
       }
+
       const format =
         mFormat && SUPPORTED_FORMATS.has(mFormat)
           ? mFormat
@@ -295,7 +296,7 @@ export function createIPX(userOptions: IPXOptions): IPX {
             : "jpeg";
 
       // Use original SVG if format is not specified
-      if (imageMeta.type === "svg" && !mFormat) {
+      if (imageMeta.type === "svg" && (!mFormat || mFormat === "svg")) {
         if (options.svgo === false) {
           return {
             data: sourceData,
diff --git a/test.mjs b/test.mjs
index e67444fb..332ebc6d 100644
--- a/test.mjs
+++ b/test.mjs
@@ -5,5 +5,5 @@ const ipx = createIPX({
 });
 
 const source = await ipx("../assets2/bliss.jpg"); // access file outside ./public dir because of same prefix folder
-const { data, format } = await source.process();
+const { format } = await source.process();
 console.log(format); // print image format
diff --git a/test/handlers/utils.test.ts b/test/handlers/utils.test.ts
index 25e679ba..55c76c34 100644
--- a/test/handlers/utils.test.ts
+++ b/test/handlers/utils.test.ts
@@ -22,12 +22,46 @@ describe("utils", () => {
   });
 
   it("clampDimensionsPreservingAspectRatio", () => {
-    const sourceDimensions = { width: 200, height: 100 };
-    const desiredDimensions = { width: 300, height: 150 };
-    const result = clampDimensionsPreservingAspectRatio(
-      sourceDimensions,
-      desiredDimensions,
-    );
-    expect(result).toEqual({ width: 200, height: 100 });
+    const dimensions = [
+      {
+        source: [200, 100],
+        desired: [300, 150],
+        expected: [200, 100],
+      },
+      {
+        source: [200, 150],
+        desired: [150, 200],
+        expected: [113, 150],
+      },
+      {
+        source: [150, 200],
+        desired: [200, 150],
+        expected: [150, 113],
+      },
+      {
+        source: [211, 40],
+        desired: [170, 170, "contain"],
+        expected: [170, 170],
+      },
+      {
+        source: [211, 40],
+        desired: [220, 110, "contain"],
+        expected: [211, 106],
+      },
+      {
+        source: [40, 211],
+        desired: [110, 220, "contain"],
+        expected: [106, 211],
+      },
+    ];
+
+    for (const d of dimensions) {
+      const result = clampDimensionsPreservingAspectRatio(
+        d.desired[2] ?? null,
+        { width: d.source[0], height: d.source[1] },
+        { width: d.desired[0], height: d.desired[1] },
+      );
+      expect(result).toEqual({ width: d.expected[0], height: d.expected[1] });
+    }
   });
 });