✨(pdf) preserve image aspect ratio in PDF export

images were distorted in PDF exports; height is now computed to fix that

Signed-off-by: Cyril <c.gromoff@gmail.com>

CHANGELOG.md

@@ -23,6 +23,7 @@ and this project adheres to
 - 🐛(frontend) fix pdf embed to use full width #1526
 - 🐛(frontend) fix fallback translations with Trans #1620
 - 🐛(pdf) fix table cell alignment issue in exported documents #1582
+- 🐛(pdf) preserve image aspect ratio in PDF export #1622
 
 ### Security
 

src/frontend/apps/impress/src/features/docs/doc-export/blocks-mapping/imageDocx.tsx

@@ -31,15 +31,10 @@ export const blockMappingImageDocx: DocsExporterDocx['mappings']['blockMapping']
       const svgText = await blob.text();
       const FALLBACK_SIZE = 536;
       previewWidth = previewWidth || blob.size || FALLBACK_SIZE;
-      pngConverted = await convertSvgToPng(svgText, previewWidth);
-      const img = new Image();
-      img.src = pngConverted;
-      await new Promise((resolve) => {
-        img.onload = () => {
-          dimensions = { width: img.width, height: img.height };
-          resolve(null);
-        };
-      });
+
+      const result = await convertSvgToPng(svgText, previewWidth);
+      pngConverted = result.png;
+      dimensions = { width: result.width, height: result.height };
     } else {
       dimensions = await getImageDimensions(blob);
     }

src/frontend/apps/impress/src/features/docs/doc-export/blocks-mapping/imageODT.tsx

@@ -28,15 +28,10 @@ export const blockMappingImageODT: DocsExporterODT['mappings']['blockMapping']['
         const svgText = await blob.text();
         const FALLBACK_SIZE = 536;
         previewWidth = previewWidth || blob.size || FALLBACK_SIZE;
-        pngConverted = await convertSvgToPng(svgText, previewWidth);
-        const img = new Image();
-        img.src = pngConverted;
-        await new Promise((resolve) => {
-          img.onload = () => {
-            dimensions = { width: img.width, height: img.height };
-            resolve(null);
-          };
-        });
+
+        const result = await convertSvgToPng(svgText, previewWidth);
+        pngConverted = result.png;
+        dimensions = { width: result.width, height: result.height };
       } else {
         dimensions = await getImageDimensions(blob);
       }

src/frontend/apps/impress/src/features/docs/doc-export/blocks-mapping/imagePDF.tsx

@@ -6,12 +6,14 @@ import { convertSvgToPng } from '../utils';
 
 const PIXELS_PER_POINT = 0.75;
 const FONT_SIZE = 16;
+const MAX_WIDTH = 600;
 
 export const blockMappingImagePDF: DocsExporterPDF['mappings']['blockMapping']['image'] =
   async (block, exporter) => {
     const blob = await exporter.resolveFile(block.props.url);
     let pngConverted: string | undefined;
-    let width = block.props.previewWidth || undefined;
+    let dimensions: { width: number; height: number } | undefined;
+    let previewWidth = block.props.previewWidth || undefined;
 
     if (!blob.type.includes('image')) {
       return <View wrap={false} />;
@@ -20,16 +22,33 @@ export const blockMappingImagePDF: DocsExporterPDF['mappings']['blockMapping']['
     if (blob.type.includes('svg')) {
       const svgText = await blob.text();
       const FALLBACK_SIZE = 536;
-      width = width || blob.size || FALLBACK_SIZE;
-      pngConverted = await convertSvgToPng(svgText, width);
+      previewWidth = previewWidth || FALLBACK_SIZE;
+
+      const result = await convertSvgToPng(svgText, previewWidth);
+      pngConverted = result.png;
+      dimensions = { width: result.width, height: result.height };
+    } else {
+      dimensions = await getImageDimensions(blob);
     }
 
+    if (!dimensions) {
+      return <View wrap={false} />;
+    }
+
+    const { width, height } = dimensions;
+
+    // Ensure the final width never exceeds MAX_WIDTH to prevent images
+    // from overflowing the page width in the exported document
+    const finalWidth = Math.min(previewWidth || width, MAX_WIDTH);
+    const finalHeight = (finalWidth / width) * height;
+
     return (
       <View wrap={false}>
         <Image
           src={pngConverted || blob}
           style={{
-            width: width ? width * PIXELS_PER_POINT : undefined,
+            width: finalWidth * PIXELS_PER_POINT,
+            height: finalHeight * PIXELS_PER_POINT,
             maxWidth: '100%',
           }}
         />
@@ -38,6 +57,21 @@ export const blockMappingImagePDF: DocsExporterPDF['mappings']['blockMapping']['
     );
   };
 
+async function getImageDimensions(blob: Blob) {
+  if (typeof window !== 'undefined') {
+    const url = URL.createObjectURL(blob);
+    const img = document.createElement('img');
+    img.src = url;
+
+    return new Promise<{ width: number; height: number }>((resolve) => {
+      img.onload = () => {
+        URL.revokeObjectURL(url);
+        resolve({ width: img.naturalWidth, height: img.naturalHeight });
+      };
+    });
+  }
+}
+
 function caption(
   props: Partial<DefaultProps & { caption: string; previewWidth: number }>,
 ) {

src/frontend/apps/impress/src/features/docs/doc-export/utils.ts

@@ -20,18 +20,21 @@ export function downloadFile(blob: Blob, filename: string) {
 }
 
 /**
- * Converts an SVG string into a PNG image and returns it as a data URL.
+ * Converts an SVG string into a PNG image and returns it as a data URL with dimensions.
  *
  * This function creates a canvas, parses the SVG, calculates the appropriate height
  * to preserve the aspect ratio, and renders the SVG onto the canvas using Canvg.
  *
  * @param {string} svgText - The raw SVG markup to convert.
  * @param {number} width - The desired width of the output PNG (height is auto-calculated to preserve aspect ratio).
- * @returns {Promise<string>} A Promise that resolves to a PNG image encoded as a base64 data URL.
+ * @returns {Promise<{ png: string; width: number; height: number }>} A Promise that resolves to an object containing the PNG data URL and its dimensions.
  *
  * @throws Will throw an error if the canvas context cannot be initialized.
  */
-export async function convertSvgToPng(svgText: string, width: number) {
+export async function convertSvgToPng(
+  svgText: string,
+  width: number,
+): Promise<{ png: string; width: number; height: number }> {
   // Create a canvas and render the SVG onto it
   const canvas = document.createElement('canvas');
   const ctx = canvas.getContext('2d', {
@@ -64,7 +67,11 @@ export async function convertSvgToPng(svgText: string, width: number) {
   svg.resize(width, height, true);
   await svg.render();
 
-  return canvas.toDataURL('image/png');
+  return {
+    png: canvas.toDataURL('image/png'),
+    width,
+    height: height || width,
+  };
 }
 
 export function docxBlockPropsToStyles(