🎆 Update image conversion transform to handle EPS images (#228)

jupyter-book · Feb 17, 2023 · a9913fc · a9913fc
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diff --git a/.changeset/sharp-cars-develop.md b/.changeset/sharp-cars-develop.md
@@ -0,0 +1,5 @@
+---
+'myst-cli': patch
+---
+
+Update image conversion transform to handle EPS images
diff --git a/packages/myst-cli/src/transforms/images.ts b/packages/myst-cli/src/transforms/images.ts
@@ -224,19 +224,23 @@ export async function transformImageFormats(
   const svgImages: GenericNode[] = [];
   const gifImages: GenericNode[] = [];
   const pdfImages: GenericNode[] = [];
+  const epsImages: GenericNode[] = [];
   const unconvertableImages: GenericNode[] = [];
 
   const allowConvertedSvg = validExts.includes('.png') || validExts.includes('.pdf');
   const allowConvertedPdf = validExts.includes('.png') || !validExts.includes('.pdf');
   const allowConvertedGif = validExts.includes('.png');
+  const allowConvertedEps = validExts.includes('.png'); // || validExts.includes('.pdf') || validExts.includes('.svg'); // inkscape
 
   unsupportedImages.forEach((image) => {
     if (allowConvertedSvg && path.extname(image.url) === '.svg') {
       svgImages.push(image);
-    } else if (allowConvertedGif && path.extname(image.url) == '.gif') {
+    } else if (allowConvertedGif && path.extname(image.url) === '.gif') {
       gifImages.push(image);
-    } else if (allowConvertedPdf && path.extname(image.url) == '.pdf') {
+    } else if (allowConvertedPdf && path.extname(image.url) === '.pdf') {
       pdfImages.push(image);
+    } else if (allowConvertedEps && path.extname(image.url) === '.eps') {
+      epsImages.push(image);
     } else {
       unconvertableImages.push(image);
     }
@@ -355,6 +359,59 @@ export async function transformImageFormats(
     }
   }
 
+  // Convert EPSs
+  // Currently the inkscpe CLI has a bug which prevents EPS conversions;
+  // once that is fixed, we may uncomment the rest of this section to
+  // enable better conversions, e.g. EPS -> SVG
+  // https://gitlab.com/inkscape/inkscape/-/issues/3524
+  let epsConversionFn: ConversionFn | undefined;
+  if (epsImages.length) {
+    // Decide if we convert to PDF, SVG, or PNG
+    // const inkscapeOutputExt = validExts.filter((ext) => ['.pdf', '.svg', '.png'].includes(ext))[0];
+    const imagemagickOutputExt = validExts.filter((ext) => ['.png'].includes(ext))[0];
+    const logPrefix = `🌠 Converting ${epsImages.length} EPS image${
+      epsImages.length > 1 ? 's' : ''
+    } to`;
+    // if (inkscapeAvailable && inkscapeOutputExt === '.pdf') {
+    //   session.log.info(`${logPrefix} PDF using inkscape`);
+    //   epsConversionFn = inkscape.convertEpsToPdf;
+    // } else if (inkscapeAvailable && inkscapeOutputExt === '.svg') {
+    //   session.log.info(`${logPrefix} SVG using inkscape`);
+    //   epsConversionFn = inkscape.convertEpsToSvg;
+    // } else if (inkscapeAvailable && inkscapeOutputExt === '.png') {
+    //   session.log.info(`${logPrefix} PNG using inkscape`);
+    //   epsConversionFn = inkscape.convertEpsToPng;
+    // } else
+    if (imagemagickAvailable && imagemagickOutputExt === '.png') {
+      // if (inkscapeOutputExt && inkscapeOutputExt !== '.png') {
+      //   addWarningForFile(
+      //     session,
+      //     file,
+      //     `To convert EPS images to ${inkscapeOutputExt
+      //       .slice(1)
+      //       .toUpperCase()}, you must install inkscape.`,
+      //     'warn',
+      //     { note: 'Images converted to PNG as a fallback using imagemagick.' },
+      //   );
+      // }
+      session.log.info(`${logPrefix} PNG using imagemagick`);
+      epsConversionFn = imagemagick.convertEpsToPng;
+    } else {
+      addWarningForFile(
+        session,
+        file,
+        'Cannot convert EPS images, they may not correctly render.',
+        'error',
+        { note: 'To convert these images, you must install imagemagick' },
+      );
+    }
+    if (epsConversionFn) {
+      conversionPromises.push(
+        ...epsImages.map(async (image) => await convert(image, epsConversionFn as ConversionFn)),
+      );
+    }
+  }
+
   // Warn on unsupported, unconvertable images
   if (unconvertableImages.length) {
     unconvertableImages.forEach((image) => {

diff --git a/packages/myst-cli/src/utils/imagemagick.ts b/packages/myst-cli/src/utils/imagemagick.ts
@@ -29,9 +29,9 @@ export async function extractFirstFrameOfGif(session: ISession, gif: string, wri
   } else {
     const executable = `convert ${gif}[0] ${png}`;
     session.log.debug(`Executing: ${executable}`);
-    const convert = makeExecutable(executable, session.log);
+    const exec = makeExecutable(executable, session.log);
     try {
-      await convert();
+      await exec();
     } catch (err) {
       session.log.error(`Could not extract an image from gif: ${gif} - ${err}`);
       return null;
@@ -40,48 +40,51 @@ export async function extractFirstFrameOfGif(session: ISession, gif: string, wri
   return pngFile;
 }
 
-export async function convertSvgToPng(session: ISession, svg: string, writeFolder: string) {
-  if (!fs.existsSync(svg)) return null;
-  const { name, ext } = path.parse(svg);
-  if (ext !== '.svg') return null;
-  const pngFile = `${name}.png`;
-  const png = path.join(writeFolder, pngFile);
-  if (fs.existsSync(png)) {
-    session.log.debug(`Cached file found for converted SVG: ${svg}`);
+async function convert(
+  inputExtension: string,
+  outputExtension: string,
+  session: ISession,
+  input: string,
+  writeFolder: string,
+) {
+  if (!fs.existsSync(input)) return null;
+  const { name, ext } = path.parse(input);
+  if (ext !== inputExtension) return null;
+  const filename = `${name}${outputExtension}`;
+  const output = path.join(writeFolder, filename);
+  const inputFormatUpper = inputExtension.slice(1).toUpperCase();
+  const outputFormatUpper = outputExtension.slice(1).toUpperCase();
+  if (fs.existsSync(output)) {
+    session.log.debug(`Cached file found for converted ${inputFormatUpper}: ${input}`);
   } else {
-    const executable = `convert -density 600 ${svg} ${png}`;
+    const executable = `convert -density 600  -colorspace RGB ${input} ${output}`;
     session.log.debug(`Executing: ${executable}`);
-    const convert = makeExecutable(executable, session.log);
+    const exec = makeExecutable(executable, session.log);
     try {
-      await convert();
+      await exec();
     } catch (err) {
-      session.log.error(`Could not convert from SVG to PNG: ${svg} - ${err}`);
+      session.log.error(
+        `Could not convert from ${inputFormatUpper} to ${outputFormatUpper}: ${input} - ${err}`,
+      );
       return null;
     }
   }
-  return pngFile;
+  return filename;
 }
 
-export async function convertPdfToPng(session: ISession, pdf: string, writeFolder: string) {
-  if (!fs.existsSync(pdf)) return null;
-  const { name, ext } = path.parse(pdf);
-  if (ext !== '.pdf') return null;
-  const pngFile = `${name}.png`;
-  const png = path.join(writeFolder, pngFile);
-  if (fs.existsSync(png)) {
-    session.log.debug(`Cached file found for converted PDF: ${pdf}`);
-  } else {
-    const executable = `convert -density 600 ${pdf} ${png}`;
-    session.log.debug(`Executing: ${executable}`);
-    const convert = makeExecutable(executable, session.log);
-    try {
-      await convert();
-    } catch (err) {
-      session.log.error(`Could not convert from PDF to PNG: ${pdf} - ${err}`);
-      return null;
-    }
-  }
-  return pngFile;
+export async function convertSvgToPng(session: ISession, input: string, writeFolder: string) {
+  const output = await convert('.svg', '.png', session, input, writeFolder);
+  return output;
+}
+
+export async function convertPdfToPng(session: ISession, input: string, writeFolder: string) {
+  const output = await convert('.pdf', '.png', session, input, writeFolder);
+  return output;
+}
+
+export async function convertEpsToPng(session: ISession, input: string, writeFolder: string) {
+  const output = await convert('.eps', '.png', session, input, writeFolder);
+  return output;
 }
 
 export async function convertImageToWebp(

diff --git a/packages/myst-cli/src/utils/inkscape.ts b/packages/myst-cli/src/utils/inkscape.ts
@@ -29,34 +29,62 @@ export function isInkscapeAvailable() {
   return which('inkscape', { nothrow: true });
 }
 
-async function convertSvgTo(format: string, session: ISession, svg: string, writeFolder: string) {
-  if (!fs.existsSync(svg)) return null;
-  const { name, ext } = path.parse(svg);
-  if (ext !== '.svg') return null;
-  const filename = `${name}.${format}`;
+async function convert(
+  inputExtension: string,
+  outputExtension: string,
+  session: ISession,
+  input: string,
+  writeFolder: string,
+) {
+  if (!fs.existsSync(input)) return null;
+  const { name, ext } = path.parse(input);
+  if (ext !== inputExtension) return null;
+  const filename = `${name}${outputExtension}`;
   const output = path.join(writeFolder, filename);
+  const inputFormatUpper = inputExtension.slice(1).toUpperCase();
+  const outputFormat = outputExtension.slice(1);
   if (fs.existsSync(output)) {
-    session.log.debug(`Cached file found for converted SVG: ${svg}`);
+    session.log.debug(`Cached file found for converted ${inputFormatUpper}: ${input}`);
   } else {
-    const inkscapeCommand = `inkscape ${svg} --export-area-drawing --export-type=${format} --export-filename=${output}`;
+    const inkscapeCommand = `inkscape ${input} --export-area-drawing --export-type=${outputFormat} --export-filename=${output}`;
     session.log.debug(`Executing: ${inkscapeCommand}`);
-    const convert = makeExecutable(inkscapeCommand, createInkscpapeLogger(session));
+    const exec = makeExecutable(inkscapeCommand, createInkscpapeLogger(session));
     try {
-      await convert();
+      await exec();
     } catch (err) {
-      session.log.error(`Could not convert from SVG to ${format.toUpperCase()}: ${svg} - ${err}`);
+      session.log.error(
+        `Could not convert from ${inputFormatUpper} to ${outputFormat.toUpperCase()}: ${input} - ${err}`,
+      );
       return null;
     }
   }
   return filename;
 }
 
-export async function convertSvgToPng(session: ISession, svg: string, writeFolder: string) {
-  const pngFile = await convertSvgTo('png', session, svg, writeFolder);
-  return pngFile;
+export async function convertSvgToPng(session: ISession, input: string, writeFolder: string) {
+  const output = await convert('.svg', '.png', session, input, writeFolder);
+  return output;
 }
 
-export async function convertSvgToPdf(session: ISession, svg: string, writeFolder: string) {
-  const pngFile = await convertSvgTo('pdf', session, svg, writeFolder);
-  return pngFile;
+export async function convertSvgToPdf(session: ISession, input: string, writeFolder: string) {
+  const output = await convert('.svg', '.pdf', session, input, writeFolder);
+  return output;
 }
+
+// EPS conversion functions do not work from the inkscape cli:
+// See: https://gitlab.com/inkscape/inkscape/-/issues/3524
+
+// export async function convertEpsToPdf(session: ISession, input: string, writeFolder: string) {
+//   const output = await convert('.eps', '.pdf', session, input, writeFolder);
+//   return output;
+// }
+
+// export async function convertEpsToSvg(session: ISession, input: string, writeFolder: string) {
+//   const output = await convert('.eps', '.svg', session, input, writeFolder);
+//   return output;
+// }
+
+// export async function convertEpsToPng(session: ISession, input: string, writeFolder: string) {
+//   const output = await convert('.eps', '.png', session, input, writeFolder);
+//   return output;
+// }