Attempt to provide better default values for the disableFontFace/nativeImageDecoderSupport API options in Node.js

This should provide a better out-of-the-box experience when using PDF.js in a Node.js environment, since it's missing native support for both `@font-face` and `Image`.
Please note that this change *only* affects the default values, hence it's still possible for an API consumer to override those values when calling `getDocument`.

Also, prevents "ReferenceError: document is not defined" errors, when running the unit-tests in Node.js/Travis.

examples/node/pdf2png/pdf2png.js

@@ -56,14 +56,8 @@ var pdfURL = '../../../web/compressed.tracemonkey-pldi-09.pdf';
 // Read the PDF file into a typed array so PDF.js can load it.
 var rawData = new Uint8Array(fs.readFileSync(pdfURL));
 
-// Load the PDF file. The `disableFontFace` and `nativeImageDecoderSupport`
-// options must be passed because Node.js has no native `@font-face` and
-// `Image` support.
-pdfjsLib.getDocument({
-  data: rawData,
-  disableFontFace: true,
-  nativeImageDecoderSupport: 'none',
-}).then(function (pdfDocument) {
+// Load the PDF file.
+pdfjsLib.getDocument(rawData).then(function (pdfDocument) {
   console.log('# PDF document loaded.');
 
   // Get the first page.

src/display/api.js

@@ -274,7 +274,9 @@ function getDocument(src) {
   const NativeImageDecoderValues = Object.values(NativeImageDecoding);
   if (params.nativeImageDecoderSupport === undefined ||
       !NativeImageDecoderValues.includes(params.nativeImageDecoderSupport)) {
-    params.nativeImageDecoderSupport = NativeImageDecoding.DECODE;
+    params.nativeImageDecoderSupport =
+      (apiCompatibilityParams.nativeImageDecoderSupport ||
+       NativeImageDecoding.DECODE);
   }
   if (!Number.isInteger(params.maxImageSize)) {
     params.maxImageSize = -1;
@@ -283,7 +285,7 @@ function getDocument(src) {
     params.isEvalSupported = true;
   }
   if (typeof params.disableFontFace !== 'boolean') {
-    params.disableFontFace = false;
+    params.disableFontFace = apiCompatibilityParams.disableFontFace || false;
   }
 
   if (typeof params.disableRange !== 'boolean') {
@@ -2168,6 +2170,8 @@ var WorkerTransport = (function WorkerTransportClosure() {
         disableStream: params.disableStream,
         disableAutoFetch: params.disableAutoFetch,
         disableCreateObjectURL: params.disableCreateObjectURL,
+        disableFontFace: params.disableFontFace,
+        nativeImageDecoderSupport: params.nativeImageDecoderSupport,
       });
     },
   };

src/display/api_compatibility.js

@@ -15,6 +15,8 @@
 
 let compatibilityParams = Object.create(null);
 if (typeof PDFJSDev === 'undefined' || PDFJSDev.test('GENERIC')) {
+  const isNodeJS = require('../shared/is_node');
+
   const userAgent =
     (typeof navigator !== 'undefined' && navigator.userAgent) || '';
   const isIE = /Trident/.test(userAgent);
@@ -42,9 +44,15 @@ if (typeof PDFJSDev === 'undefined' || PDFJSDev.test('GENERIC')) {
       compatibilityParams.disableStream = true;
     }
   })();
-}
-const apiCompatibilityParams = Object.freeze(compatibilityParams);
 
-export {
-  apiCompatibilityParams,
-};
+  // Support: Node.js
+  (function checkFontFaceAndImage() {
+    // Node.js is missing native support for `@font-face` and `Image`.
+    if (isNodeJS()) {
+      compatibilityParams.disableFontFace = true;
+      compatibilityParams.nativeImageDecoderSupport = 'none';
+    }
+  })();
+}
+
+exports.apiCompatibilityParams = Object.freeze(compatibilityParams);

web/viewer_compatibility.js

@@ -37,8 +37,5 @@ if (typeof PDFJSDev === 'undefined' || PDFJSDev.test('GENERIC')) {
     }
   })();
 }
-const viewerCompatibilityParams = Object.freeze(compatibilityParams);
 
-export {
-  viewerCompatibilityParams,
-};
+exports.viewerCompatibilityParams = Object.freeze(compatibilityParams);