Merge pull request #15306 from Snuffleupagus/Type3-only-Path2D

Only compile Type3 glyphs when `Path2D` is supported

Author: timvandermeij

src/display/canvas.js

@@ -54,8 +54,14 @@ const EXECUTION_TIME = 15; // ms
 // Defines the number of steps before checking the execution time.
 const EXECUTION_STEPS = 10;
 
-const COMPILE_TYPE3_GLYPHS = true;
-const MAX_SIZE_TO_COMPILE = 1000;
+// To disable Type3 compilation, set the value to `-1`.
+const MAX_SIZE_TO_COMPILE =
+  typeof PDFJSDev !== "undefined" &&
+  PDFJSDev.test("GENERIC") &&
+  isNodeJS &&
+  typeof Path2D === "undefined"
+    ? -1
+    : 1000;
 
 const FULL_CHUNK_HEIGHT = 16;
 
@@ -294,11 +300,7 @@ function drawImageAtIntegerCoords(
 
 function compileType3Glyph(imgData) {
   const { width, height } = imgData;
-  if (
-    !COMPILE_TYPE3_GLYPHS ||
-    width > MAX_SIZE_TO_COMPILE ||
-    height > MAX_SIZE_TO_COMPILE
-  ) {
+  if (width > MAX_SIZE_TO_COMPILE || height > MAX_SIZE_TO_COMPILE) {
     return null;
   }
 
@@ -404,12 +406,7 @@ function compileType3Glyph(imgData) {
 
   // building outlines
   const steps = new Int32Array([0, width1, -1, 0, -width1, 0, 0, 0, 1]);
-  let path, outlines, coords;
-  if (!isNodeJS) {
-    path = new Path2D();
-  } else {
-    outlines = [];
-  }
+  const path = new Path2D();
 
   for (i = 0; count && i <= height; i++) {
     let p = i * width1;
@@ -420,12 +417,7 @@ function compileType3Glyph(imgData) {
     if (p === end) {
       continue;
     }
-
-    if (path) {
-      path.moveTo(p % width1, i);
-    } else {
-      coords = [p % width1, i];
-    }
+    path.moveTo(p % width1, i);
 
     const p0 = p;
     let type = points[p];
@@ -448,21 +440,12 @@ function compileType3Glyph(imgData) {
         // set new type for "future hit"
         points[p] &= (type >> 2) | (type << 2);
       }
-
-      if (path) {
-        path.lineTo(p % width1, (p / width1) | 0);
-      } else {
-        coords.push(p % width1, (p / width1) | 0);
-      }
+      path.lineTo(p % width1, (p / width1) | 0);
 
       if (!points[p]) {
         --count;
       }
     } while (p0 !== p);
-
-    if (!path) {
-      outlines.push(coords);
-    }
     --i;
   }
 
@@ -475,18 +458,7 @@ function compileType3Glyph(imgData) {
     // the path shall be painted in [0..1]x[0..1] space
     c.scale(1 / width, -1 / height);
     c.translate(0, -height);
-    if (path) {
-      c.fill(path);
-    } else {
-      c.beginPath();
-      for (const o of outlines) {
-        c.moveTo(o[0], o[1]);
-        for (let l = 2, ll = o.length; l < ll; l += 2) {
-          c.lineTo(o[l], o[l + 1]);
-        }
-      }
-      c.fill();
-    }
+    c.fill(path);
     c.beginPath();
     c.restore();
   };