Merge pull request #8266 from brendandahl/issue6652

Normalize blend mode names.

src/core/evaluator.js

@@ -217,6 +217,50 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
     }
   };
 
+  // Convert PDF blend mode names to HTML5 blend mode names.
+  function normalizeBlendMode(value) {
+    if (!isName(value)) {
+      return 'source-over';
+    }
+    switch (value.name) {
+      case 'Normal':
+      case 'Compatible':
+        return 'source-over';
+      case 'Multiply':
+        return 'multiply';
+      case 'Screen':
+        return 'screen';
+      case 'Overlay':
+        return 'overlay';
+      case 'Darken':
+        return 'darken';
+      case 'Lighten':
+        return 'lighten';
+      case 'ColorDodge':
+        return 'color-dodge';
+      case 'ColorBurn':
+        return 'color-burn';
+      case 'HardLight':
+        return 'hard-light';
+      case 'SoftLight':
+        return 'soft-light';
+      case 'Difference':
+        return 'difference';
+      case 'Exclusion':
+        return 'exclusion';
+      case 'Hue':
+        return 'hue';
+      case 'Saturation':
+        return 'saturation';
+      case 'Color':
+        return 'color';
+      case 'Luminosity':
+        return 'luminosity';
+    }
+    warn('Unsupported blend mode: ' + value.name);
+    return 'source-over';
+  }
+
   var deferred = Promise.resolve();
 
   var TILING_PATTERN = 1, SHADING_PATTERN = 2;
@@ -606,7 +650,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
             });
             break;
           case 'BM':
-            gStateObj.push([key, value]);
+            gStateObj.push([key, normalizeBlendMode(value)]);
             break;
           case 'SMask':
             if (isName(value, 'None')) {

src/display/canvas.js

@@ -950,20 +950,7 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
             this.ctx.globalAlpha = state[1];
             break;
           case 'BM':
-            if (value && value.name && (value.name !== 'Normal')) {
-              var mode = value.name.replace(/([A-Z])/g,
-                function(c) {
-                  return '-' + c.toLowerCase();
-                }
-              ).substring(1);
-              this.ctx.globalCompositeOperation = mode;
-              if (this.ctx.globalCompositeOperation !== mode) {
-                warn('globalCompositeOperation "' + mode +
-                     '" is not supported');
-              }
-            } else {
-              this.ctx.globalCompositeOperation = 'source-over';
-            }
+            this.ctx.globalCompositeOperation = value;
             break;
           case 'SMask':
             if (this.current.activeSMask) {
@@ -1010,7 +997,7 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
       copyCtxState(currentCtx, groupCtx);
       this.ctx = groupCtx;
       this.setGState([
-        ['BM', 'Normal'],
+        ['BM', 'source-over'],
         ['ca', 1],
         ['CA', 1]
       ]);
@@ -1885,7 +1872,7 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
       copyCtxState(currentCtx, groupCtx);
       this.ctx = groupCtx;
       this.setGState([
-        ['BM', 'Normal'],
+        ['BM', 'source-over'],
         ['ca', 1],
         ['CA', 1]
       ]);