PDF.js displays blurry plots in PDF documents, e.g.

http://arxiv.org/pdf/1202.5344v1.pdf

When viewed in Chrome or Adobe Acrobat all the plots show sharp-edged squares. When viewed in Preview or PDF.js, all the squares show as blurry pixelated blobs.

offsetY,
          scaleX,
          scaleY,
          subtype: group.smask.subtype,
          backdrop: group.smask.backdrop,
          transferMap: group.smask.transferMap || null,
          startTransformInverse: null, 
        });
      } else {
        
        
        currentCtx.setTransform(1, 0, 0, 1, 0, 0);
        currentCtx.translate(offsetX, offsetY);
        currentCtx.scale(scaleX, scaleY);
      }
      
      
      copyCtxState(currentCtx, groupCtx);
      this.ctx = groupCtx;
      this.setGState([
        ["BM", "source-over"],
        ["ca", 1],
        ["CA", 1],
      ]);
      this.groupStack.push(currentCtx);
      this.groupLevel++;
      
      this.current.activeSMask = null;
    }
    endGroup(group) {