mozilla/pdf.js — pull request #1763 by yurydelendik (2012-05-27 18:54:00+00:00)
Title: Type3 smoothing: pre-scale image in the paintImageMaskXObject

Per MDN (https://developer.mozilla.org/en/Canvas_tutorial/Using_images#drawImage_example_2):

`Images can become blurry when scaling up or grainy if they're scaled down too much. Scaling is probably best not done if you've got some text in it which needs to remain legible.`

Using the simple algorithm to pre-scale the image.