Merge pull request #2572 from mduan/issue2477

Make canvas transform matrix account for devicePixelRatio

src/canvas.js

@@ -46,6 +46,8 @@ function addContextCurrentTransform(ctx) {
   // If the context doesn't expose a `mozCurrentTransform`, add a JS based on.
   if (!ctx.mozCurrentTransform) {
     // Store the original context
+    ctx._scaleX = ctx._scaleX || 1.0;
+    ctx._scaleY = ctx._scaleY || 1.0;
     ctx._originalSave = ctx.save;
     ctx._originalRestore = ctx.restore;
     ctx._originalRotate = ctx.rotate;
@@ -53,7 +55,7 @@ function addContextCurrentTransform(ctx) {
     ctx._originalTranslate = ctx.translate;
     ctx._originalTransform = ctx.transform;
 
-    ctx._transformMatrix = [1, 0, 0, 1, 0, 0];
+    ctx._transformMatrix = [ctx._scaleX, 0, 0, ctx._scaleY, 0, 0];
     ctx._transformStack = [];
 
     Object.defineProperty(ctx, 'mozCurrentTransform', {

web/viewer.js

@@ -2078,6 +2078,9 @@ var PageView = function pageView(container, pdfPage, id, scale,
     }
 
     var ctx = canvas.getContext('2d');
+    // TODO(mack): use data attributes to store these
+    ctx._scaleX = outputScale.sx;
+    ctx._scaleY = outputScale.sy;
     ctx.save();
     ctx.fillStyle = 'rgb(255, 255, 255)';
     ctx.fillRect(0, 0, canvas.width, canvas.height);