diff --git a/kallithea/public/js/graph.js b/kallithea/public/js/graph.js
--- a/kallithea/public/js/graph.js
+++ b/kallithea/public/js/graph.js
@@ -68,8 +68,9 @@ function BranchRenderer(canvas_id, conte
 		this.canvas.setAttribute('width',canvasWidth);
 		this.canvas.setAttribute('height',content.clientHeight);
 
-		// retina version needs to be scaled by 2x then halved via css
-		if (window.devicePixelRatio) {
+		// HiDPI version needs to be scaled by 2x then halved via css
+		// Note: Firefox on OS X fails scaling if the canvas height is more than 32k
+		if (window.devicePixelRatio && content.clientHeight * window.devicePixelRatio < 32768) {
 			this.canvas.setAttribute('width', canvasWidth * window.devicePixelRatio);
 			this.canvas.setAttribute('height', content.clientHeight * window.devicePixelRatio);
 			this.canvas.style.width = canvasWidth + "px";