Merge pull request #713 from atom-ide-community/squashed-minimap-4upstream

Author: aminya

lib/canvas-layer.js

@@ -61,19 +61,25 @@ module.exports = class CanvasLayer {
   }
 
   copyToOffscreen () {
-    this.offscreenContext.drawImage(this.canvas, 0, 0)
+    if (this.canvas.width > 0 && this.canvas.height > 0) {
+      this.offscreenContext.drawImage(this.canvas, 0, 0)
+    }
   }
 
   copyFromOffscreen () {
-    this.context.drawImage(this.offscreenCanvas, 0, 0)
+    if (this.offscreenCanvas.width > 0 && this.offscreenCanvas.height > 0) {
+      this.context.drawImage(this.offscreenCanvas, 0, 0)
+    }
   }
 
   copyPartFromOffscreen (srcY, destY, height) {
-    this.context.drawImage(
-      this.offscreenCanvas,
-      0, srcY, this.offscreenCanvas.width, height,
-      0, destY, this.offscreenCanvas.width, height
-    )
+    if (this.offscreenCanvas.width > 0 && this.offscreenCanvas.height > 0) {
+      this.context.drawImage(
+        this.offscreenCanvas,
+        0, srcY, this.offscreenCanvas.width, height,
+        0, destY, this.offscreenCanvas.width, height
+      )
+    }
   }
 
   clearCanvas () {