adding pixel scaling toggle issue #452

Author: Lauren McCarthy

lib/p5.js

@@ -2105,6 +2105,14 @@ var environment = function (require, core, constants) {
         }
       }
     };
+    p5.prototype.devicePixelScaling = function (val) {
+      if (val) {
+        this._pixelDensity = window.devicePixelRatio || 1;
+      } else {
+        this._pixelDensity = 1;
+      }
+      this.resizeCanvas(this.width, this.height);
+    };
     function launchFullscreen(element) {
       var enabled = document.fullscreenEnabled || document.webkitFullscreenEnabled || document.mozFullScreenEnabled || document.msFullscreenEnabled;
       if (!enabled) {