test higher pixel densities in mask

Author: Papershine

test/unit/image/p5.Image.js

@@ -51,36 +51,40 @@ suite('p5.Image', function() {
   });
 
   suite('p5.Image.prototype.mask', function() {
-    test('it should mask the image', function() {
-      let img = myp5.createImage(10, 10);
-      img.loadPixels();
-      for (let i = 0; i < img.height; i++) {
-        for (let j = 0; j < img.width; j++) {
-          let alpha = i < 5 ? 255 : 0;
-          img.set(i, j, myp5.color(0, 0, 0, alpha));
+    for (const density of [1, 2]) {
+      test(`it should mask the image at pixel density ${density}`, function() {
+        let img = myp5.createImage(10, 10);
+        img.pixelDensity(density);
+        img.loadPixels();
+        for (let i = 0; i < img.height; i++) {
+          for (let j = 0; j < img.width; j++) {
+            let alpha = i < 5 ? 255 : 0;
+            img.set(i, j, myp5.color(0, 0, 0, alpha));
+          }
         }
-      }
-      img.updatePixels();
+        img.updatePixels();
 
-      let mask = myp5.createImage(10, 10);
-      mask.loadPixels();
-      for (let i = 0; i < mask.width; i++) {
-        for (let j = 0; j < mask.height; j++) {
-          let alpha = j < 5 ? 255 : 0;
-          mask.set(i, j, myp5.color(0, 0, 0, alpha));
+        let mask = myp5.createImage(10, 10);
+        mask.pixelDensity(density);
+        mask.loadPixels();
+        for (let i = 0; i < mask.width; i++) {
+          for (let j = 0; j < mask.height; j++) {
+            let alpha = j < 5 ? 255 : 0;
+            mask.set(i, j, myp5.color(0, 0, 0, alpha));
+          }
         }
-      }
-      mask.updatePixels();
+        mask.updatePixels();
 
-      img.mask(mask);
-      img.loadPixels();
-      for (let i = 0; i < img.width; i++) {
-        for (let j = 0; j < img.height; j++) {
-          let alpha = i < 5 && j < 5 ? 255 : 0;
-          assert.strictEqual(img.get(i, j)[3], alpha);
+        img.mask(mask);
+        img.loadPixels();
+        for (let i = 0; i < img.width; i++) {
+          for (let j = 0; j < img.height; j++) {
+            let alpha = i < 5 && j < 5 ? 255 : 0;
+            assert.strictEqual(img.get(i, j)[3], alpha);
+          }
         }
-      }
-    });
+      });
+    }
 
     test('it should mask the animated gif image', function() {
       const imagePath = 'unit/assets/nyan_cat.gif';