From a201a714427e1ab186fb2e79f3dad0b92c66c2fb Mon Sep 17 00:00:00 2001
From: Ngoc Doan <ndoan@soka.edu>
Date: Sat, 17 May 2025 04:01:48 -0700
Subject: [PATCH] Add error check for pixelDesity in mask()

---
 core/src/processing/core/PImage.java | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/core/src/processing/core/PImage.java b/core/src/processing/core/PImage.java
index 666061ee9..e464058c2 100644
--- a/core/src/processing/core/PImage.java
+++ b/core/src/processing/core/PImage.java
@@ -840,6 +840,15 @@ public void mask(int[] maskArray) {  // ignore
    */
   public void mask(PImage img) {
     img.loadPixels();
+    this.loadPixels();
+    if (this.pixelWidth != img.pixelWidth || this.pixelHeight != img.pixelHeight) {
+      if (this.pixelDensity != img.pixelDensity) {
+        throw new IllegalArgumentException("mask() requires the mask image to have the same pixel size after adjusting for pixelDensity.");
+      }
+      else if (this.width != img.width || this.height != img.height) {
+        throw new IllegalArgumentException("mask() requires the mask image to have the same width and height.");
+      }
+    }
     mask(img.pixels);
   }