implement add(x, y) and sub(x, y) in PVector (fixes #3593)

core/src/processing/core/PVector.java

@@ -460,6 +460,17 @@ public class PVector implements Serializable {
   }
 
 
+  /**
+   * @param x x component of the vector
+   * @param y y component of the vector
+   */
+  public PVector add(float x, float y) {
+    this.x += x;
+    this.y += y;
+    return this;
+  }
+
+
   /**
    * @param x x component of the vector
    * @param y y component of the vector
@@ -521,6 +532,17 @@ public class PVector implements Serializable {
   }
 
 
+  /**
+   * @param x the x component of the vector
+   * @param y the y component of the vector
+   */
+  public PVector sub(float x, float y) {
+    this.x -= x;
+    this.y -= y;
+    return this;
+  }
+
+
   /**
    * @param x the x component of the vector
    * @param y the y component of the vector
@@ -543,6 +565,7 @@ public class PVector implements Serializable {
     return sub(v1, v2, null);
   }
 
+
   /**
    * Subtract one vector from another and store in another vector
    * @param v1 the x, y, and z components of a PVector object

core/todo.txt

@@ -5,6 +5,8 @@ X Zero length string passed to TextLayout constructor
 X   https://github.com/processing/processing/issues/3487
 X improve speed of text(x, y, w, h) when using large strings with no spaces
 X   https://github.com/processing/processing/issues/211
+X implement add(x, y) and sub(x, y) in PVector
+X   https://github.com/processing/processing/issues/3593
 
 earlier
 X are we clear on sketchPath() for OS X?

todo.txt

@@ -7,6 +7,8 @@ X canceling "create folder, move sketch, and continue?" will cause crash
 X   throws an NPE and then forces a quit
 X   https://github.com/processing/processing/issues/3586
 X   also showError() there shouldn't die if other Java windows open
+_ move Platform into its own class?
+_   https://github.com/processing/processing/issues/2765
 
 api changes
 X Make fields and functions in PdeKeywords protected
@@ -45,8 +47,6 @@ _ mouse events (i.e. toggle breakpoint) seem to be firing twice
 
 
 3.0 final
-_ move Platform into its own class?
-_   https://github.com/processing/processing/issues/2765
 _ Contributions Manager UI design
 _   https://github.com/processing/processing/issues/3482
 _ Ready to add contributed example packages?