implement JRybyArt grid method in java, because we can

Author: monkstone

lib/jruby_art/helper_methods.rb

@@ -37,13 +37,8 @@ def perspektiv(
 
     # A nice method to run a given block for a grid.
     # Lifted from action_coding/Nodebox.
-    def grid(cols, rows, col_size = 1, row_size = 1)
-      (0...cols * rows).map do |i|
-        x = col_size * (i % cols)
-        y = row_size * i.div(cols)
-        yield x, y
-      end
-    end
+    # def grid(cols, rows, col_size = 1, row_size = 1) { |x, y| block_stuff }
+    # NB: now implemented in java
 
     # lerp_color takes three or four arguments, in Java that's two
     # different methods, one regular and one static, so:
@@ -181,7 +176,7 @@ def key_pressed?
 
     private
 
-    FIXNUM_COL = -> (x) { x.is_a?(Integer) } 
+    FIXNUM_COL = -> (x) { x.is_a?(Integer) }
     STRING_COL = -> (x) { x.is_a?(String) }
     FLOAT_COL = -> (x) { x.is_a?(Float) }
     # parse single argument color int/double/String

src/monkstone/MathToolModule.java

@@ -1,7 +1,8 @@
 /**
  * The purpose of this tool is to allow JRubyArt users to use an alternative
- * to processing.org map, lerp and norm methods in their sketches
- * Copyright (c) 2015-16 Martin Prout. This tool is free software; you can
+ * to processing.org map, lerp and norm methods in their sketches and to implement
+ * JRubyArt convenenience method grid(width, height, stepW, stepH) { |x, y| do stuff }
+ * Copyright (c) 2015-17 Martin Prout. This tool is free software; you can
  * redistribute it and/or modify it under the terms of the GNU Lesser General
  * Public License as published by the Free Software Foundation; either version
  * 2.1 of the License, or (at your option) any later version.
@@ -17,6 +18,7 @@
 import org.jruby.RubyRange;
 import org.jruby.anno.JRubyMethod;
 import org.jruby.anno.JRubyModule;
+import org.jruby.runtime.Block;
 import org.jruby.runtime.ThreadContext;
 import org.jruby.runtime.builtin.IRubyObject;
 
@@ -201,4 +203,35 @@ public static IRubyObject constrainValue(ThreadContext context, IRubyObject recv
             return args[1];
         }
     }
+
+    /**
+     * Provides JRubyArt grid method as a ruby module method
+     *
+     * @param context ThreadContext
+     * @param recv IRubyObject
+     * @param args array of args should be Fixnum
+     * @param block { |x, y| `do something` }
+     * @return nil
+     */
+    @JRubyMethod(name = "grid", rest = true, module = true)
+    public static IRubyObject createGrid(ThreadContext context, IRubyObject recv, IRubyObject[] args, Block block) {
+        int row = (Integer) args[0].toJava(Integer.class);
+        int column = (Integer) args[1].toJava(Integer.class);
+        int rowStep = 1;
+        int colStep = 1;
+        if (args.length == 4){
+        rowStep = (Integer) args[2].toJava(Integer.class);
+        colStep = (Integer) args[3].toJava(Integer.class);
+        }
+        if (block.isGiven()) {
+            for (int x = 0; x < row / rowStep; x++){
+                for (int y = 0; y < column / colStep; y++){
+                    block.yieldSpecific(context, context.runtime.newFixnum(x * rowStep), context.runtime.newFixnum(y * colStep));
+
+                }
+            }
+        }
+        return context.nil;
+
+    }
 }

test/math_tool_test.rb

@@ -76,4 +76,22 @@ def test_constrain
     assert_in_delta(constrain(xf[1], startf, lastf), 200.0, delta = 0.00001, msg = 'constrain to 0..200')
     assert_in_delta(constrain(xf[2], startf, lastf), 0.0, delta = 0.00001, msg = 'constrain to 0..200')
   end
+
+  def test_grid_one
+    array = []
+    grid(100, 100) { |x, y| array << [x, y] }
+    assert array[0].include?(0)
+    assert array[98].include?(0)
+    assert_equal array.length, 10_000
+    assert array[50].include?(50)
+  end
+
+  def test_grid_ten
+    array = []
+    grid(100, 100, 10, 10) { |x, y| array << [x, y] }
+    assert array[0].include?(0)
+    assert array[9].include?(90)
+    assert_equal array.length, 100
+    assert array[5].include?(50)
+  end
 end