[orx-shapes] Add Rectangle.grid

orx-shapes/src/demo/kotlin/DemoRectangleGrid.kt

@@ -0,0 +1,29 @@
+import org.openrndr.application
+import org.openrndr.color.ColorRGBa
+import org.openrndr.extensions.SingleScreenshot
+import org.openrndr.extra.shapes.grid
+
+fun main() {
+    application {
+        configure {
+            width = 800
+            height = 800
+        }
+        program {
+            if (System.getProperty("takeScreenshot") == "true") {
+                extend(SingleScreenshot()) {
+                    this.outputFile = System.getProperty("screenshotPath")
+                }
+            }
+            extend {
+                drawer.fill = ColorRGBa.WHITE.opacify(0.25)
+                drawer.stroke = ColorRGBa.PINK
+                val grid = drawer.bounds.grid(8, 4, 20.0, 20.0, -20.0, -20.0)
+                for (cell in grid.flatten()) {
+                    drawer.rectangle(cell)
+                    drawer.lineSegment(cell.position(0.0, 0.0), cell.position(1.0, 1.0))
+                }
+            }
+        }
+    }
+}

orx-shapes/src/main/kotlin/RectangleGrid.kt

@@ -0,0 +1,43 @@
+package org.openrndr.extra.shapes
+
+import org.openrndr.shape.Rectangle
+
+/**
+ * Splits [Rectangle] into a grid of [Rectangle]s
+ * @param columns the number of columns in the resulting grid
+ * @param rows the number of rows in the resulting grid
+ * @param marginX the unitless margin width
+ * @param marginY the unitless margin height
+ * @param gutterX the unitless gutter width, the horizontal space between grid cells
+ * @param gutterY the unitless gutter height, the vertical space between grid cells
+ */
+fun Rectangle.grid(
+    columns: Int,
+    rows: Int,
+    marginX: Double = 0.0,
+    marginY: Double = 0.0,
+    gutterX: Double = 0.0,
+    gutterY: Double = 0.0
+): List<List<Rectangle>> {
+
+    val totalWidth = width - marginX * 2.0
+    val totalHeight = height - marginY * 2.0
+
+    val totalGutterWidth = gutterX * (columns - 1).coerceAtLeast(0)
+    val totalGutterHeight = gutterY * (rows - 1).coerceAtLeast(0)
+
+    val cellWidth = ((totalWidth - totalGutterWidth) / columns).coerceAtLeast(0.0)
+    val cellHeight = ((totalHeight - totalGutterHeight) / rows).coerceAtLeast(0.0)
+
+    val cellSpaceX = cellWidth + gutterX
+    val cellSpaceY = cellHeight + gutterY
+
+    val x0 = x + marginX
+    val y0 = y + marginY
+
+    return (0 until rows).map { row ->
+        (0 until columns).map { column ->
+            Rectangle(x0 + column * cellSpaceX, y0 + row * cellSpaceY, cellWidth, cellHeight)
+        }
+    }
+}