Merge pull request #67 from JD557/center-rect

Add centerAt method to Rect

core/src/main/scala/eu/joaocosta/interim/Rect.scala

@@ -9,10 +9,12 @@ import scala.annotation.targetName
   * Alternatively, (x1, y1) is the top left coordinate and (x2, y2) is the bottom right one.
   */
 final case class Rect(x: Int, y: Int, w: Int, h: Int):
-  def x1 = x
-  def y1 = y
-  def x2 = x + w
-  def y2 = y + h
+  def x1      = x
+  def y1      = y
+  def x2      = x + w
+  def y2      = y + h
+  def centerX = x + w / 2
+  def centerY = y + h / 2
 
   /** Returns true if the rectangle has no area
     */
@@ -33,6 +35,10 @@ final case class Rect(x: Int, y: Int, w: Int, h: Int):
   def resize(dw: Int, dh: Int): Rect =
     copy(w = w + dw, h = h + dh)
 
+  /** Centers this rectangle at the defined position. */
+  def centerAt(x: Int, y: Int): Rect =
+    copy(x = x - w / 2, y = y - h / 2)
+
   /** Shrinks this area by removing `size` pixels from each side.
     */
   def shrink(size: Int): Rect =

core/src/test/scala/eu/joaocosta/interim/RectSpec.scala

@@ -2,6 +2,15 @@ package eu.joaocosta.interim
 
 class RectSpec extends munit.FunSuite:
 
+  test("compute helper positions"):
+    val rect = Rect(10, 15, 10, 20)
+    assertEquals(rect.x1, 10)
+    assertEquals(rect.x2, 20)
+    assertEquals(rect.y1, 15)
+    assertEquals(rect.y2, 35)
+    assertEquals(rect.centerX, 15)
+    assertEquals(rect.centerY, 25)
+
   test("isMouseOver detects collisions with the mouse"):
     val rect = Rect(10, 10, 10, 10)
     assertEquals(rect.isMouseOver(using InputState(0, 0, false, "")), false)