Add mouse area layout

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

@@ -5,14 +5,8 @@ import scala.annotation.tailrec
 /** Input State to be used by the components. */
 sealed trait InputState:
 
-  /** Mouse X position, from the left */
-  def mouseX: Int
-
-  /** Mouse Y position, from the top */
-  def mouseY: Int
-
-  /** @param mouseDown whether the mouse is pressed */
-  def mouseDown: Boolean
+  /** Current Mouse state */
+  def mouseInput: InputState.MouseInput
 
   /** String generated from the keyboard inputs since the last frame. Usually this will be a single character.
     * A `\u0008` character is interpreted as a backspace.
@@ -45,63 +39,67 @@ sealed trait InputState:
   def clip(area: Rect): InputState
 
 object InputState:
-  /** Creates a new Input State
+
+  /** Creates a new InputState.
     *
     * @param mouseX mouse X position, from the left
     * @param mouseY mouse Y position, from the top
-    * @param mouseDown whether the body is pressed
+    * @param mousePressed whether the mouse is pressed
     * @param keyboardInput
     *   String generated from the keyboard inputs since the last frame. Usually this will be a single character.
     *   A `\u0008` character is interpreted as a backspace.
     */
   def apply(mouseX: Int, mouseY: Int, mouseDown: Boolean, keyboardInput: String): InputState =
-    InputState.Current(mouseX, mouseY, mouseDown, keyboardInput: String)
+    InputState.Current(InputState.MouseInput(mouseX, mouseY, mouseDown), keyboardInput)
+
+  /** Mouse position and button state.
+    *
+    * @param x mouse X position, from the left
+    * @param y mouse Y position, from the top
+    * @param isPressed whether the mouse is pressed
+    */
+  final case class MouseInput(x: Int, y: Int, isPressed: Boolean)
 
   /** Input state at the current point in time
     *
-    * @param mouseX mouse X position, from the left
-    * @param mouseY mouse Y position, from the top
-    * @param mouseDown whether the body is pressed
+    * @param mouseInput the current mouse state
     * @param keyboardInput
     *   String generated from the keyboard inputs since the last frame. Usually this will be a single character.
     *   A `\u0008` character is interpreted as a backspace.
     */
-  final case class Current(mouseX: Int, mouseY: Int, mouseDown: Boolean, keyboardInput: String) extends InputState:
+  final case class Current(mouseInput: InputState.MouseInput, keyboardInput: String) extends InputState:
 
     def clip(area: Rect): InputState.Current =
       if (area.isMouseOver(using this)) this
-      else this.copy(mouseX = Int.MinValue, mouseY = Int.MinValue)
+      else this.copy(mouseInput = mouseInput.copy(x = Int.MinValue, y = Int.MinValue))
 
   /** Input state at the current point in time and in the previous frame
     *
     * @param previousMouseX previous mouse X position, from the left
     * @param previousMouseY previous mouse Y position, from the top
     * @param mouseX mouse X position, from the left
     * @param mouseY mouse Y position, from the top
-    * @param mouseDown whether the body is pressed
+    * @param mouseDown whether the mouse is pressed
     * @param keyboardInput
     *   String generated from the keyboard inputs since the last frame. Usually this will be a single character.
     *   A `\u0008` character is interpreted as a backspace.
     */
   final case class Historical(
-      previousMouseX: Int,
-      previousMouseY: Int,
-      mouseX: Int,
-      mouseY: Int,
-      mouseDown: Boolean,
+      previousMouseInput: MouseInput,
+      mouseInput: MouseInput,
       keyboardInput: String
   ) extends InputState:
 
     /** How much the mouse moved in the X axis */
     lazy val deltaX: Int =
-      if (previousMouseX == Int.MinValue || mouseX == Int.MinValue) 0
-      else mouseX - previousMouseX
+      if (previousMouseInput.x == Int.MinValue || mouseInput.x == Int.MinValue) 0
+      else mouseInput.x - previousMouseInput.x
 
     /** How much the mouse moved in the Y axis */
     lazy val deltaY: Int =
-      if (previousMouseY == Int.MinValue || mouseY == Int.MinValue) 0
-      else mouseY - previousMouseY
+      if (previousMouseInput.y == Int.MinValue || mouseInput.y == Int.MinValue) 0
+      else mouseInput.y - previousMouseInput.y
 
     def clip(area: Rect): InputState.Historical =
       if (area.isMouseOver(using this)) this
-      else this.copy(mouseX = Int.MinValue, mouseY = Int.MinValue)
+      else this.copy(mouseInput = mouseInput.copy(x = Int.MinValue, y = Int.MinValue))

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

@@ -25,10 +25,10 @@ object InterIm extends api.Primitives with api.Layouts with api.Components with
     uiContext.currentZ = 0
     uiContext.hotItem = None
     val historicalInputState = uiContext.pushInputState(inputState)
-    if (inputState.mouseDown) uiContext.selectedItem = None
+    if (inputState.mouseInput.isPressed) uiContext.selectedItem = None
     // run
     val res = run(using historicalInputState, uiContext)
     // finish
-    if (!historicalInputState.mouseDown) uiContext.activeItem = None
+    if (!historicalInputState.mouseInput.isPressed) uiContext.activeItem = None
     // return
     (uiContext.getOrderedOps(), res)

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

@@ -21,7 +21,7 @@ final case class Rect(x: Int, y: Int, w: Int, h: Int):
   /** Checks if the mouse is over this area.
     */
   def isMouseOver(using inputState: InputState): Boolean =
-    !(inputState.mouseX < x || inputState.mouseY < y || inputState.mouseX >= x + w || inputState.mouseY >= y + h)
+    !(inputState.mouseInput.x < x || inputState.mouseInput.y < y || inputState.mouseInput.x >= x + w || inputState.mouseInput.y >= y + h)
 
   /** Translates the area to another position.
     */

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

@@ -23,7 +23,7 @@ final class UiContext private (
   ): UiContext.ItemStatus =
     if (area.isMouseOver && hotItem.forall((hotZ, _) => hotZ <= currentZ))
       hotItem = Some(currentZ -> id)
-      if (!passive && (activeItem == None || activeItem == Some(id)) && inputState.mouseDown)
+      if (!passive && (activeItem == None || activeItem == Some(id)) && inputState.mouseInput.isPressed)
         activeItem = Some(id)
         selectedItem = Some(id)
     UiContext.ItemStatus(hotItem.map(_._2) == Some(id), activeItem == Some(id), selectedItem == Some(id))
@@ -33,11 +33,10 @@ final class UiContext private (
 
   private[interim] def pushInputState(inputState: InputState): InputState.Historical =
     val history = InputState.Historical(
-      previousMouseX = previousInputState.map(_.mouseX).getOrElse(Int.MinValue),
-      previousMouseY = previousInputState.map(_.mouseY).getOrElse(Int.MinValue),
-      mouseX = inputState.mouseX,
-      mouseY = inputState.mouseY,
-      mouseDown = inputState.mouseDown,
+      previousMouseInput = previousInputState
+        .map(_.mouseInput)
+        .getOrElse(InputState.MouseInput(Int.MinValue, Int.MinValue, false)),
+      mouseInput = inputState.mouseInput,
       keyboardInput = inputState.keyboardInput
     )
     previousInputState = Some(inputState)

core/src/main/scala/eu/joaocosta/interim/api/Components.scala

@@ -36,7 +36,7 @@ trait Components:
     val buttonArea = skin.buttonArea(area)
     val itemStatus = UiContext.registerItem(id, buttonArea)
     skin.renderButton(area, label, itemStatus)
-    itemStatus.hot && itemStatus.active && summon[InputState].mouseDown == false
+    itemStatus.hot && itemStatus.active && summon[InputState].mouseInput.isPressed == false
 
   /** Checkbox component. Returns true if it's enabled, false otherwise.
     */
@@ -46,7 +46,7 @@ trait Components:
         val checkboxArea = skin.checkboxArea(area)
         val itemStatus   = UiContext.registerItem(id, checkboxArea)
         skin.renderCheckbox(area, value.get, itemStatus)
-        if (itemStatus.hot && itemStatus.active && summon[InputState].mouseDown == false) value.modify(!_)
+        if (itemStatus.hot && itemStatus.active && summon[InputState].mouseInput.isPressed == false) value.modify(!_)
         value.get
 
   /** Radio button component. Returns value currently selected.
@@ -65,7 +65,7 @@ trait Components:
       def applyRef(value: Ref[T]): Component[T] =
         val buttonArea = skin.buttonArea(area)
         val itemStatus = UiContext.registerItem(id, buttonArea)
-        if (itemStatus.hot && itemStatus.active && summon[InputState].mouseDown == false)
+        if (itemStatus.hot && itemStatus.active && summon[InputState].mouseInput.isPressed == false)
           value := buttonValue
         if (value.get == buttonValue) skin.renderButton(area, label, itemStatus.copy(hot = true, active = true))
         else skin.renderButton(area, label, itemStatus)
@@ -118,11 +118,11 @@ trait Components:
         skin.renderSlider(area, min, clampedValue, max, itemStatus)
         if (itemStatus.active)
           if (area.w > area.h)
-            val mousePos = summon[InputState].mouseX - sliderArea.x - sliderSize / 2
+            val mousePos = summon[InputState].mouseInput.x - sliderArea.x - sliderSize / 2
             val maxPos   = sliderArea.w - sliderSize
             value := math.max(min, math.min(min + (mousePos * range) / maxPos, max))
           else
-            val mousePos = summon[InputState].mouseY - sliderArea.y - sliderSize / 2
+            val mousePos = summon[InputState].mouseInput.y - sliderArea.y - sliderSize / 2
             val maxPos   = sliderArea.h - sliderSize
             value := math.max(min, math.min((mousePos * range) / maxPos, max))
         value.get

core/src/main/scala/eu/joaocosta/interim/api/Layouts.scala

@@ -121,3 +121,16 @@ trait Layouts:
         currentW -= absWidth + padding
         area.copy(x = areaX, w = absWidth)
     body(generateRect)
+
+  /** Handle mouse events inside a specified area.
+    *
+    * The body receives an optional MouseInput with the coordinates adjusted to be relative
+    * to the enclosing area.
+    * If the mouse is outside of the area, the body receives None.
+    */
+  final def mouseArea[T](area: Rect)(body: Option[InputState.MouseInput] => T)(using inputState: InputState): T =
+    body(
+      Option.when(area.isMouseOver)(
+        inputState.mouseInput.copy(x = inputState.mouseInput.x - area.x, y = inputState.mouseInput.y - area.y)
+      )
+    )

core/src/test/scala/eu/joaocosta/interim/api/LayoutsSpec.scala

@@ -87,3 +87,10 @@ class LayoutsSpec extends munit.FunSuite:
     val expected =
       Vector(Rect(10, 10, 16, 100), Rect(78, 10, 32, 100), Rect(34, 10, 36, 100))
     assertEquals(areas, expected)
+
+  test("mouseArea passes un updated mouse input"):
+    val inputState = InputState(10, 10, false, "")
+    val inArea     = Layouts.mouseArea(Rect(5, 5, 10, 10))(identity)(using inputState)
+    assertEquals(inArea, Some(InputState.MouseInput(5, 5, false)))
+    val outsideArea = Layouts.mouseArea(Rect(5, 5, 1, 1))(identity)(using inputState)
+    assertEquals(outsideArea, None)