Add mouse hover & click handling

src/main/kotlin/net/shadowfacts/asmr/TestCacaoScreen.kt

@@ -5,8 +5,11 @@ import net.shadowfacts.cacao.CacaoScreen
 import net.shadowfacts.cacao.view.View
 import net.shadowfacts.cacao.Window
 import net.shadowfacts.cacao.geometry.Axis
+import net.shadowfacts.cacao.geometry.Point
 import net.shadowfacts.cacao.geometry.Size
 import net.shadowfacts.cacao.util.Color
+import net.shadowfacts.cacao.util.MouseButton
+import net.shadowfacts.cacao.util.RenderHelper
 import net.shadowfacts.cacao.view.StackView
 
 /**
@@ -31,11 +34,29 @@ class TestCacaoScreen: CacaoScreen() {
 				intrinsicContentSize = Size(50.0, 50.0)
 				backgroundColor = Color(0x0000ff)
 			})
+			val purple = blue.addSubview(object: View() {
+				init {
+					intrinsicContentSize = Size(25.0, 25.0)
+					backgroundColor = Color(0x800080)
+				}
+
+				override fun mouseClicked(point: Point, mouseButton: MouseButton) {
+					println("hello world")
+				}
+
+				override fun drawContent(mouse: Point, delta: Float) {
+					if (mouse in bounds) {
+						RenderHelper.fill(bounds, Color.WHITE)
+					}
+				}
+			})
 
 			solver.dsl {
 				stack.topAnchor equalTo 50
 				stack.leftAnchor equalTo 50
 				stack.rightAnchor equalTo 150
+				purple.centerXAnchor equalTo blue.centerXAnchor
+				purple.centerYAnchor equalTo blue.centerYAnchor
 			}
 
 			layout()

src/main/kotlin/net/shadowfacts/cacao/CacaoScreen.kt

@@ -3,6 +3,7 @@ package net.shadowfacts.cacao
 import net.minecraft.client.gui.screen.Screen
 import net.minecraft.network.chat.TextComponent
 import net.shadowfacts.cacao.geometry.Point
+import net.shadowfacts.cacao.util.MouseButton
 import java.util.*
 
 /**
@@ -40,4 +41,11 @@ open class CacaoScreen: Screen(TextComponent("CacaoScreen")) {
 		}
 	}
 
+	override fun mouseClicked(mouseX: Double, mouseY: Double, button: Int): Boolean {
+		val window = windows.lastOrNull()
+		window?.mouseClicked(Point(mouseX, mouseY), MouseButton.fromMC(button))
+
+		return false
+	}
+
 }

src/main/kotlin/net/shadowfacts/cacao/Window.kt

@@ -1,6 +1,7 @@
 package net.shadowfacts.cacao
 
 import net.shadowfacts.cacao.geometry.Point
+import net.shadowfacts.cacao.util.MouseButton
 import net.shadowfacts.cacao.view.View
 import no.birkett.kiwi.Solver
 import java.util.*
@@ -40,6 +41,17 @@ class Window {
 		return view
 	}
 
+	/**
+	 * Attempts to find a top level view of this window that contains the given point.
+	 * If there are multiple overlapping views, which one this method returns is undefined.
+	 *
+	 * @param point The point to find views at, in the coordinate system of the window.
+	 * @return The view, if any, that contains the given point.
+	 */
+	fun viewAtPoint(point: Point): View? {
+		return views.firstOrNull { point in it.frame }
+	}
+
 	/**
 	 * Instructs the solver to solve all of the provided constraints.
 	 * Should be called after the view hierarchy is setup.
@@ -57,7 +69,25 @@ class Window {
 	 * @param delta The time elapsed since the last frame.
 	 */
 	fun draw(mouse: Point, delta: Float) {
-		views.forEach(View::draw)
+		views.forEach {
+			val mouseInView = Point(mouse.x - it.frame.left, mouse.y - it.frame.top)
+			it.draw(mouseInView, delta)
+		}
+	}
+
+	/**
+	 * Called when a mouse button is clicked and this is the active window.
+	 * This method is called by [CacaoScreen] and generally shouldn't be called directly.
+	 *
+	 * @param point The point in the window of the click.
+	 * @param mouseButton The mouse button that was used to click.
+	 */
+	fun mouseClicked(point: Point, mouseButton: MouseButton) {
+		val view = viewAtPoint(point)
+		if (view != null) {
+			val pointInView = Point(point.x - view.frame.left, point.y - view.frame.top)
+			view.mouseClicked(pointInView, mouseButton)
+		}
 	}
 
 }

src/main/kotlin/net/shadowfacts/cacao/geometry/Rect.kt

@@ -34,4 +34,8 @@ data class Rect(val left: Double, val top: Double, val width: Double, val height
 		Size(width, height)
 	}
 
+	operator fun contains(point: Point): Boolean {
+		return point.x in left..right && point.y in top..bottom
+	}
+
 }

src/main/kotlin/net/shadowfacts/cacao/util/MouseButton.kt

@@ -0,0 +1,18 @@
+package net.shadowfacts.cacao.util
+
+/**
+ * @author shadowfacts
+ */
+enum class MouseButton {
+	LEFT, RIGHT, MIDDLE;
+
+	companion object {
+		fun fromMC(button: Int): MouseButton {
+			return when (button) {
+				1 -> RIGHT
+				2 -> MIDDLE
+				else -> LEFT
+			}
+		}
+	}
+}

src/main/kotlin/net/shadowfacts/cacao/util/RenderHelper.kt

@@ -1,20 +1,49 @@
 package net.shadowfacts.cacao.util
 
+import com.mojang.blaze3d.platform.GlStateManager
 import net.minecraft.client.gui.DrawableHelper
 import net.shadowfacts.cacao.geometry.Rect
 
 /**
  * Helper methods for rendering using Minecraft's utilities from Cacao views.
+ * For unit testing, all drawing and OpenGL interaction can be disabled by setting the `cacao.drawing.disabled` JVM property to `true`.
  *
  * @author shadowfacts
  */
 object RenderHelper {
 
+	private val disabled = (System.getProperty("cacao.drawing.disabled") ?: "false").toBoolean()
+
 	/**
 	 * Draws a solid [rect] filled with the given [color].
 	 */
 	fun fill(rect: Rect, color: Color) {
+		if (disabled) return
 		DrawableHelper.fill(rect.left.toInt(), rect.top.toInt(), rect.right.toInt(), rect.bottom.toInt(), color.argb)
 	}
 
+	/**
+	 * @see org.lwjgl.opengl.GL11.glPushMatrix
+	 */
+	fun pushMatrix() {
+		if (disabled) return
+		GlStateManager.pushMatrix()
+	}
+
+	/**
+	 * @see org.lwjgl.opengl.GL11.glPopMatrix
+	 */
+	fun popMatrix() {
+		if (disabled) return
+		GlStateManager.popMatrix()
+	}
+
+	/**
+	 * @see org.lwjgl.opengl.GL11.glTranslated
+	 */
+	fun translate(x: Double, y: Double, z: Double = 0.0) {
+		if (disabled) return
+		GlStateManager.translated(x, y, z)
+	}
+
 }

src/main/kotlin/net/shadowfacts/cacao/view/Label.kt

@@ -2,6 +2,7 @@ package net.shadowfacts.cacao.view
 
 import net.minecraft.client.MinecraftClient
 import net.minecraft.client.font.TextRenderer
+import net.shadowfacts.cacao.geometry.Point
 import net.shadowfacts.cacao.geometry.Size
 import net.shadowfacts.cacao.util.Color
 
@@ -42,7 +43,7 @@ class Label(text: String): View() {
 		intrinsicContentSize = Size(width.toDouble(), height.toDouble())
 	}
 
-	override fun drawContent() {
+	override fun drawContent(mouse: Point, delta: Float) {
 		textRenderer.draw(text, 0f, 0f, textColor.argb)
 	}
 

src/main/kotlin/net/shadowfacts/cacao/view/View.kt

@@ -6,6 +6,7 @@ import net.shadowfacts.cacao.LayoutVariable
 import net.shadowfacts.cacao.geometry.*
 import net.shadowfacts.cacao.util.Color
 import net.shadowfacts.cacao.util.LowestCommonAncestor
+import net.shadowfacts.cacao.util.MouseButton
 import net.shadowfacts.cacao.util.RenderHelper
 import no.birkett.kiwi.Constraint
 import no.birkett.kiwi.Solver
@@ -137,6 +138,17 @@ open class View {
 		return view
 	}
 
+	/**
+	 * Attempts to find a subview which contains the given point.
+	 * If multiple subviews contain the given point, which one this method returns is undefined.
+	 *
+	 * @param point The point to find a subview for, in the coordinate system of this view.
+	 * @return The view, if any, that contains the given point.
+	 */
+	fun subviewAtPoint(point: Point): View? {
+		return subviews.firstOrNull { point in it.frame }
+	}
+
 	/**
 	 * Called when this view was added to a view hierarchy.
 	 * If overridden, the super-class method must be called.
@@ -191,26 +203,51 @@ open class View {
 	 * Called to draw this view.
 	 * This method should not be called directly, it is called by the parent view/window.
 	 * This method may not be overridden, use [drawContent] to draw any custom content.
+	 *
+	 * @param mouse The position of the mouse in the coordinate system of this view.
+	 * @param delta The time since the last frame.
 	 */
-	fun draw() {
-		GlStateManager.pushMatrix()
-		GlStateManager.translated(frame.left, frame.top, 0.0)
+	fun draw(mouse: Point, delta: Float) {
+		RenderHelper.pushMatrix()
+		RenderHelper.translate(frame.left, frame.top, 0.0)
 
 		RenderHelper.fill(bounds, backgroundColor)
 
-		drawContent()
+		drawContent(mouse, delta)
 
-		subviews.forEach(View::draw)
+		subviews.forEach {
+			val mouseInView = convert(mouse, to = it)
+			it.draw(mouseInView, delta)
+		}
 
-		GlStateManager.popMatrix()
+		RenderHelper.popMatrix()
 	}
 
 	/**
 	 * Called during [draw] to draw content that's part of this view.
 	 * During this method, the OpenGL coordinate system has been translated so the origin is at the top left corner
 	 * of this view. Be careful not to translate additionally, and not to draw outside the [bounds] of the view.
+	 *
+	 * @param mouse The position of the mouse in the coordinate system of this view.
+	 * @param delta The time since the last frame.
 	 */
-	open fun drawContent() {}
+	open fun drawContent(mouse: Point, delta: Float) {}
+
+	/**
+	 * Called when this view is clicked. May delegate to [subviews].
+	 * If overridden, the super-class method does not have to be called. Intentionally not calling it may be used
+	 * to prevent [subviews] from receiving click events.
+	 *
+	 * @param point The point in the coordinate system of this view that the mouse was clicked.
+	 * @param mouseButton The mouse button used to click.
+	 */
+	open fun mouseClicked(point: Point, mouseButton: MouseButton) {
+		val view = subviewAtPoint(point)
+		if (view != null) {
+			val pointInView = convert(point, to = view)
+			view.mouseClicked(pointInView, mouseButton)
+		}
+	}
 
 	/**
 	 * Converts the given point in this view's coordinate system to the coordinate system of another view or the window.

src/test/kotlin/net/shadowfacts/cacao/view/ViewClickTests.kt

@@ -0,0 +1,98 @@
+package net.shadowfacts.cacao.view
+
+import net.shadowfacts.cacao.Window
+import net.shadowfacts.cacao.geometry.Point
+import net.shadowfacts.cacao.geometry.Rect
+import net.shadowfacts.cacao.util.MouseButton
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import java.util.concurrent.CompletableFuture
+
+/**
+ * @author shadowfacts
+ */
+class ViewClickTests {
+
+	lateinit var window: Window
+
+	@BeforeEach
+	fun setup() {
+		window = Window()
+	}
+
+	@Test
+	fun testClickInsideRootView() {
+		val mouse = CompletableFuture<Point>()
+		window.addView(object: View() {
+			init {
+				frame = Rect(50.0, 50.0, 100.0, 100.0)
+			}
+
+			override fun mouseClicked(point: Point, mouseButton: MouseButton) {
+				mouse.complete(point)
+			}
+		})
+		window.mouseClicked(Point(75.0, 75.0), MouseButton.LEFT)
+
+		assertEquals(Point(25.0, 25.0), mouse.getNow(null))
+	}
+
+	@Test
+	fun testClickOutsideRootView() {
+		val clicked = CompletableFuture<Boolean>()
+		window.addView(object: View() {
+			init {
+				frame = Rect(50.0, 50.0, 100.0, 100.0)
+			}
+
+			override fun mouseClicked(point: Point, mouseButton: MouseButton) {
+				clicked.complete(true)
+			}
+		})
+		window.mouseClicked(Point(25.0, 25.0), MouseButton.LEFT)
+
+		assertFalse(clicked.getNow(false))
+	}
+
+	@Test
+	fun testClickInsideNestedView() {
+		val mouse = CompletableFuture<Point>()
+		val root = window.addView(View().apply {
+			frame = Rect(50.0, 50.0, 100.0, 100.0)
+		})
+		root.addSubview(object: View() {
+			init {
+				frame = Rect(25.0, 25.0, 50.0, 50.0)
+			}
+
+			override fun mouseClicked(point: Point, mouseButton: MouseButton) {
+				mouse.complete(point)
+			}
+		})
+		window.mouseClicked(Point(100.0, 100.0), MouseButton.LEFT)
+
+		assertEquals(Point(25.0, 25.0), mouse.getNow(null))
+	}
+
+	@Test
+	fun testClickOutsideNestedView() {
+		val clicked = CompletableFuture<Boolean>()
+		val root = window.addView(View().apply {
+			frame = Rect(50.0, 50.0, 100.0, 100.0)
+		})
+		root.addSubview(object: View() {
+			init {
+				frame = Rect(25.0, 25.0, 50.0, 50.0)
+			}
+
+			override fun mouseClicked(point: Point, mouseButton: MouseButton) {
+				clicked.complete(true)
+			}
+		})
+		window.mouseClicked(Point(0.0, 0.0), MouseButton.LEFT)
+
+		assertFalse(clicked.getNow(false))
+	}
+
+}

src/test/kotlin/net/shadowfacts/cacao/view/ViewHoverTests.kt

@@ -0,0 +1,72 @@
+package net.shadowfacts.cacao.view
+
+import net.shadowfacts.cacao.Window
+import net.shadowfacts.cacao.geometry.Point
+import net.shadowfacts.cacao.geometry.Rect
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.BeforeAll
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import java.util.concurrent.CompletableFuture
+
+/**
+ * @author shadowfacts
+ */
+class ViewHoverTests {
+
+	lateinit var window: Window
+
+	companion object {
+		@BeforeAll
+		@JvmStatic
+		fun setupAll() {
+			System.setProperty("cacao.drawing.disabled", "true")
+		}
+	}
+
+	@BeforeEach
+	fun setup() {
+		window = Window()
+	}
+
+	@Test
+	fun testHoverRootView() {
+		val point = CompletableFuture<Point>()
+		window.addView(object: View() {
+			init {
+				frame = Rect(50.0, 50.0, 100.0, 100.0)
+				bounds = Rect(0.0, 0.0, 100.0, 100.0)
+			}
+
+			override fun drawContent(mouse: Point, delta: Float) {
+				point.complete(mouse)
+			}
+		})
+		window.draw(Point(75.0, 75.0), 0f)
+
+		assertEquals(Point(25.0, 25.0), point.getNow(null))
+	}
+
+	@Test
+	fun testHoverNestedView() {
+		val point = CompletableFuture<Point>()
+		val root = window.addView(View().apply {
+			frame = Rect(50.0, 50.0, 100.0, 100.0)
+			bounds = Rect(0.0, 0.0, 100.0, 100.0)
+		})
+		root.addSubview(object: View() {
+			init {
+				frame = Rect(25.0, 25.0, 50.0, 50.0)
+				bounds = Rect(0.0, 0.0, 50.0, 50.0)
+			}
+
+			override fun drawContent(mouse: Point, delta: Float) {
+				point.complete(mouse)
+			}
+		})
+		window.draw(Point(100.0, 100.0), 0f)
+
+		assertEquals(Point(25.0, 25.0), point.getNow(null))
+	}
+
+}