[orx-camera-2d] Add Camera2DManual

orx-camera/src/commonMain/kotlin/Camera2D.kt

@@ -6,6 +6,7 @@ import org.openrndr.MouseEvents
 import org.openrndr.Program
 import org.openrndr.draw.Drawer
 import org.openrndr.draw.RenderTarget
+import org.openrndr.draw.isolated
 import org.openrndr.events.Event
 import org.openrndr.math.Matrix44
 import org.openrndr.math.Vector2
@@ -23,6 +24,8 @@ import org.openrndr.math.transforms.buildTransform
 class Camera2D : Extension, ChangeEvents {
     override var enabled = true
 
+    private lateinit var program: Program
+    private var controlInitialized = false
     var view = Matrix44.IDENTITY
     var rotationCenter = Vector2.ZERO
 
@@ -38,6 +41,30 @@ class Camera2D : Extension, ChangeEvents {
     override val hasChanged: Boolean
         get() = dirty
 
+
+    /**
+     * Executes the provided drawing function in an isolated scope, preserving the current
+     * drawing state and then restoring it after the function is executed. The `ortho` projection
+     * and custom view transformation are applied during the isolated drawing session.
+     *
+     * @param function the drawing function to be applied within the isolated scope of the `Drawer`.
+     */
+    fun isolated(function: Drawer.() -> Unit) {
+        program.drawer.isolated {
+            program.drawer.ortho(RenderTarget.active)
+
+            program.drawer.view = this@Camera2D.view
+            program.drawer.function()
+        }
+    }
+
+    /**
+     * Configures the mouse interaction events for controlling the camera view and handling
+     * transformations such as translation, rotation, and scaling via mouse inputs.
+     *
+     * @param mouse the MouseEvents instance that provides mouse interaction data, including
+     *              button presses, dragging, and scrolling events.
+     */
     fun setupMouseEvents(mouse: MouseEvents) {
         mouse.buttonDown.listen {
             rotationCenter = it.position
@@ -76,10 +103,14 @@ class Camera2D : Extension, ChangeEvents {
                 dirty = true
             }
         }
+        controlInitialized = true
     }
 
     override fun setup(program: Program) {
-        setupMouseEvents(program.mouse)
+        this.program = program
+        if (!controlInitialized) {
+            setupMouseEvents(program.mouse)
+        }
     }
 
     override fun beforeDraw(drawer: Drawer, program: Program) {
@@ -94,4 +125,13 @@ class Camera2D : Extension, ChangeEvents {
     }
 }
 
-
+/**
+ * Creates a new instance of the Camera2D extension suitable for manual application.
+ *
+ * @return a configured Camera2D instance ready to be used with the calling Program.
+ */
+fun Program.Camera2DManual(): Camera2D {
+    val camera = Camera2D()
+    camera.setup(this)
+    return camera
+}