Immediate Mode in Doodle Canvas

.scalafix.conf

@@ -1,4 +1,5 @@
 rules = [
   OrganizeImports
 ]
+OrganizeImports.removeUnused = false
 OrganizeImports.coalesceToWildcardImportThreshold = 5

canvas/src/main/scala/doodle/canvas/algebra/CanvasAlgebra.scala

@@ -29,16 +29,25 @@ final case class CanvasAlgebra(
     applyDrawing: Apply[CanvasDrawing] = Apply.apply[CanvasDrawing],
     functorDrawing: Functor[CanvasDrawing] = Apply.apply[CanvasDrawing]
 ) extends Path,
+      Raster,
       Shape,
       GenericDebug[CanvasDrawing],
       GenericLayout[CanvasDrawing],
+      GenericRaster[CanvasDrawing, Immediate],
+      GenericShape[CanvasDrawing],
       GenericSize[CanvasDrawing],
       GenericStyle[CanvasDrawing],
       GenericTransform[CanvasDrawing],
       GivenApply[CanvasDrawing],
       GivenFunctor[CanvasDrawing],
       doodle.algebra.Algebra {
   type Drawing[A] = doodle.canvas.Drawing[A]
+
+  override def empty: Finalized[CanvasDrawing, Unit] =
+    Finalized.leaf(_ =>
+      (BoundingBox.empty, Renderable.unit(CanvasDrawing.unit))
+    )
+
   implicit val drawingInstance: Monad[Drawing] =
     new Monad[Drawing] {
       def pure[A](x: A): Drawing[A] =
@@ -67,5 +76,4 @@ final case class CanvasAlgebra(
         )
       }
     }
-
 }

canvas/src/main/scala/doodle/canvas/algebra/CanvasDrawing.scala

@@ -16,6 +16,8 @@
 
 package doodle.canvas.algebra
 
+import doodle.algebra.generic.*
+
 import cats.Apply
 import doodle.algebra.generic.Fill
 import doodle.algebra.generic.Fill.ColorFill
@@ -36,6 +38,7 @@ import doodle.core.font.FontSize
 import doodle.core.font.FontStyle
 import doodle.core.font.FontWeight
 import org.scalajs.dom.CanvasRenderingContext2D
+import org.scalajs.dom.Path2D
 
 import scala.scalajs.js
 import scala.scalajs.js.JSConverters.*
@@ -44,6 +47,7 @@ import scala.scalajs.js.JSConverters.*
   * type `A` and has the side-effect of drawing on the canvas.
   */
 opaque type CanvasDrawing[A] = Function[CanvasRenderingContext2D, A]
+
 object CanvasDrawing {
   given Apply[CanvasDrawing] with {
     def ap[A, B](ff: CanvasDrawing[A => B])(
@@ -121,6 +125,21 @@ object CanvasDrawing {
     }
   }
 
+  def raster(width: Int, height: Int)(
+      f: Immediate => Unit
+  ): CanvasDrawing[Unit] = {
+    CanvasDrawing { ctx =>
+      val path = new Path2D()
+      val immediate = new ImmediateImpl(width, height, ctx, path)
+      f(immediate)
+    }
+  }
+
+  def text(text: String, x: Double, y: Double): CanvasDrawing[Unit] =
+    CanvasDrawing { ctx =>
+      ctx.fillText(text, x, y)
+    }
+
   def setFill(fill: Option[Fill]): CanvasDrawing[Unit] =
     fill.map(setFill).getOrElse(unit)