Support clearing of drawings in library (lispkit draw).

Author: objecthub

Sources/LispKit/Graphics/Drawing.swift

@@ -54,6 +54,7 @@ public final class Drawing: NativeObject {
   /// Appends a new drawing instruction.
   @discardableResult public func append(_ instruction: DrawingInstruction) -> Bool {
     switch instruction {
+      // Do not allow recursive dependencies
       case .inline(let drawing), .include(let drawing, _):
         if drawing.includes(self) {
           return false
@@ -65,6 +66,11 @@ public final class Drawing: NativeObject {
     return true
   }
 
+  /// Clears all drawing instructions
+  public func clear() {
+    self.instructions.removeAll()
+  }
+  
   /// Draws the drawing to the current graphics context clipped to a given shape. The drawing is
   /// put into a new transparency layer. Upon exit, the previous graphics state is being
   /// restored.

Sources/LispKit/Graphics/Drawing_iOS.swift

@@ -56,6 +56,7 @@ public final class Drawing: NativeObject {
   /// Appends a new drawing instruction.
   @discardableResult public func append(_ instruction: DrawingInstruction) -> Bool {
     switch instruction {
+      // Do not allow recursive dependencies
       case .inline(let drawing), .include(let drawing, _):
         if drawing.includes(self) {
           return false
@@ -67,6 +68,11 @@ public final class Drawing: NativeObject {
     return true
   }
 
+  /// Clears all drawing instructions
+  public func clear() {
+    self.instructions.removeAll()
+  }
+  
   /// Draws the drawing to the current graphics context clipped to a given shape. The drawing is
   /// put into a new transparency layer. Upon exit, the previous graphics state is being
   /// restored.

Sources/LispKit/Graphics/Shape.swift

@@ -143,6 +143,7 @@ public final class Shape: NativeObject {
   @discardableResult public func append(_ constructor: ShapeConstructor) -> Bool {
     if case .include(let other) = constructor {
       other.owners.compact()
+      // Do not allow recursive dependencies
       if other.includes(self) {
         return false
       }

Sources/LispKit/Primitives/DrawingLibrary.swift

@@ -119,6 +119,7 @@ public final class DrawingLibrary: NativeLibrary {
     self.define(Procedure("drawing?", isDrawing))
     self.define(Procedure("make-drawing", makeDrawing))
     self.define(Procedure("copy-drawing", copyDrawing))
+    self.define(Procedure("clear-drawing", clearDrawing))
     self.define(Procedure("set-color", setColor))
     self.define(Procedure("set-fill-color", setFillColor))
     self.define(Procedure("set-line-width", setLineWidth))
@@ -406,6 +407,11 @@ public final class DrawingLibrary: NativeLibrary {
     return .object(Drawing(copy: try self.drawing(from: drawing)))
   }
 
+  private func clearDrawing(drawing: Expr) throws -> Expr {
+    try self.drawing(from: drawing).clear()
+    return .void
+  }
+  
   private func setColor(color: Expr, drawing: Expr?) throws -> Expr {
     try self.drawing(from: drawing).append(.setStrokeColor(try self.color(from: color)))
     return .void

Sources/LispKit/Primitives/DrawingLibrary_iOS.swift

@@ -115,6 +115,7 @@ public final class DrawingLibrary: NativeLibrary {
     self.define(Procedure("drawing?", isDrawing))
     self.define(Procedure("make-drawing", makeDrawing))
     self.define(Procedure("copy-drawing", copyDrawing))
+    self.define(Procedure("clear-drawing", clearDrawing))
     self.define(Procedure("set-color", setColor))
     self.define(Procedure("set-fill-color", setFillColor))
     self.define(Procedure("set-line-width", setLineWidth))
@@ -385,6 +386,11 @@ public final class DrawingLibrary: NativeLibrary {
     return .object(Drawing(copy: try self.drawing(from: drawing)))
   }
 
+  private func clearDrawing(drawing: Expr) throws -> Expr {
+    try self.drawing(from: drawing).clear()
+    return .void
+  }
+  
   private func setColor(color: Expr, drawing: Expr?) throws -> Expr {
     try self.drawing(from: drawing).append(.setStrokeColor(try self.color(from: color)))
     return .void

Sources/LispKitRepl/AppInfo.swift

@@ -45,7 +45,7 @@ public struct AppInfo {
   public static let buildDate = { () -> String in
     let dateFormatter = DateFormatter()
     dateFormatter.dateFormat = "yyyy-MM-dd HH:mm"
-    return dateFormatter.string(from: Date(timeIntervalSince1970: 1699655433))
+    return dateFormatter.string(from: Date(timeIntervalSince1970: 1700948712))
   }()
   public static let buildAnnotation = " (\(AppInfo.buildDate))"
 }