Add handle to show clone stamp origin (#2190)

Fixes #1923

Author: Pashockerr

Pinta.Tools/Handles/BrushHandle.cs

@@ -0,0 +1,95 @@
+using System;
+using System.Drawing;
+using Gsk;
+using Gtk;
+using Pinta.Core;
+
+namespace Pinta.Tools;
+
+// That handle is used as second brush to show position of stamp tool origin
+public class BrushHandle : IToolHandle
+{
+	private int brush_width;
+	public int BrushWidth {
+		get { return brush_width; }
+		set {
+			if (value > 0)
+				brush_width = value;
+		}
+	}
+	public bool Active { get; set; }
+	public PointD CanvasPosition { get; set; }
+	private readonly IWorkspaceService workspace;
+
+	public BrushHandle (IWorkspaceService workspace)
+	{
+		this.workspace = workspace;
+	}
+
+	public bool ContainsPoint (PointD windowPoint)
+		=> ComputeWindowRect ().ContainsPoint (windowPoint);
+
+	/// <summary>
+	/// Drawing shape like in GdkExtensions.CreateIconWithShape
+	/// </summary>
+	public void Draw (Snapshot snapshot)
+	{
+		double zoom =
+		    (PintaCore.Workspace.HasOpenDocuments)
+		    ? Math.Min (30d, workspace.GetScale ())
+		    : 1d;
+		int clampedWidth = (int) Math.Min (800d, brush_width * zoom);
+
+		if (clampedWidth < 3)
+			return;
+
+		int halfOfShapeWidth = clampedWidth / 2;
+
+		RectangleF shapeRect = new () {
+			X = (float) (CanvasPosition.X * zoom),
+			Y = (float) (CanvasPosition.Y * zoom),
+			Width = clampedWidth,
+			Height = clampedWidth
+		};
+
+		Gdk.RGBA outerColor = new () {
+			Red = 1.0f,
+			Green = 1.0f,
+			Blue = 1.0f,
+			Alpha = .75f
+		};
+		Gdk.RGBA innerColor = new () {
+			Red = 0,
+			Green = 0,
+			Blue = 0,
+			Alpha = 1.0f
+		};
+
+		PathBuilder pathBuilder = PathBuilder.New ();
+		var originPosition = new Graphene.Point ();
+		originPosition.Init (shapeRect.X, shapeRect.Y);
+		pathBuilder.AddCircle (originPosition, halfOfShapeWidth);
+		Stroke stroke = Stroke.New (2);
+		snapshot.AppendStroke (pathBuilder.ToPath (), stroke, outerColor);
+
+		shapeRect.Inflate (-1, -1);
+		pathBuilder.AddCircle (originPosition, halfOfShapeWidth);
+		stroke.SetLineWidth (1);
+		snapshot.AppendStroke (pathBuilder.ToPath (), stroke, innerColor);
+	}
+
+	public RectangleI InvalidateRect => ComputeWindowRect ().Inflated (2, 2).ToInt ();
+
+	/// <summary>
+	/// Bounding rectangle of the handle (in window space). Similar to MoveHandle.
+	/// </summary>
+
+	private RectangleD ComputeWindowRect ()
+	{
+		double diameter = brush_width;
+		double radius = diameter / 2.0;
+
+		PointD windowPt = workspace.CanvasPointToView (CanvasPosition);
+		return new RectangleD (windowPt.X - radius, windowPt.Y - radius, diameter, diameter);
+	}
+}

Pinta.Tools/Tools/CloneStampTool.cs

@@ -25,6 +25,7 @@
 // THE SOFTWARE.
 
 using System;
+using System.Collections.Generic;
 using Gdk;
 using Pinta.Core;
 
@@ -39,11 +40,15 @@ public sealed class CloneStampTool : BaseBrushTool
 
 	private readonly SystemManager system_manager;
 	private readonly IWorkspaceService workspace;
+	private readonly BrushHandle handle;
+	private bool move_origin_handle = true;
 	public CloneStampTool (IServiceProvider services) : base (services)
 	{
 		system_manager = services.GetService<SystemManager> ();
 		workspace = services.GetService<IWorkspaceService> ();
 
+		handle = new BrushHandle (workspace);
+
 		// Update cursor on zoom
 		workspace.ViewSizeChanged += (_, _) => {
 			if (IsActiveTool ()) {
@@ -59,6 +64,7 @@ public CloneStampTool (IServiceProvider services) : base (services)
 	public override Gdk.Key ShortcutKey => new (Gdk.Constants.KEY_L);
 	public override int Priority => 47;
 	protected override bool ShowAntialiasingButton => true;
+	public override IEnumerable<IToolHandle> Handles => [handle];
 
 	public override Cursor DefaultCursor {
 		get {
@@ -94,17 +100,23 @@ protected override void OnMouseDown (Document document, ToolMouseEventArgs e)
 		} else {
 			origin = e.Point;
 			offset = null;
+			UpdateOriginHandle (document, origin.Value.X, origin.Value.Y, false);
 		}
 	}
 
 	protected override void OnMouseMove (Document document, ToolMouseEventArgs e)
 	{
-		if (!painting || !offset.HasValue)
+		if (!offset.HasValue)
 			return;
 
 		var x = e.Point.X;
 		var y = e.Point.Y;
 
+		UpdateOriginHandle (document, x - offset.Value.X, y - offset.Value.Y, true);
+
+		if (!painting)
+			return;
+
 		if (!last_point.HasValue) {
 			last_point = e.Point;
 			return;
@@ -134,6 +146,9 @@ protected override void OnMouseUp (Document document, ToolMouseEventArgs e)
 	{
 		painting = false;
 
+		if (e.IsControlPressed)
+			handle.Active = true;
+
 		using Cairo.Context g = new (document.Layers.CurrentUserLayer.Surface);
 		g.SetSourceSurface (document.Layers.ToolLayer.Surface, 0, 0);
 		g.Paint ();
@@ -152,6 +167,7 @@ protected override bool OnKeyDown (Document document, ToolKeyEventArgs e)
 	{
 		// Note that this WON'T work if user presses control key and THEN selects the tool!
 		if (e.Key.IsControlKey ()) {
+			move_origin_handle = false;
 			SetCursor (Gdk.Cursor.NewFromTexture (Resources.GetIcon ("Cursor.CloneStampSetSource.png"), 16, 26, null));
 		}
 
@@ -160,14 +176,25 @@ protected override bool OnKeyDown (Document document, ToolKeyEventArgs e)
 
 	protected override bool OnKeyUp (Document document, ToolKeyEventArgs e)
 	{
-		if (e.Key.IsControlKey ())
+		if (e.Key.IsControlKey ()) {
+			move_origin_handle = true;
 			SetCursor (DefaultCursor);
+		}
 
 		return false;
 	}
 
 	protected override void OnDeactivated (Document? document, BaseTool? newTool)
 	{
 		origin = null;
+		handle.Active = false;
+	}
+
+	private void UpdateOriginHandle (Document document, int x, int y, bool move_event)
+	{
+		if (move_origin_handle || (!move_event))
+			handle.CanvasPosition = new (x, y);
+		handle.BrushWidth = BrushWidth;
+		document.Workspace.Invalidate (handle.InvalidateRect);
 	}
 }