Add 'undo' function

AllenDang · Sep 30, 2024 · 9963037 · 9963037
1 parent 8006738
commit 9963037
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Showing 2 changed files with 12 additions and 1 deletion.
diff --git a/examples/paint/canvas.go b/examples/paint/canvas.go
@@ -156,6 +156,7 @@ func CanvasWidget() g.Widget {
 					inpos := image.Point{mousepos.X - scr.X, mousepos.Y - scr.Y}
 					if imgui.IsMouseClickedBool(imgui.MouseButtonLeft) {
 						was_drawing = true
+						canvas.UndoIndexes = append(canvas.UndoIndexes, len(canvas.DrawCommands))
 						lastTo = image.Point{0, 0}
 						buffer = append(buffer, DrawCommand{Tool: current_tool, Color: current_color, BrushSize: brush_size, From: inpos, To: inpos})
 						lastTo = inpos

diff --git a/examples/paint/toolbar.go b/examples/paint/toolbar.go
@@ -140,7 +140,17 @@ func ButtonColorMaker() *g.RowWidget {
 			current_tool = 1
 		}
 		imgui.SameLine()
-		imgui.ImageButton("##undo_tool", undoButtonImg.Texture().ID(), sz.Mul(1.7))
+		if imgui.ImageButton("##undo_tool", undoButtonImg.Texture().ID(), sz.Mul(1.7)) {
+			if len(canvas.UndoIndexes) > 0 {
+				lastUndoIndex := canvas.UndoIndexes[len(canvas.UndoIndexes)-1]
+				uind := canvas.UndoIndexes[:len(canvas.UndoIndexes)-1]
+				dc := canvas.DrawCommands[:lastUndoIndex]
+				canvas.Backend.ForceRelease()
+				canvas, _ = NewCanvas(canvasDetectedHeight)
+				canvas.UndoIndexes = uind
+				canvas.DrawCommands = dc
+			}
+		}
 		imgui.SameLine()
 		if imgui.ImageButton("##clear_tool", clearButtonImg.Texture().ID(), sz.Mul(1.7)) {
 			canvas.Backend.ForceRelease()