Adding and Manipulating Shapes

To create and manipulate shapes on a Konva.js canvas, you start by instantiating a Stage and a Layer. The Stage acts as the main container, while the Layer holds and manages your shapes. You can add a variety of shapes, such as rectangles, circles, and lines, by creating instances of Konva.Rect, Konva.Circle, and Konva.Line. Each shape accepts configuration properties like x, y, width, height, radius, fill, and stroke that determine its position, size, and appearance.

Once a shape is created and added to a layer, you can update its properties using setter methods. For example, to move a rectangle, you call rect.x(newX) and rect.y(newY). To change a color, use shape.fill(newColor). For size, you can set properties like width, height, or radius depending on the shape type. After making changes to a shape, you should call layer.batchDraw() to efficiently redraw the layer and reflect the updates on the canvas.

These methods make it easy to dynamically update your shapes. Whether you want to animate, respond to user input, or simply change how something looks, you use these property setters to control the canvas content.