CSS Shapes Editor
Create and adjust CSS Shapes values with an interactive editor overlapping the selected element.
Requires Opera 24+
The extension adds a new sidebar to the DevTools Elements panel called "Shapes". It offers controls to create and edit CSS Shapes values like polygon(), circle() and ellipse() on the selected element.
Click the edges of the shape to add new points. Drag points to change the shape. Double-click an existing point to remove it. Select the transform tool to move, scale and rotate the polygon shape.
Circles & ellipses:
Drag the shape to move it around. Pull on the edges and corners to scale and resize.