Renderer.activate

Does initial setup before rendering operations on renderer.

[pango.renderer.Renderer.deactivate] should be called when done drawing. Calls such as [pango.renderer.Renderer.drawLayout] automatically activate the layout before drawing on it.

Calls to [pango.renderer.Renderer.activate] and [pango.renderer.Renderer.deactivate] can be nested and the renderer will only be initialized and deinitialized once.