Proposal : Draw behind, z index ?

[kpym]

I'm trying to draw a path behind. But it looks like the RenderPath can add only on top of the layers stack.

Is it possible to append a new method RenderPathBehind ? Or even better add z-index parameter to the layers and when new path is added it is inserted at the right 'z'-position.

[tdewolff]

The interfaces for the specific target file formats are in "direct" mode, meaning that issuing a draw command immediately draws the path. The only exception is the general Canvas class, which keeps a record of layers to draw. We could add functionality there so that you can either set the Z-index for the next drawing commands, or set it explicitly for the current command. Thanks for the suggestion!

[kpym]

@tdewolff Thanks for your fast answer. Indeed I was talking about the general Canvas. By the way, I think that PDF has z-index capabilities.

[kpym]

I succeeded to draw white rectangle behind like this :

func onWhite(c *canvas.Canvas) *canvas.Canvas {
	cn := canvas.New(c.W, c.H)
	ctx := canvas.NewContext(cn)
	ctx.SetFillColor(canvas.White)
	ctx.DrawPath(0, 0, canvas.Rectangle(math.Ceil(c.W), math.Ceil(c.H)))
	c.Render(cn)

	return cn
}

But this is not very nice.

[tdewolff]

I've incorporated this issue in the new roadmap from where it will be tracked: #74