I tried that before. I think the problem is 0.5 pixels (between 0-1 pixel). I tested on 3 devices: samsung tab (1), nokia full hd (2), samsung full hd (3).
(1) & (2) no problem, But on (3) it has some transparent lines at the bottom (at the edge of each triangle). It occurs when the spine uses triangles and vertices.
I don't know why, but I found this.
When using Draggable. When I drag from top to bottom, it has some white lines on the edge of each triangle
canvas.drawVertices can fix this problem. :grinfake