Since other programs are running in this, you want to use as few of their resources as possible.
GPUTCHR would allow you to draw to the graphic screen instead, but is trickier and may impact performance.
Either method can be done with a 9-patch, where you have 9 graphics: 4 corners, 4 sides, and center. Corners are placed normally, but sides(+center) are 1 graphic, stretched to fill the space.
1そうだね 未プレイ