Gui textured rect

[WOTBLITZ]

I once used RenderGameOverlayEvent to add things to the game overlay. One thing was a textured rect with custom size on the game overlay that worked like this method

this.drawTexturedModalRect(x, y, textureX, textureY, width, height);

But now I don't remember what I did. Now I can make custom size textured rect but not which part of the sprite I want to use(Set the textureX and textureY), I tried other methods but it seems that only the above one you can set the textureX and textureY .  I might be stupid and just forgot how to use gui's but either way I need help.