Java - OpenGL set offset for center (0,0) coordinates

[Oskiin]

Hi I am doing something with JOGL libraries (forced to) and I can't figure out how to offset the center zero coordinates. I would like to offset them to the botom of my viewport, in the method \[code\]public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height)\[/code\]but I can't google any way to translate int height into any meaningfull offset float coordinates.