the size rectangle 1 1 is 2 2. in fact, it goes from -1 to 1. you can see that in the simple attached patch.
about the rectangle 10 10 that is not a square : this is exactly what i've got when i don't send the reset after the windows creation. on this point Gem does not react exactly the same way on linux than on windows.
ah!... now i see ... so [rectangle 1 1] is equivalent to
glBegin(GL_QUADS)
glVertex3f(-1.0, 1.0, 0.0)
glVertex3f(1.0, 1.0, 0.0)
glVertex3f(1.0, -1.0, 0.0)
glVertex3f(-1.0, -1.0, 0.0)
glEnd()
so the final width and height is actually 2 units ... this is a bit confusing in the documentation help patch, i mean i know some opengl but still when i read width height words i thought about the width and height of a rectangle in normal geometry and not opengl postion of the vertex location from the current position.
but i think all is clear now.
many thanks for the help !!!
enrike