A standalone Sketch on the Mac that is less than 128 pixels high will not render correctly. There is a black bar along the top.
100x100 render with black bar
128x128 rendered correctly
It looks like the window that the Sketch is rendered into has a minimum size, and the size of the black bar is equal to the size of the extra vertical padding given to the window. Interestingly, the error is only in the y-dimension. The X dimension renders correctly.
I don't know if this happens on any other platforms, but I see it on the Mac.
This reproduces on v2.0b8, but not on v1.5.1
I have the need to develop some quite small sketches (90 x 70), and it is very helpful to be able to develop them in the stand alone program. I need it to work for both P2D and P3D.
Here is sample code that demonstrates the problem:
prisonerjohn
commented
10 years ago 
A standalone Sketch on the Mac that is less than 128 pixels high will not render correctly. There is a black bar along the top.
It looks like the window that the Sketch is rendered into has a minimum size, and the size of the black bar is equal to the size of the extra vertical padding given to the window. Interestingly, the error is only in the y-dimension. The X dimension renders correctly.
I don't know if this happens on any other platforms, but I see it on the Mac. This reproduces on v2.0b8, but not on v1.5.1
I have the need to develop some quite small sketches (90 x 70), and it is very helpful to be able to develop them in the stand alone program. I need it to work for both P2D and P3D.
Here is sample code that demonstrates the problem:
void setup() { size(100, 100, P2D); }
void draw() { ellipse(width/2, height/2, width, height); }