On Jul 3, 2011, at 1:48 PM, Dale Satterfield wrote:

> Lines with sufficient slope always draw in Black(the set color), and the 
> specified width. However if the slope is low enough they print thinner, and 
> in a different color.
> This is an example:

The image didn’t show up, but you’re probably seeing the effects of subpixel 
antialiasing, which uses the relative positions of the R, G and B subcomponents 
of an LCD pixel to increase apparent horizontal resolution.

Another issue that’s probably exacerbating the distortion is that, if you’re 
drawing 1-pixel wide lines [or any odd integer width] you should offset their x 
and y coords by 0.5 to ensure that, if horizontal/vertical or nearly so, the 
lines end up entirely within a pixel instead of split between two pixels, which 
will smear them. (The reason for this is that the pixels are in between integer 
grid coordinates, so the pixel centers are at 0.5, 1.5, 2.5, etc.)

—Jens_______________________________________________

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