[plt-scheme] image.ss: (line ...) only draws to the SouthEast

That was an oversight. I've added the ability to make lines going in
all four directions (in svn).

Thanks,
Robby

At Sat, 18 Feb 2006 20:12:27 -0500, Felix Klock's PLT scheme proxy wrote:
> While playing around with images today, I realized that the given  
> implementation of the LINE function in image.ss calls error when  
> given negative values for the x or y parameters.
> 
> This implies that you can only pass non-negative values for x and y,  
> which in turn implies that the LINE function can't draw lines that go  
> "SouthWest."  You can manipulate the pinholes to get lines that go  
> NorthWest, but SouthWest and NorthEast are impossible with LINE.
> 
> ADD-LINE is capable of drawing lines in any direction, but wouldn't  
> it be good to fix LINE so that it does handle negative x or y (and  
> keeps the pinhole at the origin)?  Or is there some reason for  
> requiring non-negative values that I'm not seeing?
> 
> -Felix
> 
> 
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