Re: General bug - No out of bounds checking on 3D coordinates

[Daniel J S. <dan...@ie...>]

Ethan Merritt wrote:

>On Monday 05 July 2004 02:14 pm, you wrote:
>  
>
>>Ethan Merritt wrote:
>>    
>>
>>>Is everyone OK with the idea "if a label is out of bounds don't
>>>try to draw it at all"?
>>>      
>>>
>>Not totally.  It would be nice that if a partial text string were
>>supposed to show it would.  
>>    
>>
>
>That happens now for some drivers, but only for labels whose
>coordinates are out of bounds but still positive.  If they go negative
>then nothing good can happen.
>
>  
>
>>I would say that if you pin this down as the 
>>actual problem and it seems that there is no easy solution, then OK.
>>    
>>
>
>Huh?  I know exactly what the problem is.  By the time the coordinates
>for the label are passed to libpdf they have already been mangled by
>converting them to (unsigned int).
>

OK, now that I'm getting the PDF float too large error, I see that is 
the problem.

>If you want to allow the general case of labels that start off-screen
>but extend into view then we would (I think) have to change all the
>coordinates passed to terminal drivers from unsigned to signed.
>
>That would be mean changing many lines of code, but other than that
>I don't see any intrinsic problem with it.  Of course, only a subset
>of drivers could actually do anything useful with the negative numbers.
>

That is the first step I would vote for.  There will still be some 
issues, but this idea of constructing a plot with (0,0) as the reference 
point kind of suggests that negative numbers should be allowed as "work 
room".  Otherwise, it's like an artist starting his or her drawing in 
the bottom left corner of the canvas.

Dan