Re: dashed lines with GD [ was Re: symbol/color/line consistency in terminals]

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

m sutton wrote:
>> Message: 6 Date: Sat, 10 Feb 2007 11:37:47 -0800 From: Ethan A
>> Merritt <merritt@u.washington.edu> Subject: Re: symbol/color/line
>> consistency in terminals To: gnu...@li... Cc:
>> Daniel J Sebald <dan...@ie...> Message-ID:
>> <200702101137.47710.merritt@u.washington.edu> Content-Type:
>> text/plain;  charset="iso-8859-1"
>> 
>> On Saturday 10 February 2007 11:28, Daniel J Sebald wrote:
>> 
>>> Hans-Bernhard Br?ker wrote:
>>> 
>>>>> That's because GD, last I looked, didn't support linewidths
>>> 
>>> on patterned > lines.  Which made it rather pointless to try and
>>>  implement dashing for > the first three.
>>> 
>>> I'm not real familiar with GD, but the header file has:
>>> 
>>> gdImageSetStyle (); gdImageSetThickness ();
>> 
>> Take my word for it, the gd routines for dashed lines and for 
>> linewidth are useless for our purposes.
> 
> 
> I was looking at just this issued over the past week or so.  I wanted
> to make the grid lines thicker for the GD terminal.  I found some odd
> behavior when using gdImageSetStyle  and gdImageSetThickness
> together.
> 
> The pixels are not drawn in the order I expected.  I think the style
> setting will have to set uniquely for each line width.  The style may
> even have to be adjusted for horizontal and vertical lines.

Well, I agree with that fact.  But I'm not sure I can exactly say what the rule should be.  (x11 has similar issues to PNG, but symbols scale accordingly x11.)  In any case, I think it is a lot of work to keep straight so writing a patch would need a solid concept...  Guess I'm not willing to try that much at the moment.


>>Say there were a "resolution #" option that would internally scale 
>>line thickness, pointsize, and fonts (have to have a mapping to 
>>medium, large, giant... unfortunately the largest font doesn't have 
>>very high resolution).
> 
> 
> At first I thought you meant resolution to be dots per inch (DPI).  But I think you really mean scaling as Ethan has elaborated on.

No, I didn't mean DPI, more a relative sort of thing.  I believe what I meant, after thinking a bit, is dots-per-"show ticscale" on the test image.  So, yeah I guess that is scale.


> However, it would be nice to set DPI somehow through GD.  It would simplify things when I import images into Word or PowerPoint.

Well, that isn't too difficult, is it?  If you know the the size in inches of the figure in the document and the DPI of the document you can calculate size and specify that at the "set term" option.  Or does it work the other way?  That there is a DPI value in the PNG file so that Word/PowerPoint can resample the figure?

Dan