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How to get smote lines

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  How to get smote lines Cecil Westerhof <Cecil@decebal.nl> - 2014-03-26 22:03 +0100
    Re: How to get smote lines Mark Carroll <mtbc@bcs.org> - 2014-03-26 21:49 +0000
      Re: How to get smote lines Cecil Westerhof <Cecil@decebal.nl> - 2014-03-27 03:45 +0100
    Re: How to get smote lines luser- -droog <mijoryx@yahoo.com> - 2014-03-26 14:52 -0700
      Re: How to get smote lines Cecil Westerhof <Cecil@decebal.nl> - 2014-03-27 03:47 +0100
    Re: How to get smote lines Don Lancaster <don@tinaja.com> - 2014-04-02 12:21 -0700
      Re: How to get smote lines luser- -droog <mijoryx@yahoo.com> - 2014-04-02 19:17 -0700

#1829 — How to get smote lines

I have the following code:
    %!PS-Adobe-3.0 EPSF-3.0
    %%BoundingBox: 0 0 100 25

    30 12 90 {
        gsave
            0 translate
            -11 6 moveto
            0 6 rlineto
            6 0 rlineto
            0 -6 rlineto
            6 0 rlineto
            stroke
        grestore
    } for

    showpage

But I noticed that the connection is not smooth. When I change the
last rlineto to:
    7 0 rlineto

It goes to far. How can I get a smooth connection?

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof

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#1830

Cecil Westerhof <Cecil@decebal.nl> writes:
(snip)
>     30 12 90 {
(snip)
>             stroke
>         grestore
>     } for
>
>     showpage
>
> But I noticed that the connection is not smooth.
(snip)

setlinejoin and setlinecap are worth knowing about: here if you start
out with a 2 setlinecap then it goes much better.

Still, notice that you are doing a few strokes here: the difference
between the join and the cap is related to where you stroke and start a
new line, instead of continuing the previous, and the connection issues
are at those boundaries.

I hope that helps.

-- Mark

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#1833

Op Wednesday 26 Mar 2014 22:49 CET schreef Mark Carroll:

> Cecil Westerhof <Cecil@decebal.nl> writes:
> (snip)
>> 30 12 90 {
> (snip)
>> stroke
>> grestore
>> } for
>>
>> showpage
>>
>> But I noticed that the connection is not smooth.
> (snip)
>
> setlinejoin and setlinecap are worth knowing about: here if you
> start out with a 2 setlinecap then it goes much better.
>
> Still, notice that you are doing a few strokes here: the difference
> between the join and the cap is related to where you stroke and
> start a new line, instead of continuing the previous, and the
> connection issues are at those boundaries.

I thought that I had done that, but now it works. So probably I made a
mistake somewhere. This and some other things look a lot better now.

There are some other things that do not see completely correct. So I
will probably ask something again in the near future.

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof

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#1831

On Wednesday, March 26, 2014 4:03:08 PM UTC-5, Cecil Westerhof wrote:
> I have the following code:
> 
>     %!PS-Adobe-3.0 EPSF-3.0
>     %%BoundingBox: 0 0 100 25
> 
>     30 12 90 {
>         gsave
>             0 translate
>             -11 6 moveto
>             0 6 rlineto
>             6 0 rlineto
>             0 -6 rlineto
>             6 0 rlineto
>             stroke
>         grestore
>     } for
> 
>     showpage
> 
> But I noticed that the connection is not smooth. When I change the
> last rlineto to:
>     7 0 rlineto
> 
> It goes to far. How can I get a smooth connection?
> 

The usual best answer is to construct one big path and make
a single call to `stroke`. But you've kind of painted yourself
into a corner with the gsave...grestore. So, I think the 
simplest fix here is add 1/2 of the line-width.


10 10 scale
0 10 translate % just to see it better

30 12 90 { 
    gsave 
        0 translate 
        -11 6 moveto 
        0 6 rlineto 
        6 0 rlineto 
        0 -6 rlineto 
        currentlinewidth .5 mul 
        6 add 0 rlineto 
        stroke 
    grestore 
} for 

showpage 

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#1832

Op Wednesday 26 Mar 2014 22:52 CET schreef luser:

> On Wednesday, March 26, 2014 4:03:08 PM UTC-5, Cecil Westerhof wrote:
>> I have the following code:
>>
>> %!PS-Adobe-3.0 EPSF-3.0
>> %%BoundingBox: 0 0 100 25
>>
>> 30 12 90 {
>> gsave
>> 0 translate
>> -11 6 moveto
>> 0 6 rlineto
>> 6 0 rlineto
>> 0 -6 rlineto
>> 6 0 rlineto
>> stroke
>> grestore
>> } for
>>
>> showpage
>>
>> But I noticed that the connection is not smooth. When I change the
>> last rlineto to:
>> 7 0 rlineto
>>
>> It goes to far. How can I get a smooth connection?
>>
>
> The usual best answer is to construct one big path and make
> a single call to `stroke`. But you've kind of painted yourself
> into a corner with the gsave...grestore. So, I think the 
> simplest fix here is add 1/2 of the line-width.
>
>
> 10 10 scale
> 0 10 translate % just to see it better
>
> 30 12 90 { 
> gsave 
> 0 translate 
> -11 6 moveto 
> 0 6 rlineto 
> 6 0 rlineto 
> 0 -6 rlineto 
> currentlinewidth .5 mul 
> 6 add 0 rlineto 
> stroke 
> grestore 
> } for 
>
> showpage 

The idea of working with:
    2 setlinejoin
    2 setlinecap

works better. (And is also only needed on one point.) But thanks anyway.

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof

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#1847

On 3/26/2014 2:03 PM, Cecil Westerhof wrote:
> I have the following code:
>      %!PS-Adobe-3.0 EPSF-3.0
>      %%BoundingBox: 0 0 100 25
>
>      30 12 90 {
>          gsave
>              0 translate
>              -11 6 moveto
>              0 6 rlineto
>              6 0 rlineto
>              0 -6 rlineto
>              6 0 rlineto
>              stroke
>          grestore
>      } for
>
>      showpage
>
> But I noticed that the connection is not smooth. When I change the
> last rlineto to:
>      7 0 rlineto
>
> It goes to far. How can I get a smooth connection?
>

closepath

-- 
Many thanks,

Don Lancaster                          voice phone: (928)428-4073
Synergetics   3860 West First Street   Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml   email: don@tinaja.com

Please visit my GURU's LAIR web site at http://www.tinaja.com

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#1848

On Wednesday, April 2, 2014 2:21:42 PM UTC-5, Don Lancaster wrote:
> On 3/26/2014 2:03 PM, Cecil Westerhof wrote:
> 
> > I have the following code:
> 
> >      %!PS-Adobe-3.0 EPSF-3.0
> >      %%BoundingBox: 0 0 100 25
> >
> >      30 12 90 {
> >          gsave
> >              0 translate
> >              -11 6 moveto
> >              0 6 rlineto
> >              6 0 rlineto
> >              0 -6 rlineto
> >              6 0 rlineto
> >              stroke
> >          grestore
> >      } for
> >
> >      showpage
> >
> > But I noticed that the connection is not smooth. When I change the
> > last rlineto to:
> >      7 0 rlineto
> >
> > It goes to far. How can I get a smooth connection?
> >
> 
> closepath
> 

Before anybody jumps on Don for this nonsensical advice,
this bit of code:

> >              -11 6 moveto
> >              0 6 rlineto
> >              6 0 rlineto
> >              0 -6 rlineto
> >              6 0 rlineto
> >              stroke

looks very much like the idiom the drawing a square. And it 
would be a square if one of the horizontal lines went the 
other direction. And it would be good advice in that case.

But now that I've got your attention, I really think this
doodle would be better expressed as a continuous piece.
And the 2 setlinecap makes the first vertical line look 
better, even though it's not needed here for "joins".


    %10 10 scale    %the better to see you with, my dear
    %0 10 translate


    gsave
    2 setlinecap
    30 0 translate
    -11 6 moveto
    30 12 90 {
        pop
        0 6 rlineto
        6 0 rlineto
        0 -6 rlineto
        6 0 rlineto
    } for
    stroke
    grestore

    showpage

The best way to get connected lines in Postscript is:
don't move the point in the middle. Then the lines are
connected naturally.

-- 
droog

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