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Re: Re: Showing thick lines - a problem?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg39516] Re: [mg39502] Re: [mg39484] Showing thick lines - a problem?
  • From: "Mihajlo Vanevic" <mvane at eunet.yu>
  • Date: Fri, 21 Feb 2003 04:07:38 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

Hi,

Thickness is not working "as expected"!!

Make your own thickness function (with Polygon)
and all short-lines will be visible.


sl1[len_, size_] := 
    Show[Graphics[{RGBColor[0, 0, 1], 
          Polygon[{{0, 0}, {len, 0}, {len, .1}, {0, .1}}], 
          Polygon[{{0, 1}, {1, 1}, {1, 1.1}, {0, 1.1}}]}], ImageSize -> size, 
      AspectRatio -> 1/10, PlotRange -> All];

Table[sl1[1/th, s], {th, 100, 2000, 100}, {s, 400, 600, 25}]

Regards,				 
         Mihajlo Vanevic
         mvane at EUnet.yu
         2003-02-20

**************************************************************
*    At 2003-02-20, 05:13:00 
*        Uri Zwick, zwick at tau.ac.il  wrote:
**************************************************************
>David Park wrote:
>
>>Uri,
>>
>>Add the option PlotRange -> All. Otherwise Mathematica shows what it thinks
>>is "the most interesting" part of the plot, which might not be what you
>>intend.
>>
>>David Park
>>djmp at earthlink.net
>>http://home.earthlink.net/~djmp/
>>
>This doesn't solve the problem, I am afraid.
>But it does lead to another strange situation:
>
>My original definition was:
>
>sl[len_,size_] :=
>  Show[ Graphics[ {RGBColor[0,0,1],Thickness[0.01],Line[{{0,0},{len,0}}],
>        Line[{{0,1},{1,1}}]}],ImageSize->size,AspectRatio->1/10]
>
>Let us also define
>
>sl1[len_,size_] :=
>  Show[ Graphics[ {RGBColor[0,0,1],Thickness[0.01],Line[{{0,0},{len,0}}],
>        Line[{{0,1},{1,1}}]}],ImageSize->size,AspectRatio->1/10,
>        PlotRange->All]
>
>Then, sl[1/1000,450] shows both lines, while sl1[1/1000,450]
>shows only the long one. (With PlotRange->All we see less things!)
>
>Again we have a "non-monotonicity":
>sl1[1/1000,500] shows the two lines, while 
>sl1[1/1000,550] shows only the long line, even though
>the image is larger.
>
>The problem arises because the short line is very very short,
>and should therefore be barely visible, and not because it is
>out of the plot range.
>
>If possible, it would be desriable to have a "monotonicity"
>property that says that if Mathematica thinks that an object
>is large enough to be seen at a given image size, this object
>should also be seen at all larger image sizes. It is very 
>confusing to have objects disapper when an image is enlarged!
>
>Best regards,
>
>Uri
> 
>
>>From: Uri Zwick [mailto:zwick at tau.ac.il]
To: mathgroup at smc.vnet.net
>To: mathgroup at smc.vnet.net
>>
>>Hi,
>>
>>The following draws two thick blue lines, one of length 1
>>and the other of length "len" using an image size of "size":
>>
>>sl[len_,size_] :=
>>  Show[ Graphics[ {RGBColor[0,0,1],Thickness[0.01],Line[{{0,0},{len,0}}],
>>        Line[{{0,1},{1,1}}]}],ImageSize->size,AspectRatio->1/10]
>>
>>On my machine:
>>
>>sl[1/1000,450]
>>
>>Shows a long thick line and
>>a very short thick line underneath it.
>>
>>sl[1/1000,500]
>>
>>Only the long line is visible, even tough the image is larger!
>>
>>sl[1/1000,600]
>>
>>The short line reappears.
>>
>>The problem disappears when "Thickness[0.01]" is removed.
>>
>>Do others have the same problem?
>>
>>I would expect larger images to show more, and not less, details.
>>Also, it seems to me that thick lines should be visible whenever
>>thin lines are.
>>
>>Uri
>>
>>  
>>
**************************************************************






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