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Re: Showing thick lines - a problem?

  • To: mathgroup at
  • Subject: [mg39502] Re: [mg39484] Showing thick lines - a problem?
  • From: Uri Zwick <zwick at>
  • Date: Thu, 20 Feb 2003 05:13:35 -0500 (EST)
  • References: <>
  • Sender: owner-wri-mathgroup at

David Park wrote:

>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
>David Park
>djmp at
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}}],

Let us also define

sl1[len_,size_] :=
  Show[ Graphics[ {RGBColor[0,0,1],Thickness[0.01],Line[{{0,0},{len,0}}],

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,


>From: Uri Zwick [mailto:zwick at]
To: mathgroup at
>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:
>Shows a long thick line and
>a very short thick line underneath it.
>Only the long line is visible, even tough the image is larger!
>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.

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