| laying a grid on top of an image [message #15829] |
Wed, 16 June 1999 00:00  |
Lazzar
Messages: 9
Registered: February 1999
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Junior Member |
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Does anyone know of a quick easy way to put a grid of lines over top of
an existing image. I want to be able to specify the spacing on the grid
(in pixels), for example 40 columns by 100 rows, and have a grid placed
over top of an image which is already displayed in a window.
Thanks,
Brian
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| Re: laying a grid on top of an image [message #15908 is a reply to message #15829] |
Fri, 18 June 1999 00:00  |
Vapuser
Messages: 63
Registered: November 1998
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Member |
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Brian Nagy <lazzar@gte.net> writes:
x=!d.x_size
y=!d.y_size
for r=0,nrows do plots,[0,
You will
> Does anyone know of a quick easy way to put a grid of lines over top of
> an existing image. I want to be able to specify the spacing on the grid
> (in pixels), for example 40 columns by 100 rows, and have a grid placed
> over top of an image which is already displayed in a window.
>
> Thanks,
>
> Brian
>
--
William Daffer: 818-354-0161: vapuser@catspaw.jpl.nasa.gov
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| Re: laying a grid on top of an image [message #15910 is a reply to message #15829] |
Fri, 18 June 1999 00:00 |
Daniel Peduzzi
Messages: 29
Registered: June 1999
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Junior Member |
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Daniel Peduzzi wrote in message <6Rja3.16621$AB2.371314@wbnws01.ne.mediaone.net>...
>
> Brian Nagy wrote in message <37684EAA.334F0A42@gte.net>...
>> Does anyone know of a quick easy way to put a grid of lines over top of
>> an existing image. I want to be able to specify the spacing on the grid
>> (in pixels), for example 40 columns by 100 rows, and have a grid placed
>> over top of an image which is already displayed in a window.
>>
>
>
> Could you alter the image before you display it in a window?
>
> If I had a 2D array called "my_image", and I wanted different spacings in the
> row and column directions, I'd do something like this:
>
> row_freq=20
> col_freq=40
>
> s=size(my_image)
> col_indices = indgen(s[1]/col_freq+1)
> row_indices = indgen(s[2]/row_freq+1)
>
Oops, forgot the multipliers. These lines should be
col_indices = indgen(s[1]/col_freq+1) * col_freq
row_indices = indgen(s[2]/row_freq+1) * row_freq
Dan Peduzzi
peduzzi@mediaone.net
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| Re: laying a grid on top of an image [message #15913 is a reply to message #15829] |
Fri, 18 June 1999 00:00 |
Daniel Peduzzi
Messages: 29
Registered: June 1999
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Junior Member |
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Brian Nagy wrote in message <37684EAA.334F0A42@gte.net>...
> Does anyone know of a quick easy way to put a grid of lines over top of
> an existing image. I want to be able to specify the spacing on the grid
> (in pixels), for example 40 columns by 100 rows, and have a grid placed
> over top of an image which is already displayed in a window.
>
Could you alter the image before you display it in a window?
If I had a 2D array called "my_image", and I wanted different spacings in the
row and column directions, I'd do something like this:
row_freq=20
col_freq=40
s=size(my_image)
col_indices = indgen(s[1]/col_freq+1)
row_indices = indgen(s[2]/row_freq+1)
my_image[col_indices, *]=255
my_image[*, row_indices]=255
tvlct, [255], [0], [0], 255 ; Make last colormap entry "red"
tv, my_image
This would display a red grid, with the above spacings, over the image.
Dan Peduzzi
peduzzi@mediaone.net
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| Re: laying a grid on top of an image [message #15924 is a reply to message #15829] |
Thu, 17 June 1999 00:00 |
mirko_vukovic
Messages: 50
Registered: January 1998
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Member |
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In article <37684EAA.334F0A42@gte.net>,
Brian Nagy <lazzar@gte.net> wrote:
> Does anyone know of a quick easy way to put a grid of lines over top
of
> an existing image. I want to be able to specify the spacing on the
grid
> (in pixels), for example 40 columns by 100 rows, and have a grid
placed
> over top of an image which is already displayed in a window.
>
> Thanks,
>
> Brian
>
>
use plots,x,y,...,/device ? Will recquire some coordinate
conversions, allways a joy.
mirko
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