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Re: positioning a TV image within plotting region [message #77876 is a reply to message #77868]

Thu, 29 September 2011 12:19

Matthew
Messages: 18
Registered: February 2006

Junior Member

> When I do this, I plot the image first and then the axes.

This just draws the axes on top of the image and hides the fact that
the image is in the wrong spot.

> One more thing - I would use device coordinates for the plot instead of normal, because you can't size your image in normal coordinates. Otherwise, you might sometimes get a 1-pixel mismatch at the edges.

Thanks! You made me realize that I was positioning the plot with
fractions of a pixel, which does not work too well. I still have the
same problem, but now it is a fixed offset, not a varying one. It
seems as though the PLOT procedure draws the bottom and left axes
within the plotting window (defined by !x.window and !y.window),
whereas the top and right axes are outside the plotting window.

In the code below, I used the floor function to truncate any partial
pixels from the plot position, reduce the x- and y-size of the image
by 1-pixel (the apparent width of the axes), and shifted it up and to
the right by 1 pixel. This works for the display window and for all
plot sizes that I have tried so far. Now to try postscripts...

position = [x0, y0, x1, y1] ;position in normal
coordinates
position[0] = floor(position[0] * !d.x_vsize)
position[1] = floor(position[1] * !d.y_vsize)
position[2] = floor(position[2] * !d.x_vsize)
position[3] = floor(position[3] * !d.y_vsize)
xsize = (position[2] - position[0]) - 1
ysize = (position[3] - position[1]) - 1
xstart = position[0] + 1
ystart = position[1] + 1

loadct, 13
plot, time, freq, position=position, /device, /nodata, /noerase
tvscl, congrid(alog(transpose(E_pwr_dens)), xsize, ysize), xstart,
ystart

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[Message index]

		Re: positioning a TV image within plotting region By: David Fanning on Wed, 05 October 2011 11:06
		Re: positioning a TV image within plotting region By: Matthew on Wed, 05 October 2011 10:26
		Re: positioning a TV image within plotting region By: David Fanning on Fri, 30 September 2011 08:34
		Re: positioning a TV image within plotting region By: Matthew on Thu, 29 September 2011 12:19
		Re: positioning a TV image within plotting region By: greg michael on Thu, 29 September 2011 07:47
		Re: positioning a TV image within plotting region By: greg.addr on Thu, 29 September 2011 07:42
		Re: positioning a TV image within plotting region By: greg.addr on Thu, 29 September 2011 07:39
		Re: positioning a TV image within plotting region By: Matthew Argall on Mon, 10 October 2011 16:22

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