Coyote Graphics Routines

Date: Fri Mar 27 12:14:20 2015

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top cgAspect


result = cgAspect(aspect_ratio [, ALIGN=string] [, ASPECT=array] [, POSITION=array] [, /SINGLE_PLOT] [, WASPECT=float])

The purpose of this function is to calculate a position in a graphics window with a specified aspect ratio (ysize/xsize).


aspect_ratio in required type=float

The requested aspect ratio. Be careful to specify this as a float.


ALIGN in optional type=string default=center

Normally, the output position is centered in the intial input position. This keyword can alter the placement of the final position with respect to the initial position. Allowed values are "top", "right", "bottom", "left", and "center".

ASPECT in optional type=array

This keyword provides an alternative way of specifying the aspect_rato value. Pass this keyword any 2D array, and the aspect ratio will be calculated to match the 2D array.

POSITION in optional type=array

Use this keyword to specify a four-element normalized starting position for calculating the final position in the graphics window. By default, the staring position is given by [0.0, 0.0, 1.0, 1.0] (the entire window). If the Single_Plot keyword is set, the default position is given by [0.125, 0.125, 0.9, 0.9].

SINGLE_PLOT in optional type=boolean default=0

Set this keyword to change the default starting Position to [0.125, 0.125, 0.9, 0.9].

WASPECT in optional type=float

Set this keyword to the window aspect ratio. If not used, the window aspect is calculated from the current graphics window as Float(!D.Y_VSize) / !D.X_VSize.


Here is how to use this program to display two differently sized images aligned at their tops:

img1 = cgDemoData(7) img2 = congrid(img1, 360, 180) cgDisplay, 900, 450 pos = cgLayout([2,1], OYMargin=[4, 11], OXMargin=[5, 8], XGap=6) pos1 = pos[*,0] img1pos = cgAspect(Position=pos1, Aspect=img1, Align='top') cgImage, img1, CTIndex=3, /AXES, POSITION=img1pos, OPOSITION=op cgColorbar, CTIndex=3, /Fit pos2 = pos[*,1] img2pos = cgAspect(Position=pos2, Aspect=img2, Align='top') cgImage, img2, /AXES, POSITION=img2pos, CTIndex=2, /NoErase cgColorbar, CTIndex=2, /Fit

Author information



David W. Fanning 1645 Sheely Drive Fort Collins, CO 80526 USA Phone: 970-221-0438 E-mail: Coyote's Guide to IDL Programming:


Copyright (c) 2013, Fanning Software Consulting, Inc.


Change History:

Written, 12 February 2013 by David W. Fanning.

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Modification date: Fri Mar 27 11:07:37 2015
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