View Windows Mode

The <v> command is used to set the view window parameters described below.

These parameters can be used to:

 o Define a small window on the screen which is to contain the generated
   images. Using a small window speeds up calculation time (there are
   fewer pixels to generate). You can use a small window to explore
   quickly, then turn the view window off to recalculate the image at
   full screen size.

 o Generate an image with a different "aspect ratio"; e.g. in a square
   window or in a tall skinny rectangle.

 o View saved GIF images which have pixel dimensions different from any
   mode supported by your hardware. This use of view windows occurs
   automatically when you restore such an image.

"Preview display"

Set this to "yes" to turn on view window, "no" for full screen display.
While this is "no", the only view parameter which has any affect is "final
media aspect ratio". When a view window is being used, all other xmfract
functions continue to operate normally - you can zoom, color-cycle, and
all the rest.

"Reduction factor"

When an explicit size is not given, this determines the view window size,
as a factor of the screen size. E.g. a reduction factor of 2 makes the
window 1/2 as big as the screen in both dimensions.

"Final media aspect ratio"

This is the height of the final image you want, divided by the width. The
default is 0.75 because standard PC monitors have a height:width ratio of
3:4. E.g. set this to 2.0 for an image twice as high as it is wide. The
effect of this parameter is visible only when "preview display" is
enabled.

"Crop starting coordinates"

This parameter affects what happens when you change the aspect ratio. If
set to "no", then when you change aspect ratio, the prior image will be
squeezed or stretched to fit into the new shape. If set to "yes", the
prior image is "cropped" to avoid squeezing or stretching.

"Explicit size"

Setting these to non-zero values over-rides the "reduction factor" with
explicit sizes in pixels. If only the "x pixels" size is specified, the "y
pixels" size is calculated automatically based on x and the aspect ratio.