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GREG has the possibility of zooming a plot being created. Use command
ZOOM to do it. ZOOM X1 X2 Y1 Y2 will compute scale factors to
match the designed area (in Physical Coordinates) to the screen, preserving
the aspect ratio. ZOOM OFF restores the full screen,
ZOOM REFRESH redraws the plot with the current zooming factor.
Without arguments ZOOM calls the cursor, and several keys can be used
to control the zooming factor :
- ``0'' turns off zooming and displays the full plot page. The
previous zooming factor is not destroyed, so that typing a space (see
below) will restore a Viewing Window of same size as the last one
centered on the cursor position. The cursor position is not modified by
the command itself.
- `` '' (space) executes the standing zooming operations. With
``0'', it is the only effective command. The zoomed area is centered
around the cursor position and can be delimited using command B.
- ``Z'' increases the zooming factor by 1.414 and draws the
corresponding box around the zoomed area. The zooming is deferred until
`` '' has been struck, allowing zooming factors to be changed by any
power of square root of 2. The box drawn around the zoomed area is not a
part of the current plot, and will not be visible in a Hardcopy for
example.
- ``-'' decreases the zooming factor by 1.414, and draws the
corresponding box if visible.
- ``B'' draws a box delimiting the area to be zoomed.
- ``A'' to erase the alphanumeric screen
- ``E'' to exit...
Any other gives you the cursor position. Zooming can be used for example
to enlarge part of a complex drawing to make precise annotations. Note that
the zooming has no effect on the hardcopy.
On X-Window systems, the zoomed area normally appears in another window.
The mouse can be used instead of the keyboard for some actions:
- left button: as spacebar, execute the zoom
- middle button: increase zooming factor by 1.414
- right button: exit
Next: GreG Manual
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Gildas manager
2014-07-01