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|
.\" xzoom.man
.\" Copyright Itai Nahshon
.\"
.TH XZOOM 1X
.SH NAME
xzoom \- magnify part of the screen, with fast updates
.SH SYNOPSIS
.B xzoom
[ \-display \fIdisplayname\fP ] [ \-mag \fImag\fP [ \fImag\fP ] ]
[ \-x ] [ \-y ] [ \-xy ]
[ \-geometry \fIgeometry\fP ] [ \-source \fIgeometry\fP ]
.SH OPTIONS
.LP
.TP 5
.B \-display \fIdisplayname\fP \fR|\fP \-d \fIdisplayname\fP
The name of the display to use
(not very useful).
.TP 5
.B \-mag \fImag\fP [ \fImag\fP ]
What magnification to use. If two number arguments are supplied the
first is used for X magniications and the second is used for Y magnification.
Magnification should be greater than 0.
.TP 5
.B \-x
Mirror horizontally.
.TP 5
.B \-y
Mirror vertically.
.TP 5
.B \-xy \fR|\fP \-z
Exchange X and Y axes before any magnification is performed.
.TP 5
.B \-geometry \fIgeometry\fP \fR|\fP =\fIgeometry\fP
Size and position \fBxzoom\fR's window.
.TP 5
.B \-source \fIgeometry\fP
Size and position the initial source area which is magnified.
The dimensions of this area are multiplied by the magnification to
get the size of \fBxzoom\fR's window. If these dimensions are given
separately (by use of \-geometry ) then an error is reported.
.br
.SH DESCRIPTION
.IR Xzoom
displays in its window a magnified area of the X11 display.
The user can interactively change the zoomed area, the window
size, magnification (optionally different magnification for
X and Y axes) or rotate or mirror the image.
.SH COMMANDS
.LP
Once xzoom has started the user can enter simple commands
using the keyboard.
.LP
.TP 5
.B q
quit.
.TP 5
.B \+
increase magnification value by 1.
.TP 5
.B \-
decrease magnification value by 1.
.TP 5
.B w
next \+ or \- command only affect X magnification.
.TP 5
.B h
next \+ or \- command only affect Y magnification.
.TP 5
.B x
mirror the display image horizontally.
.TP 5
.B y
mirror the display image vertically.
.TP 5
.B z
rotate the displayed image 90 degrees counter-clockwise.
.TP 5
.B arrow keys
scroll the zoomed area 1 pixel in the direction of the arrow.
if the
.B control
key is pressed the zoomed area will scroll 10 pixels.
.TP 5
.B d
sets the delay between frame updates.
Built-in delays are 200, 100, 50, 10 and 0 ms.
.TP 5
.B g
toggle grid on and off.
.TP 5
.B Mouse buttons
To set the location of the magnified are click the left mouse
button inside xzoom's window and then move it (keep the button
pressed) to the place which you want to see magnified.
.sp 1
Xzoom allow you to resize it's window at any time.
.sp 1
When xzoom is iconified it simply waits to get deiconified.
.SH DISPLAYS
Xzoom uses the window's title bar to inform the user about
it's status. Normally the title says something like
.B "xzoom x2"
which means the magnification is 2 both in X and Y axes.
If the image is stretched differently on the X and Y axes
the title will say
.B "xzoom X 2; Y 4."
Negative numbers mean reflection.
If the image is rotated by 90 or 270 degrees the title
will show
.B "<=>"
between the X and Y values.
.sp 1
When
.B d
is depressed the title will display the new delay value for
approximately 2 seconds and then revert to the default display
of magnification values.
.SH PERFORMANCE
Xzoom is fast enough to display enlarged or mirrored animations
in small windows. On my 486 DX2-66 and Cirrus Logic CL-GD5428
display card (attached to Vesa local bus) update of a 256x256
window magnified by 2 (ie, source rect is 128x128) takes
approximately 30 ms. This time varies, off course when
a different size window or different magnification is used.
If we chose 50 ms between updates we can get about 12.5 frames per
second and still let an animation program do it's work.
It is possible to compile xzoom without X shared memory support.
In that case window update may be about 3 times slower (if we
are using a local display, using LAN is a different story).
.SH SEE ALSO
xmag.1x.
.br
I got the motivation for writing xzoom after I saw a similar
WindowsNT program, zoomin working. It started just as a test
for X11 performance. I don't have the fancy menus and scrollbar
like zoomin but I do have all their features (and more) accessible
from the keyboard.
.SH BUGS
.LP 5
\(dg
The maximum internal built in delay (see command
.B d
above) was set to 200 ms. Xzoom completes the delay before
polling the X event queue for the next command. Larger
delays would feel like poor response to user commands.
.LP 5
\(dg
For best performance the shared memory extension for X11 is
used. Xzoom will fail if it is compiled to use XSHM and its
display is not on the local host.
.LP 5
\(dg
The Ximage data is accessed directly, in a way which may
not be portable. Xzoom will not run with display depth other
than 8 bits per pixel.
.LP 5
\(dg
Xzoom is given with no warranty. It was tested only under
Linux with Xfree86 release 3.1.2 (X11R6).
.LP 5
\(dg
Some strange behavior may occur if the requested magnified area
falls beyond the borders of the screen. Example is when you have
magnification of 1 and a window whose width is greater than the
height of the screen and you want 90 degrees rotation. In that
case part of the window will not get updated.
.LP 5
\(dg
The frame used to mark the zoomed area may corrupt the contents
of other windows if they are modified when the frame is visible.
If you don't like it disable the \-DFRAME option when compiling
xzoom.
.SH AUTHOR
Itai Nahshon
|
