NAME

xwpick - pick images from an X11-screen and store in files

SYNOPSIS

xwpick [-local] [-window id] [-gray] [-reverse] [-pause] [-format frmt] [<file>]

DESCRIPTION

Xwpick lets you pick an image from an arbitrary window or rectangular area of an X11-server and write it to a file in a variety of formats.

The output format is defined whether by the -format option or by the extension in the file name. Possible formats/extentions are:

ps: An Encapsulated PostScript file with a compressed image. The image is centered, rotated and scaled to fill the maximum space on a page. It is displayed in color on viewers and printers that support color Postscript, otherwise it is displayed as grayscale. This format is convenient for transparency preparation.
eps: Also an Encapsulated PostScript file with a compressed image, but the image is only centered, not rotated and scaled. It is intended for insertion into a document.
epsi: The same as eps, but contains a black and white preview.
gif: Graphics Interchange Format (GIF). Use this format when you want to keep files or transfer them to other computers. It is also convenient for visualisations, for example, with xv by John Bradley.
pcx: PCX format for IBM PC.
pict: PICT format for Macintosh. It is intended for image transfer on Macintosh, but GIF format is also convenient for this purpose (see Macintosh GIFConverter by Kevin A. Mitchell).
ppm: PPM format from the PBM Plus library by Jef Poskanzer. Use it and a routine from the PBM Plus library if you wish to have the image in a format not mentioned above.

The main feature of xwpick is that it uses the Lempel-Ziv Welch (LZW) compression scheme for image encoding in Postscript, thus producing very compact files (4-5 times less than files produced with Run-Length encoding (RLE) and 10-20 times less than files produced without compression)

HOW IT WORKS

When xwpick is invoked, the user sees a blinking rectangle surrounding the contents of the window in which the mouse pointer is currently placed. When the mouse is moved to a different window, the perimeter automatically changes to the size of the new window. If the mouse pointer is placed on the Window Manager border of a window, then the blinking rectangle will surround the window together with the Window Manager border. To select the image inside the blinking rectangle it is sufficient to click the left mouse button.

If a user-defined perimeter is required, then hold down the left mouse button to choose the first corner of the perimeter and then drag the mouse to define the opposite corner. The blinking rectangle will expand with the movement of the mouse.

If it is required to produce some changes inside the selected area just before outputing to a file, for example, to change the palette or display a pop-up menu, then the -pause option can be used.

OPTIONS

-local: When -local is in the parameter list, xwpick picks an image from the window under the mouse pointer. This option is intended to pick images from pop-up menus, which are on the screen only when a mouse button is pressed and disappear immediately after the button is released.
-window id: Pick an image from the window with integer identifier equal to id. The identifier for a window can be obtained with the X Window program xwininfo. To pick the entire screen (root window) the user may use the word root as an identifier.
-gray: Transfer the image to grayscale. This option can be used to optimize output on level 1 gray scale PostScript printers.
-reverse: Transfer the image to reverse colors. This option can help you to save the toner on your printer in case when the image is too dark.
-pause: Do not output the image till the <SPACE> bar will be pressed. This option allows to use the mouse to produce some changes inside the selected image just before outputing to a file.
-format frmt: Set output format. The format is defined by frmt string. If this option is omited, then the output format is defined by the extension in the file name. Possible frmt strings/extensions are: ps, eps, epsi, gif, pcx, pict, ppm. In case when -format is in the parameter list and a file name is omited the output is directed to the standard output.

EXAMPLES

•: xwpick

This is the simplest form of use. You will be prompted to input a file name.

•: xwpick image.ppm
ppmtoxpm image >image.xpm

This is an example of how to get an image in X11 pixmap format. First you pick the image from the screen into the file image.ppm and then convert it using the ppmtoxpm routine from the PBM PLUS library.

•: xwpick -local menu.epsi

This is an example of how to pick the image of a pop-up menu window and store it in a file as encapsulated Postscript with preview.

•: xwininfo
xwpick -w 0x8000c1 -g clock.ps

This is an example of how to pick an image from the window by the window's identifier. First you find the identifier using the xwininfo command and then pick an image from the window and store it in a Postscript file as a grayscale image.

•: xwpick -window root -format ps | lpr

This is an example of how to send an image of the root window directly to the printer.

AUTHOR

Evgeni Chernyaev chernaev@mx.ihep.su