Xwd
In the X Window System, the program xwd (X Window dump) captures the content of a screen or of a window and optionally saves it into a file.[1]
xwd
runs in one of two ways: if a user specifies the whole screen or the name or identifier of a window as an argument, the program captures the content of the window; otherwise, it changes the shape of the cursor and waits for the user to click in a window, whose content is then captured.
Operation
At the X Window core protocol level, xwd uses the fact that any X client can request the content of an arbitrary window, including ones it did not create, using the GetImage
request (this is done by the XGetImage
function in the Xlib library). The content of the whole screen is obtained by requesting the content of the root window.
The file generated by xwd can then be read by various other X utilities such as xwud, sxwd, xv, and the GIMP, or converted to other formats; the ImageMagick suite allows the construction of a useful pipeline:
$ xwd | convert xwd:- screenshot.png
The dumps are larger in size than files in most image file formats – not only compressed formats such as PNG, but also uncompressed bitmap formats like BMP.
.xwd
September 1987; 36 years ago (1987-09)
Image format
Various image viewers and tools support the X11 .xwd
format, among others the GIMP, ImageMagick, Netpbm, and XnView. In version 2.1.4 FFmpeg supported pixel formats bgra, rgba, argb, abgr, rgb24, bgr24, rgb565be, rgb565le, bgr565be, bgr565le, rgb555be, rgb555le, bgr555be, bgr555le, rgb8, bgr8, rgb4_byte, bgr4_byte, pal8, gray, and monow. In these abbreviations 555 means 32768=32×32×32 colors, 565 means 65536 colors (6 bits for green), rgba is red-green-blue-alpha, 4 or 8 stands for 16 or 256 colors, le or be is the endianness, pal is an input palette, etc. as listed by ffmpeg –pix_fmts
.[3]
Details of the .xwd
format in XWDFile.h
depend on the platform, therefore it is unsuited for cross-platform applications and has no MIME image type.[2]
See also
References
- ^ Tyler, Chris (2008). X Power Tools. O'Reilly Series. O'Reilly Media, Inc. p. 107. ISBN 9780596101954. Retrieved 2014-01-23.
The X window dump (xwd) tool takes a snapshot of the current screen, a manually selected window or a window designated by its numeric ID, and outputs the image to standard output or to a file.
- ^ a b James D. Murray; William vanRyper (April 1996). Encyclopedia of Graphics File Formats, Second Edition. O'Reilly. ISBN 1-56592-161-5. Retrieved 2014-02-27.
- ^ "Image Formats". FFmpeg General Documentation. 2014. Retrieved 2014-02-23.
External links
- xwd is part of X11's standard distribution, but its source can also be downloaded separately as tar.bz2 or tar.gz
- Image::XWD Perl package at CPAN
- v
- t
- e
- ANI
- ANIM
- APNG
- ART
- AVIF
- BMP
- BPG
- BSAVE
- CAL
- CIN
- CPC
- CPT
- DDS
- DPX
- ECW
- EXR
- FITS
- FLIC
- FLIF
- FPX
- GIF
- HDRi
- HEVC
- ICER
- ICNS
- ICO / CUR
- ICS
- ILBM
- JBIG
- JBIG2
- JNG
- JPEG
- JPEG-LS
- JPEG 2000
- JPEG XL
- JPEG XR
- JPEG XS
- JPEG XT
- KRA
- MNG
- MIFF
- NRRD
- ORA
- PAM
- PBM / PGM / PPM / PNM
- PCX
- PGF
- PICtor
- PNG
- PSD / PSB
- PSP
- QOI
- QTVR
- RAS
- RGBE
- SGI
- TGA
- TIFF
- UFO / UFP
- WBMP
- WebP
- XBM
- XCF
- XPM
- XWD
Category
Comparison