ARCHIVED: What is the XBM graphics file format?
X Bit Map (XBM) is a simple graphics format used primarily in the X Window System, though it is also in limited use on the web. Although even the oldest graphical web browsers (especially in X) are able to display XBM images, their limitations make them an unpopular choice among most web designers.
XBM files are 1-bit (i.e., black and white) images. The white portions of the image are usually displayed as being transparent, which means in most cases the background color or pattern beneath the image shows through.
Also, unlike GIF, JPEG, and many other image formats, an XBM file is not compressed. In fact, if you were to open one in a text editor, you would be able to see the coordinates for the image in plain text. This means that XBM files take up much more disk space than similarly sized images of other formats.
On the web, these limitations have relegated the role of XBM files to very small images, often representing scientific formulas or characters that cannot be displayed in ASCII text (e.g., checkmarks, Greek letters, and other symbols). They are also frequently used in web counters.
Last modified on November 01, 2008.
