What is an XPM file?
A file with .xpm extension is an image file format that was used by the X Windows System. It supports transparent pixels and usually targets creating icon pixmaps. It supports monochrome, gra-scale, and color pixmap data. These were designed to be editable by hand and can be included in C code. For this purpose, XPM files are in plain text file format and follow the C programming language syntax. XPM files can be opened with a variety of image viewing application such as CorelDRAW Graphics Suite 2020, Corel PaintShop Pro, IrfanView, and Canvas X.
XPM File Format
The XPM file format uses C syntax in order for these to be integrated in C and C++ programs. It consists of the following six different sections.
- <Values>
- <Colors>
- <Pixels>
- <Extensions>
The sections are actually an array of strings as follow.
/* XPM */
static char*<variable_name>[] = {
<Values>
<Colors>
<Pixels>
<Extensions>
};
Following are the details of each section.
<Values> - This section is a string that contains four or six integers that are in base 10 and correspond to the:
- pixmap width and height
- number of Colors
- number of characters per pixel
- optional hotspot coordinates and XPMEXT tag
<Colors> - This section contains as many strings as there are colors. Each string is as follows:
<chars> {<key> <color>}+
<Pixels> - This section is composed of strings and *<chars_per_pixel> characters. Every <chars_per_pixel> length string should be one of the previously defined groups in the section.
<Extension> - The extension section must be labeled, if it is not empty, in the section. It may consist of several subsections which may be of the following two types:
- one stand alone string composed as follows: XPMEXT
- or a block composed by several strings:XPMEXT
