X11 Pixmap (XPM) Reader/Writer

Licensing options for this format begin with FME Desktop Professional Edition.

The X11 Pixmap (XPM) Reader/Writer provides FME with access to data in the XPM format.

Overview

The XPM file consists of a three-dimensional array of bits corresponding to a two-dimensional array of pixels. It is used, for example, in the X Window System to describe a memory region where graphics can be drawn without affecting the screen. Typically this is used for the efficient handling of expose events and icon images, or for animation.

XPM files have a color depth limit of 87 colors – all images converted into XPM will be reduced to 87 colors.

Currently, the XPM reader can read only 8-bit per pixel XPM images, and one-band XPM images.

Reader Overview

The FME considers a single XPM file to be a dataset. The XPM file contains pixel data. Each pixel in the file is a point in a single XPM raster feature.

Writer Overview

The XPM writer creates and writes data into a single folder specified by the Writer Dataset. The XPM writer distinguishes duplicate output files by appending numbers to the filenames.

FME Raster Features

FME raster features represent raster data and use several concepts that are unlike those used in the handling of vector data. The topics below describe how FME processes raster data.

About FME Rasters Tiling and Mosaicking
Raster Properties Band Combining and Separating
Band Properties Band and Palette Selection
Palette Properties Raster Processing
Compression Raster versus Vector Features
Pyramiding Raster File Naming
Interleaving World Files
Interpretation and Data Type TAB Files
Palette Resolution  

XPM files can only be written with square pixel dimensions.

XPM only supports rasters with a single UInt8 band that has a RGB24 palette.