PCX File Format Specification

PCX file is a native file format. This format invented by Zsoft for its PC paintbrush products. PCX format uses a run-length encoded (RLE) algorithm to compress the bitmap data. It’s very common in a bitmap image to have pixels of the same color appearing consecutively. It was the first graphics file format to be come a standard for bitmap file storage on IBM pc’s. Generally, PCX files are divided into three sections in the following order: a PCX header, the bit map data and an optional color table. The PCX format was originally developed for EGA & CGA display adapters and was later modified to support VGA and true-color adapters. PCX images can be encoded with 24,8,4 or 1 bits per pixel. Adobe photoshop can export in PCX format, but today it is rarely used for any kind of image representation. PCX file is an image editor and saving in a more common format for file conversions. This type of file format especially used for 320 X 200 X 256 VGA mode .

• It’s file format size are very large.
• It compatible only with PC.
• some older PCX version support 256 colors.
• Doesn’t support other platforms.

The PCX file structure uses colour palettes or colour planes to store pixel data for images. If color palette is used, RGB palettes are stored in the colour table. When PCX structure uses colour planes it does not required color table. Because each pixel colours information of all (Red, Green, Blue) colours is stored in the image data. The colour palette structure of PCX files vary according to different versions of it. This file format mostly used by computer games and other types of graphics utilites.