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Bitmap, abbreviated to BMP, is a raster graphic format created by Microsoft the late 1980s. Because the format was designed to work on both Windows and OS/2 Warp, it was built with portability in mind, so technical information about how to draw the image is stored in the file allowing the graphic to be displayed by a variety of hardware and software. However, due to the low sales of OS/2 Warp, few programs or libraries which support the BMP format support the OS/2 Warp variations. The format has undergone a number of changes over the years which have added numerous new functionality, but also making it difficult for viewer programs to support all the options. The latest format supports color depths of 1, 4, 8, 16, 24 and 32 bits-per-pixel, multiple compression algorithms, alpha transparency, masking, and halftoning. For a while, BMP was preferred because it required much less effort to implement than formats like GIF, PNG, or JPEG, but, with so many free libraries available for these formats, BMP has mostly fallen into disuse. Formats derived from BMP include ICO, CUR, and WMF.


I was introduced to the bitmap format in the early 1990s with Windows 3.0. This also introduced me to the Paintbrush program which allowed me to make my own. After using later versions of Windows I saw a variety of new bitmap images from the platform's games, applications, and included wallpapers. At the time, I didn't really know much about the format's internals other than it could handle 16-color and black & white images, but, as I became more interested in graphic formats, I became to learn more about what the format was capable of. I generally find the format to be a relatively simple, if severely inferior, graphic format and almost never use it unless a programming library requires it.



In its original form, bitmaps were either uncompressed or used 4-bit run-length encoding. Over the years, new compression formats were added like 8 and 24-bit RLE and Huffman 1D. The format can also encapsulate a JPEG or PNG image.


In its original format, bitmap could only support 1 or 4 bit color, that is, true black and white and 16 colors. Over the years, the format was upgraded to include 8, 16, 24, and 32 bit color as well.


Program Functions Notes
Corel Draw Open, Save Can import and export. Supports few features.
Corel Photo-Paint Open, Edit, Save Supports few features, but it does handle OS/2 Warp format.
GraphicsGale Open, Edit, Save Supports few features.
ImageMagick Open, Edit, Save Supports all features and OS/2 Warp format.
Inkscape Open Can import with some features.
IrfanView Open Can open and display most features.
LibreOffice Open, Save Can import and export with few features. Open, Edit, Save Supports few features.