Truevision TGA , often referred to as TARGA , is a raster graphics file format created by Truevision Inc. (now acquired by Avid Technology). It was the native format of TARGA and VISTA boards, which were the first graphic cards for IBM-compatible PCs to support Highcolor/truecolor display. This family of graphic cards was intended for professional computer image synthesis and video editing with PCs; for this reason, usual resolutions of TGA image files match those of the NTSC and PAL video formats.
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TGA files commonly have the extension ".tga" on PC DOS/Windows systems and Mac OS X (older Macintosh systems use the "TPIC" type code). The format can store image data with 8, 16, 24, or 32 bits of precision per pixel – the maximum 24 bits of RGB and an extra 8-bit alpha channel. Color data can be color-mapped, or in direct color or truecolor format. Image data may be stored raw, or optionally, a lossless PackBits RLE compression can be employed.
TGA files are in widespread use due to their simplicity and ease of implementation and lack of encumbering patents.
The compression method used in Targa images (Run Length Encoding) performs poorly when compressing images with many color variations, such as digital photos, but works well for textures and simpler images. |