PICtor is an

image file format An image file format is a file format for a digital image. There are many formats that can be used, such as JPEG, PNG, and GIF. Most formats up until 2022 were for storing 2D images, not 3D ones. The data stored in an image file format may be co ...

developed by John Bridges, the principal author of PCPaint, the first Paintbrush program for the PC. It was also the native file format for Pictor Paint and Graphics Animation System for Professionals (GRASP) (also by Bridges) and became the first widely accepted DOS imaging standard.

Typical file format

The PICtor format is a device-independent raster image format; the file header stores information about the display hardware (screen resolution,

color depth Color depth, also known as bit depth, is either the number of bits used to indicate the color of a single pixel, or the number of bits used for each color component of a single pixel. When referring to a pixel, the concept can be defined as bit ...

and palette information, bit planes, and so on) separately from the actual image information, allowing the image to be properly transferred and displayed on computer systems with different hardware. PIC files commonly stored palette-indexed images ranging from 2 or 4 colors to 16 and 256 colors, although the format has been extended to record true-color (24-bit) images as well. Although it is device-independent, the PIC format also contains additional information about the device that it was created on, which sometimes leads PCPaint Pictor PIC files to be described as a "device-dependent" format. The encoding of a PIC file is also optimized for decoding quickly onto the native device that it was created on. PICtor image data is compressed using an advanced form of

encoding In communications and Data processing, information processing, code is a system of rules to convert information—such as a letter (alphabet), letter, word, sound, image, or gesture—into another form, sometimes data compression, shortened or ...

, and a parent-child block-based algorithm which collapses a series of consecutive bytes with identical colors into an encoded child block within a parent block while also allowing non-consecutive bytes to be included as raw data within the same parent block. As the file is processed during decoding, the child blocks in each parent block are unpacked either into an

off-screen buffer A framebuffer (frame buffer, or sometimes framestore) is a portion of random-access memory (RAM) containing a bitmap that drives a video display. It is a memory buffer containing data representing all the pixels in a complete video frame. Mode ...

if not displaying in native mode, or directly into the display adapter if in native mode (which results in quicker unpacking).

References

External links

Pictor PC Paint File Format SummaryGRASP File Format SummaryPCPAINT/Pictor Page Format Description
Format by John Bridges. Document by Microtex Industries, Inc. Revision Date: 2/9/88
GL — Another animation format
Dr. Martin Reddy (Technical Lead, R & D, Pixar Animation Studios). The Graphics File Formats Page {{Graphics file formats Graphics file formats