PICT is a
graphics
Graphics () are visual images or designs on some surface, such as a wall, canvas, screen, paper, or stone, to inform, illustrate, or entertain. In contemporary usage, it includes a pictorial representation of the data, as in design and manufa ...
file format
A file format is a Computer standard, standard way that information is encoded for storage in a computer file. It specifies how bits are used to encode information in a digital storage medium. File formats may be either proprietary format, pr ...
introduced on the original
Apple Macintosh computer as its standard
metafile format. It allows the interchange of graphics (both
bitmapped and
vector), and some limited text support, between Mac applications, and was the native graphics format of
QuickDraw.
The PICT file format consists essentially of a series of QuickDraw commands. The original version, PICT 1, was designed to be as compact as possible while describing vector graphics. To this end, it featured single byte
opcode
In computing, an opcode (abbreviated from operation code) is an enumerated value that specifies the operation to be performed. Opcodes are employed in hardware devices such as arithmetic logic units (ALUs), central processing units (CPUs), and ...
s, many of which embodied operations such as "do the previous operation again". As such it was quite memory efficient, but not very expandable. With the introduction of the
Macintosh II and Color
QuickDraw, PICT was revised to version 2. This version featured 16-bit opcodes and numerous changes which enhanced its utility. PICT 1 opcodes were supported as a subset for backward compatibility.
Within a Mac application, any sequence of drawing operations could be simply recorded/encoded to the PICT format by opening a "Picture", then closing it after issuing the required commands. By saving the resulting byte stream as a
resource
''Resource'' refers to all the materials available in our environment which are Technology, technologically accessible, Economics, economically feasible and Culture, culturally Sustainability, sustainable and help us to satisfy our needs and want ...
, a ''PICT resource'' resulted, which could be loaded and played back at any time. The same stream could be saved to a data file on disk (with 512 bytes of unused header space added) as a PICT file.
With the change to
Mac OS X and discontinuation of QuickDraw, PICT was dropped in favor of
Portable Document Format
Portable document format (PDF), standardized as ISO 32000, is a file format developed by Adobe in 1992 to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating syste ...
(PDF) as the native metafile format, though PICT support is retained by many applications as it was so widely supported on
Classic Mac OS
Mac OS (originally System Software; retronym: Classic Mac OS) is the series of operating systems developed for the Mac (computer), Macintosh family of personal computers by Apple Computer, Inc. from 1984 to 2001, starting with System 1 and end ...
.
This "PICT" image format supports single channel and color channel RGB images and grayscale images.
Photoshop no longer has the ability to open PICT files which use QuickDraw object data (but can open simple raster-based PICTs), and cannot save files in PICT format.
PICT versions
The PICT format has two versions:
*PICT 1 format: The old format that only allowed eight colors and focused on compact storage.
*PICT 2 format: A superset of format 1 that supports 4, 8, 16 and 24-bit color and greyscale images. 32-bit color with a generally unused alpha channel is also supported. Furthermore certain compressed PixMap types can be included using QuickTime.
Compression method
With the
QuickTime 2.0 multimedia framework,
Apple
An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...
added support for compression using
JPEG
JPEG ( , short for Joint Photographic Experts Group and sometimes retroactively referred to as JPEG 1) is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degr ...
or any other QuickTime compressor to bitmaps embedded in PICT data.
References
Further reading
External links
Apple Developer Legacy documentationDescription at fileformats.archiveteam.org
Graphics file formats
Macintosh operating systems
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