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* [ grob2eps.c]
* [ grob2eps.c]
* [ My HP48 and HP49 software] → [] → hp48.dtx → grob2eps.c
* [ My HP48 and HP49 software] → [] → hp48.dtx → grob2eps.c
* [[Farbfeld Utilities]]
== Sample files ==
== Sample files ==

Latest revision as of 07:27, 8 December 2019

File Format
Extension(s) .grb, .gro, others
Released ~1990

GROB is a (usually) bi-level raster graphics format associated with HP-48 and HP-49 series calculators.

There are two ways to encode a GROB image: "binary" and "ASCII". Sometimes, GROB images are also ASC-encoded.


[edit] Format details

Binary format has an 18-byte header, followed by the pixel data.

[edit] Grayscale images

Although the format only really supports bi-level images, some images are intended to be interpreted as grayscale with 2 bits/pixel (or perhaps more). The physical image consists of the bit-planes stacked vertically. Unfortunately, there does not seem to be any way to detect whether this is the case.

[edit] Identification

A binary GROB file begins with "HPHP48" or "HPHP49", and has bytes 1E 2B at offset 8.

ASCII format apparently begins with "GROB ". An ASCII GROB might be embedded inside a script, or preceded by a "%%HP" header line, so it won't necessarily start at the beginning of the file.

[edit] Software

[edit] Sample files

[edit] Binary

[edit] ASCII

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