From 4bfd864f10b68b71482b35c818559068ef8d5797 Mon Sep 17 00:00:00 2001 From: Thomas Voss Date: Wed, 27 Nov 2024 20:54:24 +0100 Subject: doc: Add RFC documents --- doc/rfc/rfc797.txt | 116 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 116 insertions(+) create mode 100644 doc/rfc/rfc797.txt (limited to 'doc/rfc/rfc797.txt') diff --git a/doc/rfc/rfc797.txt b/doc/rfc/rfc797.txt new file mode 100644 index 0000000..14dd946 --- /dev/null +++ b/doc/rfc/rfc797.txt @@ -0,0 +1,116 @@ + + +Network Working Group A. Katz +Request for Comments: 797 ISI + September 1981 + + + FORMAT FOR BITMAP FILES + + This note describes a proposed format for storing simple bitmaps (one + bit per pixel) in a file. These files may be very large and the + intent is to use this format for short term storage and passing data + between closely coupled programs. The data in the file should be + stored in 8-bit bytes (octets). Bitmaps may be any size. + + The first 4 octets of the file gives the width of each line (x + direction), and the next 4 octets should give the number of lines of + the display (length, y direction). After this is one octet for the x + increment and one octet for the y increment. Following these 10 + octets is the bitmap itself. The length and width fields are + stored most significant octet first. + + The x and y increment octets tell how much space is between pixels. + For an ordinary display, both these would be one. + + Each line of the display should be scanned from left to right. The + lines should start at the top and work down. Each line in the bitmap + should end on an octet boundary. If the width of the display is not + divisable by 8, the rest of the last octet should be filled with + zeros on the right. + + Below is a representation of a bitmap file (each square is one + octet): + + ---------------------------------------------------------- + | 1 | 2 | 3 | 4 | 5 | + | width | width | width | width | length | + ---------------------------------------------------------- + + ---------------------------------------------------------- + | 6 | 7 | 8 | 9 | 10 | + | length | length | length |x-increment|y-increment| + ---------------------------------------------------------- + + ---------------------------------------------------------- + | 11 | 12 | 13 | 14 | 15 + | data | data | data | data | data... + ---------------------------------------------------------- + + For example, bitmaps from the RAPICOM 450 can be in Fine Detail, + Quality, or Express Mode. In Fine Detail mode the x-increment and + y-increment would be 1, for Quality mode, the x-increment would be 1 + and the y-increment would be 2, and for Express mode, the x-increment + + + +Alan R. Katz [page 1] + + + + would be 1 and the y-increment would be 3. For these bitmaps it is + intended that each scan line be repeated y-increment times when they + are displayed. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +[page 2] Alan R. Katz + -- cgit v1.2.3