docs

README.md

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+# a2fc.system
+a very small `.a2fc` graphics file viewer for Apple II computers
+
+`.a2fc` ("Apple II Full Color") files are uncompressed double hi-res graphics files that can be displayed on any Apple //e or later with an extended 80-column card.
+
+## Usage
+
+`a2fc.system` has no user interface. It is designed to take the pathname of an .a2fc file as a startup program, as explained in [ProDOS 8 Technical Reference Manual §5.1.5.1](http://www.easy68k.com/paulrsm/6502/PDOS8TRM.HTM#5.1.5.1). If this pathname is not supplied, `a2fc.system` will simply quit.
+
+ProDOS 2.4.1 users: if you rename `a2fc.system` to `basis.system` and put it in the root directory of your startup disk, you can select any `.a2fc` file in Bitsy Bye and it will be passed to `basis.system` as the startup program and displayed properly.
+
+ProSel users: you can create a ProSel item that displays an `.a2fc` graphic file. Assuming `a2fc.system` is `/HD/BIN/A2FC.SYSTEM` and your graphic file is `/HD/PHOTOS/MYPIC.A2FC`:
+
+````
+Screen title:     -your choice-
+Prefix:           ?BIN/
+Application path: A2FC.SYSTEM
+Startup:          ?PHOTOS/MYPIC.A2FC
+````
+
+## Tools to create A2FC files
+
+ * [BMPA2FC](http://www.appleoldies.ca/graphics/index.htm#dhgr) (Windows)
+ * [Buckshot](https://apple2.gs/buckshot/) (macOS)
+ 
+Beagle Graphics used separate files to store double hi-res graphics, a `.bin` and `.aux` file. You can easily combine these into a single `.a2fc` file. The `.aux` part goes first.
+
+ ````
+ ]BLOAD MYPIC.AUX,A$2000
+ ]BLOAD MYPIC.BIN,A$4000
+ ]BSAVE MYPIC.A2FC,A$2000,L$4000
+ ````
+