From 055f6e3880952fef7d4748fbe266a8ad59db01d2 Mon Sep 17 00:00:00 2001 From: cybernesto Date: Sat, 29 Jun 2013 18:12:41 +0200 Subject: [PATCH] Create README.md First short description of the display routine --- README.md | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 README.md diff --git a/README.md b/README.md new file mode 100644 index 0000000..578e9e1 --- /dev/null +++ b/README.md @@ -0,0 +1,39 @@ +VBMP +==== + +BMP Viewer for the Apple II + +Introduction +============ +This project is based on the work of Arnaud Cocquière and his hommage to Steve Jobs. +http://www.ctrl-pomme-reset.fr/2011/10/11/hommage/ + +Unlike most images shown on the Apple II, the image displayed is actually a BMP file +without additional conversion. The disk includes the sources for the BMP viewer, so I +decided to study it and learn a bit of 6502 assemmbly and graphics programming on the +Apple II. +Since my Apple IIc supports DHGR graphics I started playing with it to add support to +16 color BMPs and monochrome pictures in Double High-Res. I thought this could be useful +for someone else so I asked Arnaud for permission to publish it in GitHub. + +Usage +===== +The code uses the Merlin Assembler syntax. Just load it in Merlin on the Apple II and it +should compile without problems. +To load BMPs in the DSK Image I recommend Apple Commander, but Cider Press might do as +well. Just import the BMP as a Raw binary file. +Using Applesoft you can load the image with the following commands +BLOAD IMAGE.BMP,A$4000 +BRUN DISPLAY + +Supported formats +================= +The viewer supports BMP Images with the following resolutions and color depths +Monochrome (1bit color depth) 280 x 192 px +Monochrome (1bit color depth) 560 x 192 px +16 Color (4bit color depth) 140 x 192 px +The formats are automatically detected based on the horizontal resolution. Using different +formats as the ones listed may lead to unexpected results since the format check has been +kept as simple as possible. + +