Short: HiQuality-HAM8 IFF-24bit image viewer Author: Smack/Infect! (Michael Henke) Type: gfx/show Architecture: m68k-amigaos $VER: h8ilbm 0.1 (Sat 16-Dec-2000) #features -high quality display for AGA machines (18bit-RGB) (this program is not particularly useful for graphics board owners) -supports IFF-ILBM 24bit files only (there is a similar program called 'h8jpg' on Aminet for JPEG images) -free software (full source code included, of course) #requirements -CPU 68020+ -AmigaOS V37+ -AGA chipset -asyncio.library V39+ -developed on A1200 (68030+882 @ 40MHz, 16MB FastMem, Delfina1200 DSP) #recommended -reqtools.library V38+ -some IFF-ILBM 24bit files #how to use h8ilbm is a shell-only program, these options can be used: FILES............one or more filenames (the keyword FILES is optional). if omitted a reqtools file requester appears. MID .....screen mode ID. if omitted the default mode ID 0x8020 is used. specify a decimal or hexadecimal (prefix $ or 0x) value. (example: PAL:Super-High Res - 167968 or 0x29020) SMR..............summon a reqtools screen mode requester. Use these keys on the h8ilbm screen: Esc..................quit Space/Return/RMB.....next image cursor keys..........scroll image (8 pixels) shift + cursor keys..scroll image (32 pixels) alt + cursor keys....scroll image (maximum) (if the screen is larger than the visible area you can scroll it around with mouse movements) #known problems -images are shown in a low resolution and/or with wrong aspect ratio This is a side-effect of the particular rendering technique used in this image viewer. It's sometimes called "18bit-HAM8 RGBB" mode and has often been used in demos for colourful 3D-Effects and such stuff. The basic principle is that each original true color pixel (24bit) is represented by four screen pixels in a special HAM8 pattern. This results in the image appearing four times wider on the screen, which can be compensated by displaying the screen in a "Super-HiRes" mode (e.g. PAL: 1280x256 pixels). The screen then looks like "Low-Res" (320x256) because all those four- component pixels mix nicely into single "true color" pixels. -rendered images use very much chip memory This is another consequence of the rendering technique used: graphics memory consumption is four times higher than with "normal" image viewers. h8ilbm tries to load the entire image into chip memory, creating a large screen that can be moved smoothly and easily using the mouse. However, if the image is too large then h8ilbm switches to "buffer mode": the image is loaded to FastRAM and only a part of it is rendered to a normal-sized screen. Move this part around using the keys listed above. #author mailto: Michael Henke h8ilbm - HiQuality-HAM8 IFF-24bit image viewer Copyright (C) 2000 Michael Henke This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA