WATCH-IT - Picture Viewer for Atari ST/STE/TT/Falcon030 Version 1.0a ----------------------------------------------------------------------------- Author : Stefan Bock email : sbock@informatik.uni-kl.de All rights are reserved by the author. 1. What is it ? ---------------- WATCH-IT is a picture viewer for Atari ST/STE/TT/Falcon030 computers. It was planned as a viewer for the new Falcon computer only, supporting the 256-colour-resolution and the truecolour-resolution, but as it is a plain GEM-program, you can also start it on the "old" Ataris as well. WATCH-IT runs on all memory-configurations, but 512 KByte may be too small for big pictures. 2. How to start it ------------------- There are three ways to run the program: i) application : if you start WATCH-IT as an application, a file selector will appear. Choose a picture file here (at the moment, only GIF is supported, others will follow soon). Once the file is loaded, depacked and transformed into a bitmap, it will be displayed in a window. ii) commandline : starting the program from a shell or from the desktop with one or more filenames as arguments will load all specified files as long as - there are AES-windows left, - there is enough memory left and - the internal limit of 32 windows is not exceeded. WATCH-IT uses ARGV for extended commandlines. iii) accessory : clicking on the menu entry will give you the file-selector where you can choose a picture (see i) ). 3. How to operate it --------------------- - You can move and size the window as usual and scroll the picture with the sliders if it is bigger than the window. If you move the mouse over the window and the picture can be scrolled, the arrow will change into a sort of cross-cursor which indicates the directions the picture can be scrolled to (play around with this, it's easy). Now press and hold the left mouse-button. The picture can be scrolled by moving the mouse until the left button is released again. - Cursor keys scroll the picture, too, and SHIFT+ scrolls a page at a time. - A double-click on the picture or pressing -I or gives you an information-window: Here you find the width, height and palette size of the picture, the time it took WATCH-IT to process the picture (including loading-time) and the amount of RAM it uses. Note that WATCH-IT uses some bufferspace during depacking and dithering, so this displayed amount is smaller than the memory you need to process the picture. You will also find four buttons labeled "Greyscale", "Colour", "No dither" and "FS-Dither". These are not selectable in this release, sorry, but definitely will be in the next version, so you can choose your favourite display-mode here. At the moment, a default mode is choosen depending on the resolution (see below). - Pressing HELP reveals a help window. Click on "OK" or press to close this window. - Click on "LOAD" in the info/help-window or press -O to load another picture. In accessory-mode clicking on the menu-entry has the same effect. - Press -W to cycle through all open windows. - Press -U to close the actual window or -Q to close all windows (when the program has been started as an application, this means "Quit") 4. The picture format(s) ------------------------ At the moment this is only GIF format, but others will follow. If you have suggestions about what formats should be supported, please contact the author (format descriptions are welcome, too). GIF-formats 87a and 89a can be loaded, even though WATCH-IT only inter- pretes the main picture data. I never came across a GIF-file with more than one picture in it, but if you have such pictures which you cannot display properly with WATCH-IT, tell me, perhaps i can change it. "The Graphics Interchange Format(c) is the Copyright property of CompuServe Incorporated. GIF(sm) is a Service Mark property of CompuServe Incorporated." 5. The display modes --------------------- As mentioned earlier, WATCH-IT was written for the "Falcon resolutions", and pictures will definitely look best in these resolutions. Nevertheless I included dither-algorithms for monochrome and 16-colour-modes, too. Some more dither algorithms and greyscale modes are already finished, but didn't make it into this first release version, sorry. Note that pictures have to be processed in device-independant format and then transformed into the device-dependant format, this will take a little bit more time than writing the data directly into screen-memory, but is unavoidable in a GEM-program. On the other hand WATCH-IT will (at least it should :-)) run on all resolutions. If WATCH-IT does not run on your graphic- card, please let me know. i) Truecolour-mode: This mode has only been tested on the Falcons truecolour-mode. It should run on all resolutions with a device-independant format containing 16 planes, but i have no information about how RGB-values are coded on other graphic-cards (they _should_ do it like the falcon, otherwise the format would not be very device-independant, huh ?). You can have multiple pictures at the same time each one having its correct palette. Hey, this is so great, if you don't have a FALCON, get one :-) ! ii) 256-colour-mode: This mode is used on resolutions with 8 planes, e.g. Falcon or TT-LOW. The picture will be displayed without dithering. Anyway, WATCH-IT never uses VDI-colours 0 to 15, since these colours should be fixed for all applications. Instead, WATCH-IT shuffles around the colours and substitutes similiar ones so that the VDI-colours don't have to be used. Note that the palette can only be correct for the topped window, other pictures may look quite strange. Simply top the window you wish to look at and the correct palette is used. By the way, pictures look a little bit like "widescreen" cinema on TT-LOW. The reason is the strange pixel ratio on this resolution (320 x 480). This may be fixed in future releases. iii) 16-colour-mode: This mode is used on resolutions with 4 planes, e.g. TT-MID or ST-LOW. It is the most time-consuming mode, since reducing 256 colours to 16 colours is not that easy. A special dither-algorithm is used (3 Floyd- Steinberg-passes) so that all pictures can use the same palette, that means you can have multiple windows which all look correct at the same time). Pictures look best when viewed from some distance from the screen. There are other possibilities to reduce the colours. An often used method is to choose the 16 most used colours. This is definitely faster than dithering, but in my opinion often has too poor results. If you know better methods, please tell me ! Anyway, a 16 greyscale-mode will be included in future releases. iv) Monochrome-mode: If none of the above modes can be used (e.g. on ST-HIGH, ST-MID or TT-HIGH), WATCH-IT will switch to monochrome-mode. The picture is dithered with Floyd-Steinberg error diffusion and displayed in VDI-colours 0 and 1. This normally means black and white, but of course you can change this with the control panel (feel like Andy Warhol!) . 6. WATCH-IT and MultiTos ------------------------- WATCH-IT runs under MultiTos, even though it can't handle it's own windows during depacking and dithering. This is so because depacker and plotter are written in highly optimized assembler and calling aes-functions during depack would slow down the whole thing significantly. However other applications can run during WATCH-IT does its work. I consider writing a special MultiTos version which forks the depacker and ditherer so that they can run in the background while WATCH-IT-windows can still be moved. Any ideas about this (except from integrating the depacker into the event-loop which i definitely won't do !) are welcome ! Under MultiTos, no busy-bee is shown as this would be senseless in a multitasking environment. The help and info-dialog are shown in windows, so dialog-boxes won't block the system. 7. Error messages ------------------ Out of AES-windows : Close some windows and try again or get MultiTos Max. 32 windows allowed : This is the current limit. Read error in header, palette or image : The picture file is corrupted, you can try to load it anyway (press "Yes" in the "proceed ?" - alertbox), but the picture may look strange. 8. Disclaimer -------------- I really don't know how this program could harm you or your computer, but: The author makes no warranties of quality or performance for this program. Use it at your own risk ! 9. Feedback ------------ If you - have found bugs, - don't like the user interface, - can't get the program to work at all, - have good ideas how to improve this program, - or just want to say a few words concerning this program, contact me via email: sbock@informatik.uni-kl.de (this address will only be valid until end of september 1992) or in IRC (nickname : Robo). Enjoy !