PROGRAM: LEACH VERSION 1.3 WRITTEN BY: DREW LUCY DATE: 5/88 COPYRIGHT NOTICE This program is copyrighted. However, it may be copied and distributed freely so long as this "readme" file is distributed with the executable. USER BEWARE Leach does several things that no well behaved program would dream of doing in a multitasking environment. To date, it has never harmed any disk resident data. Version 1.3 is ALMOST impossible to crash when used with any of the Digi-View programs. However, there is always a chance that it may hang up the the Amiga. Leach also has some quirky interactions with the paint programs. The author is is not responsible for any ill effects that result from the execution of this program. DESCRIPTION Leach is potentially useful only if you own NewTek Inc's "Digi-View" system, Aegis Images or Graphicraft. It is intended for people whose interest in precision digitizing goes beyond "getting the color of her nipples to come out right". When run in parallel with a compatible Host program, Leach allows you to make fairly precise measurements of pixel distances and angles in a digitized image. The unusual feature of Leach is that you make these measurements while ALL of Host's functions are still available to you. Leach allows you to manipulate a "ruler" line that it draws directly onto the Host screen image. While all this is going on, the Host continues to function (more or less) normally. CHANGES FROM VER 1.2 TO VER 1.3 * Heavily modified method of handling Intuition <--> Host message traffic. Hopefully, this change has increased Leach's reliability. * Ruler line no longer jumps to the mouse pointer when the Host window is activated by a mouse click. CHANGES FROM VER 1.1 TO VER 1.2 * An evolutionary deadend that was never distributed. CHANGES FROM VER 1.0 TO VER 1.1 * Corrected rounding error in slope calculation. * Leach no longer disturbs the drawing color of host paint programs. * Ruler is drawn in a solid color instead of complementing the pixels of the underlying image. This has significantly slowed the ruler generation rate, but I think the improved visibility is worth it. The ruler color may be altered with the "<" & ">" gadgets at the far right of the status screen. CHANGES FROM VER 0.1 TO VER 1.0 * Leach has been run successfully against Graphicraft and Images, as well as all Digi-View programs. * New mouse pointer for easier end point placement. * Degree read out in tenths of a degree so each slope is unique. * Succesfully removes its menu from the Host's menu strip when Leach's close window gadget is clicked. Leach's menu has become the last menu item in the Host's first menu. * Ver 1.0 does a MUCH better job of handling the message traffic between Intuition and the Host, which means it won't crash nearly as often. OPERATING INSTRUCTIONS This version of Leach can not be used from WorkBench. From CLI, the procedure for using Leach is as follows: 1) "Run" the desired compatible Host program. I believe Leach will run against any of the Digi-View programs (LORES, MEDRES, INTERLACE, etc). However, leach has not been tested with the hires (640x400 color) program. Leach has also been used successfully against Graphicraft 1.1 and both Images Version 1.1 programs. 2) After the Host screen appears, switch back to the WorkBench screen by entering the "Left_Amiga-N" key combination. Click on the CLI window to reactivate it. IMAGES WARNING: Images is a tricky Host to work with. The Fast Menu window must be closed while you attach Leach to Images. 3) To start Leach use the command appropreate for the Host: Host CLI Command (quote marks are necessary) -----------------+---------------------------------------------------------- Any Digi-View | run leach Graphicraft | run leach "Graphicraft Version 1.1" Images (320x200) | run leach "Aegis Images V1.1" Images (320x400) | run leach "IHR VERSION 1.1" -----------------+---------------------------------------------------------- Leach will automatically bring the Host screen back to the front. Leach will abort shortly after it is run, if it can't find the Host in memory. 4) Once the Host screen has reappeared, you may opperate the Host exactly as you normally would, OR... 5) Notice that a "LEACH" menu item now appears at the bottom of the Host's first menu. Select the "Scr On" subitem and the Leach status screen will appear at the bottom of the display. 6) Click the "SHOW" gadget on the Leach status screen. The ruler line will appear on the Host screen and the "MOVE" gadget becomes enabled. At this point, you still can't move the ruler. 7) Click Leach's "MOVE" gadget. Now, click once on the Host's screen to reactiveate it, then clicking anywhere on the Host image (except near the ruler's endpoints) will cause the ruler to jump to the position of the mouse pointer. The ruler can not be positioned so that it would be partially off screen. Pressing and holding the Select Button very near one of the ruler's endpoints will cause that endpoint to jump to the pointer and then follow it as long as the Select Button is held down. 8) The "<" and ">" gadgets on the Leach status screen change the color register used to draw the ruler. 9) You may terminate Leach by clicking the close gadget in its status window. In this case, the Host continues to execute. Leach will also terminate if you select the Host's "QUIT" menu item. RANDOM NOTES Leach has one particularly un-nerving habit. The first time that you move a ruler endpoint, the internal disk drive may spin briefly. Leach is loading mathieeedoubbas.library from SYS:Libs, in order to perform its first trig calculation. By the way, the above mentioned library MUST be there. The Leach gadget labels always reflect the action that will be taken when they are selected, not the current state of the program. Thus if the left gadget is labeled "SHOW", the ruler will be invisible, right? If the ruler is made invisible for any reason, it will also be frozen and the move/freeze gadget will be disabled. Selecting an item from any Host menu automatically hides and freezes the ruler and turns the status screen off. After making such a selection, you must repeat steps 5, 6 and 7 to reveal and mobilize the ruler line again. Selecting the "Scr Off" submenu item turns the status screen off but does not affect the state of the ruler. When used on HAM mode screens, the ruler causes the colors to "smear" in the pixels to its immediate right. This is an unavoidable side effect of HAM. Drawing over the ruler in Graphicraft or Images will leave parts of the ruler etched into the Host image. Things can get a little weird at quitting time, if the Host throws up a requester. If you get tossed back to the CLI window but it is ghosted, use Left_Amiga-M to see if the Host is still running and waiting for you to satisfy a requestor. Digi-View doesn't have this problem but Images and Graphicraft do. Leach often spits out a "failure" message when it terminates. Don't worry about it. The command line argument you give Leach is the Host screen title exactly as it appears in the Host's Screen structure. It is case sensitive. However, leading spaces may be omitted. Note that there are two spaces between "Graphicraft" and "Version" in Graphicraft's title. IMAGES WARNING: Images makes use of the MENUVERIFY IDCMP flag. Leach currently disables this feature because the Amiga was locking up whenever the menu button was pressed. When using Leach with Images, aviod pressing the right mouse button if Images is in the middle of rendering to the screen. I understand why MENUVERIFY can cause problems but, I haven't yet come up with a clean and effective way of solving the problem. Maybe for Version 1.4. Leach exibits some other strange behaviors when used with Images. It works but, expect to receive some funny error messages. I find Leach useful for precision digitizing. Without it, even simple tasks, like making sure that horizontal lines are really horizontal, can be frustrating and time consuming. However, Leach is a kludge at best. I hope that, along with other goodies, the next release of the Digi-View software will include features similar to but better than, the one that Leach breaks the rules to provide. Bug reports and enhancement suggestions would be welcomed. I can be contacted through... CompuServe ID 76337,75 Please leave email rather than (or in addition to) Forum messages. Message life spans are shorter than the interval between my visits to the forum. US Mail Drew Lucy 6777 Upper York Road Star Route Box 102C New Hope, PA 18938