NCAUG Meeting Notes - ImageFX - Cinematte & scripts in AutoFX and IMP


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ImageFX keyboard shortcuts to remember


There are a number of useful keyboard shortcuts that aren't apparent in the menus on screen in ImageFX. These are the ones I use most often:

  • "Shift" "1" - Starts REXX recording. When you press this key combination ImageFX will ask you for the name for the rexx script you are recording and subsequently if it should record the current drawing settings.

    (Important note: Typically the filename requester will open in the REXX directory in your ImageFX directory were many macros are stored. If you intend to use your macro in the AutoFX batch processor you should save it there. Using a REXX macro in AutoFX that isn't stored in its own directory can result in "hanging" your Amiga. More information on the AutoFX batch processor is provided below.)

  • "Shift" "2" - Stops REXX recording. When you press this key combination ImageFX will stop recording your macro.
  • "r" - Forces a redraw of the active image buffer.
  • "." - Drops the currently held brush.
  • "j" - Switches the "MAIN" and "SWAP" buffers.





Recording a rexx macro script


As mentioned above, ImageFX can record any actions or steps you take to process an image into a REXX script which can be subsequently used to process multiple images or edited before further use. Simply press "Shift""1" to begin the recording process. You will be prompted for a filename and location to save your script as. Then you will be prompted if you wish to save your current drawing settings in the script. For a general script that you may use in many situations this is probably not necessary. When you've finished the processes you wish you cease recording the rexx macro by pressing "Shift""2". You will then be able to use this script to repeat your actions on any number of images.





Cinematte


Cinematte is a "Hook" in ImageFX and can be found by clicking on the "Hook" button on the control panel. It is used to composite images using what is traditionally called a "Matte" shot or the "Blue Screen" technique."Blue Screen" simply means shooting a subject against a screen of a unified color. This image of your subject is later composited with a "background" image and the areas of your subject's image where the "key" color exists are replaced with the image in your background image.

Using this "Hook" it is important to remember that your subject image, the image with the blue screen (or whatever color) behind the subject, must be loaded into the MAIN buffer and your "background" image must be loaded into the SWAP buffer. Once this is done you can call the Cinematte Hook in the "Hooks" menu.

The Cinmatte Hook presents you with a requester with a number of gadgets to allow a great deal of control of how you will composite your images.





AutoFX


AutoFX is one of two batch processors in ImageFX that allows you to process multiple images with scripts. With the release of ImageFX 4 it became possible to process multiple frames of a sequence within a single buffer window but the number of frames you may process this way is limited by the amount of ram you have in your machine. You may use Virtual Memory to allow the processing of more images in a sequence within a buffer window but I've found processing large sequences this way is somewhat unreliable and may result in lost time and unpredictable results. It is best to record rexx macros and use AutoFX or IMP to batch process images in the background when dealing with large sequences.

You may call AutoFX by starting ImageFX with the AutoFX icon or from within ImageFX by calling the AutoFX Hook in the Hook menu. This brings up the AutoFX requester which basically gives you many options for selecting files and scripts to use to process those files.

You begin by selecting files or sequences of files in the window on the left of the requester. When you have highlighted all the files you want you click on the "Add Files" button under the "Image Files" heading in the center of the requester. You will find all of the files you highlighted have been added to the window on the top-right. There is a gadget beneath them that allows you to select "MAIN","SWAP" or "Alpha Channel". You need to preset this to the appropriate buffer you wish to add images to before you click on the "Add Files" button. If you were assembling a "Blue Screen" or "Matte" shot using the Cinematte Hook you would add the sequence of blue screen images in the MAIN buffer and your background image sequence in the SWAP buffer.

After doing this you need to select the scripts you wish to use to operate on your images. By default the Load.ifx script is already in the script window. Now click on the "Add Command" to select a new script to operate on your images. If you were assembling a "Matte" sequence you would select the "CineMatte.ifx" script in the REXX/AutoFX directory. Then you would need to select a script to save your composited images like the "SaveBufferAs_ILBM.ifx script. The scripts are executed in the order you have them in the window so you need to use the "Move Commands" button to place the scripts in the order you wish them to be executed. When you have finished selecting your scripts and placing them in the proper order of execution you should click on the "Begin" button at the bottom-center of the AutoFX requester. AutoFX will execute all your scripts on your sequences of images unless there is a problem that results in an error.





IMP






Editing a script to use in IMP