In this documentation, ICON and ICN# refer to the specific resource types, while "icon" in lower case refers merely to the screen image, be it ICON or ICN#. An ICON resource is a 32x32 bit image used for illustration, while an ICN# is an ICON plus a 32x32 bit mask which is used for highlighting the icon image when selected. The finder uses the mask in two ways: First, whatever is black in either icon or mask is what you have to hit to select the file when you click, and whatever is black in the icon, or black in the mask, but NOT in both, is black when selected. You can use this feature to design some pretty spiffy images.
Pasting in icons is real easy, and only takes five minutes. If you're interested in how it works, read the articles in issues #1 and 2 of MacUser. If you just want to bang out some icons, read on.
You need the target application (call it "Target"), ResEdit, and Fedit, Setfile, or some other means of altering the file flags.
First: NEVER work with your only copy of any file. Put an extra copy of ResEdit and Target on a spare disk. If you prefer working with a ramdisk, fine. ResEdit has an annoying tendency to bomb at inopportune moments, so save your changes often.
Remember the following definitions:
Open = Double-click
Select = Single-click
Selected = Highlighted
Activate = Single-click in a window (so the bars on top light up)
Step 1.
Run ResEdit. There's one window for each disk in a drive; each has a list of all resources on each disk.
Step 2.
OPEN Target. Its internal resources will appear. Some applications may have only a CODE resource. You will need to add to this list a BNDL, FREF, ICN#, all of which you'll get from ResEdit (because it's handy) and one other type I'll describe later. (You can also take the icon from any of the icon files on this disk.) If any of those types already exist in target, the procedure is slightly different, in that some of your PASTEs below might wipe out existing resources already needed by the file. The chances are that this won't happen for files with a generic icon, so I'll stick with the easiest situation.
Step 3.
OPEN ResEdit. Select its BNDL. (You don't have to open it, ResEdit has only one BNDL.) COPY it, activate Target's window, and PASTE. OPEN the BNDL, OPEN BNDL ID = 128, and change Ownername (the top box) to a unique four-character name eg, TARG. If the application already has a creator name, you can use it if it's unique. If it's not unique, every other application with the same creator will be displayed with the same icon. Now close the BNDL windows.
Step 4.
Activate the ResEdit window, Select its FREF (again only one FREF), COPY it, activate Target's window, and PASTE. Don't alter this.
Step 5.
Activate the ResEdit window, Select its ICN#, COPY it, activate Target's window, and PASTE. Again, only one icon in this icon list, and we'll edit it later.
Step 6.
Still in the Target window, pull down NEW from the file menu. A dialog box showing different resource types will appear. Ignore them, and type the same four-letter code (in the same case) you chose for the Ownername, and then click OK. This is a "Version" resource, and it must match the Ownername which we put in the BNDL. A new, highlighted entry appears in Target's window. OPEN it. Pull down NEW again from the file menu. Another window appears, "TARGs in Target", with a single entry TARG ID= 12345 (or some other random number). This window is immediately covered by an overlying window labelled "TARG ID = 12345 in Target" containing a Data= box. Close this top window, and while TARG ID= 12345 (or whatever) is still highlighted, pull down GET INFO from the file menu. Type 0 (Zero) to change the highlighted random number to zero. Close this window, and all the other windows of Target. SAVE the changes to Target when asked. Breathe a sigh of relief that ResEdit didn't crash yet. To be safe, exit ResEdit to copy this file to another disk.
Step 7.
Now that you've got an icon in the file, you may want to customize it. The ResEdit procedure is as follows: Reopen Target, then its ICN#, and finally the icon you pasted there. You'll get a fatbits image to edit. Work on the left (icon) side. When you get the icon the way you want it, pull down Data -> Mask from the Icn# menu. Generally you want to fill in the mask. Remember how the Finder uses the mask: whatever is black in either icon or mask is what you have to hit to select the file when you click, and whatever is black in the icon, or black in the mask, but NOT in both, is black when selected.
The smaller images you see below represent various selection states of the file. All you really care about are the two images on the left, which represent the normal and selected icons respectively. When you're done editing, close all the windows and SAVE the changes when asked.
Step 8.
Now that your icon is complete, you need to run Setfile, Fedit, or its equivalent, to set the bundle bit and enter the same creator name for the Finder's use, so it knows to look for the icon. Once this is done, target should appear in all its glory.
