September 96 - Using Apple Guide 2.1 With OpenDoc
Using
Apple Guide 2.1 With OpenDoc
Peter Commons
You've
helped create an Apple Guide guide for your standalone application. Now your
company is writing an OpenDoc part editor, but it's not obvious how Apple Guide
can be used in the context of parts and compound documents. The answer is Apple
Guide 2.1, which extends the original version to allow easy use of Apple Guide
features, including Help menu management, coachmarks, and context checks, in
the world of OpenDoc. This article introduces the new features of Apple Guide
2.1 and explains in detail how to use them with OpenDoc.
The world of OpenDoc isn't like the world of the standalone "behemoth"
application -- a fact that hasn't escaped the notice of developers who want to
provide online help. An application developer can easily provide complete
online help since the application is a single self-contained unit that will run
in its own window. On the other hand, the developer of an OpenDoc part editor
never knows what other part editors will be running along with it during an
OpenDoc session. Users can have any number of part editors running in any
number of windows at the same time. All the editors might belong to a package
written by one company, or, more likely, it might be a conglomeration written
by a number of different companies. Under these circumstances, providing help
gets a little more complicated.
Since Apple Guide is such a powerful help system, wouldn't it be nice if it
could be applied to the new world of OpenDoc? Enter Apple Guide 2.1 (released
right on the heels of Cyberdog, Apple's new integrated suite of OpenDoc part
editors for the Internet). The raison d'être of Apple Guide 2.1 is to
support Apple Guide for OpenDoc, with particular emphasis on Cyberdog. This
version includes a number of new features, some of which are specific to
OpenDoc and some of which aren't. Among these new features are the following:
- a combined Full Access window (known as a Merged Access window) that
contains all the guide topic areas and index terms for OpenDoc part editors
currently running
- a similar ability to merge guides in conventional applications
- the ability to specify a list of applications for which a particular
guide is intended
- support for a whole new series of OpenDoc-related context checks
In
this article, I'll describe how Apple Guide behavior has changed in the world
of OpenDoc, and I'll also tell you about some new features of Apple Guide 2.1
that you can use in conventional applications. I'll go over the simple steps
you must take to add a guide to an OpenDoc part editor, and then I'll cover
some of the things you could do, depending on the kinds of help you want to
provide for your part editor. You'll find samples of the resources mentioned in
the article on this issue's CD.
If you haven't worked with Apple Guide before, you might want to read "Giving
Users Help With Apple Guide" in develop Issue 18 before tackling the new
concepts presented here. Apple Guide Complete is the definitive reference,
though the current (1995) edition doesn't cover Apple Guide 2.1.
From the beginning, one of the strengths of Apple Guide has been that it
enables guide authors to create guides without requiring modification of the
application being guided. While most other new Toolbox managers were saying,
"To support me, just add a NewManagerIdle call in your main event loop," Apple
Guide said simply, "I work just fine without any modifications to your
application at all!" One of the key elements enabling Apple Guide to work
without requiring changes to any code is Apple Guide's automatic population of
the Help menu.
The Help menu has also been called the Guide menu at certain times in its
history, but both names refer to the same menu (the one labeled with a question
mark).
The algorithm Apple Guide uses to determine how to populate the Help menu,
although simple on the surface, has a number of subtleties. With each new
release, the algorithm has been extended somewhat. To understand how the Help
menu is populated in Apple Guide 2.1, let's look at how the population
algorithm has developed over time. You Apple Guide experts might even discover
some little-known features.
Table 1 presents a summary of how the different versions of Apple Guide
populate the Help menu; details follow.
How populating the Help menu has evolved
Original Apple Guide
- Guide files in application's folder.
- Based on (App Creator), (Gestalt), 'QLfy'.
- Based on type [About, Tutorial, Help, Shortcuts, Othr]. There can be only one guide
file of each type except Other.
Apple Guide 2.0
- Add guide files in Global Guide Files folder.
- No changes.
- Guide files in application's folder take precedence
over those in Global Guide Files folder.
Apple Guide 2.1
- For OpenDoc shell documents, change application's folder to mean
document's folder.
- Add an exclusion check based on resources of type 'prts' [for OpenDoc]
and 'apsg' [for applications].
- Multiprocess guide files ['prts' for OpenDoc, 'mlti' for others],
if present, are accessed through the "ProcessName Guide" item in the Help type menu position. Guide files with the 'apsg' resource appear in the Help menus of multiple applications.
Note: All candidates are determined when the Help menu is built. Exclusions are
applied at the time the menu is built, except for the 'prts' resource test,
which is applied when Apple Guide is launched.
The general process of populating the Help menu hasn't changed since Apple
Guide was first introduced. At application launch time, Apple Guide does the
following:
- creates a list of possible guide file candidates
- excludes any candidates that don't match required criteria
- puts the names of all remaining guide files in their requested
positions in the Help menu
For the original version of Apple Guide (any
version before Apple Guide 2.0), the list of candidates is created by searching
for all guide files that are in the same folder as the application being
launched and that aren't Mixin guide files (see Apple Guide Complete, page
2-14, for details about Mixin guide files). A guide file with an alias in the
application's folder would also be added to the list of candidates.
Apple Guide then sees if any candidates should be excluded by subjecting them
to these tests:
- If the guide file contains an <App Creator> command specifying a
value that doesn't match the signature of the current application, it's
excluded (see Apple Guide Complete, page 10-8).
- If the guide file specifies one or more <Gestalt> checks and no
<Gestalt> selector returns its required value, the guide file is excluded
(see Apple Guide Complete, page 10-10).
- If the guide file specifies exactly one <Gestalt> check whose
selector is 'QLfy', Apple Guide looks in the guide file's resource fork for a
resource of type 'QLfy' with a resource ID equal to the requiredValue parameter
of the <Gestalt> command. If it finds such a resource, it assumes it's a
680x0 code resource that takes no parameters and returns a short in register D0
(standard C calling conventions). It calls the resource code and, if the result
is 0, the guide file is excluded (see develop Issue 18, page 19).
Apple
Guide then tries to place the name of each remaining candidate in the position
it requested with the helpType parameter of the <Help Menu> command (see
Apple Guide Complete, page 10-14). Placement of the names of different types of
guide files is shown in Figure 1. If two or more final candidate guide files
have the same type and that type isn't Other, Apple Guide includes the name of
the first guide file of that type (by alphabetical order) and excludes the
others. The names of all guide files of type Other appear in the Help menu.
Figure
1. Placement of Help menu items by type in original Apple Guide
Apple Guide 2.0 (an update to System 7.5 but backward-compatible with System 7
and 7.1) added some logic to the Help menu population algorithm that hasn't
been widely documented. The crux was adding a new place to look for candidate
guide files, called the Global Guide Files folder. The Global Guide Files
folder resides in the Extensions folder and, as its name suggests, is a place
where you can put guide files to make them available to all applications.
When Apple Guide 2.0 is creating its list of candidate guide files for an
application, it looks both in the folder containing the application and in the
Global Guide Files folder. When looking to exclude candidates, Apple Guide 2.0
works almost exactly like the original Apple Guide -- it excludes any guide
files from its candidate list that don't pass the <App Creator>,
<Gestalt>, and 'QLfy' tests.
The only difference is in how Apple Guide 2.0 selects an item for the Help menu
if there are multiple candidates. In the original Apple Guide, if two guide
files passed all the tests and were of the same type (aside from type Other),
the one sorting first alphabetically would be chosen for inclusion. In Apple
Guide 2.0, if there are two or more guide files of the same type, the first one
alphabetically is still chosen for inclusion, but any guide file in the
application's folder is chosen over any guide file in the Global Guide Files
folder. So, for example, if there are Tutorial guide files in the application's
folder and also in the Global Guide Files folder, those in the Global Guide
Files folder will be ignored, and the one that's first alphabetically in the
application's folder will be chosen for inclusion. Names of guide files of type
Other are added from both the application folder and the Global Guide Files
folder.
Apple Guide 2.1 adds two new mechanisms to the process of building the Help
menu:
- the ability to define multiprocess guide files (with an 'mlti' or a 'prts'
resource) and to access these files as a group through a single menu item that
presents the user with a combined Full Access window (available in both OpenDoc
part editors and conventional applications)
- the ability to specify a list of application signatures that your guide
supports (with an 'apsg' resource), so that the name of your guide will appear
in the Help menu for each of those applications
We'll look at these new
mechanisms in more detail in the next section.
In addition, Apple Guide 2.1 supports document-specific help. Recall that when
creating a list of candidate guide files, Apple Guide 2.0 looks in the same
folder as the application and in the Global Guide Files folder. Apple Guide 2.1
behaves exactly the same way for conventional applications, but for OpenDoc
documents launched via the OpenDoc shell application, Apple Guide 2.1 treats
the document's folder as the "application's folder," so it looks in the same
folder as the document for guide files, rather than in the same folder as the
OpenDoc shell application (besides searching the Global Guide Files folder). As
a result, the names of guide files in the same folder as the OpenDoc shell
application never appear in the Help menu; the names of guide files in the same
folder as an OpenDoc document can appear in the Help menu for that document.
Apple Guide 2.1 introduces a new concept: the multiprocess guide file. A
multiprocess guide file is specified by including in the guide file an 'mlti'
resource for conventional applications or a 'prts' resource for OpenDoc part
editors. Because these two are so similar, I'll discuss them together. I'll
also tell you more about the new 'apsg' resource, which when added to a guide
file means that the guide file's name will appear in the Help menus of multiple
applications.
Before multiprocess guide files, the name of every guide file that met Apple
Guide's criteria for inclusion in the Help menu appeared as its own menu item.
Multiprocess guide files are different. All multiprocess guide files that are
candidate guide files and that aren't excluded for any reason (other than that
there's more than one of them) get grouped together with the Help guide file
(if there is one). This group is accessed through a single Help menu item
labeled "Process Name Guide," where Process Name is the document name for
OpenDoc and the application name for conventional applications. This item is
placed in the menu position that the name of the Help guide file would
otherwise occupy. Figure 2 shows a Help menu with a multiprocess guide item for
a Cyberdog document called Peter's Notebook.
Figure
2. A Help menu with a multiprocess guide item
When users choose the multiprocess guide menu item from the Help menu in a
conventional application, they get a combined Full Access window, known as a
Merged Access window, with these features:
- Topic areas for each multiprocess guide and for the Help guide, listed
under the guide file's name in the order specified in the guide's topic area
list (see Figure 3).
- Index terms for each multiprocess guide, combined, alphabetized, and
with duplicates merged. When an index term is selected in the left pane, all
topics associated with the term are listed on the right for all guides (Figure
4).
- "Look For" search capability, which can search all multiprocess guide
files independently and return a list combining all the topics that match in
each guide file (Figure 5).
Figure
3. Merged Access window with topic areas
Figure
4. Merged Access window with index terms
Figure
5. Merged Access window with "Look For" search
If
a guide file has an 'mlti' or a 'prts' resource, Apple Guide 2.1 ignores the
guide file type specified by the <Help Menu> command. However, for
backward compatibility, you probably should declare your multiprocess guides as
type Other using the <Help Menu> command so that Apple Guide versions
before 2.1 will list them individually in the Help menu.
As I mentioned before, if there are both multiprocess guide files and a Help
guide file, the Help guide gets treated as if it were another multiprocess
guide and gets merged with them. If there's only a Help guide file and no
multiprocess guide files for an application, the name of the Help guide file
appears in its appointed slot in the Help menu, just as in previous versions of
Apple Guide. Note that if there are any multiprocess guides, the Help guide, if
supplied, must be a Full Access window guide to be listed in the Merged Access
window with the multiprocess guide files.
Multiprocess guide files aren't mixins, as explained in "Mixin vs. Multiprocess
Guide Files." For one thing, multiprocess guide files are treated independently
by Apple Guide and thus won't have resource conflicts with other multiprocess
guide files (unlike mixins). Furthermore, all multiprocess guides must have
topic areas and index terms (that is, they must be Full Access window guides);
if they don't, as you might expect, they won't be accessible in the Merged
Access window.
You might be asking, "What about mixins? Aren't they kinda like multiprocess
guide files? When would I use mixins instead?"
Mixin guide files are used to add, delete, or replace content in existing guide
files. Multiprocess guide files can't do this. Mixins work best for small,
incremental changes, but they require good resource management. They also
require a main guide file to modify.
Multiprocess guide files in OpenDoc never know which other guide files, if any,
will be there when OpenDoc is loaded, so you can't use a mixin in place of a
multiprocess guide file -- there may not be a main guide file to modify. Also,
you don't know which other mixins might be there, so resource conflicts could
easily occur.
But you can use a mixin to modify your own multiprocess guide if you do the
following:
- Put the <Mixin> command as the first line in your mixin source and
be sure to reference your multiprocess guide file's .sym file to avoid resource
conflicts.
- Add all the same exclusions as in your multiprocess guide file. Add
additional exclusions if your mixin should activate only in special situations.
- Add an 'mlti' or a 'prts' resource to your mixin if your main guide
file has one.
- Make sure your Mixin and your multiprocess guide files both use the
<Mixin Match> command so that your Mixin guide file mixes only into your
multiprocess guide file.
The 'prts' resource introduced in Apple Guide 2.1 is expressly for OpenDoc. If
the current process is an OpenDoc process (any process that supports OpenDoc
part embedding), guide files with a 'prts' resource (like those with an 'mlti'
resource) are grouped together in a Merged Access window when the user chooses
the Document Name Guide item from the Help menu.
But before Apple Guide adds multiprocess guide files for an OpenDoc process, it
performs one more exclusion check -- and unlike all the other exclusion
criteria, this one is applied each time Apple Guide is launched and not when
the Help menu is built. Apple Guide compares the list of part editor names in
the 'prts' resource with the list of part editors currently in the active
process and adds the guide file only if it finds a match. Thus, even though the
Global Guide Files folder will likely contain multiprocess guide files for
every OpenDoc part editor on the user's machine, the user will see help only
for editors currently in the active process -- sort of a "dynamic" Merged
Access window. If the 'prts' resource is empty -- that is, if it lists no part
editor names -- the guide will always be added to the Merged Access window if
the current process is an OpenDoc process.
Recall that if you specify a creator code in a guide with the <App
Creator> command, the guide file will be removed from the candidate list
unless the application's creator code matches. But what if you have a guide for
a suite of applications and you want it to appear in the Help menu for each of
those applications?
Until now, the only way to do this was to have all the applications in the same
folder as the guide file or to have a copy of the guide file (or an alias to
it) in each application's folder. With Apple Guide 2.1, you can get the desired
result much more cleanly and easily by adding to your guide file an 'apsg'
resource listing the application signatures that your guide supports. Then,
with your guide file in the Global Guide Files folder, the Help menu will be
appropriately populated for every listed application.
If you specify an 'apsg' resource and use an <App Creator> command, Apple
Guide 2.1 uses only the resource. If there's no resource, the <App
Creator> specification is used, if it exists. If you specify neither and you
put your guide file in the Global Guide Files folder, it will appear in the
Help menu for every application (which might not be what you want and could
greatly annoy your users).
That brings us to the present in the evolution of Apple Guide. Now we'll look
at the details of getting your guide file to work with OpenDoc. You'll see how
to make help for an OpenDoc part editor accessible to users, and how to add
coachmarks, context checks, and events once your guide is up and running.
Now that you know the history of Apple Guide and the Help menu, you've probably
got a pretty good idea of how to get your part editor's guide to appear where
you want it. Let's outline the preferred method to accomplish this:
- Add a 'prts' resource to your guide file. Use the 'prts' resource to
specify all the OpenDoc part editors your guide should go with -- that is, the
editors that when active should have your guide appear in the Merged Access
window. Normally, you'll specify only a single part editor, but if you're
writing a guide for a collection of related editors, you may list more. If you
want your guide to show up no matter which part editors are in the current
process, use an empty 'prts' resource (actually two bytes of zeros).
- Make your guide an Other guide file and specify a creator code of
'odtm', the signature of the OpenDoc shell. This ensures that your guide won't
appear in conventional applications if it ever ends up on a machine with an
older version of Apple Guide.
- Install your guide file in the Global Guide Files folder so that it's
available to all OpenDoc processes, regardless of how OpenDoc was launched. As
mentioned earlier, since OpenDoc is document-centered rather than
application-centered, guide files become candidates if they're in the Global
Guide Files folder or the same folder as the document the user double-clicks to
launch OpenDoc, so guide files in the OpenDoc shell application's folder won't
normally be considered.
Unless for some reason you want your guide to
appear as a multiprocess guide in conventional applications, you don't need and
shouldn't add an 'mlti' resource.
Guide Maker doesn't support the new resources yet, so they must be created by
hand where required. For the 'prts' resource needed by OpenDoc, I recommend
creating a file named MyGuideOpenDocResource that you can then reference from
your Guide Script source file with the line
<Resource> "MyGuideOpenDocResource", ALL
A
file on this issue's CD includes samples of these resources and ResEdit
templates. For the details, in Rez format, see "New Apple Guide Resources."
Apple Guide 2.1 introduces the 'mlti', 'prts', and 'apsg' resources to support
its new features. These resources must be created by hand.
The 'mlti' resource, by its mere existence, means the file is a multiprocess
guide file. This resource is four bytes of zeros.
type 'mlti' {
longint = 0;
};
The
'prts' resource is just like an 'STR#' resource -- a short specifying the
number of part editor names, followed by the names.
type 'prts' as 'STR#';
The
'apsg' resource is a long specifying the number of application signatures,
followed by those signatures.
type 'apsg' {
longint = $$Countof(SigArray);
array SigArray {
literal longint;
};
};
Here
are some examples of using these Rez templates:
// Multiprocess guide file -- conventional app
resource 'mlti' (1000) {};
// Multiprocess guide for OpenDoc to be merged
// when 'Test Clock' is in the active process
resource 'prts' (1000) {{
"Test Clock"
}};
// Guide only these two applications
resource 'apsg' (1000) {{
'ttxt', 'MSWD'
}};
You can provide access to your guide in ways other than Apple Guide's automatic
population of the Help menu if you don't mind a little code modification -- all
of the Apple Guide API calls still work just fine in OpenDoc, so you can add a
Guide button or a Help menu item to your part editor and then call AGOpen when
the user clicks or chooses that item. (See "Giving Users Help With Apple Guide"
in develop Issue 18 for a detailed description of the Apple Guide API.)
Don't modify the Help menu from within your part editor with the Toolbox calls
HMGetHelpMenuHandle and AppendMenu (although it's perfectly acceptable to do
this from within an application -- even an application that supports OpenDoc
embedding). The system, OpenDoc, and Apple Guide don't support this kind of use
and many problems will occur.*
If all you need is a simple "book" guide for your part editor, with no
coachmarks, context checks, or Apple events, you don't need to do anything else
-- carrying out the three steps listed above is enough to make Apple Guide help
for your part editor accessible within OpenDoc. If you want to provide more
elaborate help, read on.
Once your guide is up and running and the user has selected a topic, Apple
Guide 2.1 looks and acts just like previous versions of Apple Guide. The guide
window appears on top of the application, and users can click through the
guide's panels as they work in the application. But when the guide tries to
communicate with the outside world, some things become more complicated.
Specifically, you may have to take additional steps when you try to do any of
the following:
- Use a coachmark on a part.
- Get context information (perform context checks) on a part editor.
- Send Apple events to a part editor.
The good news is that sending
events to other applications such as Apple Guide or the Finder, or getting
system context information (such as how many monitors the computer has) or
anything else not specified above, works just the same, so I won't talk about
those things. Before reviewing the specific changes required to use coachmarks,
perform context checks on part editors, and send your part editor Apple events,
I need to discuss the biggest difference in approach required to use Apple
Guide with OpenDoc: I call it the "target application" problem.
Apple Guide was written to be very System 7 friendly, so almost everything
Apple Guide does relies on Apple events. Most of the Apple Guide API calls
(such as AGInstallContextHandler) secretly use Apple events to get their work
done. Unfortunately, when Apple events were designed, OpenDoc wasn't around.
Apple events rely on targeting specific processes (usually identified by
application signature). Apple Guide assumes that every application has a unique
static signature and that only one instance of the application will be running
at a time. (If you launch a second document for an application, the second
document is opened in the same process as the first one.) Neither of these
assumptions holds for OpenDoc.
The process signature for an OpenDoc process is the application signature for
the root application. For documents launched with the OpenDoc shell, that
signature is 'odtm'. For documents opened into other applications that support
embedded parts (as ClarisWorks will soon), the signature is that of the host
application. So if, for example, you target a coachmark at the 'odtm' process
and your current OpenDoc session is running in ClarisWorks, the coachmark won't
fire.
And there can be more than one process with the same signature running. If you
already have an OpenDoc document open and go to the Finder to launch a second
document, it launches as a separate process. So if both documents are launched
using the OpenDoc shell, there will be two processes with the 'odtm' signature
running concurrently. Then, for example, if you target a context check at the
'odtm' process, you have no idea which of the two processes will handle the
request.
Even if you somehow could manage to target the correct OpenDoc process, a
single OpenDoc process can have a number of part editors running inside it --
possibly multiple instances of the same part editor. How do you target a
specific editor inside a particular process?
Don't abandon hope -- all is not lost! But do keep this issue in mind as I
describe the steps you need to take to use some of the cooler Apple Guide
features.
There are two things you need to do to use coachmarks in OpenDoc: always use
the Guide Script constant FRONT (I'll give examples in a moment), and then use
context checks to ensure that your panel is displayed only when the user is in
the right process (that is, you need to ensure that the process you want to
coachmark is the front process). For the most part, you'll find that
coachmarks, except object coaches (because of the target limitation), work just
fine in OpenDoc.
Menu coaches are used to highlight a particular menu and menu item. You can
refer to a menu name and item by number or name.
Menu coaches work fine in OpenDoc. The only recommendation I have (whether or
not you're in OpenDoc) is always to specify menu titles and items by name and
not by number. This is especially important in OpenDoc, because individual
OpenDoc part editors can add menus and menu items at will (check out Cyberdog
for a great example of this). For example, to coach the Drafts item in the
Document menu, use something like this:
<Define Menu Coach> "DocumentDrafts", FRONT, REDUNDERLINE,
"Document", "Drafts...", RED, UNDERLINE
Window coaches mark static items in windows. They work in OpenDoc as in
applications. For example, you could coach the user to close the window called
Log with the following:
<Define Window Coach> "CloseBox", FRONT, REDCIRCLE,
"Log", CLOSEBOX
But
to have a window coach highlight a particular element of a part in a window is
usually impractical in OpenDoc, because the location of a part in a window
isn't predetermined. A part could be all by itself in its own window or
anywhere inside a container window. An exception to this is when a part is
viewed only in a situation where the offset from the window edges is known. A
good example of this is the Cyberdog Web browser part, shown in Figure 6. The
URL (Uniform Resource Locator) field is always in the same place because the
Web browser is always in its own window, so in this case you could coach the
URL field with the following window coach:
<Define Window Coach> "WebURLField", FRONT, REDARROW(1,4),
FRONT, Rect(0,0,125,100)
Figure
6. The Cyberdog Web browser window
Item coaches are used in Apple Guide to coachmark items specified by dialog ID
or balloon ID.
Dialog IDs work if your OpenDoc part editor brings up a standard dialog with
standard dialog items. Or you can use dialog IDs to coachmark items in the
OpenDoc shell dialogs. For example, to coach the Save Draft button in the
Drafts dialog, you could use the following item coach:
<Define Item Coach> "SaveDraftButton", FRONT, REDCIRCLE,
DialogID(1)
You'll
find that because standard Balloon Help doesn't work in OpenDoc except under
special circumstances, balloon IDs are probably too tricky to use. The reason
for this problem is conflicting assumptions in OpenDoc and Apple Guide about
the accessibility of resources. Apple Guide expects all the balloon resource
information to be available in the current resource chain. Logically, one would
store balloon resources for a part editor in its resource fork, but, due to the
intricacies of OpenDoc, a part editor's resource fork isn't available when
Apple Guide needs it. Since Apple Guide can't get at the Balloon Help
resources, it can't look up a balloon ID's rectangle, and thus you can't easily
u4e balloon IDs to coachmark items in OpenDoc.
OBJECT
COACHES
Object coaches rely on guide code inside a process to return the coaching
rectangle. The name of the desired object to be coached is passed to the
specified target application, which responds with the coaching rectangle.
Unfortunately, Apple Guide allows only one object coach handler per process. If
two part editors in one OpenDoc process both try to install object coach
handlers, the second one will override the first one (that is, any object
coaches will be handled by the second editor and never by the first). This
means you can't use object coaches reliably with OpenDoc processes.
If you decide to use object coaches in your part editor because you know that
yours will be the only one installing an object coach handler, be sure to use
the OpenDoc API to do the installation.
This obstacle to using object coaches in OpenDoc has been noted as a serious
concern by many people, including Apple Guide authors and those on the Apple
Guide and OpenDoc teams. Some possible solutions have been proposed. We can
hope that updated versions of Apple Guide and OpenDoc will support one of them
in the near future (although nothing has been promised yet).
AppleScript coaches don't require a target application at all, so they don't
suffer directly from the target application problem. To determine the target
rectangle, though, the script itself usually has to communicate with one or
more OpenDoc part editors. You can make part editors scriptable, but remember
to use OpenDoc's scripting API, not the regular AppleScript calls.
There are three sources of context checks for guides written for OpenDoc:
- the standard suite of context checks (part of the Standard Includes
package on most Apple Guide CDs)
- a new suite of standard OpenDoc context checks (designed expressly for
OpenDoc)
- any custom context checks you write for your OpenDoc part editor
only
The standard suite of context checks includes ways of testing basic elements of
the traditional Macintosh interface. Here are some examples of these context
checks:
- Is a window with a given name the frontmost window?
- Does this Macintosh have more than one monitor?
- Is the Open item in the File menu enabled?
The context check
definitions and the resources you must include in your guide to use them are on
any Apple Guide authoring CD (such as the CD that comes with Apple Guide
Complete, the Custom Solutions CD, or the Mac OS SDK CD).
These context checks work pretty well in OpenDoc processes. All of the system
information context checks work (bit depth, printer info, file sharing info,
and so on), because they all target the Finder for their information. The
application information context checks work (again, you'll have to target these
with FRONT), except for menu item checks, since OpenDoc controls how the menus
are stored and displayed. At present, if you're using the standard context
checks in an OpenDoc process, you can't determine whether a menu item is
enabled, is checked, or exists at all (though you can write a custom context
check to do this).
The process context checks do work, but they aren't very helpful because
they're based on target application signatures. For example, asking if the
current active process is 'odtm' will tell you if the active process is the
regular OpenDoc shell but won't help you determine whether it's some other
OpenDoc process (because the user could have some other OpenDoc shell
application). Nor will this confirm that the active process is the desired
process (since there could be several OpenDoc processes running).
To provide guide authors with tools to answer questions about OpenDoc
processes, a suite of OpenDoc context checks has been written. For these
context checks to work, the user must have an OpenDoc shell plug-in called
AppleGuidePlugIn correctly installed. This plug-in is installed automatically
when Apple Guide 2.1 is installed. If the plug-in isn't installed, all OpenDoc
standard context checks will always return FALSE.
Before we look at the available OpenDoc standard context checks, you should
note that for every one of these context checks that takes the name of a part
editor as one of its parameters, there are two variations: if the second SHORT
parameter is 0, the editor names must match exactly; if the second SHORT
parameter is 1, the actual editor name need only contain the text specified in
the context check. Both variations exist for all context checks that take a
part editor name. All of these functions return a Boolean result (TRUE or
FALSE).
<Define Context Check> "IsPlugInAvailable", 'odag', FRONT, SHORT:1
This
context check is a way to make sure that the plug-in has been installed
correctly and is available to run when the next OpenDoc process runs, thus
ensuring that any standard OpenDoc context check will return a correct result.
The only catch is that the plug-in isn't actually installed until the first
OpenDoc process has been launched, so this check will return FALSE if no
OpenDoc process has yet been run, even if the plug-in is available. With this
limitation in mind, you can define this context check, which ties an Apple
Guide context check name to one of the resources you included above. Then you
might use it this way:
<Define Sequence> "How do I do something?"
<If> IsPlugInAvailable()
# instruction panels
<Else>
# panel saying that this guide requires Apple Guide 2.1
<End If>
<End Sequence>
You
probably won't need to use this context check and will just assume that the
Apple Guide plug-in was installed correctly.
<DCC> "IsOpenDocActiveAndFrontmost", 'odag', FRONT, SHORT:2
Use
this context check to see whether the active process is an OpenDoc process. It
isn't application signature based and thus will return TRUE for any OpenDoc
process, no matter what the host application is.
<DCC> "PartEditorInstalled", 'odag', FRONT, SHORT:4,
SHORT:O, LPSTRING
<DCC> "PartEditorInstContains", 'odag', FRONT, SHORT:4,
SHORT:1, LPSTRING
To
determine whether a particular part editor is installed in the OpenDoc Editors
folder and is available, use this context check. It has nothing to do with
whether an instance of the part editor is currently in the active process. You
might use a call like PartEditorInstalled("MyPart 1.0") to make sure that a
particular part editor has been installed on the machine before you tell users
to do something that depends on the part editor's being available. This is one
of the functions that takes a part editor name as its argument; you could use
the less specific version of the function by calling
PartEditorInstContains("MyPart"), but take care -- you might end up matching
someone else's part editor if you're too general!
<DCC> "PartInActiveProcess", 'odag', FRONT, SHORT:6,
SHORT:O, LPSTRING
This
is a way to check whether an instance of the specified part editor is in the
active (frontmost) process. The corresponding part may or may not be in the
active (frontmost) window.
<DCC> "PartInActiveWindow", 'odag', FRONT, SHORT:7,
SHORT:O, LPSTRING
<DCC> "PartInNonActiveWindow", 'odag', FRONT, SHORT:8,
SHORT:O, LPSTRING
These
two context checks enable you to see whether there's an instance of the part
either in or not in the active (frontmost) window.
<DCC> "PartInActiveDoc", 'odag', FRONT, SHORT:14,
SHORT:O, LPSTRING
<DCC> "PartInNonActiveDoc", 'odag', FRONT, SHORT:15,
SHORT:O, LPSTRING
An
OpenDoc process can contain multiple documents. A particular document in a
process might have more than one window. These two context checks enable you to
see if an instance of the specified part is in any of the active document's
windows or any windows of a nonactive document. It's unlikely you'll need these
checks -- most of the time you'll want to check whether a part is in the active
window or the active process.
<DCC> "PartIsActiveFrame", 'odag', FRONT, SHORT:10, SHORT:O, LPSTRING
This
is a way to check whether an instance of the specified part is the currently
active part. This is useful to know because a part editor's menus are usually
available only when the part is active.
<DCC> "ActivePartIsRoot", 'odag', FRONT, SHORT:9
If
you need to determine whether the active part is the root part for the active
document, use this check.
<DCC> "ActivePartAllowsEmbedding", 'odag', FRONT, SHORT:5
With
this check you can determine whether the active part is a container part and
allows other parts to be embedded inside it. You might use this if, as part of
a task, you need to get the user to drag a new instance of a part into the
active container part.
<DCC> "ActiveDocumentIsBundled", 'odag', FRONT, SHORT:3
This
is a way to check whether the active document is bundled. Bundling a document
prevents any subparts in the document from being activated; clicking on a
subpart in a bundled document will select the subpart but won't activate it. In
essence, this makes all subparts in the document read-only.
<DCC> "ActiveDocumentIsDirty", 'odag', FRONT, SHORT:11
This
is a way to check whether the active document is dirty (needs to be saved). If
this context check returns TRUE, the Save menu item is enabled. You might use
this to tell the user to save changes if necessary.
If you still need more specific part information that isn't available through
the standard suite of context checks or the OpenDoc standard context checks,
just as with standard applications you'll need to write custom context
checks.
To define and use a custom context check, you must work around two
difficulties. The first is the target application issue we're now so familiar
with. As before, it's easy to work around: when writing the <Define Context
Check> command for your custom context check, you'll need to use the FRONT
constant for the target application. The second problem concerns the fact that
you could have multiple instances of a part editor running at the same time, in
either the same or a different OpenDoc process. This is a problem for both the
guide author and the custom context check writer.
The primary concern is for the guide author: if there are multiple instances of
the same part editor in one or more currently running OpenDoc processes, it's
impossible for your guide to identify which part editor you're providing help
for. Let's look at an example. Before step 1 of your task, you use the standard
OpenDoc context checks to make sure an instance of your part is active. You
then tell the user to do step 1. Step 2 requires step 1 to have been completed,
so you want to do a custom context check to see if step 1 has been done.
However, if there are two instances of your part around, which instance the
custom context check queries is unknown. Users may have successfully completed
step 1, but the context check may come back saying they haven't. In this case,
they'll be stuck at this point and won't be able to continue.
The context check writer has similar concerns. The way a part editor would
install and remove a context check handler would probably be to call
AGInstallContextHandler in its constructor and AGRemoveContextHandler in its
destructor. If it's done this way, anytime a new instance of the part is
created it overrides (and removes) the previous context handler, so the last
instance of the part to be created is the one that will supply context
information, no matter which process it's in. In addition, when a part editor
calls AGRemoveContextHandler, it will remove whichever handler is currently
installed; if one of two instances of the part is destroyed, the context
handler will be removed, leaving no context handler for the remaining
instance.
Unfortunately, there's no simple answer to these concerns at this time. There
are partial solutions for particular cases, though. For example, if you know
that your part editor will definitely have exactly one instance, you might just
take your chances. If you always want to have the context check respond about
the currently active instance of the part (if the active frame is the desired
part), you can write an 'extm' context check that you install in your guide
that asks OpenDoc for the currently active frame, and if the part behind that
frame is your part, do some context checking on it. As more people try to
tackle custom context checking, better solutions will evolve, perhaps using the
ODExtension mechanism of OpenDoc.
Sometimes you also want to send Apple events or launch AppleScript scripts from
your guide when a user clicks a particular button or goes to a particular
panel. As I've said before, this is still possible in OpenDoc part editor
guides. The only thing that's more challenging is when you want to send an
event to your part editor. OpenDoc supports Apple event handling for part
editors by overriding a number of the standard Apple event Toolbox routines and
by providing a way to target a particular part editor. Explaining how to do
this is beyond the scope of this article; for more information, read the
OpenDoc Programmer's Guide, especially Chapter 9, "Semantic Events and
Scripting."
As you can see, Apple Guide 2.1 provides a number of new features, both for
standard guides and guides written for OpenDoc part editors. And despite a few
limitations, writing guides for part editors is as easy as writing them for
standalone applications. So try it out! Users and reviewers seem to agree:
Apple Guide -- and thus any application or part editor that has guides -- is in
a class by itself.
- Apple Guide Complete: Designing and Developing Onscreen Assistance by
Apple Computer, Inc. (Addison-Wesley, 1995).
- "Giving Users Help With Apple Guide" by John Powers, develop Issue 18.
- OpenDoc Programmer's Guide for the Mac OS by Apple Computer, Inc.
(Addison-Wesley, 1995). Available on the OpenDoc Developer Release CD and other
places.
- The guideWorks World Wide Web page, located at
http://www.guideworks.com.
PETER COMMONS (commons@guideworks.com) is the vice president of engineering at
guideWorks, LLC. He lives happily with his wife, Claire, their dog, Chet, and
their cats, "fat cat" Clyde and "brat cat" Oliver, in Sunnyvale, California,
and wonders if he'll ever finish writing updates to Spaceward Ho!
Thanks to our technical reviewers Sharon Everson, Troy Gaul, Devon Hubbard,
James Miyake, John Powers, and Melissa Sleeter.
