Implements a dialog observer based on CDialogObserver
that handles widget changes made by the user in this
plug-in's previewable dialog.
Changes to the transparency effect are made
via the suite ITranFxSuite.
The description below talks about how commands get processed
in previewable dialogs. Note however that this dialog does not process
commands directly. Instead, it calls the suite that controls the
effect, ITranFXSuite, that in turn calls a facade, TranFxUtils,
that processes the commands. So the dialog works in tandem with
the suite and the commands that it processes. However, it is
important to understand the special way in which commands are
handled during a previewable dialog, as given below.
Modal dialogs can have a preview checkbox. The preview checkbox
allows the user to see the immediate effect on the document of
modifying some dialog control.
A previewable dialog works like this. Typically it
is implemented more like a panel in that each control has an
observer that results in a command being processed to change something when
clicked. In this implementation we have one observer watching
all the widgets in the dialog for change. Each time a widget
changes we make a suite call that processes a command to make
the requested change.
When the preview checkbox is turned off commands are buffered.
When the preview checkbox is turned on buffered commands are
processed. When the preview checkbox is turned off again the
commands are undone. When the dialog is dismissed with the OK
button buffered commands are processed.
Adding a preview checkbox to you modal dialog will give you:
<ul>
<li>buffering of commands when preview is not checked.
<li>undoing of previewed commands when the dialog is cancelled.
<li>grouping of commands into a single compound command.
<li>replacement of commands with the same ICommand::GetCreatorID.
i.e. if you process a command with the same creator id more than
once the previous command is undone and replaced by the new command.
So if you click 10 times to set the x offset to a different
value only the last set x offset command is processed. See
the methods in TranFxUtils that gets called by ITranFxSuite
for examples of how this is done.
</ul>
A preview checkbox is created by an ODFRez statement like this:
<pre>
Note the preview button CheckBoxWidget ( kPreviewButtonWidgetID, // WidgetId kSysCheckBoxPMRsrcId, // RsrcId kBindNone, Frame(192,76,272,96) // Frame kTrue, // Visible kTrue, // Enabled TriStateControlAttributes kAlignLeft, // fAlignment CTextControlData "Pre&view" // Initial text )
You can have a preview checkbox but disable all of the processing described above simply by using replacing kPreviewButtonWidgetID with a WidgetID of your own. You would then have to implement your own command management using command sequences or whatever to achieve the result you want.
- See Also
- ITranFxSuite
- TranFxUtils
Public Member Functions inherited from CDialogObserver
1.8.3.1 
