lyx_mirror/src/frontends/xforms/Dialogs.C
Lars Gullik Bjønnes 338bca184c patch from Angus and patch from Kayvan
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@930 a592a061-630c-0410-9148-cb99ea01b6c8
2000-07-27 08:55:59 +00:00

116 lines
4.8 KiB
C

#include <config.h>
#include FORMS_H_LOCATION
#include "Dialogs.h"
#include "FormCitation.h"
#include "FormCopyright.h"
#include "FormPreferences.h"
#include "FormPrint.h"
#include "FormTabular.h"
#include "FormUrl.h"
#ifdef __GNUG__
#pragma implementation
#endif
Dialogs::Dialogs(LyXView * lv)
{
dialogs_.push_back(new FormCitation(lv, this));
dialogs_.push_back(new FormCopyright(lv, this));
dialogs_.push_back(new FormPreferences(lv, this));
dialogs_.push_back(new FormPrint(lv, this));
dialogs_.push_back(new FormTabular(lv, this));
dialogs_.push_back(new FormUrl(lv, this));
// reduce the number of connections needed in
// dialogs by a simple connection here.
hideAll.connect(hideBufferDependent.slot());
}
Dialogs::~Dialogs()
{
for (vector<DialogBase *>::iterator iter = dialogs_.begin();
iter != dialogs_.end();
++iter) {
delete *iter;
}
}
/*****************************************************************************
Q. WHY does Dialogs::Dialogs pass `this' to dialog constructors?
A. To avoid a segfault.
The dialog constructors need to connect to their
respective showSomeDialog signal(*) but in order to do
that they need to get the address of the Dialogs instance
from LyXView::getDialogs(). However, since the Dialogs
instance is still being constructed at that time
LyXView::getDialogs() will *not* return the correct
address because it hasn't finished being constructed.
A Catch-22 situation (or is that the chicken and the egg...).
So to get around the problem we pass the address of
the newly created Dialogs instance using `this'.
(*) -- I'm using signals exclusively to guarantee that the gui code
remains hidden from the rest of the system. In fact the only
header related to dialogs that anything in the non-gui-specific
code gets to see is Dialogs.h! Even Dialogs.h doesn't know what a
FormCopyright class looks like or that its even going to be used!
No other gui dialog headers are seen outside of the gui-specific
directories! This ensures that the gui is completely separate from
the rest of LyX. All this through the use of a few simple signals.
BUT, the price is that during construction we need to connect the
implementations show() method to the showSomeDialog signal and this
requires that we have an instance of Dialogs and the problem mentioned
above.
Almost all other dialogs should be able to operate using the same style
of signalling used for Copyright. Exceptions should be handled
by adding a specific show or update signal. For example, spellchecker
needs to set the next suspect word and its options/replacements so we
need a:
Signal0<void> updateSpellChecker;
Since we would have to have a
Signal0<void> showSpellChecker;
in order to just see the spellchecker and let the user push the [Start]
button then the updateSpellChecker signal will make the SpellChecker
dialog get the new word and replacements list from LyX. If you really,
really wanted to you could define a signal that would pass the new
word and replacements:
Signal2<void, string, vector<string> > updateSpellChecker;
(or something similar) but, why bother when the spellchecker can get
it anyway with a LyXFunc call or two. Besides if someone extends
what a dialog does then they also have to change code in the rest of
LyX to pass more parameters or get the extra info via a function
call anyway. Thus reducing the independence of the two code bases.
We don't need a separate update signal for each dialog because most of
them will be changed only when the buffer is changed (either by closing
the current open buffer or switching to another buffer in the current
LyXView -- different BufferView same LyXView or same BufferView same
LyXView).
So we minimise signals but maximise independence and programming
simplicity, understandability and maintainability. It's also
extremely easy to add support for Qt or gtk-- because they use
signals already. Guis that use callbacks, like xforms, must have their
code wrapped up like that in the form_copyright.[Ch] which is awkward
but will at least allow multiple instances of the same dialog.
Signals will also be a great help in controlling the splashscreen --
once signalled to hide it can disconnect from the signal and remove
itself from memory.
LyXFuncs will be used for requesting/setting LyX internal info. This
will ensure that scripts or LyXServer-connected applications can all
have access to the same calls as the internal user-interface.
******************************************************************************/