API Advice needed: Mouse Shortcuts Database
rickstockton at reno-computerhelp.com
Sat Jan 7 22:18:05 GMT 2012
Before I begin- I am extremely interested in any upcoming re-factor
scheme, which could 'share' as much code as possible (between QtGui and
Widget-based shortcuts) at a 'higher" level.
With that said, however, my "little" project won't be sharing very much
of the current code, because nearly all existing code is INTIMATELY tied
into the fact that KeySequences (and their overrides, when necessary)
are tied to the keyboard. I'll 'friend' those classes, when necessary,
to get at things which can be shared immediately. The header file
'qkeysequence.h', will be included frequently to define 'standard keys'
-- or should I split out that enumeration into another file, without all
of the Method definitions ???
Anyway, her is my tentative DB design.
Mouse Shortcuts will be organized into an 2D array of
MouseShortcutButtonSets. The first index is for the type of mouse event:
0 == single-click
1 == double-click
The second index of the Table is the shift index of the responsible
'Button Number'. (i.e., the amount by which the Qt::MouseButton value
which was responsible for the event gets shifted to the right, in order
to result in value 'x1'== 0x00000001. This is, basically, the original
(int) value of the 'raw button number' which we received, and translated
_into_ a Qt::MouseButton value, within one of our platform plugins. In
Qt 5.0, the size in this Dimension includes integers from 0
(Qt::LeftButton) to 27 (Qt::MaxMouseButton).
Each Array Cell shall be the entry point of a QMultiHash() hashmap, or
maybe just a list. The thing which we need to find quickly in the set of
shortcuts for a given mouse click/doubleclick is the entries which
correspond to a particular shortcut 'owner' -- and this is PROBABLY best
done by using a QMultiHash().
*** question *** : Or, is the number of alternative 'owners' for a given
mouse click, or double-click, likely to be so small that I should simply
make it a linked list, inspected from start-to-finish?
Anyway, once we have the owner, we have a byte of bit flags (mostly unused):
value in the lowest bit: whether the shortcut is currently Disabled
(0 == Enabled, 1 == Disabled)
value next bit: whether Qt::LeftButton is being held down, concurrent
with the click (or double-click) of another button. 0 == No, 1 == Yes)
bit 2: whether Qt::RightButton is beng held down concurrently (0 ==
No, 1 == Yes)
Upper bits 3-7 are available for future use.
This ability to use Qt::LeftButton, Qt::RightButton as 'Modifier
BUTTONS' _for other buttons_ increases the number of possible mouse
shortcuts by quite a lot. For example, using just Qt::BackButton, you
Shortcut A == single-click of Qt::BackButton; (And THIS ONE will
often already be in use, as a default 'Back' action which you want to
But all these others are new, and they're not difficult for people with
fully-functional hands to Press:
Shortcut B == double-click of Qt::BackButton;
Shortcut C == single-click of Qt::BackButton with Qt::LeftButton held
Shortcut D == double-click of Qt::BackButton with Qt::RightButton
Shortcut E == single-click of Qt::BackButton with Qt::LeftButton held
Shortcut F == double-click of Qt::BackButton with Qt::MouseButton2
Shortcut G == single-click of Qt::BackButton with BOTH Qt::LeftButton
and Qt::RightButton held down;
Shortcut H == double-click of Qt::BackButton with BOTH Qt::LeftButton
and Qt::RightButton held down.
I DO NOT see any need for shortcut 'invocation sequences' with keyboard
and mouse combined. The requests are for one-handed Shortcuts, done ONLY
with the mouse. (Not needing a second hand). There will be, however, the
need for a Mouse Shortcut 'OverRideKey'. I will make this user-settable,
but I plan to insist that the permissible values be ONLY one of the
modifier keys. That's because modifier key status is given to us with
the button Event, right in the plugin.
I will probably have to duplicate the 'owner' value in each shortcut
entry. I might also need to keep track of the current Window on which
I'm trying to execute the shortcut, if they're supposed to 'escalate'
into parent widdgets and parent GUI elements auto-magically. This leads
to *** questions ***
I really don't understand the concept of 'shortcut owner', especially
with regard to Application-Wide shortcuts. If a shortcut is NOT
'Application-Wide', will it try to run it's action on each of a Widget's
parents? Or does the shortcut need to have a duplicate created into each
viable parent, differing only in the 'Widget'? And how SHOULD I handle
escalation from a GUI MouseArea?
My last question: I'm also unclear whether each shortcut in the 'map'
should be associated ONLY with the result of sending a Signal or whether
they should also have the option of linking to an Action directly.
- - - -
Thanks in advance. Yes, I can 'learn' by reading code, but my results
will be faster, BETTER with help to go from Concept to Design to Code
... rather than reading the code, trying to extract a Design, and
GUESSING at the concepts behind it. So, please tell me how shortcuts
'want' to work, in a few sentences.
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