RFC: spell checking for QTextEdit

[Aurélien Gâteau]

Le mercredi 7 août 2013 15:44:52 vous avez écrit :
> On Wed, Aug 7, 2013 at 10:13 AM, Aurélien Gâteau <agateau at kde.org> wrote:
> > Hi,
> > 
> > I'd like to reach a decision regarding spell checking for QTextEdit.
> > 
> > It was initially a Qt5 task:
> > 
> > "Allow to register a default syntax highlighter type for QTextEdit, the
> > KDE
> > backend would register the spell checking one coming from sonnet as
> > default"
> > 
> > I started working on this task and put together a first patch, but then
> > realized it would not be enough: in addition to the syntax highlighter,
> > integration with QTextEdit requires context menu support to be able to
> > provide
> > suggestions for spelling errors.
> > 
> > I already have code which integrates Sonnet (our spellchecker component)
> > with
> > QTextEdit, in the form of a helper class named (for now)
> > Sonnet::TextEditInstaller:
> > 
> > https://git.reviewboard.kde.org/r/111912/
> > 
> > 
> > There was a discussion on IRC two days ago regarding how transparent
> > should
> > spellcheck integration with QTextEdit be, with two possible positions:
> > 
> > 
> > A. Find a way to inject spellchecking in all QTextEdit through either QPA
> > or
> > our style.
> > 
> > Pros:
> > - Completely transparent to Qt app developers
> > - Porting a KDE app to KF5 is only KTextEdit => QTextEdit
> > 
> > Cons:
> > - Depends on QPA and/or style, so won't always be available depending on
> > the
> > platform
> > - Could cause problems if spellchecking is injected in QTextEdit where it
> > makes no sense to provide this feature (eg. code editor)
> > 
> > 
> > B. Only provide Sonnet::TextEditInstaller, which app developers would then
> > have to explicitly use to add spell checking to QTextEdit in their
> > applications.
> > 
> > Pros:
> > - No under-the-hood hack
> > - Independant from the platform as long as we have Sonnet plugins for it
> > - Gives more control to the app developer: for example changing the
> > spelling
> > language, adding custom words to ignore, or ignoring blocks of text (think
> > quoted email)
> > 
> > Cons:
> > - Requires developers to explicitly use the API, so porting a KDE app to
> > KF5
> > is KTextEdit => QTextEdit + use Sonnet::TextEditInstaller.
> 
> I'm not sure that is a real con.
> 
> KTextEdit still exists in KF5 and has been moved to KTextWidgets in tier 2.

Ohh! I missed that. I assumed KTextEdit was being moved to kde4support, since 
the Qt task made me think we wanted to add KTextEdit-specific features to 
QTextEdit.
 
> If I've understood correctly, with option B we would only need to port to
> QTextEdit + use Sonnet::TextEditInstaller for anything inside kdelibs tier
> 1 and to make it available for any app which only want tier 1 libs.
> 
> Porting any KDE apps can just include KTextWidgets and not change anything
> when porting to KF5.

This is correct. It may make sense to refactor KTextEdit to use 
Sonnet::TextEditInstaller to avoid code duplication.

Aurélien