[PyQt] Handling PyQT/PyKDE4 on ARM

[Michael Casadevall]

Anyway, I though it would be prudent to post the actual build failure messages

sipplasmapart0.cpp: In member function 'virtual void
sipPlasma_WebView::getContentsMargins(qreal*, qreal*, qreal*, qreal*)
const':
sipplasmapart0.cpp:3497: error: cannot convert 'qreal*' to 'double*'
in argument passing
sipplasmapart0.cpp: In member function 'virtual void
sipPlasma_TextEdit::getContentsMargins(qreal*, qreal*, qreal*, qreal*)
const':
sipplasmapart0.cpp:7563: error: cannot convert 'qreal*' to 'double*'
in argument passing
sipplasmapart0.cpp: In member function 'virtual void
sipPlasma_SignalPlotter::getContentsMargins(qreal*, qreal*, qreal*,
qreal*) const':
sipplasmapart0.cpp:10871: error: cannot convert 'qreal*' to 'double*'
in argument passing

I can post the actual failed code once I finish a rebuild. It appears
the problem is with sip.
Michael

On Sun, Dec 14, 2008 at 5:18 PM, Michael Casadevall
<sonicmctails at gmail.com> wrote:
> On Sun, Dec 14, 2008 at 5:10 PM, David Boddie <david at boddie.org.uk> wrote:
>> On Sun Dec 14 20:47:06 GMT 2008, Michael Casadevall wrote:
>>
>>> Internally, PyQT4 uses qreals in its bindings for QLists, and so
>>> forth. Although this works fine when qreal is a double since a float
>>> will be converted implicatively, when it is a float, it looses the
>>> ability to handle doubles since float is smaller than double. I
>>> believe the solution is to remove explicate qreals, and handle both
>>> float and double separately.
>>
>> It's been a while since I did anything with this, but maybe you could
>> take a look at these rough-and-ready patches for PyQt 4.3:
>>
>> http://www.diotavelli.net/PyQtWiki/PyQt4_on_the_Qtopia_Greenphone
>> http://chaos.troll.no/~dboddie/Python/Greenphone/
>>
>
> Oooh, very handy, I'll be looking into this.
>
>> What I did was to add checks for a PyQt "feature" called PyQt_FPU
>> which used MappedType declarations for double if enabled, or float
>> if disabled, for QList at least.
>>
>> So, much the same as you describe, except that I continued to use qreal
>> in declarations because it should be appropriately defined, anyway.
>> Oh, and the patches also contain lots of other Features because I was
>> using Qtopia Core (as it used to be known) instead of Qt on X11.
>>
>>> Secondly, in some cases, sip tries to pass double points into qreals,
>>> which breaks miserably on ARM. This happens when building plasma's
>>> bindings. This happens when building a widget derived from
>>> QGraphicsView, and that widget hasn't overridden getContetMargins.
>>> getContentMargins accepts four qreal pointers, and sip tries to pass
>>> in four double ones. I can provide the generated code in this
>>> instance.
>>
>> I think you'll just have to handle this in the same way as for QList and
>> friends.
>>
> No, this is a C problem with the generated code. Essentially
>
> (this assumes qreal is float)
>
> double * a;
> qreal * b;
>
> a = b;
>
> Which fails because there is no explicate cast.
> - Hide quoted text -
>
>>> I can provide access to relatively fast ARM hardware to help handle
>>> porting work and so forth, if anyone is interested in working on
>>> resolving this issue.
>>
>> Having spent a fair amount of my own time on this sort of thing, I'd love to
>> be able to help but, sadly, I just don't have the time these days. I don't
>> mind sharing experiences and testing things, though, so feel free to let me
>> know how things are progressing.
>>
>> David
>> _______________________________________________
>> PyQt mailing list    PyQt at riverbankcomputing.com
>> http://www.riverbankcomputing.com/mailman/listinfo/pyqt
>>
>
> On Sun, Dec 14, 2008 at 5:10 PM, David Boddie <david at boddie.org.uk> wrote:
>> On Sun Dec 14 20:47:06 GMT 2008, Michael Casadevall wrote:
>>
>>> Internally, PyQT4 uses qreals in its bindings for QLists, and so
>>> forth. Although this works fine when qreal is a double since a float
>>> will be converted implicatively, when it is a float, it looses the
>>> ability to handle doubles since float is smaller than double. I
>>> believe the solution is to remove explicate qreals, and handle both
>>> float and double separately.
>>
>> It's been a while since I did anything with this, but maybe you could
>> take a look at these rough-and-ready patches for PyQt 4.3:
>>
>> http://www.diotavelli.net/PyQtWiki/PyQt4_on_the_Qtopia_Greenphone
>> http://chaos.troll.no/~dboddie/Python/Greenphone/
>>
>> What I did was to add checks for a PyQt "feature" called PyQt_FPU
>> which used MappedType declarations for double if enabled, or float
>> if disabled, for QList at least.
>>
>> So, much the same as you describe, except that I continued to use qreal
>> in declarations because it should be appropriately defined, anyway.
>> Oh, and the patches also contain lots of other Features because I was
>> using Qtopia Core (as it used to be known) instead of Qt on X11.
>>
>>> Secondly, in some cases, sip tries to pass double points into qreals,
>>> which breaks miserably on ARM. This happens when building plasma's
>>> bindings. This happens when building a widget derived from
>>> QGraphicsView, and that widget hasn't overridden getContetMargins.
>>> getContentMargins accepts four qreal pointers, and sip tries to pass
>>> in four double ones. I can provide the generated code in this
>>> instance.
>>
>> I think you'll just have to handle this in the same way as for QList and
>> friends.
>>
>>> I can provide access to relatively fast ARM hardware to help handle
>>> porting work and so forth, if anyone is interested in working on
>>> resolving this issue.
>>
>> Having spent a fair amount of my own time on this sort of thing, I'd love to
>> be able to help but, sadly, I just don't have the time these days. I don't
>> mind sharing experiences and testing things, though, so feel free to let me
>> know how things are progressing.
>>
>> David
>> _______________________________________________
>> PyQt mailing list    PyQt at riverbankcomputing.com
>> http://www.riverbankcomputing.com/mailman/listinfo/pyqt
>>
>