Margins in the printer properties

[Sascha Sommer]

Thanks for the prompt reply.

On Wednesday 28 September 2005 13:28, Goffioul Michael wrote:
> > Hi,
> > what are the differences between the margin settings in the
> > text property page
> > and the margins that can be specified in the margin property page?
> > Gwenview for example will always use the later, however
> > unlike the ones from
> > the text property page, they do not seem to come from the
> > ppd. I think this
> > will be problematic when the printer requires different margins.
> > Is this the intended behaviour?
>
> The text margins are used in CUPS when plain text is sent for printing.
> In that case, CUPS converts it to PS, using the margins specified. The
> margin values are just sent as-is without processing in KDE, and the
> corresponding tab only appear in kprinter, not in the print dialog from
> a KDE application. Those margins are in no way linked to the PPD.
>

Ok.

> The other margins are the margins used within a KDE application when
> generating PS data to sent to CUPS. This means that a KDE app will get
> as printable area the selected page size reduced by those margins. The
> default values of these margins are taken from the PPD file (when
> possible).

Ok. See below:
Appologies if I'm quoting wrong versions of the sources:
From:
http://developer.kde.org/documentation/library/3.4-api/kdeprint/html/kpmarginpage_8cpp-source.html

00060 void KPMarginPage::initPageSize(const QString& ps, bool landscape)
00061 {
00062     // first retrieve the Qt values for page size and margins
00063     QPrinter    prt(QPrinter::PrinterResolution);
00064     prt.setFullPage(true);
00065     prt.setPageSize((QPrinter::PageSize)(ps.isEmpty() ? 
KGlobal::locale()->pageSize() : ps.toInt()));
00066     QPaintDeviceMetrics metrics(&prt);
00067     float   w = metrics.width();
00068     float   h = metrics.height();
00069     unsigned int    it, il, ib, ir;
00070     prt.margins( &it, &il, &ib, &ir );
00071     float   mt = it;
00072     float   ml = il;
00073     float   mb = ib;
00074     float   mr = ir;
00075 
00076     if (driver() && m_usedriver )
00077     {
00078         QString pageSize(ps);
00079 
00080         if (pageSize.isEmpty())
00081         {
00082             DrListOption    *o = 
(DrListOption*)driver()->findOption("PageSize");
00083             if (o)
00084                 pageSize = o->get("default");
00085         }
00086         if (!pageSize.isEmpty())
00087         {
00088             DrPageSize  *dps = driver()->findPageSize(pageSize);
00089             if (dps)
00090             {
00091                 w = dps->pageWidth();
00092                 h = dps->pageHeight();
00093                 mt = QMAX( mt, dps->topMargin() );
00094                 ml = QMAX( ml, dps->leftMargin() );
00095                 mb = QMAX( mb, dps->bottomMargin() );
00096                 mr = QMAX( mr, dps->rightMargin() );
00097             }
00098         }
00099     }
00100     m_margin->setPageSize(w, h);
00101     m_margin->setOrientation(landscape ? KPrinter::Landscape : 
KPrinter::Portrait);
00102     m_margin->setDefaultMargins( mt, mb, ml, mr );
00103     m_margin->setCustomEnabled(false);
00104 }

The interesting part starts at line 00093 there if I understand it correctly 
it will take the maximum of the settings from the ppd and the setting that 
come from QPrinter.

However in qt-x11-free-3.3.5/src/kernel/qprinter_unix.cpp:


/*!
    \overload

    Sets \a top, \a left, \a bottom and \a right to the margins of the
    printer.  On Unix, this is a best-effort guess, not based on
    perfect knowledge.

    If you have called setFullPage( TRUE ), the four values specify
    the smallest sane margins you can use.

    If you have called setFullPage( FALSE ) (this is the default),
    the margins are automatically subtracted from the pageSize() by
    QPrinter.

    \sa setFullPage() QPaintDeviceMetrics PageSize
*/
void QPrinter::margins( uint *top, uint *left, uint *bottom, uint *right ) 
const
{
    if ( !D->marginsSpecified ) {
        int x = orient == Portrait ? res/2 : res/3;
        int y = orient == Portrait ? res/3 : res/2;
        *top = *bottom = y;
        *left = *right = x;
    } else {
        *top = D->topMargin;
        *left = D->leftMargin;
        *bottom = D->bottomMargin;
        *right = D->rightMargin;
    }
}

Afaik the problem is, as D->marginsSpecified gets initialized to false in the 
QPrinter constructor, the guessing algorithm gets used. In my case the 
guessed values are larger than the ones from the ppd and in the end it will 
use the guessed values. Making it impossible for me to exactly position a 
cdlabel or whatever.

The question is how to fix. Maybe simply removing the QMAXs would help.
What do you think?


Regards

Sascha