QPainting to an eps file

[netterfield]

In my app, we are able to export to bitmap graphics files with QImage, and with qprinter, to export proper PDF and PS files.

However, we also need to be able to export to encapsulated postscript (which is just a ps file with bounding box info). Using qimage produces a bitmap, which isn't what we want - we need a proper postscript file with vector lines and proper fonts.

In the past, we've exported to a regular .ps file, edited it to insert the bounding box info, and renamed it. This really sounds like a hack. Is there a better way to do this?

[qwertyone]

Hello

I just did something similar: I draw an image and some markings into a pdf file. If you look at the generated pdf file, you can see that it generates vector graphics.

Here is a fragment of the code:

// Setup printer
QPrinter printer(QPrinter::HighResolution);
printer.setOutputFormat(QPrinter::PdfFormat);
printer.setOutputFileName(pdfFileName);
printer.setFullPage(true);
printer.setPageSize(QPrinter::Custom);
printer.setPaperSize(QSizeF(pdfWidth,pdfHeight),QPrinter::Millimeter);
printer.setPageMargins(0,0,0,0,QPrinter::Millimeter);
 
// Get the painting context from the printer
QPainter painter(&printer); // Destructing painter writes the pdf file
 
// Set the scale, so we can draw in millimeter
double scale = printer.width()/pdfWidth;
painter.setTransform(QTransform(scale,0,0, 0,scale,0, 0,0,1.0));
 
// Draw the image
QRectF src(0,0,image.width(),image.height());
QRectF dst(imageOffsetX,imageOffsetY,imageWidth,imageHeight);
painter.drawImage(dst,image,src);
 
// Draw the markings
QPen pen;
pen.setWidthF(m_lineWidth);
pen.setColor(Qt::red);
QVector<qreal> dashes;
dashes << m_solidDashLength/m_lineWidth << m_blankDashLength/m_lineWidth;
pen.setDashPattern(dashes);
painter.setPen(pen);
painter.drawRect(QRectF(m_pdfMargin-m_lineWidth/2,m_pdfMargin-m_lineWidth/2,productionWidth+m_lineWidth,productionHeight+m_lineWidth));

// Setup printer
QPrinter printer(QPrinter::HighResolution);
printer.setOutputFormat(QPrinter::PdfFormat);
printer.setOutputFileName(pdfFileName);
printer.setFullPage(true);
printer.setPageSize(QPrinter::Custom);
printer.setPaperSize(QSizeF(pdfWidth,pdfHeight),QPrinter::Millimeter);
printer.setPageMargins(0,0,0,0,QPrinter::Millimeter);

// Get the painting context from the printer
QPainter painter(&printer); // Destructing painter writes the pdf file

// Set the scale, so we can draw in millimeter
double scale = printer.width()/pdfWidth;
painter.setTransform(QTransform(scale,0,0, 0,scale,0, 0,0,1.0));

// Draw the image
QRectF src(0,0,image.width(),image.height());
QRectF dst(imageOffsetX,imageOffsetY,imageWidth,imageHeight);
painter.drawImage(dst,image,src);

// Draw the markings
QPen pen;
pen.setWidthF(m_lineWidth);
pen.setColor(Qt::red);
QVector<qreal> dashes;
dashes << m_solidDashLength/m_lineWidth << m_blankDashLength/m_lineWidth;
pen.setDashPattern(dashes);
painter.setPen(pen);
painter.drawRect(QRectF(m_pdfMargin-m_lineWidth/2,m_pdfMargin-m_lineWidth/2,productionWidth+m_lineWidth,productionHeight+m_lineWidth));

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[netterfield]

Yes... painting to a QPrinter works perfectly, and does what I want for postscript and pdf files.

The question is, how can I make an *encapsulated* postscript file, other than by printing to a postscript file, and then editing it? Or is that the only way (I'm guessing that it is... )

http://en.wikipedia.org/wiki/Encapsulated_PostScript

[wysota]

I think it is - Qt doesn't support EPS natively.

[Piskvorkar]

Hi!
I have small question. By this way of generating postscript file, is it realy vector format postscript file or is it some sort of bitmap wrapped inside generated postscript file. I have similar problem with EPS and I rather use handly maked export to EPS :-). Do you think it's realy so hard to implement EPS support, even if it needs only Bounding box to define? :-).
Is here some way how to easy reimplment Qt provided printer by own and use it in my program?
Thanks for replay.

[enno]

Qt 4.5.3 (and maybe 4.4) solved this problem by the including a new overloaded setPaperSize function in the QPrinter class:

printer.setPaperSize(QSizeF(80, 80), QPrinter::Millimeter);

The paperSize code gets set to Unknown/user defined but when printing to a file the size set above is set as the bounding box for the eps file.

By the way the output file is proper PostScript, not an encapsulated bitmap.

[cafu]

Thanks this is exactly what i was looking for

[Piskvorkar]

thanks, it works realy prety fine :-)

[dexli]

Qt 4.5.3 (and maybe 4.4) solved this problem by the including a new overloaded setPaperSize function in the QPrinter class:

printer.setPaperSize(QSizeF(80, 80), QPrinter::Millimeter);

The paperSize code gets set to Unknown/user defined but when printing to a file the size set above is set as the bounding box for the eps file.

Do I have to provide the code which sets the bounding box or is it done simply by calling the above code ??

By the way the output file is proper PostScript, not an encapsulated bitmap.

But without the ps showpage command and a bounding box ??

Have a nice day
dexli