How to create a Print Preview Dialog for a method

LT-K101

Hi,
Is it possible to create a print preview dialog for a method that prints to a local printer. The print method does not display any GUI dialog for user to choose from available printers listed to be used. Below is the example I tried but it does not work. Please any assistance would be much appreciated. Thanks in advance.

def printReport(self,printer):
    report details


def printpreviewDialog(self):
    printer = QPrinter(QPrinter.HighResolution)
    previewDialog = QPrintPreviewDialog(printer, self)
    previewDialog.paintRequested.connect(self.printReport)
    previewDialog.exec_()

jsulm

@LT-K101 said in How to create a Print Preview Dialog for a method:

but it does not work

In what way it does not work?

LT-K101

@jsulm The printpreview Dialog pops up empty without the report deails

imene sa

This post is deleted!

jsulm

@LT-K101 Are you doing anything in printReport slot?

LT-K101

@jsulm Below is the printReport method details.

def printReport(self,printer):
    c = canvas.Canvas("hello.pdf")
    c.drawString(100,700, "First time using reportlab")
    c.save()

JonB

@LT-K101
And what is canvas, and what do you expect this to do? The docs for QPrintPreviewDialog::paintRequested(QPrinter *printer) tell you

The printer instance supplied is the paint device onto which you should paint the contents of each page, using the QPrinter instance in the same way as you would when printing directly.

LT-K101

@JonB I want to call the printReport() in the printpreviewDialog to initiate a QDialog popup for the user to view the pdf created in printReport method and then print.

JonB

@LT-K101
Well, your current code does not presently do anything like that....

You are inside a method of an already-created QPrintPreviewDialog, at the paintRequested stage. This is not where or for popping up dialogs, and you don't want some dialog there to view the PDF since you are already inside a previewer.

jsulm

@LT-K101 said in How to create a Print Preview Dialog for a method:

Below is the printReport method details.

No wonder there is nothing in preview dialog.
As documentation explains (see @JonB post) you need to use the provided printer to generate the preview...

LT-K101

@jsulm Honestly, I'm lost since this is the first time trying to implement this, I was following some examples online which is getting me confused. Please how do I use the provided printer to generate the preview in my case. I know it easy for you and @JonB to do this.Please I need assistance with this. Thanks

jsulm

@LT-K101 Did you check https://doc.qt.io/qt-5/qtprintsupport-index.html ?

JonB

@LT-K101
Please start by following @jsulm's reference. You can also get help by Googling, say, qprintpreviewdialog paintrequested example. We do not even know what it is that you want to print/print preview....

LT-K101

@jsulm Please I did check it but I did not understand it

jsulm

@LT-K101 said in How to create a Print Preview Dialog for a method:

but I did not understand it

What exactly?
There is an example:

printer.setOutputFileName("print.ps");
QPainter painter;
painter.begin(&printer);
for (int page = 0; page < numberOfPages; ++page) {
    // Use the painter to draw on the page.
    if (page != lastPage)
        printer.newPage();
 }
painter.end();

LT-K101

@JonB It's the C++ syntax that confuses me. Sorry for bothering you.Please below is a report method I want to preview and print. It works perfectly without a Dialog by saving to disk so I wanted to use QPrintPreviewDialog to let user preview the report before printing.

def printReport(self):
    filename, ok = QtWidgets.QFileDialog.getSaveFileName(self, 'Save file', '', 'Pdf files (*.pdf)')  
    if ok:
         # Open local project
         project = valentina.project.connect('./temp.vsp')

         # Make report instance
         report = project.report(name='tempofficials_summary',
                                        dsn='sqlite://C:/Users/PC/Desktop/PROJECT/temp.db',
                                        query="SELECT firstname,surname,email,phone,address,dob, '{}' || image as full_path FROM temp_table WHERE id_no={}".format(
                                            'C:/Users/LTK101/Desktop/PROJECT/img/', id))

        # Print result as PDF
        report.printToDisk(filename)

jsulm

@LT-K101 said in How to create a Print Preview Dialog for a method:

I wanted to use QPrintPreviewDialog to let user preview the report before printing.

Then please do what was suggested here. Something like (should not be difficult to translate it to Python):

def reportPreview(self, printer):
    QPainter painter;
    painter.begin(printer);
    for (int page = 0; page < numberOfPages; ++page) {
        // Use the painter to draw on the page.
        // Put here code to draw preview using painter
        if (page != lastPage)
            printer.newPage();
     }
    painter.end();

def printpreviewDialog(self):
    printer = QPrinter(QPrinter.HighResolution)
    previewDialog = QPrintPreviewDialog(printer, self)
    previewDialog.paintRequested.connect(self.reportPreview)
    previewDialog.exec_()

JonB

@LT-K101
Noone can answer this without knowing exactly what a valentina.project is. I see it has some printToDisk() method. QPrintPreviewDialog requires a QPrinter. So does a valentina.project offer to print to a QPrinter?

LT-K101

@JonB It has printToDisk() which save the report as pdf and printToLocalPrinter() which print to any default printer set as default without a dialog so I was trying to see if I could use QPrintPreviewDialog.

JonB

@LT-K101 said in How to create a Print Preview Dialog for a method:

printToLocalPrinter() which print to any default printer

If that accepts a QPrinter it can be sent to a QPrintPreviewDialog. But it does not look like it can? Looks like it does something about the printer internally instead?

If I had been asking for help on whatever a valentina.project is or whatever your "report"/"report writer" is, which provides these print...() calls, I would have supplied a link reference to it, plus however it interacts with Qt. But you would like us to answer without having that. I'm not even sure it integrates with Qt, let alone QPrinter, if it is just some Python thing what Qt integration does it have?