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Combine Multiple Images Into a Single PDF

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pdfsavewidget
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  • georG geor

    @Wieland I keep getting qpainter::begin() reutnr false

    I am even using your exact code

            const QString fileName("C:/Qt");
    const QImage image("C:/Users/georg/Desktop/testPdf/Untitled.jpg");
    const QPoint imageCoordinates(0,0);
    
    QPdfWriter pdfWriter(fileName);
    pdfWriter.setPageSize(QPagedPaintDevice::A1);
    QPainter painter(&pdfWriter);
    
    for (int i=0; i<3; ++i)
    {
        painter.drawImage(imageCoordinates, image);
        pdfWriter.newPage();
        qDebug()<<2;
    }
    

    except for the page size becuase I am using qt 5.2.1

    do you have any idea why ebcuase I cannot figure it out the debug still runs i just get the eror and it does not save

    mrjjM Offline
    mrjjM Offline
    mrjj
    Lifetime Qt Champion
    wrote on last edited by
    #13

    @geor said:

    const QString fileName("C:/Qt");

    that is the actual filename ?

    I would expect something like
    const QString fileName("c:/mydoc.pdf");

    georG 1 Reply Last reply
    2
    • ? Offline
      ? Offline
      A Former User
      wrote on last edited by
      #14

      To add to what @mrjj said, do you have write access to C:/?

      georG 2 Replies Last reply
      3
      • mrjjM mrjj

        @geor said:

        const QString fileName("C:/Qt");

        that is the actual filename ?

        I would expect something like
        const QString fileName("c:/mydoc.pdf");

        georG Offline
        georG Offline
        geor
        wrote on last edited by
        #15

        @mrjj said:

        @
        I still get the same error

        mrjjM 1 Reply Last reply
        0
        • ? A Former User

          To add to what @mrjj said, do you have write access to C:/?

          georG Offline
          georG Offline
          geor
          wrote on last edited by
          #16
          This post is deleted!
          1 Reply Last reply
          0
          • ? A Former User

            To add to what @mrjj said, do you have write access to C:/?

            georG Offline
            georG Offline
            geor
            wrote on last edited by
            #17

            @Wieland

            once again thank you for your help it worked when I switch to the drive where the build is saved .However for some reason it is 4 empty pages maybe it's becuase of the size or something I'll try another image and see but again thank you

            mrjjM 1 Reply Last reply
            0
            • georG geor

              @mrjj said:

              @
              I still get the same error

              mrjjM Offline
              mrjjM Offline
              mrjj
              Lifetime Qt Champion
              wrote on last edited by
              #18

              @geor
              I think its just a path thing

              void writePdf()
              {
                  const QString fileName("e:/mydoc.pdf");
                     QPdfWriter pdfWriter(fileName);
                  pdfWriter.setPageSize(QPageSize(QPageSize::A4));
                  QPainter painter(&pdfWriter);
              
                  for (int i=0; i<3; ++i) {
                      painter.drawPixmap(QRect(0,0,pdfWriter.logicalDpiX()*8.3,pdfWriter.logicalDpiY()*11.7), QPixmap("e:/truck.png"));
                      pdfWriter.newPage();
                  }
              }
              
              works here. makes PDF on e:
              
              1 Reply Last reply
              2
              • georG geor

                @Wieland

                once again thank you for your help it worked when I switch to the drive where the build is saved .However for some reason it is 4 empty pages maybe it's becuase of the size or something I'll try another image and see but again thank you

                mrjjM Offline
                mrjjM Offline
                mrjj
                Lifetime Qt Champion
                wrote on last edited by
                #19

                @geor
                hi
                You will / might need to scale the picture or its really small.

                georG 2 Replies Last reply
                1
                • mrjjM mrjj

                  @geor
                  hi
                  You will / might need to scale the picture or its really small.

                  georG Offline
                  georG Offline
                  geor
                  wrote on last edited by
                  #20

                  @mrjj

                  yeh it worked after scaling thank you.

                  1 Reply Last reply
                  1
                  • mrjjM mrjj

                    @geor
                    hi
                    You will / might need to scale the picture or its really small.

                    georG Offline
                    georG Offline
                    geor
                    wrote on last edited by
                    #21

                    @mrjj one more question lol

                    the size of my widget is too big to fit well on a A4 paper without looking deformed. So I want to break the layout of it's parent, resize my widget it and then take it's pixmap to put it in an A4 so it is not deformed (with the grab function) but the problem is I can't break the layout of the parent i can only delete (in code) and when I delete it it deletes everything in it any tips?

                    mrjjM 1 Reply Last reply
                    0
                    • georG geor

                      @mrjj one more question lol

                      the size of my widget is too big to fit well on a A4 paper without looking deformed. So I want to break the layout of it's parent, resize my widget it and then take it's pixmap to put it in an A4 so it is not deformed (with the grab function) but the problem is I can't break the layout of the parent i can only delete (in code) and when I delete it it deletes everything in it any tips?

                      mrjjM Offline
                      mrjjM Offline
                      mrjj
                      Lifetime Qt Champion
                      wrote on last edited by mrjj
                      #22

                      @geor
                      Hi you can use the takeAt method to get your widget back from a layout.
                      But maybe you can just ask the widget to render directly?
                      it has a render function that can draw itself to anything you like.
                      http://doc.qt.io/qt-5/qwidget.html#render

                      georG 1 Reply Last reply
                      3
                      • mrjjM mrjj

                        @geor
                        Hi you can use the takeAt method to get your widget back from a layout.
                        But maybe you can just ask the widget to render directly?
                        it has a render function that can draw itself to anything you like.
                        http://doc.qt.io/qt-5/qwidget.html#render

                        georG Offline
                        georG Offline
                        geor
                        wrote on last edited by
                        #23

                        @mrjj

                        it doesn't seem to chnage much unless I am using it wrong? here is my code 1870 and 994 is the size of my widget.making the pixmap the same as the size of my widget gives me excatly the same ouput as before so i made it smaller it's better but cuts most of the widget out

                                           ui->page1->setBackgroundRole(QPalette::BrightText);
                        
                                     QPixmap pixMap1(600,900);
                                   ui->page1->render(&pixMap1,QPoint(),QRegion(0,0,1870,994));
                        
                        
                        
                        
                            const QString fileName("D:/mydoc2.pdf");
                               QPdfWriter pdfWriter(fileName);
                            pdfWriter.setPageSize(QPagedPaintDevice::A4);
                            QPainter painter(&pdfWriter);
                        
                           
                                painter.drawPixmap(QRect(0,0,pdfWriter.logicalDpiX()*8.3,pdfWriter.logicalDpiY()*11.7), pixMap1);
                                pdfWriter.newPage();
                        
                        mrjjM 1 Reply Last reply
                        1
                        • georG geor

                          @mrjj

                          it doesn't seem to chnage much unless I am using it wrong? here is my code 1870 and 994 is the size of my widget.making the pixmap the same as the size of my widget gives me excatly the same ouput as before so i made it smaller it's better but cuts most of the widget out

                                             ui->page1->setBackgroundRole(QPalette::BrightText);
                          
                                       QPixmap pixMap1(600,900);
                                     ui->page1->render(&pixMap1,QPoint(),QRegion(0,0,1870,994));
                          
                          
                          
                          
                              const QString fileName("D:/mydoc2.pdf");
                                 QPdfWriter pdfWriter(fileName);
                              pdfWriter.setPageSize(QPagedPaintDevice::A4);
                              QPainter painter(&pdfWriter);
                          
                             
                                  painter.drawPixmap(QRect(0,0,pdfWriter.logicalDpiX()*8.3,pdfWriter.logicalDpiY()*11.7), pixMap1);
                                  pdfWriter.newPage();
                          
                          mrjjM Offline
                          mrjjM Offline
                          mrjj
                          Lifetime Qt Champion
                          wrote on last edited by
                          #24

                          @geor
                          hi
                          Sorry, didn't read the right docs.
                          The rect is for clipping not resize the widget.
                          So render will not help you to render it smaller.

                          so yes, i guess to render it in different size, you must take widget out , call resize +render and put it back it.
                          Not sure how well it will work if there is other stuff in the layout.
                          If sole widget, it should work ok.

                          georG 1 Reply Last reply
                          1
                          • mrjjM mrjj

                            @geor
                            hi
                            Sorry, didn't read the right docs.
                            The rect is for clipping not resize the widget.
                            So render will not help you to render it smaller.

                            so yes, i guess to render it in different size, you must take widget out , call resize +render and put it back it.
                            Not sure how well it will work if there is other stuff in the layout.
                            If sole widget, it should work ok.

                            georG Offline
                            georG Offline
                            geor
                            wrote on last edited by
                            #25

                            @mrjj Yeah I tried this method and It works but it's not perfect even if I resize the widget to the size of an A4 and then take it's pixmap fore some reason in the pdf it loses some quality (it looks a lot better in the user interface then in the pdf )even tho they are both the same size.I tried different functions from the painter class to draw the pixamp but the all seam the same not so good .If I draw the pixmap withouth any scaling it is very small in the pdf .. any ideas?

                            mrjjM 1 Reply Last reply
                            0
                            • georG geor

                              @mrjj Yeah I tried this method and It works but it's not perfect even if I resize the widget to the size of an A4 and then take it's pixmap fore some reason in the pdf it loses some quality (it looks a lot better in the user interface then in the pdf )even tho they are both the same size.I tried different functions from the painter class to draw the pixamp but the all seam the same not so good .If I draw the pixmap withouth any scaling it is very small in the pdf .. any ideas?

                              mrjjM Offline
                              mrjjM Offline
                              mrjj
                              Lifetime Qt Champion
                              wrote on last edited by
                              #26

                              @geor
                              hi , have you tried to render it really large and then
                              scale down to fit A4?

                              georG 1 Reply Last reply
                              0
                              • mrjjM mrjj

                                @geor
                                hi , have you tried to render it really large and then
                                scale down to fit A4?

                                georG Offline
                                georG Offline
                                geor
                                wrote on last edited by
                                #27

                                @mrjj yep no matter how large the pixmap awlays appears very small on the pdf

                                mrjjM 1 Reply Last reply
                                0
                                • georG geor

                                  @mrjj yep no matter how large the pixmap awlays appears very small on the pdf

                                  mrjjM Offline
                                  mrjjM Offline
                                  mrjj
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #28

                                  @geor
                                  well a screen is 72/96 DPI
                                  and a printer is 600/1200/2400 DPI
                                  so images do get really small.

                                  As far as I remember, QPdfWriter have some setting for pdf resolution.
                                  maybe it can produce better output.

                                  georG 1 Reply Last reply
                                  2
                                  • mrjjM mrjj

                                    @geor
                                    well a screen is 72/96 DPI
                                    and a printer is 600/1200/2400 DPI
                                    so images do get really small.

                                    As far as I remember, QPdfWriter have some setting for pdf resolution.
                                    maybe it can produce better output.

                                    georG Offline
                                    georG Offline
                                    geor
                                    wrote on last edited by
                                    #29

                                    @mrjj yeah I saw that but unfortunately I am using qt 5.2.1

                                    mrjjM 1 Reply Last reply
                                    0
                                    • georG geor

                                      @mrjj yeah I saw that but unfortunately I am using qt 5.2.1

                                      mrjjM Offline
                                      mrjjM Offline
                                      mrjj
                                      Lifetime Qt Champion
                                      wrote on last edited by
                                      #30

                                      @geor
                                      maybe you could try to scale it before
                                      drawing it to pdf.
                                      the scale function can be adjusted to aim for quality
                                      http://doc.qt.io/qt-5/qpixmap.html#scaled
                                      with Qt::SmoothTransformation

                                      note. it returns the scaled pixmap not modify the original.
                                      so something like
                                      mypixmap = mypixmap.scaled(xx)

                                      georG 1 Reply Last reply
                                      1
                                      • mrjjM mrjj

                                        @geor
                                        maybe you could try to scale it before
                                        drawing it to pdf.
                                        the scale function can be adjusted to aim for quality
                                        http://doc.qt.io/qt-5/qpixmap.html#scaled
                                        with Qt::SmoothTransformation

                                        note. it returns the scaled pixmap not modify the original.
                                        so something like
                                        mypixmap = mypixmap.scaled(xx)

                                        georG Offline
                                        georG Offline
                                        geor
                                        wrote on last edited by
                                        #31

                                        @mrjj It is abit better but still low quality

                                        mrjjM 1 Reply Last reply
                                        0
                                        • georG geor

                                          @mrjj It is abit better but still low quality

                                          mrjjM Offline
                                          mrjjM Offline
                                          mrjj
                                          Lifetime Qt Champion
                                          wrote on last edited by
                                          #32

                                          @geor
                                          well it was worth a shot.
                                          I assume you play around with different scales?
                                          Have you tried huge image like 1920x1080 and scale it down?
                                          You are using http://doc.qt.io/qt-5/qpaintdevice.html#logicalDpiX
                                          to calc how much to scale it?

                                          I dont remember quality being so bad but i was using a fairly
                                          large resolution so the widget was not that small.

                                          georG 1 Reply Last reply
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