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Forum Update on Monday, May 27th 2025

Combine Multiple Images Into a Single PDF

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pdfsavewidget
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  • ? A Former User

    @geor Like this:

    void writePdf()
    {
        const QString fileName("/home/patrick/mydoc.pdf");
        const QImage image("/home/patrick/truck.jpg");
        const QPoint imageCoordinates(0,0);
    
        QPdfWriter pdfWriter(fileName);
        pdfWriter.setPageSize(QPageSize(QPageSize::A4));
        QPainter painter(&pdfWriter);
    
        for (int i=0; i<3; ++i) {
            painter.drawImage(imageCoordinates, image);
            pdfWriter.newPage();
        }
    }
    
    georG Offline
    georG Offline
    geor
    wrote on last edited by
    #10

    @Wieland thank you

    ? 1 Reply Last reply
    0
    • georG geor

      @Wieland thank you

      ? Offline
      ? Offline
      A Former User
      wrote on last edited by
      #11

      @geor :-)

      georG 1 Reply Last reply
      1
      • ? A Former User

        @geor :-)

        georG Offline
        georG Offline
        geor
        wrote on last edited by
        #12

        @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 1 Reply Last reply
        1
        • 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
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