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QPixmap Problem

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  • O Offline
    O Offline
    ofmrew
    wrote on last edited by
    #11

    @Charlie_Hdz I change to what created the parcels.png file and got nothing. I do not see what is wrong it is very simple. I will try reducing the size and try with both QPixmap and QImage, then I will post the results.

    In what folder did the file from pixmap.save( "path.png" ); end up.

    C 1 Reply Last reply
    0
    • O ofmrew

      @Charlie_Hdz I change to what created the parcels.png file and got nothing. I do not see what is wrong it is very simple. I will try reducing the size and try with both QPixmap and QImage, then I will post the results.

      In what folder did the file from pixmap.save( "path.png" ); end up.

      C Offline
      C Offline
      Charlie_Hdz
      wrote on last edited by
      #12

      @ofmrew said in QPixmap Problem:

      In what folder did the file from pixmap.save( "path.png" ); end up.

      Depends, it can be saved at Home(root directory) or in the project output folder. I tried in Ubuntu.

      Kind Regards,
      Enrique Hernandez
      gearstech.com.mx
      chernandez@gearstech.com.mx

      O 1 Reply Last reply
      0
      • O ofmrew

        @Charlie_Hdz I had to convert your program into a console application, but I got nothing. How did you creat yours, I did mine with QtCreator.
        Here is mine:
        #include <QCoreApplication>
        #include <QPainter>
        #include <QPainterPath>
        #include <QFont>
        #include <QPixmap>

        int main(int argc, char *argv[])
        {
        QCoreApplication a(argc, argv);;

          QPixmap pixmap( 200, 200 );
          pixmap.fill( Qt::white );
        
          QPainterPath path;
        
          path.addEllipse( 80, 80, 80, 80 );
        
          path.moveTo( 120, 120 );
          path.lineTo( 120, 40 );
          path.arcTo( 40, 40, 160, 160, 90, 90 );
          path.lineTo( 120, 120 );
        

        // QFont font = QCoreApplication::font();
        // font.setPixelSize( 40 );

        // path.addText( 20, 180, font, "Path" );

          QPainter painter( &pixmap );
          painter.setRenderHint( QPainter::Antialiasing );
        
          painter.setPen( Qt::black );
          painter.setBrush( Qt::gray );
        
          painter.drawPath( path );
        
          pixmap.save( "//home//bobwilliams//Pictures//path.png" );
        
        return a.exec();
        

        }

        C Offline
        C Offline
        Charlie_Hdz
        wrote on last edited by
        #13

        @ofmrew said in QPixmap Problem:

        I had to convert your program into a console application

        So, hadn't have an error when QApplication header was not detected? In the console application, GUI is removed... So it causes errors.

        Create a Qt Widget Application, then insert the code and compile. It should work in that way!

        Kind Regards,
        Enrique Hernandez
        gearstech.com.mx
        chernandez@gearstech.com.mx

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        • C Charlie_Hdz

          @ofmrew said in QPixmap Problem:

          In what folder did the file from pixmap.save( "path.png" ); end up.

          Depends, it can be saved at Home(root directory) or in the project output folder. I tried in Ubuntu.

          O Offline
          O Offline
          ofmrew
          wrote on last edited by
          #14

          @Charlie_Hdz

          What I meant was when you executed the code you posted, in what folder did you find the path.png file?

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          • SGaistS Offline
            SGaistS Offline
            SGaist
            Lifetime Qt Champion
            wrote on last edited by
            #15

            This one is working fine. I get a white image with several rectangles on it

            #include <QCoreApplication>
            #include <QFile>
            #include <QImage>
            #include <QPainter>
            #include <QPointF>
            #include <QtDebug>
            
            int main(int argc, char **argv)
            {
                QCoreApplication app(argc, argv);
                QImage parcelMap(20000, 10000, QImage::Format_ARGB32);
                parcelMap.fill(Qt::white);
                QPainter pm(&parcelMap);
                static const QPointF points1[5] = {
                QPointF(200, 200),
                QPointF(20000-200, 200),
                QPointF(20000-200, 5000-100),
                QPointF(200, 5000-100),
                QPointF(200, 200)};
                pm.drawPolyline(points1, 5);
                static const QPointF points2[5] = {
                    QPointF(200, 5000+100),
                    QPointF(10000-100, 5000+100),
                    QPointF(10000-100, 5000-100),
                    QPointF(200, 5000-100),
                    QPointF(200, 200)};
                pm.drawPolyline(points2, 5);
                static const QPointF points3[5] = {
                    QPointF(10000+100, 5000+100),
                    QPointF(20000+200, 5000+100),
                    QPointF(20000+200, 5000-100),
                    QPointF(10000+100, 5000-100),
                    QPointF(10000+100, 200)};
                pm.drawPolyline(points3, 5);
                pm.end();
            
                QFile file("parcels.png");
                if (!file.open(QIODevice::WriteOnly)) {
                    qDebug() << "Failed to open file" << file.errorString();
                }
                parcelMap.save(&file, "PNG");
                return 0;
            

            Interested in AI ? www.idiap.ch
            Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

            O 1 Reply Last reply
            1
            • O ofmrew

              @Charlie_Hdz

              What I meant was when you executed the code you posted, in what folder did you find the path.png file?

              C Offline
              C Offline
              Charlie_Hdz
              wrote on last edited by
              #16

              @ofmrew

              You define the output directory, in Project, Run Working Directory.

              In this image, you can search for the "Working DIrectory"

              0_1515184782782_Screenshot from 2018-01-05 14-38-48.png

              Kind Regards,
              Enrique Hernandez
              gearstech.com.mx
              chernandez@gearstech.com.mx

              1 Reply Last reply
              0
              • SGaistS SGaist

                This one is working fine. I get a white image with several rectangles on it

                #include <QCoreApplication>
                #include <QFile>
                #include <QImage>
                #include <QPainter>
                #include <QPointF>
                #include <QtDebug>
                
                int main(int argc, char **argv)
                {
                    QCoreApplication app(argc, argv);
                    QImage parcelMap(20000, 10000, QImage::Format_ARGB32);
                    parcelMap.fill(Qt::white);
                    QPainter pm(&parcelMap);
                    static const QPointF points1[5] = {
                    QPointF(200, 200),
                    QPointF(20000-200, 200),
                    QPointF(20000-200, 5000-100),
                    QPointF(200, 5000-100),
                    QPointF(200, 200)};
                    pm.drawPolyline(points1, 5);
                    static const QPointF points2[5] = {
                        QPointF(200, 5000+100),
                        QPointF(10000-100, 5000+100),
                        QPointF(10000-100, 5000-100),
                        QPointF(200, 5000-100),
                        QPointF(200, 200)};
                    pm.drawPolyline(points2, 5);
                    static const QPointF points3[5] = {
                        QPointF(10000+100, 5000+100),
                        QPointF(20000+200, 5000+100),
                        QPointF(20000+200, 5000-100),
                        QPointF(10000+100, 5000-100),
                        QPointF(10000+100, 200)};
                    pm.drawPolyline(points3, 5);
                    pm.end();
                
                    QFile file("parcels.png");
                    if (!file.open(QIODevice::WriteOnly)) {
                        qDebug() << "Failed to open file" << file.errorString();
                    }
                    parcelMap.save(&file, "PNG");
                    return 0;
                
                O Offline
                O Offline
                ofmrew
                wrote on last edited by
                #17

                @SGaist Ran it and got an image of thousands of small squares. I have a screen shot, but I so not know how to post it to this message; how do I do it?

                Also, I moved the project to windows and got a blank white image!

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                0
                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #18

                  There's an upload image button just above the editor, third from the right.

                  Interested in AI ? www.idiap.ch
                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                  • SGaistS SGaist

                    There's an upload image button just above the editor, third from the right.

                    O Offline
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                    ofmrew
                    wrote on last edited by
                    #19

                    @SGaist I have narrowed the problem to my Mint Linux computer because I moved the one above to a Win 10 computer and I got a white rectangle with just visible rectangles. I moved the .png file to the Win 10 machine and, guess what, it showed a white rectangle with just visible rectangles. So the problem appears to be Image Viewer. Which viewer do you use on Linux computers.

                    As for the icons on the editor, to tell the truth, I never really noticed them. Is the some documentation on their meaning and how to use them. Most are obvious, but link, picture, zen mode and the one on the end, require more explanation.

                    Seems we spent all this time running to ground a non-problem with Qt, while the real culprit was software provided by the operating system; however, just for grins I tried GIMP Image Viewer and of course it showed the image correctly. Warning to Mint Linux users, Image Viewer is not to be trusted.

                    Thanks to all for the help.

                    1 Reply Last reply
                    1
                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #20

                      It depends on the desktop environment so there are several possible like Gwenview, Okular, etc.

                      Zen mode simply puts the editor in full screen so you don't have any distraction and the last one on the right allows to easily insert code sample.

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                      O 1 Reply Last reply
                      1
                      • SGaistS SGaist

                        It depends on the desktop environment so there are several possible like Gwenview, Okular, etc.

                        Zen mode simply puts the editor in full screen so you don't have any distraction and the last one on the right allows to easily insert code sample.

                        O Offline
                        O Offline
                        ofmrew
                        wrote on last edited by
                        #21

                        @SGaist Thanks. That really helps; now I can start correctly adding code and images to my posts.

                        1 Reply Last reply
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