Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
  • Search
  • Get Qt Extensions
  • Unsolved
Collapse
Brand Logo
  1. Home
  2. Qt Development
  3. General and Desktop
  4. Make a palette image from palette data
Forum Updated to NodeBB v4.3 + New Features

Make a palette image from palette data

Scheduled Pinned Locked Moved Solved General and Desktop
35 Posts 4 Posters 4.3k Views 2 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • K Kris Revi

    @mpergand yes but how would that work in my code? you setup all the points manualy here

    i need to go through QJsonArray jsonArr and in this case QJsonArray jsonArr contains

    // Position (X), Red, Green, Blue
    0, 255, 0, 0,
    32,171,85,0,
    64,171,171,0,
    96,0,255,0,
    128,0,171,85,
    160,0,0,255,
    192,85,0,171,
    224,171,0,85,
    255,255,0,0
    

    as this is the default but i plan to add more palettes to the json so it can be bigger (more points) or less but always 0 (start) and 255 (end) point but there could be many points in between

    M Offline
    M Offline
    mpergand
    wrote on last edited by
    #14

    As you can see in my example, you need to define a step variable base of the number of points.
    float step=1.0/(points-1)

    K 1 Reply Last reply
    0
    • M mpergand

      As you can see in my example, you need to define a step variable base of the number of points.
      float step=1.0/(points-1)

      K Offline
      K Offline
      Kris Revi
      wrote on last edited by
      #15

      @mpergand but how can i count the points in that array? :S

      M 1 Reply Last reply
      0
      • K Kris Revi

        @mpergand but how can i count the points in that array? :S

        M Offline
        M Offline
        mpergand
        wrote on last edited by mpergand
        #16

        jsonArr.count() ?

        As the first param in the json array defines the point position, you need to convert the range 0-255 to 0.0-1.0

        K 1 Reply Last reply
        0
        • M mpergand

          jsonArr.count() ?

          As the first param in the json array defines the point position, you need to convert the range 0-255 to 0.0-1.0

          K Offline
          K Offline
          Kris Revi
          wrote on last edited by
          #17

          @mpergand but would that not count every int in the array? :S

          {
              "Palettes": [
                  {
                      "Name": "Rainbow",
                      "imageURL": "",
                      "palette": [
                          0,
                          255,
                          0,
                          0,
                          32,
                          171,
                          85,
                          0,
                          64,
                          171,
                          171,
                          0,
                          96,
                          0,
                          255,
                          0,
                          128,
                          0,
                          171,
                          85,
                          160,
                          0,
                          0,
                          255,
                          192,
                          85,
                          0,
                          171,
                          224,
                          171,
                          0,
                          85,
                          255,
                          255,
                          0,
                          0
                      ]
                  }
              ]
          }
          
          1 Reply Last reply
          0
          • M Offline
            M Offline
            mpergand
            wrote on last edited by mpergand
            #18

            jsonArr.count()/4 ?

            K 1 Reply Last reply
            0
            • M mpergand

              jsonArr.count()/4 ?

              K Offline
              K Offline
              Kris Revi
              wrote on last edited by
              #19

              @mpergand

                  int amountPoint;
                  amountPoint = jsonArr.count()/4;
              

              gives 9 so now i can do

              float p=0,s=1.0/amountPoint;
              

              ?

              M 1 Reply Last reply
              0
              • K Kris Revi

                @mpergand

                    int amountPoint;
                    amountPoint = jsonArr.count()/4;
                

                gives 9 so now i can do

                float p=0,s=1.0/amountPoint;
                

                ?

                M Offline
                M Offline
                mpergand
                wrote on last edited by
                #20

                float p=0,s=1.0/(amountPoint-1);

                K 1 Reply Last reply
                0
                • M mpergand

                  float p=0,s=1.0/(amountPoint-1);

                  K Offline
                  K Offline
                  Kris Revi
                  wrote on last edited by
                  #21

                  @mpergand

                  QImage MainWindow::createPaletteImage(QJsonArray jsonArr)
                  {
                      int width = 500;
                      int height = 26;
                      QImage image(width, height, QImage::Format_RGB32);
                      image.fill(Qt::white);
                  
                      QPainter painter(&image);
                  
                      int amountPoint;
                      amountPoint = jsonArr.count()/4;
                  
                      for (int i = 0; i < jsonArr.size(); i++)
                      {
                          float p=0,s=1.0/(amountPoint-1);
                          QLinearGradient gradient = QLinearGradient(0,0, rect().width(), 0);
                      }
                      return image;
                  }
                  

                  so far correct?

                  now what?

                  M 1 Reply Last reply
                  0
                  • K Kris Revi

                    @mpergand

                    QImage MainWindow::createPaletteImage(QJsonArray jsonArr)
                    {
                        int width = 500;
                        int height = 26;
                        QImage image(width, height, QImage::Format_RGB32);
                        image.fill(Qt::white);
                    
                        QPainter painter(&image);
                    
                        int amountPoint;
                        amountPoint = jsonArr.count()/4;
                    
                        for (int i = 0; i < jsonArr.size(); i++)
                        {
                            float p=0,s=1.0/(amountPoint-1);
                            QLinearGradient gradient = QLinearGradient(0,0, rect().width(), 0);
                        }
                        return image;
                    }
                    

                    so far correct?

                    now what?

                    M Offline
                    M Offline
                    mpergand
                    wrote on last edited by mpergand
                    #22
                    for each point
                          get pos, r, v, b
                          set color gradiant from the vars above
                    
                    K 1 Reply Last reply
                    0
                    • M mpergand
                      for each point
                            get pos, r, v, b
                            set color gradiant from the vars above
                      
                      K Offline
                      K Offline
                      Kris Revi
                      wrote on last edited by Kris Revi
                      #23

                      @mpergand sooo

                          int amountPoint;
                          amountPoint = jsonArr.count()/4;
                          float p=0,s=1.0/(amountPoint-1);
                          QLinearGradient gradient = QLinearGradient(0,0, rect().width(), 0);
                      
                          for (int i = 0; i < amountPoint; i++)
                          {
                              // but how to get the pos, r, g, b since its just a long array of ints
                             // gradient.setColorAt(p, QColor(r,g,b));
                          }
                      
                      1 Reply Last reply
                      0
                      • M Offline
                        M Offline
                        mpergand
                        wrote on last edited by
                        #24

                        qjsonarray.at

                        K 1 Reply Last reply
                        0
                        • M mpergand

                          qjsonarray.at

                          K Offline
                          K Offline
                          Kris Revi
                          wrote on last edited by
                          #25

                          @mpergand

                          int pos = jsonArr.at(i).toInt();
                          

                          but what about R, G, B?

                          int r = jsonArr.at(i).toInt();
                          int g = jsonArr.at(i).toInt();
                          int b = jsonArr.at(i).toInt();
                          
                          1 Reply Last reply
                          0
                          • K Offline
                            K Offline
                            Kris Revi
                            wrote on last edited by
                            #26

                            am i doing something wrong here?

                            QImage MainWindow::createPaletteImage(QJsonArray jsonArr)
                            {
                                int width = 500;
                                int height = 26;
                                QImage image(width, height, QImage::Format_RGB32);
                                image.fill(Qt::white);
                            
                                QPainter painter(&image);
                            
                                int amountPoint;
                                amountPoint = jsonArr.count()/4;
                                float p=0,s=1.0/(amountPoint-1);
                                QLinearGradient gradient = QLinearGradient(0,0, rect().width(), 0);
                            
                                for (int i = 0; i < amountPoint; i++)
                                {
                                    int pos = jsonArr.at(i).toInt();
                                    int r = jsonArr.at(i+1).toInt();
                                    int g = jsonArr.at(i+2).toInt();
                                    int b = jsonArr.at(i+3).toInt();
                            
                                    gradient.setColorAt(p, QColor(r,g,b));
                                }
                                return image;
                            }
                            
                            1 Reply Last reply
                            0
                            • Christian EhrlicherC Online
                              Christian EhrlicherC Online
                              Christian Ehrlicher
                              Lifetime Qt Champion
                              wrote on last edited by
                              #27

                              @Kris-Revi said in Make a palette image from palette data:

                              int pos = jsonArr.at(i).toInt();
                              gradient.setColorAt(p, QColor(r,g,b));

                              Apart from the really strange idea to store a image in such an extensive way you want 'pos' in the second call.

                              Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                              Visit the Qt Academy at https://academy.qt.io/catalog

                              K 1 Reply Last reply
                              1
                              • Christian EhrlicherC Christian Ehrlicher

                                @Kris-Revi said in Make a palette image from palette data:

                                int pos = jsonArr.at(i).toInt();
                                gradient.setColorAt(p, QColor(r,g,b));

                                Apart from the really strange idea to store a image in such an extensive way you want 'pos' in the second call.

                                K Offline
                                K Offline
                                Kris Revi
                                wrote on last edited by
                                #28

                                @Christian-Ehrlicher said in Make a palette image from palette data:

                                you want 'pos' in the second call.

                                        int pos = jsonArr.at(i).toInt();
                                        int r = jsonArr.at(i+1).toInt();
                                        int g = jsonArr.at(i+2).toInt();
                                        int b = jsonArr.at(i+3).toInt();
                                
                                        gradient.setColorAt(pos, QColor(r,g,b));
                                

                                huh like so? :S

                                1 Reply Last reply
                                0
                                • M Offline
                                  M Offline
                                  mpergand
                                  wrote on last edited by mpergand
                                  #29
                                  for(int p=0; p<amountPoint; p++)
                                          {
                                              int pos=jsonArr[p*4];
                                              int r=jsonArr[p*4+1];
                                              int g=jsonArr[p*4+2];
                                              int b=jsonArr[p*4+3];
                                              
                                              gradient.setColorAt(pos/255.0, QColor(r,g,b));
                                          }
                                         
                                  
                                  K 1 Reply Last reply
                                  0
                                  • M mpergand
                                    for(int p=0; p<amountPoint; p++)
                                            {
                                                int pos=jsonArr[p*4];
                                                int r=jsonArr[p*4+1];
                                                int g=jsonArr[p*4+2];
                                                int b=jsonArr[p*4+3];
                                                
                                                gradient.setColorAt(pos/255.0, QColor(r,g,b));
                                            }
                                           
                                    
                                    K Offline
                                    K Offline
                                    Kris Revi
                                    wrote on last edited by
                                    #30

                                    @mpergand

                                    QImage MainWindow::createPaletteImage(QJsonArray jsonArr)
                                    {
                                        int width = 500;
                                        int height = 26;
                                        QImage image(width, height, QImage::Format_RGB32);
                                        image.fill(Qt::white);
                                    
                                        QPainter painter(&image);
                                    
                                        int amountPoint;
                                        amountPoint = jsonArr.count()/4;
                                        float p=0,s=1.0/(amountPoint-1);
                                        QLinearGradient gradient = QLinearGradient(0,0, rect().width(), 0);
                                    
                                        for (int p = 0; p < amountPoint; p++)
                                        {
                                            int pos=jsonArr[p*4].toInt();
                                            int r=jsonArr[p*4+1].toInt();
                                            int g=jsonArr[p*4+2].toInt();
                                            int b=jsonArr[p*4+3].toInt();
                                    
                                            gradient.setColorAt(pos/255.0, QColor(r,g,b));
                                        }
                                        painter.fillRect(rect(),QBrush(gradient));
                                        return image;
                                    }
                                    

                                    produces
                                    b31f83ea-6644-4c2d-af87-1ff271f7a8f2-image.png

                                    1 Reply Last reply
                                    0
                                    • M Offline
                                      M Offline
                                      mpergand
                                      wrote on last edited by
                                      #31

                                      Check the values in the debugger.

                                      K 1 Reply Last reply
                                      0
                                      • M mpergand

                                        Check the values in the debugger.

                                        K Offline
                                        K Offline
                                        Kris Revi
                                        wrote on last edited by Kris Revi
                                        #32

                                        @mpergand all i got is

                                        POS :  0
                                        RGB :  255 0 0
                                        GRAD :  QBrush(QColor(Invalid),LinearGradientPattern)
                                        POS :  0.12549
                                        RGB :  171 85 0
                                        GRAD :  QBrush(QColor(Invalid),LinearGradientPattern)
                                        POS :  0.25098
                                        RGB :  171 171 0
                                        GRAD :  QBrush(QColor(Invalid),LinearGradientPattern)
                                        POS :  0.376471
                                        RGB :  0 255 0
                                        GRAD :  QBrush(QColor(Invalid),LinearGradientPattern)
                                        POS :  0.501961
                                        RGB :  0 171 85
                                        GRAD :  QBrush(QColor(Invalid),LinearGradientPattern)
                                        POS :  0.627451
                                        RGB :  0 0 255
                                        GRAD :  QBrush(QColor(Invalid),LinearGradientPattern)
                                        POS :  0.752941
                                        RGB :  85 0 171
                                        GRAD :  QBrush(QColor(Invalid),LinearGradientPattern)
                                        POS :  0.878431
                                        RGB :  171 0 85
                                        GRAD :  QBrush(QColor(Invalid),LinearGradientPattern)
                                        POS :  1
                                        RGB :  255 0 0
                                        GRAD :  QBrush(QColor(Invalid),LinearGradientPattern)
                                        
                                        1 Reply Last reply
                                        0
                                        • M Offline
                                          M Offline
                                          mpergand
                                          wrote on last edited by
                                          #33

                                          Don't paste my code as this !
                                          QLinearGradient gradient = QLinearGradient(0,0, rect().width(), 0);

                                          should be the image width no ?

                                          K 1 Reply Last reply
                                          0

                                          • Login

                                          • Login or register to search.
                                          • First post
                                            Last post
                                          0
                                          • Categories
                                          • Recent
                                          • Tags
                                          • Popular
                                          • Users
                                          • Groups
                                          • Search
                                          • Get Qt Extensions
                                          • Unsolved