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  1. 29th March 2014, 11:05 #1
    kolqhoz
    kolqhoz is offline Beginner
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    Default Coordinates of a widget inside QGridLayout

    Hi everyone !

    I am trying to find the coordinates of a class derived from a QWidget inside a QGridLayout relative to its parent. I have tried several things such as x() and y() and pos() (returned 0,0) from QWidget class, adding a QRect to the class and using getCoords from QRect class and the mapToParent class from QWidget but it always returns 0. I can't seem to find the anser so I seek your help !

    thanks in advance for your help, you can find the code of my program attached to this post.

    render_area.cpp

    Qt Code: 
    1. #include "render_area.hpp"
    2.  
    3. #include <GL/glu.h>
    4. #include <iostream>
    5. #include <cmath>
    6.  
    7. #include <QPainter>
    8. #include <QMouseEvent>
    9. #include <QKeyEvent>
    10. #include <QGridLayout>
    11.  
    12.  
    13. render_area::render_area(QWidget *parent)
    14.     :QWidget(parent)
    15. {
    16.     setFocusPolicy(Qt::StrongFocus);
    17.     setBackgroundRole(QPalette::Base);
    18.     setAutoFillBackground(true);
    19.  
    20.     bar=new QRect(width()/2,height()+50,150,10);
    21.     grid=new Grid(this);
    22.     grid->fill_grid(this);
    23.     std::cout<<"Grid filled !"<<std::endl;
    24.  
    25.     QPoint point;
    26.     point=grid->getBrick(5)->pos();
    27.     grid->getBrick(5)->mapToParent(point);
    28.     std::cout<<point.y()<<std::endl;
    29.  
    30.     dt=1/30.0f;
    31.     connect(&timer, SIGNAL(timeout()), this, SLOT(update_timer()));
    32.     timer.start(5);
    33.  
    34.     draw_circle=true;
    35.  
    36.     x_old=0;
    37.     y_old=0;
    38.     x_old2=0;
    39.     y_old2=0;
    40.  
    41.     xc=500;
    42.     yc=500;
    43.     diametre=15;
    44.  
    45.     vxc=20.0f;
    46.     vyc=-20.0f;
    47.  
    48.     is_fixed=false;
    49. }
    50.  
    51. render_area::~render_area()
    52. {}
    53.  
    54.  
    55.  
    56. void render_area::paintEvent(QPaintEvent*)
    57. {
    58.     QPainter painter(this);
    59.     painter.setRenderHint(QPainter::Antialiasing, true);
    60.     painter.drawRect(*bar);
    61.  
    62.     QPen pen;
    63.     pen.setWidth(1.0);
    64.     pen.setColor(Qt::blue);
    65.     painter.setPen(pen);
    66.  
    67.     QBrush brush = painter.brush();
    68.     brush.setColor(Qt::gray);
    69.     brush.setStyle(Qt::SolidPattern);
    70.     painter.setBrush(brush);
    71.  
    72.     if(draw_circle)
    73.         painter.drawEllipse(xc,yc,diametre,diametre);
    74. }
    75.  
    76. void render_area::change_draw_circle()
    77. {
    78.     draw_circle=!draw_circle;
    79.     repaint();
    80. }
    81.  
    82. void render_area::keyPressEvent(QKeyEvent *event)
    83. {
    84.     switch(event->key())
    85.     {
    86.     case Qt::Key_Right:
    87.         bar->translate(15,0);
    88.         break;
    89.     case Qt::Key_Left:
    90.         bar->translate(-15,0);
    91.         break;
    92.     default:
    93.         break;
    94.     }
    95. }
    96.  
    97. void render_area::mousePressEvent(QMouseEvent *event)
    98. {
    99.     x_old=event->x();
    100.     y_old=event->y();
    101.     std::cout<<event->x()<<"|"<<event->y()<<std::endl;
    102.     is_fixed=true;
    103. }
    104.  
    105. void render_area::mouseReleaseEvent(QMouseEvent *event)
    106. {
    107.  
    108.     float x=event->x();
    109.     float y=event->y();
    110.  
    111.  
    112.     vxc=60*(x-x_old2);
    113.     vyc=60*(y-y_old2);
    114.  
    115.     is_fixed=false;
    116.  
    117. }
    118.  
    119. void render_area::mouseMoveEvent(QMouseEvent *event)
    120. {
    121.     int x=event->x();
    122.     int y=event->y();
    123.  
    124.     float R=diametre/2.0f;
    125.     float x0=xc+R;
    126.     float y0=yc+R;
    127.  
    128.     if( (x-x0)*(x-x0)+(y-y0)*(y-y0)<R*R )
    129.     {
    130.         xc+=(x-x_old);
    131.         yc+=(y-y_old);
    132.     }
    133.  
    134.     x_old2=x_old;
    135.     y_old2=y_old;
    136.     x_old=x;
    137.     y_old=y;
    138.  
    139.     repaint();
    140. }
    141.  
    142. void render_area::update_timer()
    143. {
    144.     int x1,x2,y1,y2;
    145.     bar->getCoords(&x1,&y1,&x2,&y2);
    146.  
    147.     if(is_fixed==false)
    148.     {
    149.         //gestion du sol
    150.         if(yc+diametre>height())
    151.         {
    152.                 vyc=-vyc;
    153.  
    154.         }
    155.  
    156.         if(xc>x1 && xc<x1+150)
    157.         {
    158.             if(yc+diametre>y1)
    159.             {
    160.                 vyc=-vyc;
    161.             }
    162.         }
    163.         //plafond
    164.         if(yc-diametre<0)
    165.         {
    166.             vyc=-vyc;
    167.         }
    168.  
    169.         //bord droit
    170.         if(xc+diametre>width())
    171.         {
    172.                 vxc=-vxc;
    173.         }
    174.  
    175.         //bord gauche
    176.         if(xc<0)
    177.         {
    178.                 vxc=-vxc;
    179.         }
    180.  
    181.         //integration (Euler explicite)
    182.         xc=xc+dt*vxc;
    183.         yc=yc+dt*vyc;
    184.  
    185.     }
    186.     repaint();
    187. }
    188.  
    189. Grid* render_area::getGrid() const
    190. {
    191.     return grid;
    192. }
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    grid.cpp

    Qt Code: 
    1. #include "grid.hpp"
    2.  
    3. Grid::Grid(QWidget *parent) :
    4.     QWidget(parent)
    5. {
    6.     grid=new QGridLayout(parent);
    7.     grid->setContentsMargins(0,0,0,0);
    8.     grid->setAlignment(Qt::AlignTop);
    9.     grid->setSpacing(2);
    10. }
    11.  
    12. void Grid::fill_grid(QWidget* parent)
    13. {
    14.     for (int i=0;i<10;i++)
    15.     {
    16.         for (int j=0;j<12;j++)
    17.         {
    18.             brick* fillingBrick=new brick(parent);
    19.             grid->addWidget(fillingBrick->getLabel(),j,i);
    20.             qDebug()<<fillingBrick->parentWidget();
    21.             brickVector.push_back(fillingBrick);
    22.         }
    23.     }
    24. }
    25.  
    26. std::vector<brick*> Grid::getBrickVector() const
    27. {
    28.     return brickVector;
    29. }
    30.  
    31. brick* Grid::getBrick(int indice)
    32. {
    33.     return brickVector.at(indice);
    34. }
    35.  
    36. QGridLayout* Grid::getGrid() const
    37. {
    38.     return grid;
    39. }
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    brick.cpp

    Qt Code: 
    1. #include "brick.hpp"
    2.  
    3. brick::brick(QWidget *parent) :
    4.     QWidget(parent)
    5. {
    6.     label=new QLabel;
    7.     brickPic=new QPixmap(100,15);
    8.     brickPic->fill(QColor(255,0,0));
    9.     label->setPixmap(*brickPic);
    10. }
    11.  
    12. brick::~brick()
    13. {
    14. }
    15.  
    16. QLabel* brick::getLabel() const
    17. {
    18.     return label;
    19. }
    20.  
    21. QPixmap* brick::getPixmap() const
    22. {
    23.     return brickPic;
    24. }
    25.  
    26. QRect* brick::getRect() const
    27. {
    28.     return rect;
    29. }
    30.  
    31. void brick::setRect(QRect recttmp)
    32. {
    33.     int x,y,w,h;
    34.     recttmp.getRect(&x,&y,&w,&h);
    35.     rect=new QRect(x,y,w,h);
    36. }
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    I'll put here the things I tried to solve the problem :
    in the fill_grid member function : tried to change the parent of the brick by using setparent(parent) -> failed
    in the render_area contructor : tried adding show() before getting grid->getBrick(5)->pos() failed
    Even after showing the main windows fenetre.getRender()->getGrid()->getBrick(5)->x() shows 0
    in fill_grid member function : qDebug() << fillingBrick->parentWidget() shows "render_area(0x64f570)" which is good but the brick still can't find its position inside its parent (0,0)
    Attached Files Attached Files
    Last edited by kolqhoz; 29th March 2014 at 12:03.
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