c++ - Stretching a QLabel in a QGridLayout -

i manually creating set of qlabels being put qgridlayout, , should distributed evenly. when create test form using qt designer , add series of labels, , put them in qgridlayout, labels occupy full size of cells in grid. when manually in c++, labels don't expand , minimum size text. able these labels expand vertically, not horizontally.

here how i'm creating qgridlayout:

m_layout = new qgridlayout; m_layout->sethorizontalspacing( 1 ); m_layout->setverticalspacing( 1 ); m_layout->setcontentsmargins(0,0,0,0); m_layout->setmargin(0); m_layout->setsizeconstraint( qgridlayout::setdefaultconstraint ); //m_layout->setsizeconstraint( qgridlayout::setmaximumsize ); 

when change size constraint, not affect size of labels @ all, assumed issue may lie on how i'm creating labels, happens this:

qlabel *label = new qlabel; label->setalignment( qt::aligncenter ); label->setframestyle( qframe::raised ); label->setminimumsize( qsize(0,0) ); label->setmaximumsize( qsize(16777215, 16777215) ); label->setsizepolicy( qsizepolicy::preferred, qsizepolicy::preferred ); 

right now, qlabels same size, have differing sizes, why i'm using packed-bin algorithm. designed algorithm around classes this:

struct buttonfittingnode {     buttonfittingnode( qrect rectangle, qgridlayout *layout )         : used( false )         , node( rectangle )         , down( null )         , right( null )         , m_layout( layout )     { }      ~buttonfittingnode()     {         if ( down ) delete down;         if ( right ) delete right;     }      buttonfittingnode *findnode( qlabel *btn )     {         int w = 1;         int h = 1;         if ( this->used )         {             buttonfittingnode *bfn = null;             if ( this->right ) bfn = this->right->findnode( btn );             if ( this->down && !bfn ) bfn = this->down->findnode( btn );             return bfn;         }         else if ( ( w <= node.width() ) && ( h <= node.height() ) )         {             qdebug() << "placing @ " << node.x() << node.y();             m_layout->addwidget( btn, node.y(), node.x(), w, h, qt::alignjustify );             this->used = true;             this->splitnode( qsize( w, h ) );             return this;         }          return null;     }      void splitnode( qsize sz )     {         int w = 0, h = 0;          // create down node         w = this->node.width();         h = this->node.height() - sz.height();         if ( h > 0 )         {             qrect n( this->node.x(), this->node.y() + sz.height(), w, h );             this->down = new buttonfittingnode( n, m_layout );         }          // create right node         w = this->node.size().width() - sz.width();         h = sz.height();         if ( w > 0 )         {             qrect n( this->node.x() + sz.width(), this->node.y(), w, h );             this->right = new buttonfittingnode( n, m_layout );         }     }      bool                used;     qrect               node;     buttonfittingnode   *down;     buttonfittingnode   *right; private:     qgridlayout         *m_layout; }; 

using 3x2 grid, following output:

sorry, had blur text, since work related project, grey background, white label's background. can see, tall, skinny. want these labels tall , fat. setting of attributes wrong?

this really simple. size constraint of layout has got nothing you're seeing. you're including bunch of useless boilerplate code. rid of explicit setting of minimum , maximum sizes unless have non-default sizes in mind. useless:

label->setminimumsize( qsize(0,0) ); label->setmaximumsize( qsize(16777215, 16777215) ); 

you need set label's sizepolicy expanding in horizontal direction. that's there's it:

label->setsizepolicy( qsizepolicy::expanding, qsizepolicy::preferred ); 

i see want bin packing system, won't work as-is, since column/row sizes in grid vary grid gets resized. packer choose column/row spans based on then current row/column sizes. upon resizing, packer's decisions won't adequate anymore.

what want custom layout packing on fly. the flow layout example may close want.