problem with back-buffered widget

In order to learn the fox toolkit I decided to write a sudoku game.  It's not complete yet, but so far does what's expected of it except for some confusing problems.

When first started up it outputs to the console the following errors:

X Error: code 9 major 152 minor 4: BadDrawable (invalid Pixmap or Window parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 23: RenderBadPicture (invalid Picture parameter).
X Error: code 170 major 152 minor 7: RenderBadPicture (invalid Picture parameter).

I suspect these have something to do with the font resizing on the server, but I'm not sure what to do about it.  When the app is resized, these errors are repeated and the canvas widget goes blank except for the background and the lines drawn to make the board.  Doing things like passing another window over it will restore those parts which shouldn't be blank and doing anything which causes a canvas update restores the whole thing.

Also, the flush left "renderAll= true;" in the method layoutBuffer was necessary in order to have the canvas update restore everything.  I would much prefer to have only the dirty bits repainted as oulined in the FAQ about back-buffered widgets.

I have learned much from the docs, FAQs and mailing list archives, but obviously am missing some basic understanding of the repainting process.  Whenever I try to include a layout() method as suggested in the FAQ, things go really bad with the canvas always remaining grey and even the menus not getting painted.

The full source is attached, but here are the bits which I would expect to be relevant.  I am using fox 1.6.35 and gcc 4.4.0  Any help would be appreciated.

Mike

---

  FXMAPFUNC(SEL_PAINT,           sudokuWindow::ID_CANVAS,   sudokuWindow::onPaint),

---

long sudokuWindow::onPaint(FXObject *, FXSelector, void *ptr)
{
   FXEvent *ev = (FXEvent *)ptr;
   layoutBuffer();
   FXDCWindow dc(canvas,ev);
   dc.drawImage(dbuf,0,0);
   return 1;
}

---

void sudokuWindow::layoutBuffer()
{
   FXDCWindow dc(dbuf);
   // builds the game board from the ground up
   int w= canvas->getWidth();
   int h= canvas->getHeight();
   int h9= h/9;   int w9= w/9;
   if (lastw != w || lasth != h || font==NULL)
   {
      renderAll= true;      // resizing means repaint all
      dbuf->resize(w,h);
      lastw= w;   lasth= h;
      // simple guess for proper font size that works well
      int fs=h9/2;
      if (fs != fontSize)
      {
         fontSize= fs;
         if (font!=NULL)
         {
            font->destroy();
            delete font;
         }
         font= new FXFont(getApp(),"times",fs);
         font->create();
      }
      // now for the hint font
      fs=h9/5;
      if (fs != hfontSize)
      {
         hfontSize= fs;
         if (hfont!=NULL)   delete hfont;
         hfont= new FXFont(getApp(),"times",fs);
         hfont->create();
      }
   }
renderAll=true;
   if (renderAll)
   {
      dc.setForeground(bgColor);
      dc.fillRectangle(0,0,w,h);
   }
   for (int i=0; i<81; ++i)
   {
      if (renderAll || dirty[i] || board[i].error)
      {
         int x= i%9;  int y=i/9;
         int w9= dbuf->getWidth()/9;
         int h9= dbuf->getHeight()/9;
         // correct for extra space in last row/column
         int w= x==8? dbuf->getWidth()-8*w9  : w9;
         int h= y==8? dbuf->getHeight()-8*h9 : h9;

         // refresh background
         if (i==cursor)    dc.setForeground(curColor);
         else              dc.setForeground(bgColor);
         dc.fillRectangle(x*w9,y*h9,w,h);
         int v= board[i].val;
         if (v>0)    // square has been solved show number
         {
            dc.setFont(font);
            string text;   text.append(1,'0'+v);
            int xpos= w9*x+w/2-font->getCharWidth('0'+v)/2;
            int ypos= h9*y+h/2+h9/4;
            if (board[i].error)     dc.setForeground(errorColor);
            else                    dc.setForeground(fgColor);
            dc.drawText(xpos,ypos,text.c_str() );
         }
         else        // square not solved show hints
         if (allhints || (curshints && i==cursor) )
         {
            dc.setFont(hfont);
            dc.setForeground(hintColor);
            set<int>::const_iterator it;
            for (it=board[i].possible.begin(); it!=board[i].possible.end(); ++it)
            {
               int v= *it;
               string text;   text.append(1,'0'+v);
               int fw= hfont->getCharWidth('0'+v)/2;
               int xpos= (x*w9)+2*w/10+((v-1)%3)*3*w/10-fw;
               int ypos= (y*h9)+3*h/10+((v-1)/3)*3*h/10;
               dc.drawText(xpos,ypos,text.c_str() );
            }
         }
      }
      if (board[i].error)  dirty[i]= true;
      else                 dirty[i]= false;
   }
   if (renderAll)
   {
      dc.setForeground(fgColor);
      for (int i=1; i<9; ++i)
      {
         if ( i%3==0 )  dc.setLineWidth(3);
         else           dc.setLineWidth(1);
         dc.drawLine(i*w9,0,i*w9,h);
         dc.drawLine(0,i*h9,w,i*h9);
      }
   }
   renderAll= false;
}

------------------------------------------------------------------------------
Are you an open source citizen? Join us for the Open Source Bridge conference!
Portland, OR, June 17-19. Two days of sessions, one day of unconference: $250.
Need another reason to go? 24-hour hacker lounge. Register today!
http://ad.doubleclick.net/clk;215844324;13503038;v?http://opensourcebridge.org
_______________________________________________
Foxgui-users mailing list
Foxgui-users@...
https://lists.sourceforge.net/lists/listinfo/foxgui-users