Technical Q&A's

TB24 - Using 'ictb' to Change Edit Fields (25-October-96)

Q I have created a dialog box that has two edit text fields in it and have used an 'ictb' resource to change the font and the size of the fields to 10 point Geneva. When I move the insertion point into the second field and delete a character, the character just before the one I deleted drops down a couple of pixels and overwrites itself. What can be done about this?

A You have run into a problem with the Dialog Manager's support of 'ictb'. The Dialog Manager forgets to reset some of the fields of the TextEdit record when it swaps the font and font size information stored in the 'ictb'. You need to reset the fontAscent and lineHeight fields of the TextEdit Record to match the size of the font specified in the 'ictb'. By default those fields are set to the lineHeight and fontAssent of 12 point Chicago.

Below is code that shows how to set up the TextEdit record.

//------------------------------------------------------------------
static void SetUpEditField (DialogRef dlog,short fontNum,short fontSize)
//------------------------------------------------------------------
{
  FontInfo  info;
  DialogPeek  dpeek = (DialogPeek)dlog;

  if (dpeek != nil) {
    TEHandle te = dpeek->textH;       //get the TEHandle

    if (te != nil) {
      short oldFont = dlog->txFont;   //save old info
      short oldSize = dlog->txSize;

      TextFont(fontNum);              //set the port to correct font info
      TextSize(fontSize);

      GetFontInfo(&info);

      // ok lets fix the TE record since the dialog manager left it at 12 point

      te[0]->txFont   = fontNum;        // set font
      te[0]->txSize     = fontSize;
      te[0]->lineHeight = info.ascent + info.descent + info.leading;
//calculate the correct info
      te[0]->fontAscent = info.ascent ;
      TextFont(oldFont);  //reset the font info
      TextSize(oldSize);
    }
  }
}

//------------------------------------------------------------------
static  short DoDialog(short resID)
//------------------------------------------------------------------
{
  DialogRef   dlog;
  GrafPtr   oldPort;
  short   itemHit = 0;

  GetPort(&oldPort);
  dlog = GetNewDialog(resID,nil,(WindowRef)-1);
  if (dlog) {
    SetPort(dlog);
    SelectDialogItemText(dlog,2,0x8000,0x8000); //set the cursor
    SetUpEditField(dlog,geneva,10);             // set the edit field
    (void)SetDialogDefaultItem(dlog,1);         // hilight the ok button
    ShowWindow(dlog);                           // show the dialog
    while (itemHit != ok) {
      ModalDialog(nil,&itemHit);
    }
    SetPort(oldPort);
    DisposeDialog(dlog);
  }
  return itemHit;
}

-- Matthew Xavier Mora
devsupport@apple.com

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