Question

The question is simple. How to draw following text into TStringGrid cell?

Operating system is Windows XP (or Windows Vista or Windows 7). Preferred development environment is C++ Builder 6, but I will accept also solutions for C++ Builder XE of Delphi. Preferred API function is DrawText, but if better function exists than this no problem. Font name is Times New Roman, font size is 11. Currently I am using this method to render cell content (simplified):

void __fastcall TForm_Main::StringGrid_DrawCell(TObject *Sender,
  int ACol, int ARow, TRect &Rect, TGridDrawState State)
{
   TStringGrid *grid = (TStringGrid*)Sender;
   if (grid == NULL) return;

   // 1. BACKGROUND
   grid->Canvas->Brush->Color = grid->Color;
   grid->Canvas->FillRect(Rect);

   // 2. TEXT
   grid->Canvas->Font->Assign(grid->Font);   // Times New Roman, 11pt

   // horizontal centering
   RECT RText = static_cast<RECT>(Rect);
   AnsiString text = grid->Cells[ACol][ARow];
   if (!text.IsEmpty()) {
      int text_len = strlen(text.c_str());
      SIZE size;
      memset(&size, 0, sizeof(SIZE));
      GetTextExtentPoint32(grid->Canvas->Handle, text.c_str(), text_len, &size);
      int offset_x = (Rect.Width() - size.cx) >> 1;
      RText.left += offset_x; RText.right += offset_x;

      // rendering
      DrawText(grid->Canvas->Handle, text.c_str(), text_len, &RText, DT_LEFT | DT_VCENTER | DT_SINGLELINE);
   }
}

Some characters have subscript glyph as special unicode character (for example code 0x2081 is assigned to subscript one) but unfortunately this is not case for capital letter U. Also these characters are not supported by all fonts (for example Times New Roman font doesnt support code range 0x2070 – 209F), see this Wikipedia article. I am searching for a more general solution like those implemented by Microsoft Word. MS Word doesn’t have problem to render capital letter U as subscript using Times New Roman font.

Answer 1

If you want some char to render as superscript you must prefix it with ^. Likewise subscript characters must be prefixed with _.

void __fastcall TForm_Main::StringGrid_DrawCell(TObject *Sender, int ACol, int ARow, TRect &Rect, TGridDrawState State)
{
   TStringGrid *grid = (TStringGrid*)Sender;
   if (grid == NULL)
   {
      return;
   }
   WideString wtext = L"φ_U = 120";
   if (wtext.IsEmpty()) return;

   // layout
   SIZE size;
   memset(&size, 0, sizeof(SIZE));
   SSGetTextExtentPoint(grid->Canvas, wtext, size);
   int offset_x = (Rect.Width() - size.cx + 1) >> 1;  // horizontal centering
   RECT RText = static_cast<RECT>(Rect);
   RText.left += offset_x;
   RText.right += offset_x;

   // rendering
   SetBkMode(grid->Canvas->Handle, TRANSPARENT);
   SSDrawText(grid->Canvas, wtext, RText, DT_LEFT);
}

int TForm_Main::SSGetTextExtentPoint(TCanvas *canvas, WideString text, SIZE &size)
{
   // Source: http://www.codeproject.com/Articles/12660/Using-Subscripts-and-Superscripts-When-Showing-Tex
   SaveDC(canvas->Handle);

   SIZE sz;
   RECT outRect =
   {0, 0, 0, 0};

   HFONT oldFont;

   LOGFONT lf;
   GetObject(canvas->Font->Handle, sizeof(LOGFONT), &lf);

   POINT sub, sup, subofs, supofs;

   // Calculate subscript/superscript size and offsets
   bool use_pixel_unit = false;
   if (lf.lfHeight < 0)
   {
      lf.lfHeight    = MulDiv(-lf.lfHeight, 72, GetDeviceCaps(canvas->Handle, LOGPIXELSY));
      use_pixel_unit = true;
   }
   sub.x = lf.lfWidth / 2;
   sup.x = lf.lfWidth / 2;
   sub.y = lf.lfHeight / 3 * 2;
   sup.y = lf.lfHeight / 3 * 2;

   subofs.x = lf.lfWidth / 2;
   supofs.x = lf.lfWidth / 2;
   subofs.y = lf.lfHeight / 6;
   supofs.y = lf.lfHeight / 3;

   lf.lfWidth  = sub.x;
   lf.lfHeight = sub.y;
   if (use_pixel_unit)
   {
      lf.lfHeight = -MulDiv(lf.lfHeight, GetDeviceCaps(canvas->Handle, LOGPIXELSY), 72);
   }
   HFONT SubFont;
   SubFont = CreateFontIndirect(&lf);

   lf.lfWidth  = sup.x;
   lf.lfHeight = sup.y;
   HFONT SupFont;
   if (use_pixel_unit)
   {
      lf.lfHeight = -MulDiv(lf.lfHeight, GetDeviceCaps(canvas->Handle, LOGPIXELSY), 72);
   }
   SupFont = CreateFontIndirect(&lf);

   WideString temp = text;
   TCHAR c;

   // Calculate the size of the text that needs to be displayed
   do
   {
      int x1       = 1, x2 = 1, x = 1;
      WideString s = "";
      c            = ' ';
      bool bFind   = true;

      // Find the first "^" or "_", indicating the sub- or superscript
      while (bFind)
      {
         x1 = text.Pos(L"^");
         x2 = text.Pos(L"_");
         if ((x1 == 0) && (x2 == 0))
         {
            x = 0;
         }
         else if ((x1 > 0) && (x2 > 0))
         {
            x = min(x1, x2);
         }
         else if (x1 > 0)
         {
            x = x1;
         }
         else
         {
            x = x2;
         }
         if (x == 0)
         {
            bFind = false;
            x     = text.Length() + 1;
         }
         else if (x == text.Length())
         {
            bFind = false;
         }
         else if (text[x] != text[x + 1])
         {
            bFind = false;
            c     = text[x];
         }
         else
         {
         x++;
         }
         s = s + text.SubString(1, x - 1);
         text.Delete(1, min(x, text.Length()));
      }
      sz = canvas->TextExtent(s);
      outRect.right += sz.cx;
      if ((outRect.bottom - outRect.top) < sz.cy)
      {
         outRect.top = outRect.bottom - sz.cy;
      }

      switch (c)
      {
      case '^':
         oldFont = (HFONT)SelectObject(canvas->Handle, SupFont);
         GetTextExtentPoint32W(canvas->Handle, text.c_bstr(), 1, &sz);
         outRect.right += sz.cx + supofs.x;
         text.Delete(1, 1);
         SelectObject(canvas->Handle, oldFont);
         break;
      case '_':
         oldFont = (HFONT)SelectObject(canvas->Handle, SubFont);
         GetTextExtentPoint32W(canvas->Handle, text.c_bstr(), 1, &sz);
         outRect.right += sz.cx + subofs.x;
         text.Delete(1, 1);
         SelectObject(canvas->Handle, oldFont);
         break;
      }
   }
   while (c != ' ');

   // Adjust text position
   outRect.bottom += subofs.y;
   outRect.top -= subofs.x;

   size.cx = outRect.right - outRect.left;
   size.cy = outRect.bottom - outRect.top;

   DeleteObject(SubFont);
   DeleteObject(SupFont);
   // Done, restoring the device context
   RestoreDC(canvas->Handle, -1);
   return 0;
}

// ---------------------------------------------------------------------------
int TForm_Main::SSDrawText(TCanvas *canvas, WideString text, RECT &drawRect, int justification)
{
   // Source: http://www.codeproject.com/Articles/12660/Using-Subscripts-and-Superscripts-When-Showing-Tex
   SaveDC(canvas->Handle);

   SIZE sz;
   RECT outRect =
   {0, 0, 0, 0};

   HFONT oldFont;
   LOGFONT lf;
   GetObject(canvas->Font->Handle, sizeof(LOGFONT), &lf);

   POINT sub, sup, subofs, supofs;
   bool contains_subscript   = false;
   bool contains_superscript = false;

   // Calculate subscript/superscript size and offsets
   bool use_pixel_unit = false;
   if (lf.lfHeight < 0)
   {
      lf.lfHeight    = MulDiv(-lf.lfHeight, 72, GetDeviceCaps(canvas->Handle, LOGPIXELSY));
      use_pixel_unit = true;
   }

   sub.x = (lf.lfWidth + 1) >> 1;
   sup.x = (lf.lfWidth + 1) >> 1;
   sub.y = (lf.lfHeight << 1) / 3;
   sup.y = (lf.lfHeight << 1) / 3;
   if (lf.lfHeight == 10)
   {
      sub.y++; // make subscript a little larger
   }

   subofs.x = (lf.lfWidth + 1) >> 1;
   supofs.x = (lf.lfWidth + 1) >> 1;
   subofs.y = (lf.lfHeight + 3) / 6;
   supofs.y = (lf.lfHeight) / 3;

   long sub_shift_down = lf.lfHeight - sub.y;

   lf.lfWidth  = sub.x;
   lf.lfHeight = sub.y;
   if (use_pixel_unit)
   {
      lf.lfHeight = -MulDiv(lf.lfHeight, GetDeviceCaps(canvas->Handle, LOGPIXELSY), 72);
   }
   HFONT SubFont;
   SubFont = CreateFontIndirect(&lf);

   lf.lfWidth  = sup.x;
   lf.lfHeight = sup.y;
   if (use_pixel_unit)
   {
      lf.lfHeight = -MulDiv(lf.lfHeight, GetDeviceCaps(canvas->Handle, LOGPIXELSY), 72);
   }
   HFONT SupFont;
   SupFont = CreateFontIndirect(&lf);

   WideString temp = text;
   TCHAR c;

   // Calculate the size of the text that needs to be displayed
   do
   {
      int x1       = 1, x2 = 1, x = 1;
      WideString s = "";
      c            = ' ';
      bool bFind   = true;

      // Find the first "^" or "_", indicating the sub- or superscript
      while (bFind)
      {
         x1 = text.Pos(L"^");
         x2 = text.Pos(L"_");
         if ((x1 == 0) && (x2 == 0))
         {
            x = 0;
         }
         else if ((x1 > 0) && (x2 > 0))
         {
            x = min(x1, x2);
         }
         else if (x1 > 0)
         {
            x = x1;
         }
         else
       {
            x = x2;
         }
         if (x == 0)
         {
            bFind = false;
            x     = text.Length() + 1;
         }
         else if (x == text.Length())
         {
            bFind = false;
         }
         else if (text[x] != text[x + 1])
         {
            bFind = false;
            c     = text[x];
         }
         else
         {
            x++;
         }
         s = s + text.SubString(1, x - 1);
         text.Delete(1, min(x, text.Length()));
      }
      sz = canvas->TextExtent(s);
      outRect.right += sz.cx;
      if ((outRect.bottom - outRect.top) < sz.cy)
      {
         outRect.top = outRect.bottom - sz.cy;
      }

      switch (c)
      {
      case '^':
         oldFont = (HFONT)SelectObject(canvas->Handle, SupFont);
         GetTextExtentPoint32W(canvas->Handle, text.c_bstr(), 1, &sz);
         outRect.right += sz.cx + supofs.x;
         text.Delete(1, 1);
         SelectObject(canvas->Handle, oldFont);
         contains_superscript = true;
         break;
      case '_':
         oldFont = (HFONT)SelectObject(canvas->Handle, SubFont);
         GetTextExtentPoint32W(canvas->Handle, text.c_bstr(), 1, &sz);
         outRect.right += sz.cx + subofs.x;
       text.Delete(1, 1);
         SelectObject(canvas->Handle, oldFont);
         contains_subscript = true;
         break;
      }
   }
   while (c != ' ');

   // Adjust text position
   if (contains_subscript)
   {
      outRect.bottom += subofs.y;
   }
   if (contains_superscript)
   {
      outRect.top -= supofs.y;
   }
   POINT Origin;
   Origin.y = drawRect.top + (((drawRect.bottom - drawRect.top) - (outRect.bottom - outRect.top) + 1) >> 1);

   switch (justification)
   {
   case DT_CENTER:
     Origin.x = (drawRect.right - drawRect.left) / 2 - (outRect.right - outRect.left) / 2 + drawRect.left;
     break;
   case DT_LEFT:
     Origin.x = drawRect.left;
     break;
   case DT_RIGHT:
     Origin.x = drawRect.right - (outRect.right - outRect.left);
   }

   POINT pnt = Origin;

   text = temp;

   // Draw text
   do
   {
      int x1       = 1, x2 = 1, x = 1;
      WideString s = "";
      c            = ' ';
      bool bFind   = true;

      // Find the first "^" or "_", indicating the sub- or superscript
     while (bFind)
      {
         x  = text.Pos(L"^_");
         x1 = text.Pos(L"^");
         x2 = text.Pos(L"_");
         if ((x1 == 0) && (x2 == 0))
         {
            x = 0;
         }
         else if ((x1 > 0) && (x2 > 0))
         {
            x = min(x1, x2);
         }
         else if (x1 > 0)
         {
            x = x1;
         }
         else
         {
            x = x2;
         }
         if (x == 0)
         {
            bFind = false;
            x     = text.Length() + 1;
         }
         else if (x == text.Length())
         {
            bFind = false;
         }
         else if (text[x] != text[x + 1])
         {
            bFind = false;
            c     = text[x];
         }
         else
         {
            x++;
         }
         s = s + text.SubString(1, x - 1);
         text.Delete(1, min(x, text.Length()));
      }
      // Draw main text
      ExtTextOutW(canvas->Handle, pnt.x, pnt.y, 0, &drawRect, s.c_bstr(), s.Length(), NULL);
      GetTextExtentPoint32W(canvas->Handle, s.c_bstr(), s.Length(), &sz);
     pnt.x += sz.cx;

      // Draw subscript or superscript
      switch (c)
      {
      case '^':
         oldFont = (HFONT)SelectObject(canvas->Handle, SupFont);
         ExtTextOutW(canvas->Handle, pnt.x + supofs.x, pnt.y - supofs.y, 0, &drawRect, text.c_bstr(), 1, NULL);
         GetTextExtentPoint32W(canvas->Handle, text.c_bstr(), 1, &sz);
         pnt.x += sz.cx + supofs.x;
         text.Delete(1, 1);
         SelectObject(canvas->Handle, oldFont);
         break;
      case '_':
         oldFont = (HFONT)SelectObject(canvas->Handle, SubFont);
         ExtTextOutW(canvas->Handle, pnt.x + subofs.x, pnt.y + subofs.y + sub_shift_down, 0, &drawRect, text.c_bstr(), 1, NULL);
         GetTextExtentPoint32W(canvas->Handle, text.c_bstr(), 1, &sz);
         pnt.x += sz.cx + subofs.x;
         text.Delete(1, 1);
         SelectObject(canvas->Handle, oldFont);
         break;
      }
   }
   while (c != ' ');

   DeleteObject(SubFont);
   DeleteObject(SupFont);
   // Done, restoring the device context
   RestoreDC(canvas->Handle, -1);
   return 0;
}