Coding at a lower level for a deeper understanding.

From:

=?UTF-8?Q?Jeff=E2=98 Relf?= <Jeff_Relf@Yahoo.COM>

Newsgroups:

microsoft.public.vc.language

Date:

1 Nov 2007 11:33:08 GMT

Message-ID:

<Jeff_Relf_2007_Nov_1__4_33_AL@Cotse.NET>

Coding at a lower level might give you
the deeper understanding you're looking for, TonyJeffs,
and, to boot, it's a more stable target, instead of the latest fad.

My hand-rolled newsreader ( X.EXE ), for example,
employs only one WinProc() and one CreateWindow(),
and the WinProc is merely:

  long __stdcall WinProc ( HWND Wnd, uint _WM, uint C, long C2 ) {
    PostMessage( Win, _WM, C, C2 ); return 1 ; }

I never use ??? member functions ??? and the like.

I cache Unicode glyphs onto DirectDraw surfaces
and, as I employ only one window ( always maximized ),
my buttons don't use WinProc() or CreateWindow().

My glyph-caching routines are too complex to mention here,
but here is a code snippet showing how a Device Context works:

  // Monospaced fonts have different width-to-height ratios,
  // hence: _CharH( WtoH )
  #define _CharH( WtoH ) ( CacheW / ( WtoH ) )

  // ScrW is the width of our maximized window, in pixels.
  // This give us 123 columns of monospaced glyphs per line:
  CharW = ScrW / ( ScrCols = 123 );
  CacheW = CharW + 1, ColsDC = ScrW / CacheW ;

  CharH = _CharH( 120. / 256 );
  CacheH = CharH + 1, ScrRows = ScrH / CharH ;

  Fnt = CreateFont(
    CharH, 0,0,0,0,0,0,0,0,0,0,0, FIXED_PITCH, L"Consolas");

  SymFnt = CreateFont(
    _CharH( 128. / 256 ),0,0,0,0,0,0,0,0,0,0,0, FIXED_PITCH, L"MS Mincho");
  BassFnt = CreateFont(
    _CharH( 1 / 4.5 ),0,0,0,0,0,0,0,0,0,0,0, 0, L"Musical Symbols");
  ............

  // The Double Sharp and Bass glyphs
  // are merely examples of Plane One Glyphs.
  //
  // The code that chaches them is a total hack
  // because no other Plane One Glyphs can be cached.

  int ColsCh, CacheW, CacheH ;
  const int Dub = 2, Highest_Consolas = 0xFFF;
_CacheGlyph( GyP P, int I_Hue, _SurT TheCache, int _X ) {
  // 0xD834 Double Sharp: DD2A Bass: DD1E

  int Bass = P->Ch >= 0xDC00 && P->Ch <= 0xDFFF ;

  static wchar_t B[ 2 ];
  wchar_t Ch = B[ Bass ] = P->Blank ? * L"???" : P->Ch ;
  if ( Bass ) * B = 0xD834 ;

  HDC DC ; Chk( TheCache->GetDC( & DC ) );
  SetTextAlign( DC , TA_LEFT | TA_TOP | TA_UPDATECP );
  SetPtr( DC, Bass ? BassFnt : Fnt );

  if ( ! Bass ) { ushort Good ;

    GetGlyphIndices( DC, B, 1, & Good, GGI_MARK_NONEXISTING_GLYPHS );
    if ( short( Good ) == -1 ) SetPtr( DC, SymFnt );
    GetGlyphIndices( DC, B, 1, & Good, GGI_MARK_NONEXISTING_GLYPHS );

    if ( short( Good ) == -1 ) { // Give up, we don't have the font.
      Chk( TheCache->ReleaseDC( DC ) ); return 1 ; } }

  P->RowsCh = Bass + 1 ;
  int WW = CacheW * ( ! P->ColsCh ? Dub : P->ColsCh )
  , HH = CacheH * P->RowsCh , X = _X * CacheW ;

  RECT CacheR = _R( X, 0, WW, HH ); MvTo( X, 0 ), SetBkColor( DC, 0 );
  SetTextColor( DC, * ( ( ulong * ) & Hues + I_Hue ) );

  ExtTextOut(
    DC, 0, 0, ETO_CLIPPED | ETO_OPAQUE, & CacheR, B, 1 + Bass, 0 );
  MvTo( X, 0 ); Chk( TheCache->ReleaseDC( DC ) );
  ColsCh = Bass ? Dub : ( WW = XY.x - X + 1 ) > CharW + 3 ? Dub : 1 ;

  return WW < CharW ; }