Herd Software Development
DaVinci Graphics Library
DaVinci Documentation

Using DaVinci with TImage

This topic shows precisely how easy it is to import images in a wide range of formats, including vector-based formats, into a TImage using DaVinci.

• Before using either DaVinci or Leonardo functions in an application, you need to insure that the uses clause in the current unit includes Leonardo and DaVinci. Since you're not working with a VCL component, these units have to be added manually. If the .DCU or .PAS import units for your version of Delphi are not already installed in a directory where Delphi can find them, you'll have to add their current directory to the search paths list for the current application in Project Options dialog.
  
  
• Drop a TImage or TImage-descended component on your form. Custom components which enhance, but don't exclude, standard TImage properties and methods should be compatible with these examples.
  
  
• Set up a menu item or other control for data import.
  
  
• To get a more complete picture of this routine, browse or open the sample program examples\delphi\davproj.pas

  { Let the user select an image to display from all supported formats }
  
  procedure TDavForm.ImportPictureUsingDaVinci(FileName : String);
  var            szFileName     : Array[0..128] of char;
                 hdb            : THandle;                   { handle of the imported bitmapped image }
                 hMetafile      : THandle;                   { handle of imported metafile }
                 Resolution     : METARESOLUTION;            { metric size data if user picks a metafile. }
                 ipErr          : Integer;                   { DaVinci - Errorcode Variable }
  const          WmfPointSize   : TPoint = ( x:96; y:96 ); { Dimensions of metafile if user selects one }
  
  Begin
    { initialize the variables needed by ipImportExt }
    StrPCopy(szFileName, FileName);
    hdb := 0;
    hMetaFile := 0;
  
    ipErr    := ipImportExt(
                         @hdb,                   { pointer address of the DIB handle, NOT the handle itself }
                         @hMetaFile,             { pointer address of metafile }
                         szFileName,		{ name of file user will select }
  		       { IPF_FILEDIALOG or } IPF_MSGBOX or IPF_DIB or IPF_META,	{ allow bitmaps AND metafiles, and show errors in messagebox }
  		       NIL,		        { callback function...no progress bar used here so not needed }
  		       IPT_SELECT,	        { user can pick any supported image type }
  		       Handle,		        { parent window for the file dialog }
  		       @WmfPointSize,           { pointer to dimensions of a metafile if selected }
                         @Resolution,             { metafile dimensions }
                         0);
  
    if (ipErr = IPE_OK) then                      { Imported OK, so... }
    Begin
  
      {-------------- Change form caption -------------------------- }
      Davform.Caption := 'DaVinci import demo: ' + StrPas(szFileName);
  
      if (hdb <> 0) Then                            { there's a DIB handle here... }
      Begin
        {-------------- Place the new DIB in the Form --------------- }
        ShowNewDib(hdb);
      End
  
      else
  
      if (hMetaFile <> 0) then                      { we've got a metafile }
      Begin
        {-------------- Place the new metafile in the Form ---------- }
        ShowNewMetafile(hMetaFile, @Resolution);
      End
    End;
  End;

Delphi 1:

The GETDIB.PAS and GETTEST.PAS samples are offered for use with 16 bit applications and show how to directly access DIB data contents with more than 64 KByte of data from a Delphi 1 application as an alternative to the RWxxxx functions.

See also:

Some useful background on TImage