QWMF class (inherits QPaintDevice)

Implements WMF export and can be used more or less like QPrinter.
In general, it works rather well; unsupported as of now are clipping
and viewport operations and pixmaps. Using the transformation matrix
seems to work most of the time, but I still have to iron out some
strance cases which appear with QtiPlot.

Any help is greatly appreciated!

Options:
  setFileName(QString filename)  - set filename
  setInch(int)            - set DPI = number of (logical) pixels per inch
  setHeight(int)          - set max number of (logical) pixels in y direction
  setWidth(int)           - set max number of (logical) pixels in x direction

Currently, all images start at (0,0) and extend to (width,height).

Supported paint commands (see QPainter and QPaintDevice::cmd for details):
- PdcBegin
- PdcEnd
- PdcSave
- PdcRestore
- PdcSetROP
- PdcSetFont
- PdcSetBkMode
- PdcSetBkColor
- PdcSetBrush (Dense*Pattern style not yet supported)
- PdcSetPen   (MPenStyle is currently not supported)
- PdcSetWXform
- PdcSetWMatrix

- PdcDrawPie (need to add WMatrix support)
- PdcDrawRect
- PdcMoveTo
- PdcLineTo
- PdcDrawLine
- PdcDrawPolyline
- PdcDrawLineSegments
- PdcDrawPoint
- PdcDrawEllipse (need to add WMatrix support)
- PdcDrawPolygon
- PdcDrawText
- PdcDrawText2
- PdcDrawTextFormatted
- PdcDrawText2Formatted

Unsupported:
- PdcDrawRoundRect   * 
- PdcDrawArc         *
- PdcDrawChord       *<--- these are pretty easy to implement(other might also be, not checked)
- PdcDrawCubicBezier
- PdcDrawPixmap
- PdcDrawImage
- PdcDrawTextItem

- PdcSetDev
- PdcSetBrushOrigin
- PdcSetTabStops
- PdcSetTabArray
- PdcSetUnit
- PdcSetVXform
- PdcSetWindow
- PdcSetViewport
- PdcSaveWMatrix
- PdcRestoreWMatrix
- PdcSetClip
- PdcSetClipRegion


Bugs:
- Missing functionallity (see above)
- SelectObject could call DeleteObject, is this useful?
- Comments are missing
- support height() etc. to return set values
- should optimize
- check for off by one problems (e.g. MoveTo(x,y)->LineTo(x+1) draws only a dot)
  not that easy to fix, maybe moveTo(x,y)->LineTo(x,y)->LineTo(x,y+1)?
- check when true and when false needs to be returned in ::cmd
  seems to be rather arbitrary, but some of the values (esp. false) are tested for
  in qpainter.cpp
- check whether endian problems exist

Missing features:
- See above
- EMF should be supported
- ClipBoard format should be supported
- Plain WMF w/o placeable header should be supported (trivial, remove one block)
  Then META_SETMAPMODE matters!
  -> myInch is then determined by MM_TEXT, MM_LOMETRIC,MM_HIMETRIC, MM_LOENGLISH,
  MM_HIENGLISH,MM_TWIPS,MM_ISOTROPIC,MM_ANISOTROPIC (not all of them make sense ?!?)


Example:
1. Drop the two files into ./chart/ of the Qt examples
2. Add this block to chartform_files.cpp
  void ChartForm::fileSaveAsWmf() {
      QString filename = QFileDialog::getSaveFileName(
                              QString::null, "WMF (*.wmf)",
                              this, "file save as wmf",
                              "Chart -- File Save As WMF" );
      if(filename.isEmpty()) return;
      if ( !m_wmf )
         m_wmf = new QWMF();
      m_wmf->file(filename);
      QPainter painter( m_wmf );
      m_canvas->drawArea( QRect( 0, 0, m_canvas->width(), m_canvas->height() ),
                          &painter, FALSE );
  }
3. Declare this function in chartform.h and add "QWMF *m_wmf;" and #include "qwmf.h"
4. You may want to set m_wmf to 0 in ChartForm::ChartForm and to delete it in the destructor
5. Add this to chartform.cpp
    fileSaveAsWmfAction = new QAction(
            "Save Chart As WMF", QPixmap( file_save ),
            "Save As &WMF...", CTRL+Key_W, this, "save as WMF" );
    connect( fileSaveAsWmfAction, SIGNAL( activated() ),
             this, SLOT( fileSaveAsWmf() ) );
6. Try it out and be happy


Credits:
See qwmf.h for details, special thank goes to the libwmf authors,
to Murray and van Ryper, to Caolán McNamara, and (indirectly) to the WINE authors.



Tobias [dot] Burnus
[At-sign] Physik [dot] FU-Berlin [dot] De
November 2004