metafile.cpp


//----------------------------------------------------------------------------
// ObjectWindows
// Copyright (c) 1992, 1997 by Borland International, All Rights Reserved
//
/// \file
/// Implementation of TMetaFilePict class
//----------------------------------------------------------------------------
#include <owl/pch.h>
#include <owl/metafile.h>
#include <owl/gdiobjec.h>
#include <owl/clipboar.h>
#include <owl/except.h>
#include <owl/file.h>
 
#if defined(__BORLANDC__)
# pragma option -w-ccc // Disable "Condition is always true/false"
#endif
 
using namespace std;
 
namespace owl {
 
OWL_DIAGINFO;
DIAG_DECLARE_GROUP(OwlGDI);        // General GDI diagnostic group
 
 
/// Constant for checking validity of a METAFILEHEADER
//
const uint32 TMetaFilePict::MFHeaderKey = 0x9AC6CDD7L;
 
// header description
static TBinField MetaFileHeaderField[]={
  {varLONG, 4, 1},     /* DWORD   key                               */
  {varSHORT,2, 1},     /* WORD hmf unused (0)                       */
  {varSHORT,2, 4},     /* RECT16 bbox;  // bounding rectangle       */
  {varSHORT,2, 1},     /* WORD inch; // units per inch              */
  {varLONG, 4, 1},     /* DWORD reserved; // unused (0)             */
  {varSHORT,2, 1},     /* WORD checksum;  // XOR of previous fields */
  {varEnd,0,0}
};
 
//
/// Creates a TMetaFilePict object using the given handle argument.
//
TMetaFilePict::TMetaFilePict(HMETAFILE handle, TAutoDelete autoDelete)
:
  TGdiBase(handle, autoDelete),
  Extent(0,0),
  Placeable(false)
{
  Mm = MM_ANISOTROPIC;
}
 
//
/// Creates a TMetaFilePict object for the metafile stored in the named file.
//
TMetaFilePict::TMetaFilePict(const tstring& filename)
:
  Extent(0,0),
  Placeable(false)
{
  TFile file;
 
  file.Open(filename,TFile::ReadOnly|TFile::OpenExisting|TFile::PermRead);
  file.ReadStruct(&MFHeader, MetaFileHeaderField, boLittle_Endian);
 
  // Determine whether this file begins with a valid METAFILEHEADER
  // struct and load the file accordingly.
  //
  if ((MFHeader.key == MFHeaderKey)
      && (MFHeader.checksum == CalcHeaderChecksum(MFHeader)))
  {
    // Determine size of metafile data
    //
    TFileStatus status;
    file.GetStatus(status);
    long size = status.size - sizeof(METAFILEHEADER);
 
    // Convert the data to a metafile
    //
    HGLOBAL hMem = ::GlobalAlloc(GMEM_MOVEABLE, size);
    if (!hMem)
      TXOutOfMemory::Raise();
    uint8 * pMem = (uint8 *)GlobalLock(hMem);
    file.Read((void *)pMem, size);
 
    Handle = SetMetaFileBitsEx(size, pMem);
 
    GlobalUnlock(hMem);
    GlobalFree(hMem);
 
    // Remember that this metafile comes with a placeable header
    // (in other words, MFHeader holds valid data)
    //
    if (Handle)
      Placeable = true;
 
    // Placeable metafiles are meant to be played back in
    // the unconstrained mapping mode.  The header tells
    // the desired size and aspect ratio.
    //
    Mm = MM_ANISOTROPIC;
 
    // Set metafile dimensions according to info in header
    //
    Extent.cx = MFHeader.bbox.right - MFHeader.bbox.left;
    Extent.cy = MFHeader.bbox.bottom - MFHeader.bbox.top;
 
    // Convert dimensions to HIMETRIC units (.001 cm)
    //
    Extent.cx = MulDiv(Extent.cx, 2540, MFHeader.inch);
    Extent.cy = MulDiv(Extent.cy, 2540, MFHeader.inch);
  }
  else {
    Mm = MM_ANISOTROPIC;
    Handle = ::GetMetaFile(filename.c_str());
   }
  ShouldDelete = true;
  file.Close();
  CheckValid();
}
 
//
/// Constructs a TMetaFilePict that represents the metafilepict on the clipboard.
/// Should be copied if metafile needs to be kept.
//
TMetaFilePict::TMetaFilePict(const TClipboard&)
:
  Extent(0,0),
  Placeable(false)
{
  HGLOBAL hmfp = ::GetClipboardData(CF_METAFILEPICT);
  METAFILEPICT * mfp = (METAFILEPICT *)::GlobalLock(hmfp);
 
  if (mfp) {
    Mm = mfp->mm;
    Extent = TSize(mfp->xExt, mfp->yExt);
    Handle = mfp->hMF;
    ::GlobalUnlock(hmfp);
  }
  else
    Handle = 0;
 
  ShouldDelete = false;
  CheckValid();
}
 
 
//
/// Creates a TMetaFilePict object for the memory-based metafile specified by data.
/// The data buffer must hold a metafile of length size bytes.
//
TMetaFilePict::TMetaFilePict(uint size, void* data)
:
  TGdiBase(::SetMetaFileBitsEx(size, (LPBYTE)data), NoAutoDelete),
  Extent(0,0),
  Placeable(false)
{
  CheckValid();
  Mm = MM_ANISOTROPIC;
}
 
 
//
/// Copies the metafile src to the named file. If filename is 0 (the default), the
/// metafile is copied to a memory-based metafile.
//
TMetaFilePict::TMetaFilePict(const TMetaFilePict& src, LPCTSTR fileName)
:
  TGdiBase(::CopyMetaFile(src, fileName), AutoDelete),
  Extent(src.Extent),
  Placeable(false)
{
  CheckValid();
  Mm = src.Mm;
}
 
//
/// String-aware overload
/// If the filename is empty, the metafile is copied to a memory-based metafile.
//
TMetaFilePict::TMetaFilePict(const TMetaFilePict& src, const tstring& fileName)
:
  TGdiBase(::CopyMetaFile(src, fileName.empty() ? 0 : fileName.c_str()), AutoDelete),
  Extent(src.Extent),
  Placeable(false)
{
  CheckValid();
  Mm = src.Mm;
}
 
//
/// Deletes the metafile.
//
TMetaFilePict::~TMetaFilePict()
{
  if (ShouldDelete && Handle)
    ::DeleteMetaFile(HMETAFILE(Handle));
}
 
//
/// Reads the fields in the file header structure of a placeable
/// metafile and computes a checksum value for verifying the
/// header's integrity.
//
uint16
TMetaFilePict::CalcHeaderChecksum(const METAFILEHEADER& header)
{
  LPWORD lpw;             // pointer to words in header
  uint16 checksum = 0;
 
  for (lpw = (LPWORD)&header;
       lpw < (LPWORD)&header.checksum;
       ++lpw)
  {
    // XOR current checksum with next field
    //
    checksum ^= *lpw;
  }
 
  return checksum;
}
 
 
//
/// Retrieves the contents of the metafile associated with this object
/// and copies them (up to size bytes) to the data buffer. If data is nonzero and
/// the call succeeds, the actual number of bytes copied is returned. If data is 0,
/// a successful call returns the number of bytes required by the buffer. A return
/// value of 0 always indicates a failure.
//
uint32
TMetaFilePict::GetMetaFileBitsEx(uint size, void* data)
{
  return ::GetMetaFileBitsEx(HMETAFILE(Handle), size, (LPBYTE)data);
}
 
 
//
/// Calculates target play size based on info from the metafilepict (if any)
/// and default target size as necessary
//
TSize
TMetaFilePict::CalcPlaySize(TDC& dc, const TSize& defSize) const
{
  // Given a fixed mapping mode, return precalculated extents
  //
  if (Mm != MM_ISOTROPIC && Mm != MM_ANISOTROPIC) {
    WARNX(OwlGDI, (Extent.X() == 0) || (Extent.Y() == 0), 0, "Constrained metafile extent == 0");
    return Extent;    // Assumes extents were calculated correctly.
  }
 
  //
  // Metafile uses partially constrained or unconstrained mapping mode
  //
 
  // If no extent info given, then use defaults
  //
  if (Extent.X() == 0) {
    WARNX(OwlGDI, (defSize.X() == 0) || (defSize.Y() == 0), 0, "Metafile using default extent == 0");
    return defSize;
  }
 
  // Use positive extents scaled to 0.01mm units
  //
  else if (Extent.cx > 0) {
    return TSize(
        int(long(Extent.cx)*dc.GetDeviceCaps(HORZRES)/dc.GetDeviceCaps(HORZSIZE)/100),
        int(long(Extent.cy)*dc.GetDeviceCaps(VERTRES)/dc.GetDeviceCaps(VERTSIZE)/100)
      );
  }
  // Use negative extents scaled to 0.01mm units w/ aspect ratio scaling
  //
  else {
    long xscale = 100L * defSize.cx *
      dc.GetDeviceCaps(HORZSIZE)/dc.GetDeviceCaps(HORZRES) / -Extent.cx;
    long yscale = 100L * defSize.cy *
      dc.GetDeviceCaps(VERTSIZE)/dc.GetDeviceCaps(VERTRES) / -Extent.cy;
    long scale = std::min(xscale, yscale);
    return TSize(
      int(long(-Extent.cx)*scale*dc.GetDeviceCaps(HORZRES)/dc.GetDeviceCaps(HORZSIZE) / 100),
      int(long(-Extent.cy)*scale*dc.GetDeviceCaps(VERTRES)/dc.GetDeviceCaps(VERTSIZE) / 100)
    );
  }
}
 
//
/// Plays this metafile onto a dc, possibly using a default size if this
/// metafile doesn't have one. Does not save dc state.
//
bool
TMetaFilePict::PlayOnto(TDC& dc, const TSize& defSize) const
{
  // Set target dc's mapping mode to this metafile's if there is one
  //
  if (Mm)
    dc.SetMapMode(Mm);
 
  // Set the viewport extent to the area that the metafile will fill
  //
  if ((Mm == MM_ISOTROPIC || Mm == MM_ANISOTROPIC) && Extent.cx && Extent.cy)
//  if (Mm == MM_ISOTROPIC || Mm == MM_ANISOTROPIC)
    dc.SetViewportExt(CalcPlaySize(dc, defSize));
 
  return ::PlayMetaFile(dc, *this);
}
 
//
/// Moves this metafile to the clipboard inside of a metafilepict struct.
/// Ownership of the metafilepict as well as the metafile is passed to the
/// clipboard.
//
void
TMetaFilePict::ToClipboard(TClipboard& clipboard, unsigned mapMode,
                           const TSize& extent)
{
 
  HGLOBAL hmfp = ::GlobalAlloc(GMEM_MOVEABLE, sizeof(METAFILEPICT));
  if (!hmfp)
    TXOutOfMemory::Raise();
  METAFILEPICT * mfp = (METAFILEPICT *)::GlobalLock(hmfp);
  mfp->mm = mapMode;
  mfp->xExt = extent.cx;
  mfp->yExt = extent.cy;
  mfp->hMF = (HMETAFILE)Handle;
  ::GlobalUnlock(hmfp);
 
  clipboard.SetClipboardData(CF_METAFILEPICT, hmfp);
  ShouldDelete = false;
}
 
 
//
/// Alias for an existing enhanced metafile handle.
//
TEnhMetaFilePict::TEnhMetaFilePict(HENHMETAFILE handle, TAutoDelete autoDelete)
:
  TGdiBase(handle, autoDelete)
{
}
 
//
/// Creates an enhanced metafile from an external file.
//
TEnhMetaFilePict::TEnhMetaFilePict(const tstring& filename)
:
  TGdiBase(::GetEnhMetaFile(filename.c_str()), AutoDelete)
{
}
 
//
/// Copies a metafile.
/// If the filename is 0 (the default), then the metafile is copied to a memory-based metafile.
//
TEnhMetaFilePict::TEnhMetaFilePict(const TEnhMetaFilePict& metafilepict,
                                   LPCTSTR filename)
:
  TGdiBase(::CopyEnhMetaFile(metafilepict, filename), AutoDelete)
{
}
 
//
/// String-aware overload
/// If the filename is empty, the metafile is copied to a memory-based metafile.
//
TEnhMetaFilePict::TEnhMetaFilePict(const TEnhMetaFilePict& metafilepict, const tstring& fileName)
  : TGdiBase(::CopyEnhMetaFile(metafilepict, fileName.empty() ? 0 : fileName.c_str()), AutoDelete)
{}
 
//
/// Creates metafile from buffer.
//
TEnhMetaFilePict::TEnhMetaFilePict(uint bytes, const void* buffer)
:
  TGdiBase(::SetEnhMetaFileBits(bytes, (const BYTE*)buffer), AutoDelete)
{
}
 
//
/// Destroys the enhanced metafile picture.
//
TEnhMetaFilePict::~TEnhMetaFilePict()
{
  if (ShouldDelete && Handle)
    ::DeleteEnhMetaFile(HENHMETAFILE(Handle));
}
 
//
/// Plays the metafile onto a device context.
//
bool
TEnhMetaFilePict::PlayOnto(TDC& dc, const TRect* rect) const
{
  return ::PlayEnhMetaFile(dc, *this, rect);
}
 
 
 
} // OWL namespace
/* ========================================================================== */
↑ V730 Not all members of a class are initialized inside the constructor. Consider inspecting: MFHeader.