LoadInfo example for Visual C++ 5.0

LoadInfo... example for C++ 5.0 and later

Take the following steps to exercise the LoadInfo event and LoadInfo... properties. The example creates a raw FAX file, then loads the file it just created. (Getting format information from an unfamiliar file is beyond the scope of this example.)

1.	Start with the project that you created in Loading and Displaying an Image.
2.	Edit TUTORDLG.H and insert the following lines in the definition of CTutorDlg after DECLARE_MESSAGE_MAP():

public:
// Declare variables for demonstrating raw FAX.
int MyInfoBits;
long MyInfoFlags;
int MyInfoFormat;
float MyInfoHeight;
long MyInfoOffset;
float MyInfoWidth;
int MyInfoXRes;
int MyInfoYRes;

3.	$image\btncmd.gif$ Add a CommandButton control and code its click procedure as follows:

void CTutorDlg::OnButton1()
{
  ILEADRasterProcess *pRasterProc=NULL;
  CoCreateInstance(CLSID_LEADRasterProcess, NULL, CLSCTX_ALL,
                   IID_ILEADRasterProcess, (void**)&pRasterProc);
  m_LEADRasterView1.SetScaleMode (3); // Pixels
  // Make the image look OK as a 1-bit image.
  pRasterProc->Size(m_LEADRasterView1.GetRaster(),
                    m_LEADRasterView1.GetScaleWidth(),
                    m_LEADRasterView1.GetScaleHeight(),
                    RESIZE_RESAMPLE);
  pRasterProc->Halftone(m_LEADRasterView1.GetRaster(),
                        HALFTONE_VIEW, 45);
  // Set the form-level variables to the values we will use when loading.
  MyInfoBits = 1;
  MyInfoFlags = LOADINFO_TOPLEFT;
  MyInfoFormat = FILE_FAX_G3_2D;
  MyInfoHeight = m_LEADRasterView1.GetRaster().GetBitmapHeight();
  MyInfoOffset = 0;
  MyInfoWidth = m_LEADRasterView1.GetRaster().GetBitmapWidth();
  MyInfoXRes = m_LEADRasterView1.GetRaster().GetBitmapXRes();
  MyInfoYRes = m_LEADRasterView1.GetRaster().GetBitmapYRes();
  // Save the image as raw FAX; then load the saved file.
  // Format information will be supplied in the LoadInfo event.
  m_pRasterIO->Save(m_LEADRasterView1.GetRaster(),
                    "d:\\temp\\tmp.tif", FILE_FAX_G3_2D,
                    1, (QFactorConstants)1, SAVE_OVERWRITE);
  m_pRasterIO->Load(m_LEADRasterView1.GetRaster(),
                    "d:\\temp\\tmp.tif", 0, 0, 1);
  // Repaint the newly loaded image.
  m_LEADRasterView1.ForceRepaint();
  pRasterProc->Release();
}

4.	Edit the TUTORDLG.H file and change the definition of CTutorDlg : CDialog by inserting the following lines after DECLARE_MESSAGE_MAP:

public:
   ILEADRasterIO *m_pRasterIO;
   CRasterIOSink *m_pRasterIOSink;
   IConnectionPoint *m_pIOCP;
   DWORD m_dwIOCookie;

5.	Edit the TUTORDLG.CPP file and add the following code to the end of the OnInitDialog function:

   //Instantiate the sink class and hold a pointer to it.
   m_pRasterIOSink = new CRasterIOSink;
   m_pRasterIOSink->m_pDlg = this;

   //Create the RasterIO object
   CoCreateInstance(CLSID_LEADRasterIO, NULL, CLSCTX_ALL,
                    IID_ILEADRasterIO, (void**)&m_pRasterIO);

   //Establish a connection between source and sink.
   LPUNKNOWN pIOUnkSink = m_pRasterIOSink->GetIDispatch(FALSE);
   AfxConnectionAdvise(m_pRasterIO, DIID__LEADRasterIOEvents, pIOUnkSink, FALSE, &m_dwIOCookie);

6.	Press Ctrl-W to go to the MFC Class Wizard; then do the following:
	a.	Click the Add Class button.
	b.	Click New....
	c.	Type CRasterIOSink for the name of the class
	d.	Select CCmdTarget for the base class of the new class.
	e.	Under Automation, click the Automation radio button.
	f.	Click OK to create the class.
	g.	In the RasterIOSink.h file, move the destructor so that it is public:

// Implementation
virtual ~CRasterIOSink();
protected:

In the RasterIOSink.h file, add the following to the top of the file:
class CTutorDlg;

In the RasterIOSink.h file, add the following to the CRasterIOSink class in the //Attributes public section:

// Attributes
public:
CTutorDlg *m_pDlg;

In the RasterIOSink.cpp file, add the following to the top of the file (after the #include "RasterIOSink.h")

#include "tutorDlg.h"

7.	Add #include statements so you can access the new class:
	a.	In the Project Workspace, click the FileView tab.
	b.	Double-click the tutor files folder to open it.
	c.	Double-click the Header Files folder to open it.
	d.	Double-click the StdAfx.h file to edit it.
	e.	Add the following lines to the end of the file:

#include <AFXCTL.H>
#include "RasterIOSink.h"

8.	Edit the header for the Sink class:
	a.	In the Project Workspace, click the FileView tab.
	b.	Double-click the tutor files folder to open it.
	c.	Double-click the Header Files folder to open it.
	d.	Double-click the RasterIOSink.h file to edit it.
	e.	Add the following just before //}}AFX_MSG:

afx_msg void OnLoadInfo(void);

9.	Edit the source for the Sink class:
	a.	In the Project Workspace, click the FileView tab.
	b.	Double-click the tutor files folder to open it.
	c.	Double-click the Source Files folder.
	d.	Double-click the RasterIOSink.cpp file to edit it.
	e.	Add the following to the DISPATCH_MAP:

DISP_FUNCTION_ID(CRasterIOSink,"LoadInfo",2,OnLoadInfo,VT_EMPTY,VTS_NONE)

Inside the BEGIN_INTERFACE_MAP section, change the INTERFACE_PART tothe following:

INTERFACE_PART(CRasterIOSink, DIID__LEADRasterIOEvents, Dispatch)

Add the following to the end of the file:

void CRasterIOSink::OnLoadInfo()
{
  // Use the form-level variables to supply format information.
  m_pDlg->m_pRasterIO->PutLoadInfoBits(m_pDlg->MyInfoBits);
  m_pDlg->m_pRasterIO->PutLoadInfoFlags((LoadInfoFlagConstants)m_pDlg->MyInfoFlags);
  m_pDlg->m_pRasterIO->PutLoadInfoFormat((RasterFileConstants)m_pDlg->MyInfoFormat);
  m_pDlg->m_pRasterIO->PutLoadInfoHeight(m_pDlg->MyInfoHeight);
  m_pDlg->m_pRasterIO->PutLoadInfoOffset(m_pDlg->MyInfoOffset);
  m_pDlg->m_pRasterIO->PutLoadInfoWidth(m_pDlg->MyInfoWidth);
  m_pDlg->m_pRasterIO->PutLoadInfoXRes(m_pDlg->MyInfoXRes);
  m_pDlg->m_pRasterIO->PutLoadInfoYRes(m_pDlg->MyInfoYRes);
}

10.	Press Ctrl-W to go to the MFC Class Wizard; then do the following:
	a.	In the Class name combo box, select CTutorDlg.
	b.	In the Object IDs list box, select CTutorDlg.
	c.	In the Messages list box, select WM_DESTROY.
	d.	Click the Add function button. Choose OK for the default function name (OnDestroy).
	e.	Click the Edit Code button to start entering the code.
11.	Enter new code as follows:

void CTutorDlg::OnDestroy()
{
   //Terminate a connection between source and sink.
   LPUNKNOWN pIOUnkSink = m_pRasterIOSink->GetIDispatch(FALSE);
   AfxConnectionUnadvise(m_pRasterIO, DIID__LEADRasterIOEvents,
                         pIOUnkSink, FALSE, m_dwIOCookie);
   delete m_pRasterIOSink;
   m_pRasterIO->Release();
   CDialog::OnDestroy();
}

12.	Run your program to test it.