Ondraw function have so much delay in vc++ with ImageMagick - c++

Question

Now I'm trying to display an image in view in the dialog in MFC.
The code as following.
void CTestview::OnDraw(CDC* pDC)
{
CDocument* pDoc = GetDocument();
// TODO: add draw code here
CRect rcWin;
GetWindowRect( &rcWin );
double ff;
ff=rcWin.Width();
rcWin.Height();
DoDisplayImage();
}
and
void CTestview::DoDisplayImage(void)
{
CPoint pt;
CRect rectClient;
CDC * pDC;
pDC = GetDC();
GetClientRect(rectClient);
int ii;
ii=slider_val;
(void) MagickCore::SetClientPath(fileposition);
InitializeMagick(fileposition);
Image m_Image;
Image m_blurgray;
int _imageHeight;
try {
//C:\work\mfc_test5\mfc_test5
m_Image.read(fileposition);
}
catch(Exception)
{
return ;
}
char str_x[10];
char str_y[10];
if (pDC != NULL)
{
m_blurgray.gaussianBlur(20,2); //blur
int nImageY;
int nImageX;
CSize sizeScaled;
// Clear the background
pDC->FillSolidRect(rectClient,pDC->GetBkColor());
pt = rectClient.TopLeft();
nImageX= m_Image.columns() ;
//nImageY = m_Image.rows();
CPoint aa;
aa = rectClient.Size();
// Extract the pixels from Magick++ image object
PixelPacket *pPixels = m_Image.getPixels(0,0,m_Image.columns(),m_Image.rows());
// Set up the Windows bitmap header
BITMAPINFOHEADER bmi;
bmi.biSize = sizeof(BITMAPINFOHEADER);
bmi.biWidth =m_Image.columns();
bmi.biHeight = (-1)*m_Image.rows();
bmi.biPlanes = 1;
bmi.biBitCount = 32;
bmi.biCompression = BI_RGB;
bmi.biSizeImage = 0;
bmi.biXPelsPerMeter = 0;
bmi.biYPelsPerMeter = 0;
bmi.biClrUsed = 0;
bmi.biClrImportant = 0;
// Blast it to the device context
SetStretchBltMode(pDC->m_hDC,COLORONCOLOR);
StretchDIBits(pDC->m_hDC,
0,
0,
m_Image.columns(),
m_Image.rows(),
0,
0,
m_Image.columns(),
m_Image.rows(),
pPixels,
(BITMAPINFO *)&bmi,
DIB_RGB_COLORS,
SRCCOPY);
//UpdateData(FALSE);
}
}
The problem is that display image have so much delay when I display an image into view.
I don't know exactly what should I do for solving this problem.
update 1
I have update the code as following.
#pragma once
#include <Magick++.h>
// CTestview view
class CTestview : public CScrollView
{
DECLARE_DYNCREATE(CTestview)
protected:
CTestview(); // protected constructor used by dynamic creation
virtual ~CTestview();
public:
#ifdef _DEBUG
virtual void AssertValid() const;
#ifndef _WIN32_WCE
virtual void Dump(CDumpContext& dc) const;
#endif
#endif
protected:
virtual void OnDraw(CDC* pDC); // overridden to draw this view
virtual void OnInitialUpdate(); // first time after construct
DECLARE_MESSAGE_MAP()
public:
void DoDisplayImage(void);
Image m_image
};
When I compile above code then I've got some error as following.
------ Build started: Project: mfc_test5, Configuration: Release Win32 ------
Build started
PrepareForBuild:
Creating directory "C:\work\mfc_test5\mfc_test5\Release\".
InitializeBuildStatus:
Creating "Release\mfc_test5.unsuccessfulbuild" because "AlwaysCreate" was specified.
ClCompile:
stdafx.cpp
mfc_test5.cpp
c:\program files\imagemagick-6.8.6-q8\include\magick/pixel-accessor.h(160): warning C4244: '=' : conversion from 'double' to 'MagickCore::MagickRealType', possible loss of data
c:\work\mfc_test5\mfc_test5\mfc_test5\Testview.h(33): error C2143: syntax error : missing ';' before '}'
mfc_test5Dlg.cpp
c:\program files\imagemagick-6.8.6-q8\include\magick/pixel-accessor.h(160): warning C4244: '=' : conversion from 'double' to 'MagickCore::MagickRealType', possible loss of data
c:\work\mfc_test5\mfc_test5\mfc_test5\Testview.h(33): error C2143: syntax error : missing ';' before '}'
C:\Program Files\Intel\plsuite\include\ipl.h(778): warning C4819: The file contains a character that cannot be represented in the current code page (949). Save the file in Unicode format to prevent data loss
C:\Program Files\Intel\plsuite\examples\Tutorial.IPL\IPLROOMS\COOKROOM\macros.inc(21): warning C4005: '_ASSERTE' : macro redefinition
C:\Program Files\Microsoft Visual Studio 10.0\VC\include\crtdbg.h(213) : see previous definition of '_ASSERTE'
Build FAILED.
Time Elapsed 00:00:37.30
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
I have found some reference code as following.as you can see, the following code use Image m_image.
How could it use like that?
// NtMagickView.h : interface of the CNtMagickView class
//
/////////////////////////////////////////////////////////////////////////////
#if !defined(AFX_NTMAGICKVIEW_H__8A45000C_6176_11D4_AC4F_400070168026__INCLUDED_)
#define AFX_NTMAGICKVIEW_H__8A45000C_6176_11D4_AC4F_400070168026__INCLUDED_
#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
#define NTMAGICK_DEFEXT "*.JPG;*.JPEG"
#define NTMAGICK_ALL "All Files (*.*)|*.*|"
#define NTMAGICK_BMP "Bitmaps (*.BMP;*.RLE)|*.BMP;*.RLE|"
#define NTMAGICK_GIF "GIF (*.GIF)|*.GIF|"
#define NTMAGICK_TIF "TIF (*.TIF;*.TIFF)|*.TIF;*.TIFF|"
#define NTMAGICK_JPEG "JPEG (*.JPG;*.JPEG)|*.JPG;*.JPEG|"
#define NTMAGICK_ICON "Icons (*.ICO)|*.ICO|"
class CNtMagickView : public CView
{
protected: // create from serialization only
CNtMagickView();
DECLARE_DYNCREATE(CNtMagickView)
// Attributes
public:
CString m_szFile;
Image * m_pImage;
CNtMagickDoc* GetDocument();
void DoDisplayError(CString szFunction, CString szCause);
void DoDisplayImage();
BOOL DoReadImage();
CSize Scale(CSize sizeSrc, CSize sizeTgt);
float ScaleFactor(BOOL bAllowZoom, CSize sizeSrc, CSize sizeTgt);
void UpdateUI(CCmdUI* pCmdUI);
// Operations
public:
// Overrides
// ClassWizard generated virtual function overrides
//{{AFX_VIRTUAL(CNtMagickView)
public:
virtual void OnDraw(CDC* pDC); // overridden to draw this view
virtual BOOL PreCreateWindow(CREATESTRUCT& cs);
protected:
//}}AFX_VIRTUAL
// Implementation
public:
virtual ~CNtMagickView();
#ifdef _DEBUG
virtual void AssertValid() const;
virtual void Dump(CDumpContext& dc) const;
#endif
protected:
// Generated message map functions
protected:
//{{AFX_MSG(CNtMagickView)
afx_msg void OnFileOpen();
afx_msg void OnImageFlipHorizontal();
afx_msg void OnUpdateImageFlipHorizontal(CCmdUI* pCmdUI);
afx_msg void OnImageFlipVertical();
afx_msg void OnUpdateImageFlipVertical(CCmdUI* pCmdUI);
afx_msg void OnImageRotate180();
afx_msg void OnUpdateImageRotate180(CCmdUI* pCmdUI);
afx_msg void OnImageRotate90();
afx_msg void OnUpdateImageRotate90(CCmdUI* pCmdUI);
afx_msg void OnImageRotate90ccw();
afx_msg void OnUpdateImageRotate90ccw(CCmdUI* pCmdUI);
afx_msg void OnFileClear();
afx_msg void OnUpdateFileClear(CCmdUI* pCmdUI);
//}}AFX_MSG
DECLARE_MESSAGE_MAP()
};
#ifndef _DEBUG // debug version in NtMagickView.cpp
inline CNtMagickDoc* CNtMagickView::GetDocument()
{ return (CNtMagickDoc*)m_pDocument; }
#endif
/////////////////////////////////////////////////////////////////////////////
//{{AFX_INSERT_LOCATION}}
// Microsoft Visual C++ will insert additional declarations immediately before the previous line.
#endif // !defined(AFX_NTMAGICKVIEW_H__8A45000C_6176_11D4_AC4F_400070168026__INCLUDED_)
Update 2
I have edited like as following but it is not called ever. is this right? when do it call this function?
void CTestview::OnInitialUpdate()
{
CScrollView::OnInitialUpdate();
CSize sizeTotal;
// TODO: calculate the total size of this view
sizeTotal.cx = sizeTotal.cy = 100;
SetScrollSizes(MM_TEXT, sizeTotal);
m_pimage.read(fileposition);
}

Answer 1

You should not draw directly on the TestView's DC, but instead create a compatible memory DC, do all the drawing on there, then copy the contents of the memory DC to the view's DC. Because it is way faster!
To do it, you can change the functions to call from OnDraw to receive a parameter that is the memory DC, and forbid yourself to do GetDC() everywhere except on creating the memory DC and copying back its contents to the view DC.
Your OnDraw should look like
void CTestview::OnDraw(CDC* pDC)
{
CDocument* pDoc = GetDocument();
// TODO: add draw code here
CDC draw_dc;
CBitmap draw_bitmap;
CBitmap* old_bitmap;
CRect draw_area;
pDC->GetClipBox(draw_area);
draw_dc.CreateCompatibleDC(pDC);
draw_bitmap.CreateCompatibleBitmap(pDC, draw_area.Width(), draw_area.Height());
old_bitmap = (CBitmap*)draw_dc.SelectObject(&draw_bitmap);
OnPrepareDC(&draw_dc, NULL);
pDC->LPtoDP(draw_area);
draw_dc.OffsetViewportOrg(-draw_area.left, -draw_area.top);
pDC->DPtoLP(draw_area);
draw_dc.IntersectClipRect(draw_area);
DoDisplayImage(&draw_dc);
pDC->BitBlt(draw_area.left, draw_area.top, draw_area.Width(), draw_area.Height(), &draw_dc, 0, 0, SRCCOPY);
draw_dc.SelectObject(old_bitmap);
DeleteObject(draw_bitmap);
DeleteDC(draw_dc);
}
You may have noticed that there is some clipping code; it makes drawing faster because it will not draw on places where it doesn't need to do it. The most important parts are the draw_dc.CreateCompatibleDC(pDC); which creates the memory DC; and the pDC->BitBlt( ... , SRCCOPY); which copies the contents from memory to the view.
Side note: I removed the lines you had above because they seemed useless to me.
Now your DoDisplayImage function should be:
void CTestview::DoDisplayImage(CDC* pDC)
{
CPoint pt;
CRect rectClient;
GetClientRect(rectClient);
int ii;
ii=slider_val;
(void) MagickCore::SetClientPath(fileposition);
InitializeMagick(fileposition);
Image m_Image;
Image m_blurgray;
int _imageHeight;
try {
//C:\work\mfc_test5\mfc_test5
m_Image.read(fileposition);
}
catch(Exception)
{
return ;
}
char str_x[10];
char str_y[10];
if (pDC != NULL)
{
m_blurgray.gaussianBlur(20,2); //blur
int nImageY;
int nImageX;
CSize sizeScaled;
// Clear the background
pDC->FillSolidRect(rectClient,pDC->GetBkColor());
pt = rectClient.TopLeft();
nImageX= m_Image.columns() ;
//nImageY = m_Image.rows();
CPoint aa;
aa = rectClient.Size();
// Extract the pixels from Magick++ image object
PixelPacket *pPixels = m_Image.getPixels(0,0,m_Image.columns(),m_Image.rows());
// Set up the Windows bitmap header
BITMAPINFOHEADER bmi;
bmi.biSize = sizeof(BITMAPINFOHEADER);
bmi.biWidth =m_Image.columns();
bmi.biHeight = (-1)*m_Image.rows();
bmi.biPlanes = 1;
bmi.biBitCount = 32;
bmi.biCompression = BI_RGB;
bmi.biSizeImage = 0;
bmi.biXPelsPerMeter = 0;
bmi.biYPelsPerMeter = 0;
bmi.biClrUsed = 0;
bmi.biClrImportant = 0;
// Blast it to the device context
SetStretchBltMode(pDC->m_hDC,COLORONCOLOR);
StretchDIBits(pDC->m_hDC,
0,
0,
m_Image.columns(),
m_Image.rows(),
0,
0,
m_Image.columns(),
m_Image.rows(),
pPixels,
(BITMAPINFO *)&bmi,
DIB_RGB_COLORS,
SRCCOPY);
//UpdateData(FALSE);
}
}
Side note: You seem to also have useless code here, namely the parts with aa and ii variables.