[RESOLVED] Displaying a jpeg image - Page 2
CodeGuru Home VC++ / MFC / C++ .NET / C# Visual Basic VB Forums Developer.com
Page 2 of 3 FirstFirst 123 LastLast
Results 16 to 30 of 31

Thread: [RESOLVED] Displaying a jpeg image

  1. #16
    Join Date
    Jun 1999
    Posts
    488

    Re: Displaying a jpeg image

    Hi,
    I checked the file name again and i found that i was making mistake in the extension.


    D:\>dir images
    Volume in drive D has no label.
    Volume Serial Number is 8E4F-05BE

    Directory of D:\images

    03/21/2014 10:12 PM <DIR> .
    03/21/2014 10:12 PM <DIR> ..
    03/13/2014 02:21 PM 9,634 after_cut2.jpg
    1 File(s) 9,634 bytes
    2 Dir(s) 512,298,229,760 bytes free

    D:\>

    Code:
    void CRotateImageScrollView::OnDraw(CDC* pDC)
    {
    	CRotateImageScrollDoc* pDoc = GetDocument();
    	ASSERT_VALID(pDoc);
    	if (!pDoc)
    		return;
       
    
    	
    	CString szStr,szstr1;
    	szStr= "D:\\images\\after_cut2.jpg";
    	HRESULT hr=img.Load(szStr);
        
    	CRect m_ShowDRect;
    	m_ShowDRect=CRect(0,0,img.GetWidth(),img.GetHeight());
    	SetScrollSizes(MM_TEXT,CSize(img.GetWidth(),img.GetHeight()));
    	img.Draw(pDC->m_hDC,CRect(&m_ShowDRect));
    	// TODO: add draw code for native data here
    }
    
    void CRotateImageScrollView::OnInitialUpdate()
    {
    	CScrollView::OnInitialUpdate();
        Invalidate();
    	CSize sizeTotal;
    	// TODO: calculate the total size of this view
    	sizeTotal.cx = sizeTotal.cy = 100;
    	SetScrollSizes(MM_TEXT, sizeTotal);
    }
    Thanks for solving this difficult problem. Sorry for taking your time. If I do not write call Invalidate() in OnInitialUpdate(), it would give Debug Assertion Failed message again.

    Zulfi.
    Last edited by Zulfi Khan2; March 23rd, 2014 at 05:06 AM.

  2. #17
    Join Date
    Jun 1999
    Posts
    488

    Re: [RESOLVED] Displaying a jpeg image

    Hi,
    Still I am getting "Debug Assertion Failed" message. If I minimize the output window and then display it again. Kindly guide me. This problem is not yet solved.

    Zulfi.
    Last edited by Zulfi Khan2; March 23rd, 2014 at 05:43 AM.

  3. #18
    VictorN's Avatar
    VictorN is offline Super Moderator Power Poster
    Join Date
    Jan 2003
    Location
    Wallisellen (ZH), Switzerland
    Posts
    17,274

    Re: [RESOLVED] Displaying a jpeg image

    Quote Originally Posted by Zulfi Khan2 View Post
    If I do not write call Invalidate() in OnInitialUpdate(), it would give Debug Assertion Failed message again.
    What does Invalidate have to do with the assertion?
    What exactly is on the line (and around it) where the assertion failed?

    I also have to repeat my following question:
    Quote Originally Posted by VictorN View Post
    Besides, why do you call it in OnDraw handler? The same question - about loading an image. Why not to do it once somewhere in OnInitialUpdate?
    Victor Nijegorodov

  4. #19
    Join Date
    Jun 1999
    Posts
    488

    Re: [RESOLVED] Displaying a jpeg image

    Hi,
    Actually,
    for Question:
    why do you call it in OnDraw handler?
    I dont have any obligation to use OnDraw(). I just want to display image but OnInitialUpdate doesnt have CDC*.
    I would say:
    You must draw only in response to WM_PAINT message that means (for CView derived classes) - withiin OnDraw() method.
    Even though its not CView derived class, when i wrote this code in OnInitialUpdate() i wont get pDC (i.e CDC* pDC). So i declared the variable (CDC* pDC) and I wrote this whole code in OnInitialUpdate( ) but its not even showing the output window when i click Debug->start without debugging.
    What Invalidate has to do with Assertion??
    I am just guessing b/c when view changes it calls OnInitialupdate and the Invalidate code calls OnDraw(...)

    What exactly is on the line (and around it) where the assertion failed?
    I hope this is your answer:
    \VCProg\VC2008\RotateImageScroll\Debug\RotateImageScroll.exe
    File: c:\program files (x86) \ microsoft visual Studio 9.0\vc\atlmfc\include\atlImage.h

    Expression: m_hBitmap==0


    I have even tried by commenting SetScrollSizes (in OnDraw) method in code in previous post. (#16)
    Kindly guide me.

    Zulfi.
    Last edited by Zulfi Khan2; March 23rd, 2014 at 06:29 AM.

  5. #20
    VictorN's Avatar
    VictorN is offline Super Moderator Power Poster
    Join Date
    Jan 2003
    Location
    Wallisellen (ZH), Switzerland
    Posts
    17,274

    Re: [RESOLVED] Displaying a jpeg image

    Quote Originally Posted by Zulfi Khan2 View Post
    I dont have any obligation to use OnDraw(). I just want to display image but OnInitialUpdate doesnt have CDC*.
    ...
    Even though its not CView derived class, when i wrote this code in OnInitialUpdate() i wont get pDC (i.e CDC* pDC). So i declared the variable (CDC* pDC) and I wrote this whole code in OnInitialUpdate( )
    You do have the "obligation to use OnDraw()". It is by design. It is how Windows application works.
    OnInitialUpdate is (how its name sounds) for initialisation, not for drawing. Besides, using any wrong or uninitialized or absent DC (your pDC was set to NULL) is wrong!

    Quote Originally Posted by Zulfi Khan2 View Post
    ...its not even showing the output window when i click Debug->start without debugging.
    Why do you "start without debugging"? You have to debug, so, please start with debugging!

    Quote Originally Posted by Zulfi Khan2 View Post
    I am just guessing b/c when view changes it calls OnInitialupdate and the Invalidate code calls OnDraw(...)
    OnInitialupdate is called not when view changes but when view has been created before displaying it.
    And yes, Invalidate causes window to be redrawn. But it is called by the framework before displaying the view, so you do NOT need to call it from OnInitialupdate.


    Quote Originally Posted by Zulfi Khan2 View Post
    I hope this is your answer:
    \VCProg\VC2008\RotateImageScroll\Debug\RotateImageScroll.exe
    File: c:\program files (x86) \ microsoft visual Studio 9.0\vc\atlmfc\include\atlImage.h

    Expression: m_hBitmap==0
    It means, I guess, that the bitmap handle (m_hBitmap member of CImage class) is supposed to be NULL, but it is not.
    The problem appears to be because you load the image every time the OnDraw is called without destroyng the existent one. Besides, you produces the resource leaks!
    Therefore I suggested you to load the image only once - in OnInitialupdate.


    Quote Originally Posted by Zulfi Khan2 View Post
    I have even tried by commenting SetScrollSizes (in OnDraw) method in code in previous post. (#16)
    SetScrollSizes has nothing to do with your problems.

    Dear Zulfi Khan,
    as Igor already wrote you, now there "is time for you to get back to school bench and learn C++ basics".
    I'd also recommend you to download the MFC sample SCRIBBLE, debug it to see and learn how it works!
    Victor Nijegorodov

  6. #21
    Join Date
    Jun 1999
    Posts
    488

    Re: [RESOLVED] Displaying a jpeg image

    Hi,
    Thanks. Its working now. These are very difficult concepts. No teacher can tell me. Only professional people like you can provide me insight. I would download the Scribble stuff but I am more interested in Computer Graphics content.
    Code:
    void CRotateImageScrollView::OnDraw(CDC* pDC)
    {
    	CRotateImageScrollDoc* pDoc = GetDocument();
    	ASSERT_VALID(pDoc);
    	if (!pDoc)
    		return;
    	
    
    
    	CString szStr,szstr1;
    	
        
    	CRect m_ShowDRect;
    	m_ShowDRect=CRect(0,0,img.GetWidth(),img.GetHeight());
    	//SetScrollSizes(MM_TEXT,CSize(img.GetWidth(),img.GetHeight()));
    	img.Draw(pDC->m_hDC,CRect(&m_ShowDRect));
    
    	
    	
    	// TODO: add draw code for native data here
    }
    
    void CRotateImageScrollView::OnInitialUpdate()
    {
    	CScrollView::OnInitialUpdate();
        CString szStr;
    	CSize sizeTotal;
    	// TODO: calculate the total size of this view
    	sizeTotal.cx = sizeTotal.cy = 100;
        SetScrollSizes(MM_TEXT, sizeTotal);
    	szStr= "D:\\images\\after_cut2.jpg";
    	HRESULT hr=img.Load(szStr);
    	
    }
    
    //*view.h
    #include "atlimage.h"
    #include "atltypes.h" 
    
    #pragma once
    
    class CRotateImageScrollView : public CScrollView
    {
    protected: // create from serialization only
    	CRotateImageScrollView();
    	DECLARE_DYNCREATE(CRotateImageScrollView)
    
    // Attributes
    public:
    	CRotateImageScrollDoc* GetDocument() const;
    
    // Operations
    public:
    CImage img;
    // Overrides
    :
    :
    :
    };
    Zulfi.
    Last edited by Zulfi Khan2; March 23rd, 2014 at 09:10 AM.

  7. #22
    Join Date
    Dec 2012
    Location
    England
    Posts
    2,264

    Re: [RESOLVED] Displaying a jpeg image

    Its working now
    ...and your final code is? There's 'working' and working! Just because some code appears to be doing what is expected, doesn't mean that the code is 'correct'. Time after time I've seen c++ code that 'seems to work' but isn't correct and doesn't really work properly - it just gives the impression it does!

    These are very difficult concepts
    Yes, but do you now understand them - that is the important point. Can you explain every line in the program - what is does and why it's needed.
    All advice is offered in good faith only. You are ultimately responsible for effects of your programs and the integrity of the machines they run on.

  8. #23
    Join Date
    Jun 1999
    Posts
    488

    Re: [RESOLVED] Displaying a jpeg image

    Hi,
    Thanks for your attention. VC has a very tough code. I have heard people saying that its a cut and paste language. You dont write any code. You just search the code and paste it in your program. However with some effort we develop familiarity and understanding of the code. But knowledge of underlying VC framework is difficult and so the commands (or keyword) associated with it. Simple programming statements can be grasped with time. In this code I understand all statements accept the ones which are specifically related to VC framework.

    Thanks for your time.

    Zulfi.
    Last edited by Zulfi Khan2; March 23rd, 2014 at 01:01 PM.

  9. #24
    Join Date
    Apr 1999
    Posts
    27,422

    Re: [RESOLVED] Displaying a jpeg image

    Quote Originally Posted by Zulfi Khan2 View Post
    I have heard people saying that its a cut and paste language. You dont write any code. You just search the code and paste it in your program.
    Those people do not know what they're talking about.

    Even if you don't do any GUI or MFC, C++ by itself is not an easy language, and is definitely not a "cut and paste" language.

    Regards,

    Paul McKenzie

  10. #25
    Join Date
    Nov 2000
    Location
    Voronezh, Russia
    Posts
    5,927

    Re: [RESOLVED] Displaying a jpeg image

    Quote Originally Posted by Zulfi Khan2 View Post
    I would download the Scribble stuff but I am more interested in Computer Graphics content.
    You may be interested in whatever you want, but you cannot ignore programming basics. If you want to create Windows programs, you need to learn basics of programming Windows prior to getting any further to what you're interested in. I provided you three Win32 API samples, but it turned out you preferred to go with MFC. Which implies you have to get along with MFC basics as well prior to getting to programming graphics with MFC.

    Please keep in mind that this is going to happen each time you meet with another technology you're unfamiliar with. First you learn the technology basics, then you learn how to adapt it to your needs.

    Adapting technology by no means implies a copy-paste "technique." This is a dead end. You have to understand every single line you put to your code.
    Best regards,
    Igor

  11. #26
    Join Date
    Jun 1999
    Posts
    488

    Re: [RESOLVED] Displaying a jpeg image

    Hi,
    Thanks for your replies. I just want to improve the things related to VC guides. I have many books of VC but none of them tell me about the data types of VC. Only yesterday i came to know about HRESULT and that its similar to integer. If you want i can tell you their names but none of the books tell me about the data types yet its a basic. I bought these books as a effort to increase my knowledge about VC. However it went in vain. They have lengthy chapters related to Doc/View architecture which in my view is a secondary stuff. I bought the original VC and got scribble Manual with C++ book but it doesnt say anything about the basics i.e the data type of VC. I am just saying this because if we dont have good books we cant have good knowledge.

    Any way I thank you people for your patience and continued support towards me and towards other people asking for help from you.
    Code Guru is better than any other source of knowledge related to VC.

    Zulfi.

  12. #27
    VictorN's Avatar
    VictorN is offline Super Moderator Power Poster
    Join Date
    Jan 2003
    Location
    Wallisellen (ZH), Switzerland
    Posts
    17,274

    Re: [RESOLVED] Displaying a jpeg image

    Did you ever try to use (read/search for the info in) MSDN?
    Victor Nijegorodov

  13. #28
    Join Date
    Dec 2012
    Location
    England
    Posts
    2,264

    Re: [RESOLVED] Displaying a jpeg image

    none of the books tell me about the data types yet its a basic
    I think you are looking at the wrong books!

    For c++ programming with Visual Studio
    Beginning Visual c++ 2012 by Ivor Horton
    http://www.amazon.co.uk/Ivor-Hortons...visual+c%2B%2B

    For programming with Windows API
    Programming Windows by Charles Petzold
    http://www.amazon.co.uk/Programming-...ywords=petzold

    For MFC
    Programming Windows with MFC by Jeoff Prosise
    http://www.amazon.co.uk/Programming-...fc+programming

    Once you have mastered the basics, then there are other more advanced books - but you must master the basics first. It's like having to learn to walk before you can run.
    Last edited by 2kaud; March 24th, 2014 at 02:41 PM.
    All advice is offered in good faith only. You are ultimately responsible for effects of your programs and the integrity of the machines they run on.

  14. #29
    Join Date
    Jun 1999
    Posts
    488

    Re: [RESOLVED] Displaying a jpeg image

    Hi,
    Thanks for your information. I have lots of VC books definitely more than 10. So I am not going to spend any more on VC books. I am with VC since 1997. However if there is a specialized book like for Computer Graphics i would surely buy it.
    Did you ever try to use (read/search for the info in) MSDN?
    Just now i searched MSDN for "data types in " it showed me (vb, vb.net, C++, C##). Where is VC++??

    Sorry i rarely get good response from MSDN.

    Zulfi.

  15. #30
    Join Date
    Nov 2000
    Location
    Voronezh, Russia
    Posts
    5,927

    Re: [RESOLVED] Displaying a jpeg image

    Quote Originally Posted by Zulfi Khan2 View Post
    Hi,
    Thanks for your information. I have lots of VC books definitely more than 10. So I am not going to spend any more on VC books. I am with VC since 1997. However if there is a specialized book like for Computer Graphics i would surely buy it.
    You definitely have to understand the difference between programming language C++ and product Visual C++. As well, you have to learn to tell product VC from technologies like Win32 API, COM, ODBC, OpenGL, .NET, etc. and frameworks like MFC, ATL, Qt, etc. Technologies are typically language independent, while frameworks are mostly not. But any of those require a decent knowledge of programming language those are used with.

    I don't know how good that lots of books at explaining this difference. Maybe it's worth to go through those once again? Or start buying books on particular frameworks but not on VC in general?

    Just now i searched MSDN for "data types in " it showed me (vb, vb.net, C++, C##). Where is VC++??

    Sorry i rarely get good response from MSDN.
    In fact, books have to help you to start understanding official documentation language, that's it. As you still find yourself not getting along with MSDN, you need to keep working on books. Or try to switch to other technology stack, like Java or C#/.NET.
    Best regards,
    Igor

Page 2 of 3 FirstFirst 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


Azure Activities Information Page

Windows Mobile Development Center


Click Here to Expand Forum to Full Width

This is a CodeGuru survey question.


Featured


HTML5 Development Center