CPictureHolder

Hello everyone,

I see that many people have posted threads about using CPictureHolder and none of them have helped me. I would like to use this class to load a jpg from a file path and display it on my dialog. I have been trying to use the extended class that was created by someone here on codeguru and was put in an article:

"http://www.codeguru.com/cpp/g-m/multimedia/imaging/article.php/c1589"

Code:

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HDC hdc;
CDC* pDC = GetDC();
CPictureHolderEx pict;
pict.CreateFromFile(userFileName);
pict.Render(pDC, CRect(10,10,100,100),CRect(9,9,110,110));

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1>c:\2.7\sample\vc\cameracontrol\command\downloadcommand.h(137) : error C2660: 'GetDC' : function does not take 0 arguments

1>c:\2.7\sample\vc\cameracontrol\command\downloadcommand.h(139) : error C2039: 'CreateFromFile' : is not a member of 'CPictureHolderEx'

These are the two errors I have been receiving. Am I correct in thinking it is possible to load an image from a file path with this class? Can anyone offer any guidance please really need to display an image from a filepath have been trying for a week and a half now and failing.

Where are you calling GetDC() from?
There are at least two different GetDC():
Windows API

Quote:

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HDC GetDC(HWND hWnd);

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and CWnd::GetDC

Quote:

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CDC* GetDC( );

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Which one are you using?

I'm sorry I'm pretty new to C++ so I don't really know if I had to guess I would say the 2nd one I'm developing in Microsoft Visual studio 2008 using MFC. From the code sample I'm using that I posted it looks like the CDC* one.

try to use this->GetDC()

or GetDC(this->hwnd)

Quote:

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Originally Posted by syg19

I'm sorry I'm pretty new to C++ so I don't really know if I had to guess I would say the 2nd one I'm developing in Microsoft Visual studio 2008 using MFC. From the code sample I'm using that I posted it looks like the CDC* one.

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You haven't answer my question:

Quote:

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Originally Posted by VictorN

Where are you calling GetDC() from?

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In what class are you using the code you had posted? Isn't it a CWnd derived class?

"class DownloadCommand : public Command" so I would think it's not a CWnd derived class..right?

Quote:

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Originally Posted by vcdebugger

try to use this->GetDC()

or GetDC(this->hwnd)

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Those produced different errors respectively:

GetDC() is not a member of DownloadCommand

hwnd is not a member of DownloadCommand

Quote:

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Originally Posted by syg19

"class DownloadCommand : public Command" so I would think it's not a CWnd derived class..right?

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How can we know it?
This class Command appears to be some non-Microsoft class, so I have no idea what it is.

But if it is not CWnd derived - then using either CDC::GetDC or ::GetDC API does not make any sense unless the correct HWND (window handle) is used (passed in ::GetDC API.

this is the command:

Code:

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class Command {

protected:
        ..

public:
        ..
};

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Quote:

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Originally Posted by syg19

this is the command:

[code]

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Where? :confused:

If you're using MFC and VS2008, then you can use the built-in CImage class to do this more seamlessly.

Highly simplified but works:

Code:

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//in class definition:
class CDlgAppDlg : CDialog
{
  //...
public:
  CImage m_MyImage;
  //...
};


BOOL CDlgAppDlg::OnInitDlg()
{
  //...
  m_MyImage.Load(L"C:\\test.jpg");
  //...
}

void CDlgAppDlg::OnPaint()
{
    CPaintDC dc(this);
    m_MyImage.BitBlt(dc,0,0);
}

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hosie I tried usingwhat you showed but got this error

error C2509: 'OnPaint' : member function not declared in 'CCameraControlDlg'

Is there a specific header I need for OnPaint?

You must implement the message handler for WM_PAINT message in your 'CCameraControlDlg' class.

Quote:

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Originally Posted by VictorN

You must implement the message handler for WM_PAINT message in your 'CCameraControlDlg' class.

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First of all, thank you both for this help I really appreciate it sorry for so many questions.
Secondly how do I implement the message handler for WM_PAINT?

Quote:

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Originally Posted by syg19

First of all, thank you both for this help I really appreciate it sorry for so many questions.
Secondly how do I implement the message handler for WM_PAINT?

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These questions indicate that your knowledge of C++, Windows and C++ is pretty sparse. You're not going to get very far just asking a bulletin board random questions because there will be a lot of them.

I'd recommend you work through a good tutorial to get a handle on C++ and MFC basics. You're trying to run before you can walk.