How to load PNG images in mfc?

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I want to load PNG images. because png file may have transparent background. And I want to be replacing it with different png picture on any event.How can I display png images in a desired position on the dialog?

Posted 3-May-12 0:22am

chaiein

Updated 3-May-12 0:23am

v2

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4 solutions

Solution 3

Hi,

Try this code.

void CTestMFCDlg::OnBnClickedButtonLoadPng()
{
	CString pngPath=L"c:\\test.png";
    	CImage pngImage;
	CBitmap pngBmp;	
	CDC bmDC;
	CBitmap *pOldbmp;
	BITMAP  bi;
	UINT xPos=450,yPos=300;

	CClientDC dc(this);
	
    	pngImage.Load(pngPath);
	// new code
	
	pngBmp.Attach(pngImage.Detach());
	
	bmDC.CreateCompatibleDC(&dc);

	 pOldbmp= bmDC.SelectObject(&pngBmp);
	 pngBmp.GetBitmap(&bi);
	 dc.BitBlt(xPos,yPos,bi.bmWidth,bi.bmHeight,&bmDC,0,0,SRCCOPY);	 
	 bmDC.SelectObject(pOldbmp);	 
}

-Ganesh Jeevaa

Posted 6-Nov-13 21:59pm

Ganesh Jeevaa

Comments

rtischer8277 21-Jan-16 7:28am

This code helped me understand that original MFC does not operate natively with PNG files which contain transparency Alpha data, and that they have to be Detached and Attached to make them work. Fortunately, BCGSoft's modern MFC libraries have CBCGPToolBarImages that reads PNG files simply (Load) and directly with only a couple lines of code to implement. Transparent background is automatic.

Solution 4

If you want to load from resource use below function.

C++

bool Utils::LoadBitmapFromPNG(UINT uResourceID, CBitmap& BitmapOut)
{
    bool bRet = false;
    
    HINSTANCE hModuleInstance = AfxGetInstanceHandle();
    HRSRC hResourceHandle = ::FindResource(hModuleInstance, MAKEINTRESOURCE(uResourceID), L"PNG");
    if (0 == hResourceHandle)
    {
        return bRet;
    }

    DWORD nImageSize = ::SizeofResource(hModuleInstance, hResourceHandle);
    if (0 == nImageSize)
    {
        return bRet;
    }

    HGLOBAL hResourceInstance = ::LoadResource(hModuleInstance, hResourceHandle);
    if (0 == hResourceInstance)
    {
        return bRet;
    }

    const void* pResourceData = ::LockResource(hResourceInstance);
    if (0 == pResourceData)
    {
        FreeResource(hResourceInstance);
        return bRet;
    }

    HGLOBAL hBuffer = ::GlobalAlloc(GMEM_MOVEABLE, nImageSize);
    if (0 == hBuffer)
    {
        FreeResource(hResourceInstance);
        return bRet;
    }

    void* pBuffer = ::GlobalLock(hBuffer);
    if (0 != pBuffer)
    {
        CopyMemory(pBuffer, pResourceData, nImageSize);
        IStream* pStream = 0;
        if (S_OK == ::CreateStreamOnHGlobal(hBuffer, FALSE, &pStream))
        {
            CImage ImageFromResource;
            ImageFromResource.Load(pStream);
            pStream->Release();
            BitmapOut.Attach(ImageFromResource.Detach());
            bRet = true;
        }
        ::GlobalUnlock(hBuffer);
    }
    ::GlobalFree(hBuffer);

    UnlockResource(hResourceInstance);
    FreeResource(hResourceInstance);

    return bRet;
}

Posted 4-Mar-14 7:05am

Junaij

Comments

CHill60 4-Mar-14 15:59pm

Post is nearly 2 years old and OP confirmed that solution 2 was the correct solution

Michael Haephrati 16-May-20 13:33pm

I checked solution 2 and one of the most important parts (LoadFromResource) doesn't work, so this isn't a good solution for loading an image from a resource.

CHill60 18-May-20 3:59am

Ah … but did it work back in 2012 :-D

Michael Haephrati 18-May-20 5:44am

Nope, it never worked and had it worked back in 2012, it would have worked today. There is a comment by the author saying it doesn't work. Coders come here to find answers and it doesn't mater if a good answer is from 2012.

CHill60 18-May-20 10:47am

I was being facetious by asking if it worked in 2012 - Six years ago we, as a group, were less tolerant of old QA posts being resurrected years later, especially if the original questioner had expressed that they were happy with the solutions posted. Which is why I posted that comment.
If this 2014 response is a good answer to the 2012 question (which I gather from your comment, it isn't) then upvote it and downvote the OP's accepted solution

Michael Haephrati 18-May-20 12:31pm

Again, being a member of the CP community since 2003, I hold an opinion in which any question / article / answer are valid as long as they refer to a topic is relevant today. If you show me a recent answer to an old question about Windows 95, I would agree, but this question is about an ability used today hence my comment. To be more specific, I have noticed that the article mentioned https://www.codeproject.com/Articles/24969/An-MFC-picture-control-to-dynamically-show-picture, could have been relevant today, however it contain the following statement: "Loading an image from a resource is disabled due to problems recognizing it correctly as an image", and the question happens to be about that exact disabled feature.

Michael Haephrati 16-May-20 13:32pm

Please explain how your function should be called / used. Its not enough to post a function as is.

Member 14521984 18-May-20 4:24am

I am also not able to make it work @Junaij please check

Solution 1

With CImage[^] class.

Posted 3-May-12 0:24am

CPallini

Comments

chaiein 3-May-12 6:36am

how can i do without mouse or key event? that is using CRect

chaiein 3-May-12 6:40am

Error 3 error C2065: 'CImage' : undeclared identifier

CPallini 3-May-12 6:44am

From the documentation page:
"Requirements
Header: atlimage.h"
You have to include "atlimage.h"

chaiein 3-May-12 6:49am

image.Load(_T("./res/acoustic grand piano_small.png"));
CDC* pDC = CDC::FromHandle(image.GetDC());
CBitmap bitmap;
bitmap.Attach(image.Detach());
pDC->SelectObject(bitmap);

image.ReleaseDC();

Please correct me there is some mistake and I need to give position to place the pic

CPallini 3-May-12 7:51am

I would ask the authors:
http://msdn.microsoft.com/en-us/library/ms177536(VS.80).aspx

chaiein 4-May-12 2:09am

Thank you all I solved the problem as in solution 2 :)

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

chaiein · Accepted Answer · 2012-05-03T20:03:00

Solution 2

An MFC picture control to dynamically show pictures in a dialog[^]

Posted 3-May-12 20:03pm

chaiein

Comments

Michael Haephrati 18-May-20 12:34pm

The article mentioned in this solution contains the following statement: "Loading an image from a resource is disabled due to problems recognizing it correctly as an image", and the question happens to be about that exact disabled feature.

How to load PNG images in mfc?

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How to load PNG images in mfc?

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