Image Loading in Device context of SDI(MFC VC++) - mfc

How to load Images from disk to Device context of and SDI MFC application. I want to choose images from existing folder at runtime.

It is probably the easiest to use CImage, see: http://msdn.microsoft.com/en-us/library/bwea7by5(v=vs.80).aspx
It's something like:
void CMyDlg::OnBnClickedOpenImage()
{
CFileDialog dialog(TRUE, NULL, NULL,
OFN_FILEMUSTEXIST | OFN_HIDEREADONLY,
L"Windows Bitmap (*.bmp)|*.bmp|JPEG Compressed Image (*.jpg;*.jpeg)|*.jpg; *.jpeg|PNG Image (*.png)|*.png|All Images (*.bmp;*.jpg;*.jpeg;*.png)|*.bmp; *.jpg; *.jpeg; *.png|All Files (*.*)|*.*||");
if (dialog.DoModal() == IDOK)
{
HDC hDC = pDC->GetSafeHdc();
CImage image;
image.Load(dialog.GetPathName());
image.Draw(hDC, 0, 0);
}
}
Edit: Added the open file dialog.

Related

Win32 Unable to add custom toolbar icon having transparency

I am using this code to add a toolbar to the window with one button having a custom image:
HWND hToolbar = CreateWindow(TOOLBARCLASSNAME, NULL,WS_CHILD |
TBSTYLE_FLAT|TBSTYLE_AUTOSIZE |TBSTYLE_LIST|CCS_BOTTOM, 0, 0, 0, 0,
hwnd, NULL, ghInstance, NULL); //create the toolbar
SendMessage(hToolbar, WM_SETFONT, (WPARAM)hFontBold,
static_cast<LPARAM>(MAKELONG(TRUE, 0))); //set the font. there cannot be the problem
//↓↓↓↓↓**ILC_COLOR32 is specificied here but 32bit bmp is still not showing**//
auto hImagelist = ImageList_Create(32, 32,ILC_COLOR32|ILC_MASK,1, 0);
//↑↑↑↑↑**ILC_COLOR32 is specificied here but 32bit bmp is still not showing**//
HBITMAP bitmap = static_cast<HBITMAP>(ghInstance,
MAKEINTRESOURCE(ID_IMG_SPAWN),// <- ID_IMG_SPAWN is my custom resource
IMAGE_BITMAP, 32, 32, NULL));
ImageList_Add(hImagelist, bitmap, nullptr);
SendMessage(hToolbar, TB_SETIMAGELIST,static_cast<WPARAM>(0),(LPARAM)hImagelist);
In the code above, ID_IMG_SPAWN is the resource bmp image I imported to Visual Studio. However, Visual Studio threw an error saying it didn't recognize my bmp, and the bmp showed up blank when running the application.
Visual Studio told me my bmp wasn't recognized, see the below error:
When the app runs it looks as below:
I learned that Visual Studio hereby recognizes ONLY 24bit bmp.
So, I converted the bmp to 24bit and imported it again, changed ILC_COLOR32 to ILC_COLOR24, that really worked. No error and my image were shown on the button.
However, I lost my alpha channel. Because 24bit bitmap does not support an alpha channel, my image ended up having an ugly square background.
Try something like this (Note I used a "BINARY" resource.. maybe it will work with others too but not sure.. This code works with 32-bit bitmaps, alpha-transparent PNGs, and JPEG):
#include <windows.h>
#include <gdiplus.h>
HBITMAP LoadBitmapFromResource(DWORD ResourceID, bool transparent = true)
{
HANDLE hGlobal = NULL;
ULONG_PTR GDIToken = 0;
Gdiplus::Image* Img = NULL;
Gdiplus::GdiplusStartupInput GDIStartInput = NULL;
Gdiplus::GdiplusStartup(&GDIToken, &GDIStartInput, NULL);
HRSRC hResource = FindResource(NULL, MAKEINTRESOURCE(ResourceID), "BINARY");
if (!hResource) {return NULL;}
HGLOBAL hFileResource = LoadResource(NULL, hResource);
if (!hFileResource) {return NULL;}
LPVOID lpFile = LockResource(hFileResource);
if (!lpFile) {return NULL;}
DWORD dwSize = SizeofResource(NULL, hResource);
if (!dwSize) {return NULL;}
void* data = LockResource(hFileResource);
if (!data) {return NULL;}
IStream* pStream = NULL;
hGlobal = GlobalAlloc(GMEM_FIXED, dwSize);
memcpy(hGlobal, data, dwSize);
UnlockResource(hFileResource);
FreeResource(hFileResource);
if (CreateStreamOnHGlobal(hGlobal, true, &pStream) == S_OK)
{
Img = new Gdiplus::Image(pStream, false);
pStream->Release();
GlobalFree(hGlobal);
hGlobal = NULL;
HBITMAP hBitmap = NULL;
static_cast<Gdiplus::Bitmap*>(Img)->GetHBITMAP(transparent ? Gdiplus::Color::Transparent : Gdiplus::Color(0, 0, 0), &hBitmap);
delete Img;
Gdiplus::GdiplusShutdown(GdiImage::GDIToken);
GDIStartInput = NULL;
GDIToken = 0;
return hBitmap;
}
GlobalFree(hGlobal);
hGlobal = NULL;
Gdiplus::GdiplusShutdown(GdiImage::GDIToken);
GDIStartInput = NULL;
GDIToken = 0;
return NULL;
}
You will have to link against GDIPlus. It's not very nice to constantly startup and shutdown GDIPlus for every image you load.. so it's best to move that somewhere.. but other than that, everything should work just fine.
There are other ways without GDIPlus but it makes for a long post..
I learned that Visual Studio hereby recognizes ONLY 24bit bmp.
No, that's wrong. Visual Studio supports alpha-premultiplied 32-bit bitmaps.
32-bit bitmap has 8 bits for ALPHA, it's capable to make a smooth effect.
To show a 32-bit bitmap properly, you have to:
specify ILC_COLOR32
change the resource of ID_IMG_SPAWN to a 32-bit bitmap with premultiplied alpha.
create a DIB section to your bitmap when loading
(Win32's format requirement is very strict)
Q: How to create a DIB section to the bitmap?
A: Specify LR_CREATEDIBSECTION in the last parameter of LoadImage.
Explanation:
LoadImage((HINSTANCE)GetWindowLong(hwnd,GWL_HINSTANCE),MAKEINTRESOURCE(ID_IMG_SPAWN), IMAGE_BITMAP,32, 32,NULL)
This is your code of the LoadImage function. See the MSDN document of LoadImage, to create the DIB section, all you need is to specify LR_CREATEDIBSECTION in the last parameter of LoadImage.
Q: How to get a BMP with premultiplied alpha?
A: Pixelformer can help you convert your alpha-channeled file to a premultiplied-alpha BMP.
The steps are
Open your image (any format) in Pixelformer and choose Export from the menu
Select A8:R8:G8: B8 (32bpp) and Premultiplied Alpha, then click Ok.
Then you can save your BMP file! Import this BMP file to Visual Studio resources, replacing your previous 24-bit BMP.
Then, you don't need to use the ImageList_AddMasked (which makes the image sharp) anymore, because you already have a recognizable ALPHA in your 32-bit BMP. So, straight use ImageList_Add.
Okay, after the manipulations explained above your code should be this:
// Create the toolbar
HWND hToolbar = CreateWindow(TOOLBARCLASSNAME,NULL,
WS_CHILD | TBSTYLE_FLAT | TBSTYLE_AUTOSIZE | TBSTYLE_LIST | CCS_BOTTOM,
0, 0, 0, 0, hwnd, NULL, ghInstance, NULL);
// Set the font (this cannot be the problem)
SendMessage(hToolbar, WM_SETFONT, (WPARAM)hFontBold,
static_cast<LPARAM>(MAKELONG(TRUE, 0)));
auto hImagelist =
ImageList_Create(32, 32,ILC_COLOR32 /*DON'T NEED THE MASK. CHANGED TO ILC_COLOR32.*/, 1, 0);
HBITMAP bitmap = static_cast<HBITMAP>(LoadImage((HINSTANCE)GetWindowLong(hwnd,
GWL_HINSTANCE), MAKEINTRESOURCE(ID_IMG_SPAWN), IMAGE_BITMAP,
32, 32, LR_CREATEDIBSECTION /*THIS IS IMPORTANT*/ ));
ImageList_Add(hImagelist, bitmap, NULL);
SendMessage(hToolbar, TB_SETIMAGELIST, static_cast<WPARAM>(0), (LPARAM)hImagelist);
This worked fine as below.
These I answered above is well enough to solve this problem. You may wonder "What means DIB bitmaps?" "What is Premultiplied Alpha?". Those are the deep topics.
To learn DIB bitmaps and Premultiplied Alpha, see the links.
If you are using Visual Studio 2010 or higher (i guess), you can use PNG files. As stated here.

Error with displaying an .bmp image using mfc dialog

I am trying to display a bitmap image using MFC application.
I am using a browse button to select file which is working properly. But when I try to load an image by double clicking on the file, the application is launched, but the image is not displayed.
Here is my code for browse button and function to open a double clicked image.
void COpenImageDlg::OnBnClickedButton1()
{
// TODO: Add your control notification handler code here
CString path;
CFileDialog dlg(TRUE);
int result=dlg.DoModal();
if(result==IDOK)
{
path=dlg.GetPathName();
UpdateData(FALSE);
}
HBITMAP hBmp = (HBITMAP)::LoadImage(NULL, path, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE|LR_CREATEDIBSECTION);
CBitmap bmp;
bmp.Attach(hBmp);
CClientDC dc(this);
CDC bmDC;
bmDC.CreateCompatibleDC(&dc);
CBitmap *pOldbmp = bmDC.SelectObject(&bmp);
BITMAP bi;
bmp.GetBitmap(&bi);
dc.BitBlt(0,0,bi.bmWidth,bi.bmHeight,&bmDC,0,0,SRCCOPY);
bmDC.SelectObject(pOldbmp);
}
void COpenImageDlg::OpenImage1(CString path)
{
//CString path;
CFileDialog dlg(TRUE);
int result=dlg.DoModal();
if(result==IDOK)
{
path=dlg.GetPathName();
UpdateData(FALSE);
}
HBITMAP hBmp = (HBITMAP)::LoadImage(NULL, path, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE|LR_CREATEDIBSECTION);
CBitmap bmp;
bmp.Attach(hBmp);
CClientDC dc(this);
CDC bmDC;
bmDC.CreateCompatibleDC(&dc);
CBitmap *pOldbmp = bmDC.SelectObject(&bmp);
BITMAP bi;
bmp.GetBitmap(&bi);
dc.BitBlt(0,0,bi.bmWidth,bi.bmHeight,&bmDC,0,0,SRCCOPY);
}
Init class :
`BOOL COpenImageApp::InitInstance()
{
// InitCommonControlsEx() is required on Windows XP if an application
// manifest specifies use of ComCtl32.dll version 6 or later to enable
// visual styles. Otherwise, any window creation will fail.
INITCOMMONCONTROLSEX InitCtrls;
InitCtrls.dwSize = sizeof(InitCtrls);
// Set this to include all the common control classes you want to use
// in your application.
InitCtrls.dwICC = ICC_WIN95_CLASSES;
InitCommonControlsEx(&InitCtrls);
CWinApp::InitInstance();
AfxEnableControlContainer();
// Create the shell manager, in case the dialog contains
// any shell tree view or shell list view controls.
CShellManager *pShellManager = new CShellManager;
// Standard initialization
// If you are not using these features and wish to reduce the size
// of your final executable, you should remove from the following
// the specific initialization routines you do not need
// Change the registry key under which our settings are stored
// TODO: You should modify this string to be something appropriate
// such as the name of your company or organization
SetRegistryKey(_T("Local AppWizard-Generated Applications"));
COpenImageDlg dlg;
m_pMainWnd = &dlg;
INT_PTR nResponse = dlg.DoModal();
char* buff;
char* command_line = GetCommandLine();
buff = strchr(command_line, ' ');
buff++;
buff = strchr(buff, ' ');
buff++;
buff = strchr(buff, ' ');
buff++;
if (buff != NULL)
{
HBITMAP hBmp = (HBITMAP)::LoadImage(NULL, "C:\Users\Raguvaran\Desktop\tiger.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE|LR_CREATEDIBSECTION);
CBitmap bmp;
bmp.Attach(hBmp);
dlg.RedrawWindow();
CClientDC dc(m_pMainWnd);
CDC bmDC;
bmDC.CreateCompatibleDC(&dc);
CBitmap *pOldbmp = bmDC.SelectObject(&bmp);
BITMAP bi;
bmp.GetBitmap(&bi);
dc.BitBlt(0,0,bi.bmWidth,bi.bmHeight,&bmDC,0,0,SRCCOPY);
}
//RedrawWindow(dlg, NULL, NULL, RDW_INVALIDATE);
//UpdateWindow(dlg);
if (nResponse == IDOK)
{
// TODO: Place code here to handle when the dialog is
// dismissed with OK
}
else if (nResponse == IDCANCEL)
{
// TODO: Place code here to handle when the dialog is
// dismissed with Cancel
}
// Delete the shell manager created above.
if (pShellManager != NULL)
{
delete pShellManager;
}
// Since the dialog has been closed, return FALSE so that we exit the
// application, rather than start the application's message pump.
return FALSE;
}`
I used the same code for browse button and it displays the image. But when I double click the file, the image is not displayed. Please tell me what I am doing wrong.
If you have associated your application with a particular file extension, it will be launched automatically when you double-click such a file (as you have said).
When this happens, your application is launched with the file name (actually the full path) supplied as a command line argument to your application.
In SDI MFC applications, this is handled automatically by the framework as long as you haven't overridden the default File/Open handling mechanism, but if you have a dialog-based application you will need to add code for this yourself.
Your dialog COpenImageDlg is created and displayed inside the call to DoModal before the command line has a chance to be processed. When the DoModal returns, the dialog is already destroyed, so there is no dialog for the code to draw upon.
I understand that when you double click the file to choose a image on file dialog, the image doesn't show. I just tried your code of function OnBnClickedButton1 and OpenImage1. And it turns out that the image is displayed when double click to choose a image. I use VS2010 on win7. I hope this will help you though i donot find the error of your code.
I found the answer to my question.
It was actually a very stupid mistake.
When I read the file address using Commandline, the address has single slash, whereas I need to pass the address using double slash.
Such a silly bug. Sorry to waste your time.

Displaying image in WIN32, Why its not displayed?

I want to load a BitMap image in a pic box I created inside a window...picBoxDisp is created using following mechanism..
picBoxDisp = CreateWindow("STATIC", "image box",
WS_VISIBLE |WS_CHILD | SS_BITMAP |WS_TABSTOP | WS_BORDER,
50, 50, 250, 300, hwnd , (HMENU)10000, NULL, NULL);
Now Next I created a hBitmap object and loaded an image in to it...
hBitmap = (HBITMAP) LoadImage(NULL,szFileName,IMAGE_BITMAP,0,0,
LR_LOADFROMFILE| LR_DEFAULTSIZE);
SendMessage(picBoxDisp,STM_SETIMAGE,(WPARAM) IMAGE_BITMAP,(LPARAM) NULL);
//now assign the new image
//Create a compatible DC for the original size bitmap, for example originalMemDc.
HDC originalDC = GetDC((HWND)hBitmap);
HDC originalMemDC = CreateCompatibleDC(originalDC);
if(originalMemDC==NULL){
MessageBox(NULL,"Problem while creating DC.","Error",MB_OK);
}
//Select hBitmap into originalMemDc.
SelectObject(originalMemDC,hBitmap);
//Create a compatible DC for the resized bitmap, for example resizedMemDc.
HDC picBoxDC = GetDC(picBoxDisp);
HDC resizedMemDC = CreateCompatibleDC(picBoxDC);
//Create a compatible bitmap of the wanted size for the resized bitmap,
HBITMAP hResizedBitmap = CreateCompatibleBitmap(picBoxDC,250,300);
//Select hResizedBitmap into resizedMemDc.
SelectObject(resizedMemDC,hResizedBitmap);
//Stretch-blit from originalMemDc to resizedMemDc.
//BitBlt(resizedMemDC,0,0,250,300,originalMemDC,0,0,SRCCOPY);
BITMAP bmp_old,bmp_new;
GetObject(hBitmap,sizeof(bmp_old),&bmp_old);
GetObject(hResizedBitmap,sizeof(bmp_new),&bmp_new);
StretchBlt ( resizedMemDC,0,0,bmp_new.bmWidth,bmp_new.bmHeight,
originalMemDC,0,0,bmp_old.bmWidth,bmp_new.bmHeight,
SRCCOPY);
////De-select the bitmaps.
if((resizedMemDC==NULL)||(hResizedBitmap == NULL)) {
MessageBox(NULL,"Something is NULL","Error",MB_OK);
}
else
//Set hResizedBitmap as the label image with STM_SETIMAGE
SendMessage(picBoxDisp,STM_SETIMAGE, (WPARAM) IMAGE_BITMAP,(LPARAM) hResizedBitmap);
I just cant understand, why the above code is not working ?
Thanks in advance,
You misunderstood the STM_SETIMAGE usage. Do this:
hBitmap = (HBITMAP)::LoadImage(NULL, szFileName, IMAGE_BITMAP,
0, 0, LR_LOADFROMFILE| LR_DEFAULTSIZE);
if (hBitmap != NULL)
{
::SendMessage(picBoxDisp, STM_SETIMAGE,
(WPARAM)IMAGE_BITMAP, (LPARAM)hBitmap);
}
EDIT: If you want to resize the bitmap before setting it as the label image, then follow this scheme for the simplest possible way to do it (with sub-optimal quality in the resized image...):
Create a compatible DC for the original size bitmap, for example originalMemDc.
Select hBitmap into originalMemDc.
Create a compatible DC for the resized bitmap, for example resizedMemDc.
Create a compatible bitmap of the wanted size for the resized bitmap, for example hResizedBitmap.
Select hResizedBitmap into resizedMemDc.
Stretch-blit from originalMemDc to resizedMemDc.
De-select the bitmaps.
Set hResizedBitmap as the label image with STM_SETIMAGE
Should work!
The static control won't stretch the image to its size. You could use SS_CENTERIMAGE but it either clips or fills the empty space with the color of the top left pixel (see http://msdn.microsoft.com/en-US/library/b7w5x74z.aspx). You'd have to stretch the bitmap yourself before sending it to the static control.
You're trying to assign an image to a static control, so you don't need to draw the image but to set the image on it.
// set the image
HBITMAP hold = (HBITMAP)SendMessage(hpicBoxDc, STM_SETIMAGE, IMAGE_BITMAP, LPARAM(hBitmap));
// clear the old image
if(hold && hold != hBitmap)
DeleteObject(hold );

how to load image from file using MFC

My browse button code is
void CFileOpenDlg::OnBnClickedButton1()
{
// TODO: Add your control notification handler code here
CFileDialog dlg(TRUE);
int result=dlg.DoModal();
if(result==IDOK)
{
path=dlg.GetPathName();
UpdateData(FALSE);
}
}
and this is the code for loading an image from resource but that does not work for loading an image from file. i know LoadImage(); is used for this but how? how can i edit this code to load image from file. Plzz help.....
void CFileOpenDlg::OnBnClickedButton2()
{
// TODO: Add your control notification handler code here
CRect r;
CBitmap* m_bitmap;
CDC dc, *pDC;
BITMAP bmp;
m_bitmap = new CBitmap();
m_bitmap->LoadBitmapW(IDB_BITMAP1);
m_bitmap->GetBitmap(&bmp);
pDC = this->GetDC();
dc.CreateCompatibleDC(pDC);
dc.SelectObject(m_bitmap);
pDC->BitBlt(200, 200, bmp.bmWidth, bmp.bmHeight, &dc,0 , 0, SRCCOPY);
m_bitmap->DeleteObject();
m_bitmap->Detach();
}
MSDN LoadImage
HANDLE hBitMap = ::LoadImage(0, "c:\\mybmp.bmp",IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
CBitmap bmp;
bmp.Attach((HBITMAP)hBitMap);
If you want to open .JPG, .PNG ... eventually you can use CImage (is a shared class between MFC and ATL)
CImage image;
image.Load ( "picture.jpg" );
image.Draw ( pDC , 200, 200 );

Load a CBitmap dynamically

I have a Bitmap image that i want to load dynamically. But I am unable to load it.
CBitmap bmp;
bmp.LoadBitmap("c:\\aeimg");
it does not seem to be working.
Can someone please help me.
Thanks.
You can also try something like this:
CImage image;
image.Load(_T("C:\\image.png"));
CBitmap bitmap;
bitmap.Attach(image.Detach());
According to CBitmap documentation: LoadBitmap() function takes resource identifier of the bitmap or resource id of the bitmap.
You can't specify the path of the bitmap file.
E.g.
MyProject.rc
------------
MYBMP BITMAP "res\myimage.bmp"
and make sure that resource.h does not have any entry of MYBMP otherwise during preprocessing its replaced by id and ultimately LoadBitmap() will fail since application can't locate the resource as FindResource() fails.
Now do this :
CBitmap bmp;
bmp.LoadBitmap(L"MYBMP");
It will definitely load the bitmap.
To load a bitmap from a file, you want to use LoadImage with the LR_LOADFROMFILE flag.
CBitmap doesn't support directly reading from a .bmp file. You can instead make use of CImage class as suggested in other answers. You'll need to include atlimage.h in your code to make CImage work:
#include <atlimage.h>
:
CImage img;
img.Load (_T("C:\\image.bmp"));
CBitmap bitmap;
bitmap.Attach(img.Detach());
Another way is to load the image using LoadImage Win32 API and then attaching CBitmap to that:
HBITMAP hBitmap = (HBITMAP)LoadImage(NULL,"c:\\image.bmp",
IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
if (hBitmap != NULL)
bitmap.Attach(hBitmap);
CImage doesn't work with png last time I tried / checked. Have a look at CxImage - http://www.codeproject.com/KB/graphics/cximage.aspx .
It could be as simple as you forgetting to escape the backslash.
Instead of
bmp.LoadBitmap("c:\aeimg");
use
bmp.LoadBitmap("c:\\aeimg");
Otherwise you're passing an invalid path to the LoadBitmap method.
CString filename;
TCHAR szFilter[] = _T("Bitmap (*.bmp)|*.bmp|PNG (*.png)|*.png||");
CFileDialog selDlg(TRUE, NULL, NULL, OFN_OVERWRITEPROMPT | OFN_EXTENSIONDIFFERENT, szFilter, this);
if (selDlg.DoModal() == IDOK)
{
filename = selDlg.GetPathName();
CImage image;
HBITMAP hBitmap = (HBITMAP)LoadImage(NULL,filename, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
if (hBitmap)
{
// Delete the current bitmap
if (m_bmpBitmap.DeleteObject())
m_bmpBitmap.Detach(); // If there was a bitmap, detach it
// Attach the currently loaded bitmap to the bitmap object
m_bmpBitmap.Attach(hBitmap);
Invalidate();
}
}
When using the solutions mentioned to date, with a member variable of CBitmap I kept getting memory leaking every time I loaded the CImage onto the CBitmap. I solved this with the following code:
CString _fileName(/*Path to image*/);
CImage _image;
HRESULT hr = _image.Load(_fileName);
if (SUCCEEDED(hr)) {
if (m_Display.m_bmpImage.DeleteObject())
m_Display.m_bmpImage.Detach();
m_bmpImage.Attach(_image->Detach());
}