Re: Bitmaps and DCs - C / C++ / MFC Discussion Boards

Am I doing something wrong here? Because this crashes on the marked line.
Oh and how would I create a DC that is compatible with a bitmap that I want to select into it?

CDC dc;<br />
CBitmap bmp;<br />
<br />
// Create the DC here<br />
<br />
bmp.CreateCompatibleBitmap(&dc, width, height);<br />
CBitmap *old = (CBitmap*)dc.SelectObject(bmp);<br />
<br />
// Do whatever here<br />
<br />
dc.SelectObject(old); // BOOM! Crashes here. Access violation. Said address is not 0.

when you select bmp into the DC, use &bmp.

-c

Image tools: ThumbNailer, Bobber, TIFFAssembler

I can't believe it compiled with out that.

Jason Henderson
"You must be the change you wish to see in the world." - Gandhi

articles profile

Really eh?

Should have caught that... Confused | :confused:

CGDIObject has an override that will cast it to some type that SelectObject likes - but i think it's the wrong value, or it's not attached to the CGDIObject anymore, or something really strange and unexpected.

i've been bitten by it a number of times.

-c

Image tools: ThumbNailer, Bobber, TIFFAssembler

Jason Henderson wrote:
I can't believe it compiled with out that.

The beauty of conversion operators designed by... um, less experienced designers. If you weren't aware - MFC is (almost?) the hallmark of bad C++ design.

Ah! I am used to not noticing things like that unless the compiler errors :p
Thanks, I'll see what I can patch up. But what about the 2nd question? How do I create a compatible CD for a bitmap?

HDC hdcScreen,hdcCompatible;
HBITMAP hbmScreen;
hdcScreen = ::CreateDC("DISPLAY", NULL, NULL, NULL);
hdcCompatible = ::CreateCompatibleDC(hdcScreen);
hbmScreen = ::CreateCompatibleBitmap(hdcScreen,width,height);
::SelectObject(hdcCompatible, hbmScreen);

Now draw in the hdcCompatible !
/**/
PBITMAPINFO CreateBitmapInfoStruct(HBITMAP hBmp)
{
BITMAP bmp;
PBITMAPINFO pbmi;
WORD cClrBits;
GetObject(hBmp, sizeof(BITMAP), (LPSTR)&bmp);
cClrBits = (WORD)(bmp.bmPlanes * bmp.bmBitsPixel);
if (cClrBits == 1) cClrBits = 1;
else
if(cClrBits <= 4) cClrBits = 4;
else
if (cClrBits <= 8) cClrBits = 8;
else
if (cClrBits <= 16)cClrBits = 16;
else
if (cClrBits <= 24)cClrBits = 24;
else cClrBits = 32;
if (cClrBits != 24) pbmi = (PBITMAPINFO) LocalAlloc(LPTR,sizeof(BITMAPINFOHEADER)+sizeof(RGBQUAD) * (2^cClrBits));
else pbmi = (PBITMAPINFO) LocalAlloc(LPTR,sizeof(BITMAPINFOHEADER));
pbmi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
pbmi->bmiHeader.biWidth = bmp.bmWidth;
pbmi->bmiHeader.biHeight = bmp.bmHeight;
pbmi->bmiHeader.biPlanes = bmp.bmPlanes;
pbmi->bmiHeader.biBitCount = bmp.bmBitsPixel;
if (cClrBits < 24)
pbmi->bmiHeader.biClrUsed = 2^cClrBits;
pbmi->bmiHeader.biCompression = BI_RGB;
pbmi->bmiHeader.biSizeImage = (pbmi->bmiHeader.biWidth + 7) /8 * pbmi->bmiHeader.biHeight * cClrBits;
pbmi->bmiHeader.biClrImportant = 0;
return pbmi;
}

void CreateBMPFile(LPTSTR pszFile, PBITMAPINFO pbi,HBITMAP hBMP, HDC hDC)
{
HANDLE hf;
BITMAPFILEHEADER hdr;
PBITMAPINFOHEADER pbih;
LPBYTE lpBits;
DWORD dwTotal;
DWORD cb;
BYTE *hp;
DWORD dwTmp;
pbih = (PBITMAPINFOHEADER) pbi;
lpBits = (LPBYTE) GlobalAlloc(GMEM_FIXED, pbih->biSizeImage);
GetDIBits(hDC, hBMP, 0, (WORD) pbih->biHeight,lpBits, pbi, DIB_RGB_COLORS);
hf = CreateFile(pszFile,GENERIC_READ | GENERIC_WRITE,(DWORD) 0, (LPSECURITY_ATTRIBUTES) NULL, CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL, (HANDLE) NULL);
if(hf == INVALID_HANDLE_VALUE)
return;
hdr.bfType = 0x4d42;
hdr.bfSize = (DWORD) (sizeof(BITMAPFILEHEADER) +pbih->biSize + pbih->biClrUsed * sizeof(RGBQUAD) + pbih->biSizeImage);
hdr.bfReserved1 = 0;
hdr.bfReserved2 = 0;
hdr.bfOffBits = (DWORD) sizeof(BITMAPFILEHEADER) + pbih->biSize + pbih->biClrUsed * sizeof (RGBQUAD);
WriteFile(hf, (LPVOID) &hdr, sizeof(BITMAPFILEHEADER), (LPDWORD) &dwTmp, (LPOVERLAPPED) NULL);
WriteFile(hf, (LPVOID) pbih, sizeof(BITMAPINFOHEADER)+ pbih->biClrUsed * sizeof (RGBQUAD), (LPDWORD) &dwTmp, (LPOVERLAPPED) NULL);
dwTotal = cb = pbih->biSizeImage;
hp = lpBits;
while (cb > sizeof(hp)) {
WriteFile(hf, (LPSTR) hp, (int) sizeof(hp),(LPDWORD) &dwTmp, (LPOVERLAPPED) NULL);
cb-= sizeof(hp);
hp += sizeof(hp);
}
WriteFile(hf, (LPSTR) hp, (int) cb,(LPDWORD) &dwTmp, (LPOVERLAPPED) NULL);
CloseHandle(hf);
GlobalFree((HGLOBAL)lpBits);
}
/*have fun*/
To save use this :
PBITMAPINFO pbi=CreateBitmapInfoStruct((HBITMAP)hbmScreen);
CreateBMPFile(d.m_ofn.lpstrFile,pbi,(HBITMAP)hbmScreen,(HDC)hdcCompatible);
DeleteObject(hbmScreen);
DeleteDC(hdcCompatible);
DeleteDC(hdcScreen);

I am the mighty keeper of the book on knowledge . Contact me to get your copy .

Thank you

I would like change all the text font on a CListCtrl, and I don't know make it !
I can change the CListCtrl font but not the text inside List !
Please Help Me !
MyEden

MyEden

Open up the .rc file, search for the IDD of the dialog involved.
look where the font is defined, something like this:

FONT 8, "MS Sans Serif", 0, 0, 0x1

type in the font you want instead e.g:

FONT 9, "Verdana", 0, 0, 0x1. This will change font in whole dialog, but you could just put a clistctrl in a child window, and use this child dialog instead of clistctrl everywhere. Big Grin | :-D

"Life begins at 140"

One solution is customdraw.

OnNMCustomdrawList(...)
{
NMLVCUSTOMDRAW *pLVCD = reinterpret_cast<nmlvcustomdraw *="">(pNMHDR);
*pResult = CDRF_NEWFONT;
pLVCD->nmcd.hdc = someFontHandle;
return pResult ;
}

Kuphryn

Hello,

I've found something curious:

In a dialog based app in which I used xml and HTML, I was modifying HTML contents and using XML in the same class...

The surprise has arised when I have noticed that when I've separated the XML Class and the HTML class, the HTML part needed the msxml.dll imported too in order to work...

I suppose that this is just a coincidence and that I could use another header file included or another import (at least) I'd like to know how to do it in order not to import the msxml.dll (if I don't want to use xml...)

NOTE:
if I don't import that dll the compiler doesn't know anything about this declaration:
IHTMLDocument2Ptr m_pHTMLDoc;

Thank you in advance.

it would be nice if we could use the xml parsing engine with no microsoft dll ! yeah ... well things are like this ! all the objects you use are contained by it ! no msxml.dll no ms parsing ! do your own parser !
it`s quite hard !

I am the mighty keeper of the book on knowledge . Contact me to get your copy .

OK, that's great, but what happens when you have a lot of work and you cannot do every brick of your house? and moreover, what happens when tecnologies get improved and you can benefit yourself from improvements done by Microsoft (or someone else)?

I don't think that an own parser would be the solution, and moreover, my question was not about how to avoid that dll for xml parsing, is in order to avoid using that dll in order to avoid it's needing in using html com pointers...

Although all said above, thank you for your interest.

Hi!

I'm writing a Win32 application (not MFC) and i have done everything about dialog boxes and their controls.
The problem is that i want to read from a *.mdb(MSACCESS) file and write in it.
, and i don't know how to do it.
I tried to use an ActiveX control (Microsoft ADO data control version 6.0 (OLEDB)) and it didn't work.
The truth is that i don't know how to use an ActiveX control or to "play around" with databases.
My program is very simple: just to add some phones, names, adresses etc in a database
and then read them!
this is the first program i'm making with a database
I know that it would be easier to use MFC... but i want to do that in Win32 SDK app.
I just want to see how it works..

Can anyone tell me what should i use or do ???

I believe you can do it through the ODBC SDK functions. Look up "ODBC Function Summary" and "SQLConnect". You will have to learn about ODBC data sources and the like. This is not trivial. MFC is definitely WAY easier.

You also may have to download/install the Microsoft SDK to get access to those functions (not sure about that). It is a free download. Good luck!

~Steve

use DAO

Hush,hush...
thought I heard you call my name now.

Kula Shaker.

Amit Dey
Latest articles at CP -
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I need a little app (I'll write it if I have to) that when a server becomes availible (due to a VPN connection being established) will map a drive off that server to the client.

Can someone point me in the right direction on how to do this in a windows app for 95-XP.

Technically, I just need to know the API calls, and what hoops I mist jump through.

Thank you.

I believe the WNet* family of functions is what you are looking for.

Hi,

The code to create new MFC controls on heap is available on the net.

<br />
CButton *pMyButton = new CButton();<br />
pMyButton->Create( ... );<br />
/* delete pMyButton at appropriate time */<br />

Can someone explain how to do message handling for this dynamically created button? Thanks in advance.

Mandar Confused | :confused:

One solution is to ass message handlers for the buttons via their ID which you passed into Create().

ON_BN_CLICKED(ID, Handler().

Kuphryn

I have a tabctrl that controls 2 tabs(dialog each). I want each
dialog(tab) to be informed when it is selected/deselected. How do I get the tabctrl to inform the tab children dialogs that this event has occurred.
Thank you

This may be kind of kludgy, but I can listen for the change indirectly by listening for the OnPaint message from the framework.

if you are using mfc you have the TCN_SELCHANGE if not WM_NOTIFY and the same message !

on MFC :
switch(tab.GetCurSel())
{
case 1:
dlg1->YouROn();
dlg2->YouROff();
break;
case 2:
dlg1->YouROff();
dlg2->YouROn();
break;
default:
dlg1->YouROff();
dlg2->YouROff();
break;
}

on win32 sdk way :

int GetCurSel(HWND tab)
{
return SendMessage(tab,TCM_GETCURSEL ,0,0);
}

void OnTabCtrlSelChanged(int idTabCtl, HWND tabWnd)
{
here use the MFC switch i showed above
}

case WM_NOTIFY:
switch(((LPNMHDR)lParam)->code)
{
case TCN_SELCHANGE:
OnTabCtrlSelChanged(((LPNMHDR)lParam)->idFrom,((LPNMHDR)lParam)->hwndFrom);
break;
}

Be cool !

I am the mighty keeper of the book on knowledge . Contact me to get your copy .