C / C++ / MFC

Re: Copy part of an image to clipboard

14-Oct-06 9:57

An easy way is to create a new bitmap the size of the region rect.
Step through each source pixel in the region rect and use PtInRegion() to determine if it's in
the region. If it is, copy the pixel to the new bitmap. If not write a background-color pixel
to the new bitmap. Then place the bitmap on the clipboard.

Another way is create a new bitmap (DIB section) the size of the region rect.
Select it into a memory DC
Use StretchBlt() or whatever to draw the source region rect to the dc.
If the region is not rectangular go through the pixels using PtInRegion() like above to
remove the pixels outside the region.

Mark

Yaron Abershitz15-Oct-06 5:17

Yaron Abershitz

15-Oct-06 5:17

Thanks for your help.
This is probabely a silly question, but placing a background-color will cause the image to be copied with a background in the specified color and not as cliped one, right?
Anyway this is what I did and I tried to set those pixels to be transparent but it didn't work for me for some reason (I set the rgbReserved member of RGBQUAD to 0 and also tried 255), I still get the color I have set as a bg. What should I do so that when I paste the image, the bg will be transparent?

thanks,
Yaron.

Re: Copy part of an image to clipboard

Mark Salsbery15-Oct-06 7:54

15-Oct-06 7:54

That would depend on which function you use to blit it to the screen.

Regular GDI you have to use an AND mask to get transparency.
GDI+ you can use the alpha channel byte.

Mark

Bitmaps

Waldermort14-Oct-06 6:45

Waldermort

14-Oct-06 6:45

Probably a stupid question, but I can't seem to get his to work. I have an array of 20 DWORD values, each DWORD represents a 20 pixel line in a bitmap. How can I convert this array into a bitmap handle (HBITMAP)?

I have tried calling CreateDIBSection() then copy the array data over to the retrieved void pointer, but I am unable to display the image. All I see is a black square which tells me the bitmap has not been created correctly.

Re: Bitmaps

Mark Salsbery14-Oct-06 7:06

14-Oct-06 7:06

Are you setting up the BITMAPINFO structure correctly for the format of your pixels?

Mark

Re: Bitmaps

Waldermort14-Oct-06 7:19

Waldermort

14-Oct-06 7:19

Yeah. It was my own stupid fault, I had the byte order the wrong way around. 3 hours of debugging just to find that!

Re: Bitmaps

Mark Salsbery14-Oct-06 7:29

14-Oct-06 7:29

waldermort wrote:
3 hours of debugging just to find that!

Fun Fun!

Glad you found it!

Mark

programming

Dure-Shehwar14-Oct-06 5:42

Dure-Shehwar

14-Oct-06 5:42

Q1 As we know that in a windows application whenever a key is pressed, a message is sent to the active window. We are developing a DOS based application and want to detect whenever a key is pressed from keyboard. How can we do so?

Q2
We are writing a DOS based application in which we have to display the system date and time. Write down the code for doing so.

Re: programming

Sceptic Mole14-Oct-06 9:28

Sceptic Mole

14-Oct-06 9:28

Q1 kbhit
Q2 #include <time.h>

Good luck with your homework

Re: programming

Mark Salsbery14-Oct-06 10:04

14-Oct-06 10:04

Still no "please" LOL

Re: programming

Hamid_RT14-Oct-06 19:13

Hamid_RT

14-Oct-06 19:13

I think you asked these questions and you get answers.

WhiteSky

hook mousewheel problem

Michael ZY14-Oct-06 5:24

Michael ZY

14-Oct-06 5:24

I want to hook the WM_MOUSEWHEEL msg in globel and identify whether it is scroll in or scroll out by 'zDelta', but the 'zDelta'(below) always seem to be zero. Can any one help me.
Thanks!

extern "C" _declspec(dllexport) LRESULT WINAPI MouseProc(int nCode,WPARAM wParam,LPARAM lParam)
{
   if(nCode < 0)
      return CallNextHookEx(g_hHook,nCode,wParam,lParam);
   
   if(nCode == HC_ACTION)
   {
      switch(wParam)
      {
         case WM_MOUSEWHEEL:
            short zDelta = (short)HIWORD(wParam);// The 'zDelta' always seem to be zero
            break;
         ...........
         default:
            return CallNextHookEx(g_hHook,nCode,wParam,lParam);
      }
   }
}

Mark Salsbery14-Oct-06 6:59

14-Oct-06 6:59

Michael ZY wrote:
extern "C" _declspec(dllexport) LRESULT WINAPI MouseProc(int nCode,WPARAM wParam,LPARAM lParam)

I'm not sure why zdelta would be zero all the time.

Is "extern "C" the same linkage as __stdcall?
The hook func needs to be __stdcall.

try
extern _declspec(dllexport) LRESULT CALLBACK WINAPI MouseProc(int nCode,WPARAM wParam,LPARAM lParam)

Mark

Michael ZY14-Oct-06 14:40

Michael ZY

14-Oct-06 14:40

Thanks for reply, but still not Work.
i hooked other mouse msg like WM_LBUTTONDOWN are all fine.
Is that use the WH_MOUSE can not identify wheel scroll direction (need WH_MOUSE_LL?)

what i use now is:
g_hHook=SetWindowsHookEx(WH_MOUSE,MouseProc,g_hInstance,0);

Mark Salsbery14-Oct-06 15:01

14-Oct-06 15:01

I see it.

short zDelta = (short)HIWORD(wParam);

won't work. wParam is WM_MOUSEWHEEL, not the wheel delta Smile | :)

extern "C" _declspec(dllexport) LRESULT WINAPI MouseProc(int nCode,WPARAM wParam,LPARAM lParam){   
   if(nCode < 0)      
      return CallNextHookEx(g_hHook,nCode,wParam,lParam);      
   if(nCode == HC_ACTION)   
   {      
      switch(wParam)      
      {         
         case WM_MOUSEWHEEL:            
            short zDelta = (short)HIWORD(wParam);// The 'zDelta' always seem to be zero
            break;
         default:            
            return CallNextHookEx(g_hHook,nCode,wParam,lParam);      
      }   
   }
   return CallNextHookEx(g_hHook,nCode,wParam,lParam);
}

I can't find how to get the wheel delta in a hook proc LOL I'll let you know when/if I do!

Mark

Mark Salsbery14-Oct-06 15:10

14-Oct-06 15:10

Here it is Smile | :)

MOUSEHOOKSTRUCTEX Structure[^]

I learn something new every day!

How to catch keyboard event before the operation system ?

Michael ZY15-Oct-06 1:20

Michael ZY

15-Oct-06 1:20

Got it!
Thanks a lot Mark! Smile | :)

Use the code like this:
case WM_MOUSEWHEEL:
{
typedef struct
{
MOUSEHOOKSTRUCT MOUSEHOOKSTRUCT;
DWORD mouseData;
}MOUSEHOOKSTRUCTEX,*PMOUSEHOOKSTRUCTEX;

MOUSEHOOKSTRUCTEX *MHSEX;
MHSEX=(MOUSEHOOKSTRUCTEX*)lParam;

if(MHSEX->mouseData==(WHEEL_DELTA<<16))
AfxMessageBox("up");
if(MHSEX->mouseData==(-WHEEL_DELTA<<16))
AfxMessageBox("down");
}
break;

Yanshof14-Oct-06 5:21

Re: How to catch keyboard event before the operation system ?

14-Oct-06 5:21

I need to catch every keyboard event before operation system ( windows xp ) does.

What i mean is in case user click on key 'enter' ( or every other key ) my application need to check if the key is 'X' key - and in any case this key event need to continue as key event to the operation system.

I'm sure there is some win32 API function to do it - but i don't remember it.

Someone can help me ?

Thanks.

Sceptic Mole14-Oct-06 10:44

Sceptic Mole

14-Oct-06 10:44

Yanshof wrote:
I need to catch every keyboard event before operation system ( windows xp ) does.

Yanshof wrote:
I'm sure there is some win32 API function to do it - but i don't remember it.

Do you see a contradiction between those 2 sentences??

Re: How to catch keyboard event before the operation system ?

Yanshof14-Oct-06 22:49

Re: How to catch keyboard event before the operation system ?

14-Oct-06 22:49

Sorry ... but i don't see any contradiction.

I need some way to catch keyboard event - something like keyboard logger.

I did not found something useful in Google until now.

Thanks for any help.

Diagon Alley16-Oct-06 20:34

Diagon Alley

16-Oct-06 20:34

Hi! Will this [^]help?

--------------------------------------------------------------------
If you need a hammer get C and shut up. If you need a nail gun get C++ and shut up. If you don't need *those* things (and good design should tell you) then by all means get a factory, factory, factory.

--code-frog@codeproject

Why use Dll ?

Yanshof16-Oct-06 21:32

Problem with using class wincrypt.h

16-Oct-06 21:32

Why do not use the Hook in the code and beside this - why thay use in this example DLL ?

Yanshof14-Oct-06 1:55

Re: Problem with using class wincrypt.h

14-Oct-06 1:55

Hi All,

I need to use the class wincrypt.h with some of my application that i writing.
I try to compile the application but all the object and function of this class is are not recognize by my compiler.

I even try to get demo application from here :

http://www.codeproject.com/cpp/cryptest.asp[^]

but my compiler repeat the message "undeclared identifier".

Some one can help me ?

Thanks.

Waldermort14-Oct-06 2:04

Waldermort

14-Oct-06 2:04

What is the error you are getting?

Re: Problem with using class wincrypt.h

Yanshof14-Oct-06 2:19