How to draw a bitmap on top of button?

Igor Jerosimic

I want to draw a small arrow bitmap on top of already drawn button. I tried with calling default drawing proc before my code for drawing bitmap but it gives me some error. OnDrawItem(int nIDCtl, LPDRAWITEMSTRUCT lpDrawItemStruct) { CDialog::OnDrawItem(nIDCtl, lpDrawItemStruct); HDC thdc = CreateCompatibleDC(lpDrawItemStruct->hDC); HGDIOBJ tobj = SelectObject(thdc, LoadBitmap(AfxGetInstanceHandle(), MAKEINTRESOURCE(IDB_ARROW_DOWN))); TransparentBlt(lpDrawItemStruct->hDC, lpDrawItemStruct->rcItem.right - 20, lpDrawItemStruct->rcItem.top + (lpDrawItemStruct->rcItem.bottom - lpDrawItemStruct->rcItem.top - 16) / 2, 16, 16, thdc, 0, 0, 16, 16, RGB(255, 0, 255)); SelectObject(thdc, tobj); DeleteDC(thdc); } if i exclude "CDialog::OnDrawItem(nIDCtl, lpDrawItemStruct);" then code works, but there is no borders and caption text, just my bitmap.

Naveen

Igor Jerosimic wrote:

but it gives me some error.

Whats the error? After making the button owner draw, you have to draw the entire button your self. the DrawItem() function of CButton only contains Assert(FALSE);, which will result in a Abort-Retry--Ignore dialog.

nave

prasad_som

Igor Jerosimic wrote:

OnDrawItem(int nIDCtl, LPDRAWITEMSTRUCT lpDrawItemStruct) { CDialog::OnDrawItem(nIDCtl, lpDrawItemStruct);

As told by Navin, you need to do all drawing stuff in case of owner drawn controls. And should not call base version, as this function is supposed to override in derived control.

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Igor Jerosimic

It stops on some ASSERT... I know that i have to draw the entire button by myself, but my question is how do i let windows draw that button for me (with al it's visual styles) and i just want to draw small bitmap in right corner of button?

Naveen

why dont u use CBitmapButton? Another way is to handle the WM_PAINT message of the button and draw the bitmap after the default paint.For this you need to derive a class from CButton and make control variable of button of this class type.I am not sure about this technique. eg: void CMyBotton::OnPaint() { CButton::OnPaint(); // Draw the bitmap }

nave

prasad_som

Naveen R wrote:

CButton::OnPaint();

Should not call base class. :)

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Naveen

prasad_som wrote:

Should not call base class

why? I said him to do so in a non owner draw button.

nave

prasad_som

It doesn't have any effect there.

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David Crow

Have you see this?

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

Hamid Taebi

See A Better Bitmap Button Class[^] if helpfuls

WhiteSky

ThatsAlok

WhiteSky wrote:

See A Better Bitmap Button Class[^] if helpfuls

i liked it sometime before

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers, Alok Gupta VC Forum Q&A :- I/ IV Support CRY- Child Re

Naveen

prasad_som wrote:

It doesn't have any effect there.

Whats do you mean. If I didnt called the default procedure for WM_PAINT, then how will the button get painted? Nothing will appear in the place of button. Isn't it?

nave

prasad_som

Naveen R wrote:

Whats do you mean. If I didnt called the default procedure for WM_PAINT, then how will the button get painted?

You are confusing between painting a control and drawing a control. In case of of non-owner drawn control windows takes care of drawing/creating control. WM_PAINT message is meant to paint invalidated area. Now about calling base class OnPaint. It simply does default painting routines and validates invalidated area. So Consider this function,

void CMyButton::OnPaint()
{
CButton::OnPaint();//
//Here at above line invlaidated client area will be validated
and code following has no effect
CPaintDC dc(this); // device context for painting
//drawing routine follows
}

Consider another scenario,

void CMyButton::OnPaint()
{
CPaintDC dc(this); // device context for painting
//drawing routine follows
//till this point due to call to CPaintDC c'tor
invalidated area will be validated and
CButton::OnPaint has no effect.
CButton::OnPaint();//

}

Hope this clears your doubts.

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Naveen

prasad_som wrote:

void CMyButton::OnPaint(){ CButton::OnPaint();// //Here at above line invlaidated client area will be validated and code following has no effect CPaintDC dc(this); // device context for painting //drawing routine follows}

I never said to create another CPaintDC below the CButton::OnPaint(); He can use CClientDC dc(this) to create a device context and do painting to it. Surely it will work.

nave

Igor Jerosimic

I already tried something with WM_PAINT, but it didn't work. And after reading this article in MSDN i give up on WM_PAINT... "Handling WM_PAINT The most extreme choice is to implement a WM_PAINT handler and do all the painting yourself." http://msdn2.microsoft.com/en-us/library/ms364048(vs.80).aspx

Igor Jerosimic

OK thank you all for your answers, i will try it out and let you know if it's woking. In case my english is so bad that nobody understood what i want to do :), I want to draw something like this http://img252.imageshack.us/img252/2254/codeprojectkc1.png

Naveen

Why dont you use the class CBitmapButton???

nave

Igor Jerosimic

I will try.

prasad_som

Naveen R wrote:

I never said to create another CPaintDC below the CButton::OnPaint();

Yes, but it is what should be used in OnPaint messages. CClientDC associated with whole client area of window, as opposed to CPaintDC which is associated to invalidated rect only. So consider how logical is it to use CClientDC there. BTW,havn't you come across this line whenever added WM_PAINT message handler throught class wizard ? // Do not call CButton::OnPaint() for painting messages

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Igor Jerosimic

Can you explain how do you think that i should use CBitmapButton class? As i see that class only helps in inserting bitmaps on to buttons, but it still needs me to draw the button (because my bitmap is displayed only on one small portion of button).