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A simple transparent CStatic-derived class

Zorglab

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16 Dec 2002

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This class allows you to create transparent static controls. For instance, you can add text on a bitmap in a dialog.

Description

Sometimes, transparent static controls are very useful. For example, you have a dialog with a bitmap in it and want to add some text in the picture. If you create a static control, your text will appear on an opaque background, even if you've selected the WS_EX_TRANSPARENT style (this style is *very* buggy).

How to implement

To use the class in your application you need to do the following:

Insert the .h and .cpp files into your project.
Add a static control into your dialog resource.
Add a member variable for that static control.
Modify the variable declaration.
Change this:
```
CStatic m_Static
```
To this:
```
CTransparentStatic m_Static
```
Don't forget the #include at the top of the include file:
```
#include "TransparentStatic.h"
```

That's it. You should now have a transparent background.

Features

The following Static Styles are implemented:

SS_LEFT
SS_LEFTNOWORDWRAP
SS_RIGHT
SS_CENTER
SS_CENTERIMAGE (center text vertically)
SS_NOPREFIX
SS_WORDELLIPSIS
SS_ENDELLIPSIS
SS_PATHELLIPSIS

The various borders (SS_SUNKEN, WS_EX_CLIENTEDGE, ...) are also supported.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

Written By

Zorglab

Web Developer

Belgium

This member has not yet provided a Biography. Assume it's interesting and varied, and probably something to do with programming.

Comments and Discussions

Re: It Does Not Work with Multiple Inheritance

Zorglab14-Feb-03 9:07

14-Feb-03 9:07

Quite strange... Hmmm | :|

Hmmm | :|

What's that MyOtherClass ? Where is it derived from ?

Re: It Does Not Work with Multiple Inheritance

Julio Fabio Chagas17-Feb-03 1:49

Julio Fabio Chagas

17-Feb-03 1:49

Copy of MyLabel.cpp and MyLabel.h files

// MyLabel.cpp : implementation file
//

#include "stdafx.h"
#include "LabelT.h"
#include "MyLabel.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

Teste::Teste()
{
}

Teste::~Teste()
{
}

/////////////////////////////////////////////////////////////////////////////
// MyLabel

MyLabel::MyLabel()
{
}

MyLabel::~MyLabel()
{
}

BEGIN_MESSAGE_MAP(MyLabel, CStatic)
//{{AFX_MSG_MAP(MyLabel)
ON_WM_PAINT()
//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// MyLabel message handlers

void MyLabel::OnPaint()
{
CPaintDC dc(this); // device context for painting

// Where to draw text
CRect client_rect;
GetClientRect(client_rect);

// Get the caption
CString szText;
GetWindowText(szText);

// Get the font
CFont *pFont, *pOldFont;
pFont = GetFont();
pOldFont = dc.SelectObject(pFont);

// Map "Static Styles" to "Text Styles"
#define MAP_STYLE(src, dest) if(dwStyle & (src)) dwText |= (dest)
#define NMAP_STYLE(src, dest) if(!(dwStyle & (src))) dwText |= (dest)

DWORD dwStyle = GetStyle(), dwText = 0;

MAP_STYLE( SS_RIGHT, DT_RIGHT );
MAP_STYLE( SS_CENTER, DT_CENTER );
MAP_STYLE( SS_CENTERIMAGE, DT_VCENTER | DT_SINGLELINE );
MAP_STYLE( SS_NOPREFIX, DT_NOPREFIX );
MAP_STYLE( SS_WORDELLIPSIS, DT_WORD_ELLIPSIS );
MAP_STYLE( SS_ENDELLIPSIS, DT_END_ELLIPSIS );
MAP_STYLE( SS_PATHELLIPSIS, DT_PATH_ELLIPSIS );

NMAP_STYLE( SS_LEFTNOWORDWRAP |
SS_CENTERIMAGE |
SS_WORDELLIPSIS |
SS_ENDELLIPSIS |
SS_PATHELLIPSIS, DT_WORDBREAK );

// Set transparent background
dc.SetBkMode(TRANSPARENT);

// Draw the text
dc.DrawText(szText, client_rect, dwText);

// Select old font
dc.SelectObject(pOldFont);
}
///////// end of file .cpp ////////////////////////

#if !defined(AFX_MYLABEL_H__90C354CD_12A8_4EDF_B7C4_60F52CDF2093__INCLUDED_)
#define AFX_MYLABEL_H__90C354CD_12A8_4EDF_B7C4_60F52CDF2093__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
// MyLabel.h : header file
//

class Teste
{
public:
Teste();
virtual ~Teste();
int a;
};

/////////////////////////////////////////////////////////////////////////////
// MyLabel window

class MyLabel : public CStatic, public Teste
{
// Construction
public:
MyLabel();

// Attributes
public:

// Operations
public:

// Overrides
// ClassWizard generated virtual function overrides
//{{AFX_VIRTUAL(MyLabel)
//}}AFX_VIRTUAL

// Implementation
public:
virtual ~MyLabel();

// Generated message map functions
protected:
//{{AFX_MSG(MyLabel)
afx_msg void OnPaint();
//}}AFX_MSG

DECLARE_MESSAGE_MAP()
};

/////////////////////////////////////////////////////////////////////////////

//{{AFX_INSERT_LOCATION}}
// Microsoft Visual C++ will insert additional declarations immediately before the previous line.

#endif // !defined(AFX_MYLABEL_H__90C354CD_12A8_4EDF_B7C4_60F52CDF2093__INCLUDED_)

WS_EX_TRANSPARENT

Marc Clifton18-Dec-02 0:52

18-Dec-02 0:52

Doesn't that work in a CStatic directly?

WS_EX_TRANSPARENT Specifies that a window created with this style is to be transparent. That is, any windows that are beneath the window are not obscured by the window.

Marc

Help! I'm an AI running around in someone's f*cked up universe simulator.
Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
Every line of code is a liability - Taka Muraoka

Re: WS_EX_TRANSPARENT

Zorglab18-Dec-02 1:44

18-Dec-02 1:44

I thought so, but it doesn't. The CStatic still appear opaque.

Re: WS_EX_TRANSPARENT

Marc Clifton18-Dec-02 1:50

18-Dec-02 1:50

WTF | :WTF:

Don't you just hate it when this kind of sh*t happens?

Mad | :mad:

Mad | :mad:

Good article.

I am curious about one other thing though. Since you probably would be using this class on top of a window that is already owner drawn, wouldn't you just put the text you want to display into that window, instead of layering a transparent static window on top of it? Or is my assumption about usage wrong?

Marc

Help! I'm an AI running around in someone's f*cked up universe simulator.
Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
Every line of code is a liability - Taka Muraoka

Re: WS_EX_TRANSPARENT

Zorglab18-Dec-02 22:54

18-Dec-02 22:54

Don't you just hate it when this kind of sh*t happens?
Yes, indeed.

Good article.
Thanks.

I am curious about one other thing though. Since you probably would be using this class on top of a window that is already owner drawn, wouldn't you just put the text you want to display into that window, instead of layering a transparent static window on top of it? Or is my assumption about usage wrong?
Of course, that's a possible solution, but I wanted to make an already existing static control transparent. And since my bitmap isn't owner drawn...

The biggest advantage, I think, of the transparent CStatic, is you define it's position and attributes in the dialog resource editor which is WYSIWYG and you get a real time preview (except the transparency).

Re: WS_EX_TRANSPARENT

Paolo Messina18-Dec-02 14:56

18-Dec-02 14:56

To my experience, WS_EX_TRANSPARENT is *almost* like returning TRUE to WM_ERASEBKGND. If you draw something in reply to WM_PAINT, as a Static control does, you can't see the difference (unless the control is bigger than the contained text, maybe).
The Static control paints the text using an opaque background, that you can disable by handling WM_CTLCOLORSTATIC messages and calling SetBkMode() on the given HDC. This way you have to explicitly refresh the control whenever the background changes or the control is resized.

Cheers,
Paolo

------
"airplane is cool, but space shuttle is even better" (J. Kaczorowski)

Re: WS_EX_TRANSPARENT

Zorglab18-Dec-02 22:46

18-Dec-02 22:46

I tried this, but it doesn't work. Why ? Confused | :confused:

Confused | :confused:

Re: WS_EX_TRANSPARENT

Paolo Messina19-Dec-02 0:23

19-Dec-02 0:23

I have the following code in a CStatic-derived class:

// transparent text
pDC->SetBkMode(TRANSPARENT);
return (HBRUSH)GetStockObject(NULL_BRUSH);

At the end of my CStatic::CtlColor() override and it works. As I said, there are also other things to consider: for example, if you change the font attributes (bold, italic, underline, etc.) dynamically you may have to invalidate the portion of the parent window (or underlying controls) overlapped by the static control.

Paolo

------
"airplane is cool, but space shuttle is even better" (J. Kaczorowski)

Re: WS_EX_TRANSPARENT

Zorglab2-Apr-03 7:14

2-Apr-03 7:14

After giving it a last try, I found a better way to make all static control on a dialog transparent : put the following code in the CWnd::OnCtlColor() override of the dialog.

HBRUSH CMyDialog::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)
{
	HBRUSH hbr = CDialog::OnCtlColor(pDC, pWnd, nCtlColor);

	if (nCtlColor == CTLCOLOR_STATIC)
	{
		pDC->SetBkMode(TRANSPARENT);
		hbr = (HBRUSH) GetStockObject(NULL_BRUSH);
	}

	return hbr;
}

Thanks for your help and sorry for the late answer Wink | ;)

Wink | ;)

.

Zorglab

BTW : the WS_EX_TRANSPARENT style enables transparency for the mouse. This means mouse clicks and moves are not forwarded (or forwarded after all controls).

Re: WS_EX_TRANSPARENT

RancidCrabtree29-Sep-05 7:13

29-Sep-05 7:13

While this will work, wait until you change the text of your static control. The old text won't be erased and the new text will be drawn on top of it. It will be a garbled mess.

One of the above replies mentioned invalidating the portion of the parent window the underlies the static control. I'm going to experiment with that. I hope it works, because I really need it to.

Re: WS_EX_TRANSPARENT

AndrewSmirnov11-Aug-03 16:12

11-Aug-03 16:12

YES!!!!
It works!!!

Many, Many thanks!!!!

F@#ing Microsoft! How in the h#ll would I know to use GetStockObject(NULL_BRUSH) ??? Mad | :mad:

Mad | :mad:

Mad | :mad:

Mad | :mad:

Re: WS_EX_TRANSPARENT

lbs7516-Nov-05 18:28

16-Nov-05 18:28

hi,it will work fine.

void CTransparentStatic::PreSubclassWindow()
{
// TODO: Add your specialized code here and/or call the base class
// We want to get mouse clicks via STN_CLICKED
DWORD dwStyle = GetStyle();
::SetWindowLong(GetSafeHwnd(), GWL_EXSTYLE, dwStyle | SS_NOTIFY | WS_EX_TRANSPARENT);

CStatic::PreSubclassWindow();
}

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