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i build these function from VB6(programming language):
but i get an error from messagebox:Code:void Transparent()
{
long test=GetWindowLong(hwnd, GWL_EXSTYLE);
SetWindowLong( hwnd, GWL_EXSTYLE,test | WS_EX_LAYERED);
SetLayeredWindowAttributes (hwnd, clrBackColor, 0, LWA_COLORKEY);
const char *text;
text=to_string( GetLastError()).c_str();
MessageBox(NULL,text,"erro",MB_OK);
}
87:ERROR_INVALID_PARAMETER - The parameter is incorrect.
(these code is for hide the backcolor)
can anyone advice me?
Are you compiling as ASCII or UNICODE?
You should not call GetLastError unless the API function (SetLayeredWindowAttributes in your case) has failed.
sorry i don't know answer to that question... i'm using the Code Blocks IDE.Quote:
Originally Posted by 2kaud
VictorN: yes... theres no error, on compiling, but no results on running. that's why i used the GetLastError()
MessageBox takes 4 parameters, The second and third parameters are typed as LPCTSTR. If you are compiling as UNICODE, then these become LPCWSTR which is const WCHAR* which is const wchar_t*. If you are compiling as ASCII, LPCTSTR becomes LPCSTR which is const char*. As text is defined as const char *, this is ASCII. If you are compiling as UNICODE, then MessageBox would be expecting a type of const wchar_t* and not const char* which is being provided - which could be the reason for the error 87. Try changing MessageBox to MessageBoxA().
Victor is quite right. The value returned by GetLastError() is only valid when an error has actually occured and the function in error states that the error number can be obtained by calling this function. Calling GetLastError() in a context in which it is not expected to be called can provide erronous information. SetLayeredWindowAttributes() returns 0 on failure and only in that case should GetLastError() be used.
i change for MessageBoxA() and i get the same error message.Quote:
Originally Posted by 2kaud
1 question: SetLayeredWindowAttributes() is only for main window and not child window?
now i tested the same code with main window and works fine.. so what is needed for work with child windows?
But do you ask this question instead of just read MSDN? :(:confused:Quote:
Originally Posted by Cambalinho
FYI: SetLayeredWindowAttributes function
inside of my class... it's a class member... so i can't hide the backcolor and make opacy?Quote:
Originally Posted by 2kaud
But if read the MSDN documentation for SetLayeredWindowAttributes(), as pointed out by Victor, this function only works on child windows with Windows 8/8.1. What OS are you using? If you are using a Windows OS prior to version 8 then this function only works for top level windows. Read the MSDN on-line documentation!
my windows is 7, so is there another way for transparent and opacity?Quote:
Originally Posted by 2kaud
Yes, but its nasty and involves a bit of work and sneaky tricks.
See http://stackoverflow.com/questions/7...trols-or-child
Also
http://www.codeguru.com/cpp/controls...ic-Control.htm
and an explanation
http://blogs.msdn.com/b/oldnewthing/.../10230811.aspx
i'm trying learn how use Regions, but i have 2 questions:Quote:
Originally Posted by 2kaud
1 - i belive that i can do it pixel by pixel. but i'm confused... but i think that i can do it... at least i did with VB2010;
2 - with Regions, can i do opacy?
from here: http://msdn.microsoft.com/en-us/libr...=vs.85%29.aspx
i read:
"With WS_EX_COMPOSITED set, all descendants of a window get bottom-to-top painting order using double-buffering. Bottom-to-top painting order allows a descendent window to have translucency (alpha) and transparency (color-key) effects, but only if the descendent window also has the WS_EX_TRANSPARENT bit set. Double-buffering allows the window and its descendents to be painted without flicker."
but i'm confused :(
i think that, when i create the main window, i must add the WS_EX_TRANSPARENT extended style and add the WS_EX_COMPOSITED with child window extended style.
but or i don't understand what these means or i did something wrong :(
because the STATIC control isn't created
But see also the community additions section on
http://msdn.microsoft.com/en-us/libr...=vs.85%29.aspx
which refers to
http://blogs.msdn.com/b/oldnewthing/.../10230811.aspx
as I referenced in my post #11.
With my test code (as posted previously), setting the main window as WS_EX_COMPOSITED and setting the static control WS_EX_TRANSPARENT has no effect as expected (non Windows 8 computer). I still get the static control created as if these styles weren't specified.
finally i found 1 solution(doublebuffering for avoid flickers and others):
(these code is in my label window procedure)
but i get these strange error on TransparenBlt():Code:case WM_ERASEBKGND:
{
HDC mdc = CreateCompatibleDC(NULL);//creating the doublebuffer
Size a=inst->GetSize();//get the control size
Position b=inst->GetPosition();//get ocntrol position
HBITMAP mbmp = CreateBitmap(a.Width,a.Height,1,24,NULL); //create the bimap with a size
HBITMAP moldbmp = (HBITMAP)SelectObject(mdc,mbmp);//select the DC from that bitmap
HDC labeldc=GetDC(inst->hwnd);//get the label DC
BitBlt(mdc,0,0,a.Width,a.Height,GetDC(GetParent(inst->hwnd)),b.X, b.Y,SRCCOPY);//copy the parent control
TransparentBlt(mdc,0,0,a.Width,a.Height,labeldc,0,0,a.Width,a.Height,(UINT)inst->clrBackColor);//copy the label DC to mdc(double buffer), without backcolor
BitBlt(GetDC(inst->hwnd),0,0,a.Width,a.Height,mdc,b.X, b.Y,SRCCOPY);//now copy the double buffer to label dc
//clean objects
SelectObject(mdc,moldbmp);
DeleteObject(mbmp);
DeleteDC(mdc);
}
"obj\Debug\main.o||In function `ZN5label7WndProcEP6HWND__jjl@16':"
"undefined reference to `_imp__TransparentBlt@44'"
the clrBackColor it's a COLORREF type.
isn't the 1st time that i get these strange error, can you please give me more information?
It means you did NOT find a solution yet! :rolleyes:Quote:
Originally Posted by Cambalinho
It is a Linker error. Some .lib or .obj file containing TransparenBlt was not included (nor added) in your project.Quote:
Originally Posted by Cambalinho
Didn't you read the MSDN documentation about TransparenBlt ?
Didn't you add the Msimg32.lib library?
you have right... i never thot that... thanksQuote:
Originally Posted by VictorN
and yes the code seems not working :(
maybe i will do it in other time
I hope the version of this case code you use has a break statement at the end.Quote:
finally i found 1 solution(doublebuffering for avoid flickers and others):
(these code is in my label window procedure)
yes.. it haveQuote:
Originally Posted by 2kaud
see the 2 cases:
or the WM_ERASEBKGND message is ignored or the text override it:(Code:case WM_ERASEBKGND:
{
if (inst->blnTransparent==true)
{
HDC mdc = CreateCompatibleDC(NULL);//creating the doublebuffer
Size a=inst->GetSize();//get the control size
Position b=inst->GetPosition();//get ocntrol position
HBITMAP mbmp = CreateBitmap(a.Width,a.Height,1,24,NULL); //create the bimap with a size
HBITMAP moldbmp = (HBITMAP)SelectObject(mdc,mbmp);//select the DC from that bitmap
HDC labeldc=GetDC(inst->hwnd);//get the label DC
BitBlt(mdc,0,0,a.Width,a.Height,GetDC(GetParent(inst->hwnd)),b.X, b.Y,SRCCOPY);//copy the parent control
TransparentBlt(mdc,0,0,a.Width,a.Height,labeldc,0,0,a.Width,a.Height,(UINT)inst->clrBackColor);//copy the label DC to mdc(double buffer), without backcolor
BitBlt(GetDC(inst->hwnd),0,0,a.Width,a.Height,mdc,b.X, b.Y,SRCCOPY);//now copy the double buffer to label dc
//clean objects
SelectObject(mdc,moldbmp);
DeleteObject(mbmp);
DeleteDC(mdc);
}
}
break;
case WM_CTLCOLORSTATIC:
{
if (inst->blnTransparent==false)
{
HDC hdcStatic = (HDC)wParam;
SetTextColor(hdcStatic, inst->clrTextColor);
SetBkMode(hdcStatic, TRANSPARENT);
SetBkColor(hdcStatic,inst->clrBackColor);
g_hbrBackground = CreateSolidBrush(inst->clrBackColor);
return (LONG)g_hbrBackground;
}
}
break;
Have you put a break point on it in the debugger to see if you are getting this message? Or do what I had in one of my earlier code posts, output all message values received to a text file so then you can easily establish what messages are received in what order.Quote:
or the WM_ERASEBKGND message is ignored
If you are receiving this message, then obviously the code is not doing what you expected - which is what exactly?
Also note from the documentation for WM_ERASEBKGND that if this message is processed, then you need to return a non-zero value. Returning a zero value indicates that the window will be erased and redrawn. Read the documentation! http://msdn.microsoft.com/en-us/libr...=vs.85%29.aspx
i recive a black rectangle with the text:Quote:
Originally Posted by 2kaud
so the problem is how i use bitblt()?Code:case WM_ERASEBKGND:
{
if (inst->blnTransparent==true)
{
HDC mdc = CreateCompatibleDC(NULL);//creating the doublebuffer
Size a=inst->GetSize();//get the control size
Position b=inst->GetPosition();//get ocntrol position
HBITMAP mbmp = CreateBitmap(a.Width,a.Height,1,24,NULL); //create the bimap with a size
HBITMAP moldbmp = (HBITMAP)SelectObject(mdc,mbmp);//select the DC from that bitmap
HDC labeldc=GetDC(inst->hwnd);//get the label DC
BitBlt(mdc,0,0,a.Width,a.Height,GetDC(GetParent(inst->hwnd)),b.X, b.Y,SRCCOPY);//copy the parent control
TransparentBlt(mdc,0,0,a.Width,a.Height,labeldc,0,0,a.Width,a.Height,(UINT)inst->clrBackColor);//copy the label DC to mdc(double buffer), without backcolor
BitBlt(GetDC(inst->hwnd),0,0,a.Width,a.Height,mdc,b.X, b.Y,SRCCOPY);//now copy the double buffer to label dc
//clean objects
SelectObject(mdc,moldbmp);
DeleteObject(mbmp);
DeleteDC(mdc);
Sleep(2000);
return DefWindowProc(hwnd, msg, wParam, lParam);;
}
}
break;
You're supposed to return a non-zero value - not call defproc.Code:Sleep(2000);
return DefWindowProc(hwnd, msg, wParam, lParam);
now i changed to:Quote:
Originally Posted by 2kaud
Code:return (LONG)CreateSolidBrush(NULL_BRUSH)
Now you have a resource leak as you are creating a brush every time you change the background but you never delete the object.
See http://msdn.microsoft.com/en-us/libr...=vs.85%29.aspx
Why don't you just return 1?
you have right. but i continue with same result: a black rectangle :(Quote:
Originally Posted by 2kaud
And you think this code does what? From where did you obtain it?Code:HDC mdc = CreateCompatibleDC(NULL);//creating the doublebuffer
Size a=inst->GetSize();//get the control size
Position b=inst->GetPosition();//get ocntrol position
HBITMAP mbmp = CreateBitmap(a.Width,a.Height,1,24,NULL); //create the bimap with a size
HBITMAP moldbmp = (HBITMAP)SelectObject(mdc,mbmp);//select the DC from that bitmap
HDC labeldc=GetDC(inst->hwnd);//get the label DC
BitBlt(mdc,0,0,a.Width,a.Height,GetDC(GetParent(inst->hwnd)),b.X, b.Y,SRCCOPY);//copy the parent control
TransparentBlt(mdc,0,0,a.Width,a.Height,labeldc,0,0,a.Width,a.Height,(UINT)inst->clrBackColor);//copy the label DC to mdc(double buffer), without backcolor
BitBlt(GetDC(inst->hwnd),0,0,a.Width,a.Height,mdc,b.X, b.Y,SRCCOPY);//now copy the double buffer to label dc
//clean objects
SelectObject(mdc,moldbmp);
DeleteObject(mbmp);
DeleteDC(mdc);
copy the parent HDC to doublebuffer... copy the child HDC to doublebuffer(transparent... without backcolor) and then copy the doublebuffer to child HDCQuote:
Originally Posted by 2kaud
You have checked, haven't you, that GetSize() and GetPosition() are returning the expected values?
yes.. i have tested now:Quote:
Originally Posted by 2kaud
Code:struct Position
{
int X;
int Y;
};
struct Size
{
int Width;
int Height;
};
Position GetPosition()
{
RECT LabelSize;
GetWindowRect(hwnd,&LabelSize);
Position crdSize = {LabelSize.left,LabelSize.top};
return crdSize;
}
Size GetSize()
{
RECT LabelSize;
GetWindowRect(hwnd,&LabelSize);
Size crdSize = {LabelSize.right-LabelSize.left,LabelSize.bottom-LabelSize.top};
return crdSize;
}
...and clrBackColor is set where?
Quote:
Originally Posted by 2kaud
Code:void SetBackColor(COLORREF color)
{
clrBackColor=color;
ShowWindow(hwnd,SW_HIDE);
ShowWindow(hwnd,SW_SHOW);
}
color GetBackColor()
{
return clrBackColor;
}
...and SetBackColor() is called from where? And is it called before the WM_ERASEBKGND message is received?
it's a class member... the ShowWindow() helps me do the control updateQuote:
Originally Posted by 2kaud
But have you checked that SetBackColor() is called before the WM_ERASEBKGND message is recieved? If it is called after, then clrBackColor won't have been set before it's used in the message process code.
you came 1st?Quote:
Originally Posted by 2kaud
WM_CTLCOLORSTATIC or WM_ERASEBKGND?
Output the received msg codes to a file or a debug window and see. It's for this sort of thing that I had the msg codes output to a file in an earlier example I posted.
it's the WM_ERASEBKGND message.. is the 1st. and then cames the WM_CTLCOLORSTATIC messageQuote:
Originally Posted by 2kaud