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Mezmirous

[.net] Odd error w/painting

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case ID_ABOUT_HELLOWORLD:
{
	hdc = BeginPaint(hWnd, &ps);
	BeginPaint(hWnd,&ps);
	char szMessage[] = "Omg this is so cool!!!111one";
	TextOut(ps.hdc, 0, 0, szMessage, strlen(szMessage));
      EndPaint(hWnd,&ps);
      break;
}
What i'm trying to do with this is when the HELLOWORLD menu item is clicked it'll print szMessage[] out on the window at 0,0, now i'm new to WinAPI and just started really messing around with VC7 :D, it's fun stuff so far but it confuses me now..it's giving me an error on the TextOut(); line that says "warning C4267:'argument': conversion from 'size_t' to 'int', possible loss of data" Some things I notice that are probable, my code is wrong somehow..or i'm just putting it in the wrong place. The reason I put this in the ID_ABOUT_HELLOWORLD case, was because I figure if I put it in the normal WM_PAINT case i'de just be painting the message on window creation/update, I wouldn't be painting it when the menu item is clicked. The thing I would really need..is for it to paint szMessage[] and keep it there while processing all other messages..not just putting the paint data in a while loop or something and let it sit there..right now it would seem(if my code is right) that it would paint it once when I click the menu item and then it would go about its business, it wouldn't make it stay there. I want it to stay until the window is destroyed.. But in any case, ID_ABOUT_HELLOWORLD is a menu item within IDM_ABOUT, however you say that in winapi terminology..I obviously have no clue ^_^, but it's a menu item that when you hover over IDM_ABOUT it has a black arrow that points to the right, then a new menu appears, that's where ID_ABOUT_HELLOWORLD lies. What is wrong with my code and conceptualization? Am I just coding it wrong or am I putting this in the wrong place? Or is it both? Thank you for your time, ~Mezmirous [Edited by - Mezmirous on December 5, 2004 5:38:02 PM]

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First thing, I think this forum is for .NET development, as in using the .NET framework, not just Visual Studio .NET. But anyway...

Quote:
Original post by Mezmirous
it's giving me an error on the TextOut(); line that says "warning C4267:'argument': conversion from 'size_t' to 'int', possible loss of data"

That's not a problem, to get rid of that warning just put an explicit cast to int in front of strlen, e.g.

TextOut(ps.hdc, 0, 0, szMessage, (int)strlen(szMessage));

The reason it says that is that size_t (what strlen returns) is 32 bits unsigned, and int is 31 bits of number plus a sign bit, so theoretically for very large numbers there could be issues; however, I doubt you have a 2 billion character long string, so I wouldn't worry about it.

Quote:
Original post by Mezmirous
Some things I notice that are probable, my code is wrong somehow..or i'm just putting it in the wrong place. The reason I put this in the ID_ABOUT_HELLOWORLD case, was because I figure if I put it in the normal WM_PAINT case i'de just be painting the message on window creation/update, I wouldn't be painting it when the menu item is clicked.

The thing I would really need..is for it to paint szMessage[] and keep it there while processing all other messages..not just putting the paint data in a while loop or something and let it sit there..right now it would seem(if my code is right) that it would paint it once when I click the menu item and then it would go about its business, it wouldn't make it stay there. I want it to stay until the window is destroyed..

But in any case, ID_ABOUT_HELLOWORLD is a menu item within IDM_ABOUT, however you say that in winapi terminology..I obviously have no clue ^_^, but it's a menu item that when you hover over IDM_ABOUT it has a black arrow that points to the right, then a new menu appears, that's where ID_ABOUT_HELLOWORLD lies.

What is wrong with my code and conceptualization? Am I just coding it wrong or am I putting this in the wrong place? Or is it both?

Thank you for your time,
~Mezmirous

The simplest way to accomplish this would be to store a flag representing whether or not that menu item has been clicked, and in WM_PAINT you only draw the text if the flag is set to true. In your handler for ID_ABOUT_HELLOWORLD, you'd just set the flag and then call
InvalidateRect(hWnd, NULL, TRUE);
to force your window to redraw (and thus invoke your WM_PAINT handler.) That way the message will "stay" on the screen, but also only show up when you click the menu item. If you need any further clarification just ask.

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