GDI+ DrawString() related problem

[Waugh]

WARNING: Advanced C++ (take excedrin now)

*Deep breath*

Ok... I'm creating a class which will represent a line of text on a display. The goal is, of course, encapsulation and a desire to be able to use it like this:

  pTitleLine = new DisplayLine(rect1, pageTitle);	// Create title
  pTitleLine->AlignCenter();				// Center text

  pTitleLine->Draw(pGraphics);

The DisplayLine class has a constructor that looks like this:

DisplayLine ::DisplayLine (RectF rect, string str) 
    : strBrush(Color((int)(brightness * 2.55), 0, 255, 0))
{
	lineRect	= rect;   // RectF for DisplayString()
	lineText	= str;     // string to display

	pStrFormat = new StringFormat();
}

You'll note the brush has to be initialized like the above due to being a const.

Now, with the above, I can do this:

void DisplayLine ::Draw(Graphics *pGraphics)
{
  Font		font_big	(L"FIXEDSYS", 18, FontStyleBold, UnitPixel);
  Font		font_small (L"FIXEDSYS", 12, FontStyleBold, UnitPixel);
  //StringFormat	sFormat = new StringFormat();
  SolidBrush	gbrush(Color((int)(brightness * 2.55), 0, 255, 0));

  //sFormat.SetAlignment(StringAlignmentCenter);
  //sFormat.SetLineAlignment(StringAlignmentFar);

  wchar_t buf[20+1] = { 0 };
  MultiByteToWideChar(CP_ACP, MB_PRECOMPOSED, lineText.c_str(), (int)lineText.length(), buf, 20);
  pGraphics->DrawString(buf, -1, &font_big, lineRect, pStrFormat, &gbrush);
}

And this will compile fine. However, it crashes in flight sim due to:

  pTitleLine->AlignCenter();	// Crashes FS

  // Coded like this:
  void DisplayLine::AlignCenter()
  {
    pStrFormat->SetAlignment(StringAlignmentCenter);
  }

Now, if I uncomment and use sFormat above (vs. pStrFormat), it works fine. Problem is, then I couldn't allow it to be adjusted. I'm baffled why this doesn't work. Any ideas fellow gurus?

 

[Waugh]

I figured out one way around the problem, and finally also realized what I was "missing".

What I really want to do is set up a static StringFormat. I had forgotten that I could define these outside the constructor, so I'm going to try that. If not, I'm just going to construct one in the draw() function with enums from member vars.

It is a pain trying to switch back and forth between C, C++, and C#, haha. Scrambles the brain.

 

[scruffyduck]

It is a pain trying to switch back and forth between C, C++, and C#, haha. Scrambles the brain.

Bit like banging your head against a brick wall - it is so noce when you stop

 

[Waugh]

It's interesting....

Although I've found another way, I have found that if I setup a static variable like this:

// .h file
class CduLine
{
	static		SolidBrush		s_solidBrush;
	...
};

and initialize it like this:

// .cpp file
	SolidBrush DisplayLine::s_solidBrush(Color(255, 0, 255, 0));

and then in the draw() routine do this:

void DisplayLine::Draw(Graphics *pGraphics)
{
	s_solidBrush.SetColor(Color(255, 0, 255, 0));

	// Draw the text
	pGraphics->DrawString(buf, -1, &font_big, lineRect, &sFormat, &s_solidBrush);
}

that the text will not draw due to the brush being black. Weird.

Anyone know what is going on here?