GUI based dynamic font stroking

[kthuul]

Hi, I needed to draw stroked fonts in my GUI, since I couldn't predict what the background image would look like, and therefore contrast issues would crop up.

Now I'm pretty sure there is a much more effective way of achieving this effect, and if you have one, please please post it. Anyway, here is my little hack:

Code: Select all

void drawStrokedFont(IGUIFont* pFont, const wchar_t* text, const SColor& strokeCol, const SColor& textCol, const rect<s32>& rect)
{
	core::rect<s32> tRect = rect;
	struct offset_values
	{
		s32 xOff;
		s32 yOff;
	} offsets[] =
	{	{  0, -1 },	{ -1, -1 }, { -1,  0 },	{ -1,  1 },	{  0,  1 },	{  1,  1 },	{  1,  0 },	{  1, -1 } };

	for ( int i = 0; i < 8; i++ )
	{
		tRect = rect;
		tRect.UpperLeftCorner.X += offsets[i].xOff; tRect.UpperLeftCorner.Y += offsets[i].yOff;
		tRect.LowerRightCorner.X += offsets[i].xOff; tRect.UpperLeftCorner.Y += offsets[i].yOff;
		pFont->draw( text, tRect, strokeCol, true, true, &tRect);

	}

	// draw the white text
  pFont->draw( text, rect, textCol, true, true, &rect);
}

I hope someone has a better/quicker hack/method for doing this

Cheers

[bitplane]

It would be 9 times faster to do this inside the font generator instead.

[kthuul]

True, but this will work for TT and OT fonts as well.

[FuzzYspo0N]

The other option would be to make the font stroked up front like hybrid suggested, or if thats undesirable you can make two fonts, one "solid" and one "outline" and align them code side... we did this in one project and it looks great (using two fonts, simply drawing the text with two fonts, the solid and THEN the edges)

[hybrid]

Eh, what did I say?

[FuzzYspo0N]

my bad :> bitplane...

[kthuul]

I was thinking that the other way of doing this 'dynamically' (without pregenerated font sets) is to render the text to an offscreen buffer and then do edge detection to create the stroke. The benefit of doing this would be that the stroke could be wider than 1 pixel (current limitation of my hack).

So, I guess no one has a better algorithm for doing this dynamically?