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Re: Images for disabled button in "Classic" style [message #26107 is a reply to message #26105]

Thu, 01 April 2010 14:54

mrjt
Messages: 705
Registered: March 2007
Location: London

Contributor

Yes, it is a transparency issue. This is the filter being used for DisabledImage with XP classic:

RGBA sEtchFilter::operator()(const RGBA **mx)
{
	RGBA t;
	RGBA s = mx[1][1];
	if(s.a == 255 && s.r + s.g + s.b < 400) {
		t.r = t.g = t.b = 128;
		t.a = 255;
		return t;
	}
	s = mx[0][0];
	if(s.a == 255 && s.r + s.g + s.b < 400) {
		t.r = t.g = t.b = t.a = 255;
		return t;
	}
	Zero(t);
	return t;
}

ImageOp.cpp
The alpha limit is there because you don't want to etch invisible pixels, it would look wierd.

IMO a good compromise would be this version that checks for alpha > 128:

RGBA sEtchFilter::operator()(const RGBA **mx)
{
	RGBA t;
	RGBA s = mx[1][1];
	if(s.a & 0x80 && s.r + s.g + s.b < 400) {
		t.r = t.g = t.b = 128;
		t.a = s.a;
		return t;
	}
	s = mx[0][0];
	if(s.a & 0x80 && s.r + s.g + s.b < 400) {
		t.r = t.g = t.b = 255;
		t.a = s.a;
		return t;
	}
	Zero(t);
	return t;
}

[Updated on: Thu, 01 April 2010 15:13]

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