Bug: Incorrect or inconsistent specification of colour

[rleigh]

In the current specification:

<xsd:documentation>A color used render this channel - encoded as RGBA The default value "-2147483648" is #FFFFFFFF so solid white (it is a signed 32 bit value)</xsd:documentation>

Two problems with this:

1) "-2147483648" is #FFFFFFFF

This is from what I can tell, false. 0xFFFFFFFF is -1 and 0x80000000 is -2147483648.

2) For the default, -2147483648 would be 0x80000000 i.e. mid intensity transparent red, i.e. completely invisible. 0xFFFFFFFF would be opaque white, i.e. completely visible.

(The above assumes A=0 is transparent, A=255 is opaque; is this the interpretation used in our spec?)

Regards,
Roger

[rleigh]

Test code:

class test
{

public static void main(String[] args)
{

int n1 = 0xFFFFFFFF&0xFFFFFFFF;
System.out.println("0xFFFFFFFF=" + n1);

int n2 = 0x80000000&0xFFFFFFFF;

System.out.println("0x80000000=" + n2);

}

}

Output:
0xFFFFFFFF=-1
0x80000000=-2147483648

[ajpatterson]

Roger and I looked through some old spreadsheets of rgba values I had used when we are tackling the colour bug the last time and worked out where the -2147483648 came from (2009-09 schema era) . It looks like the default value should have been updated to -1 when this old bug was fixed (between 2010-04 and 2010-06) and the docs/default changed to reflect this.

[rleigh]

After discussion with Andrew, it looks like this is a historical mistake from a much earlier version of the schema in 2010 or earlier. In this version, 0xFFFFFFFF did equal -2147483648. But this was fixed in 2010.

What wasn't changed is the default, so the comment is incorrect. 0xFFFFFFFF is -1. But the default is still set to -2147483648. This may have been preserved to avoid changing the default behaviour. However, given that the default behaviour is to set the colour to invisible transparent red, I have to question whether this is useful. Surely setting to -1 to give white would be the correct change to make here?

[jburel]

Moved from sprint 2012-05-22 (15)

[ajpatterson]

Default value changed to "-1" and docs in xsd files updated.