WritePixel argb format

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Yan

The 32 bit integer used by write/read pixel uses:
The first 8bits to represent the RED component of a colour, the next 8bits to represent the GREEN component of a colour, the next 8 bits to represent the Blue componet and the top 8 bits to represent the alpha component (this is ignored in normal 2D operations and is always set to 255)

To make it clearer:

 [   A  ] [  R   ] [  G   ] [  B   ]
%00000000 00000000 00000000 00000000 - Binary

 A  R  G  B
$00 00 00 00 - Hex

Therefore, if I had a pixel who's RED, BLUE and GREEN components were each set to 128 (mid grey) the integer would look like this:

%11111111100000001000000010000000 - Binary
$FF808080 - Hex
4286611584 - Decimal (-8355712 in Blitz cos it uses signed integers)

In your example above, you can now see that -65536 is $FFFF000 (use Print Hex$(-65536)).
This is indeed pure red with full alpha (Blitz will return always full alpha from a readpixel command [edit]for 2D stuff[/edit]).

Probably as clear as mud...But I tried ;o)

[edit]
The above assumes a 32bit screen mode. Things get really 'interesting' for 16bit modes...
http://www.blitzbasic.com/Community/posts.php?topic=31316
[/edit]

YAN