One way to understand what is going on is to debugIt
It seems that Pen>>print:withFont: assumes that the background pixel
code of the character form is zero.
This does not happen to be true, is it an effect of anti-aliasing ?
I join the
    (form magnifyBy: 16) asMorph openInWorld
of the first letter T.

The character form is currently of depth 16.
In my 4.3 updated trunk image, background code seems to be 32767
(I don't know why 15 bits when form depth is 16, maybe 5 bits per
color channel...).

I guess the code was written for depth 1 forms (0 = pen up = white, 1
= pen down = black).

Maybe we can try using this snippet:
    backgroundColorCode := 1 << (form depth // 3 * 3) - 1.
This would work both for depth 16 and 1...

Then use:
    value = backgroundColorCode
instead of:
    value = 0

But I'm not sure this hack is general enough...

Anyway, the result still looks ugly.
Again this is probably related to anti-aliasing.

Nicolas

2011/4/28 Chris Wright <cawright.99 at gmail.com>:
> Hi folks
>
> I posted this to the beginners' list
> OSX 10.6.7 Intel
> Squeak 4.2 update #10977
>
>
> running the example from the Pen class
> Display restoreAfter:
> [Pen new squareNib: 2; color: Color red; turn: 45;
>        print: 'The owl and the pussycat went to sea in a beautiful pea green
> boat.' withFont: TextStyle defaultFont]
>
> draws a patterned red line at the correct angle, but with no recognisable text.
>
> same problem with the "Terse guide to squeak" Pen example.
>
> I'm not sure where to look to see if this is a known problem... and if
> there's a fix :?
>
> and received the following reply from Jerome Peace (thanks!)
>
> I tried your code in a 4.3 squeak and got your described results. Went
> back to a 3.9 squeak and got the results expected with the printing
> actually working. So I suspect there is a problem. I suspect it is not
> known. I wonder if the problem is that color is now setting both
> foreground and background.
>
> I am not actively doing bug tracking in squeak right now. So hopefully
> someone else will look to see what changed. Anyway you have found a
> real bug. A good place to note it would be on the squeak-dev list and
> the mantis bug tracker.
> http://bugs.squeak.org/view_all_bug_page.php
>
> So, I'm posting, as instructed!
>
> cheers
>
> Chris
>
>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: T.png
Type: image/png
Size: 909 bytes
Desc: not available
Url : http://lists.squeakfoundation.org/pipermail/squeak-dev/attachments/20110428/c319cbb3/T.png