on 22/5/01 7:38 PM, Dominique at [EMAIL PROTECTED] wrote:
> Geoff Canyon ecrivait / wrote:
>
>> I think of Bic pens. What the heck _does_ it stand for?
>
> Black Is Changed
>
Following summary adapted from Apple's QuickDraw documentation:
Action on destination pixel
If source pixel If source pixel
Source mode is black is white
----------- --------------- ---------------
srcCopy Force black Force white
notSrcCopy Force white Force black
srcOr Force black Leave alone
notSrcOr Leave alone Force black
srcXor Invert Leave alone
notSrcXor Leave alone Invert
srcBic Force white Leave alone
notSrcBic Leave alone Force white
The COPY operation (srcCopy) completely replaces the pixels in the
destination bitmap with the pixels in the source bitmap. The
inverse COPY operation (notSrcCopy) completely replaces the pixels
in the destination bitmap with a "photographic negative" of the
source bitmap.
The OR operation (srcOr) adds the black pixels from the source
bitmap to the destination bitmap. The inverse OR operation
(notSrcOr) takes a "photographic negative" of the source bitmap,
and then adds the black pixels from this negative to the
destination bitmap.
The XOR operation (srcXor) inverts the pixels in the destination
bitmap that correspond to black pixels in the source bitmap. The
inverse XOR operation (notSrcXor) inverts the pixels in the
destination bitmap that correspond to white pixels in the source
bitmap.
The BIC operations (srcBic modes) turns pixels in the destination
bitmap white when they correspond to black pixels in the source
bitmap. The inverse BIC operation (notSrcBic) turns pixels in the
destination bitmap white when they correspond to white pixels in
the source bitmap.
NB: these are the modes as they apply to black-and-white source and
destination. For colour, things are a little more complex - and the
interpration less consistent between platforms. See Apple's documentation
at
http://developer.apple.com/techpubs/mac/QuickDraw/QuickDraw-199.html#HEADING
199-76
and for the 'arithmetic transfer modes' (including "blend" and
"transparent")
http://developer.apple.com/techpubs/mac/QuickDraw/QuickDraw-199.html#MARKER-
9-141
I have to say that I agree with Andu: for some things you have to learn
about the domain and the concepts, and there are names that go with those
concepts. I know nothing about music; if I want MetaCard to play some notes
(can it? let say HyperCard), I imagine I'm going to have learn about some
new concepts, and the names associated with them.
Ben Rubinstein | Email: [EMAIL PROTECTED]
Cognitive Applications Ltd | Phone: +44 (0)1273-821600
http://www.cogapp.com | Fax : +44 (0)1273-728866
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