| From: | Hynek Schlawack |
| Date: | 01 Jun 2000 at 11:24:00 |
| Subject: | Re: Graphics |
On 01-Jun-00 wrote Allan Odgaard:
>> That's exactly my problem! I have a algorithm for scaling pictures
>> but they have to be chunky...:-(
> Well, BitMapScale() (from graphics.library) can scale plain Amiga
> bitmaps or even chunky bitmaps, if the user uses P96 or CGX.
I suppose it will eat a lot of Chip RAM, right?
>> ...I suppose I can use WritePixelLine8()
> Yes, use that for chunky -> screen (screen might be chunky) unless
> you deal with high or true colour graphics. Here you should use the
Stands the 8 for eight bit?
> special functions of the cybergraphics.library, or just use
> BltBitMapRastPort(), assuming the bitmap is allocated and treated
> correctly...
What do you mean with allocated and treated correctly? Can
BltBitMapRastPort() also use chunky data? I definitly don't want to
use the cybergraphics.library as I have AGA and no PPC.
>> get it into the chunky format?
> Well, how do you obtain the image data? Most image formats are
> stored in chunky (or RGB) -- so normally the image is decoded and
> then *later* converted into planar (if necessary), i.e. *after*
> scaling etc.
Erhm, until now, I have only implemented the ILBM format and want to
get a little bit in Imageprocessing until I start to implement
others...
>> And...what is chunky exactly about?
> Each pixel is represented by a byte, this byte can have a value of
> 0-255 (or maybe 0-15) which is the index into the palette table.
And for truecolor pictures? I suppose that 255 pens ain't enough :-):
>> That's what I need too...I actually need more a planar2chunky than
>> chunky2planar. I'm really desperate as I don't know where to
> hmm... normally you should do all you can to avoid any explicit
> conversions. For example on graphic cards the data never needs to be
> in planar format (though ILBM is stored in planes, so here's an
> exception).
That's my problem...how to scale ILBM pictures...and the datatypes
library returns planar data too...but I heard I can use
ReadPixelLine8() for the planar->chunky conversion?
Regards,
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