pds@quintus.UUCP (Peter Schachte) (03/12/88)
I'm trying to create multiple rastports that write on the same bitmap. I also want each rastport to think of the upper left corner of the part of the bitmap that it can write into as 0,0 (i.e., I'd like the system to do translation for me). I looked around in the RKM (vol 1) and couldn't see how to do it. Could someone point me to the right section, or give me a code fragment? BTW, I'm using this to write into a window, if that makes it easier (or harder). I assume I can just grab the bitmap from the window and build a few rastport and rasinfo structures to do this, but can't figure out how. Thanks in advance. (PS: I tried to send this to comp.sys.amiga.tech, but we don't get it, so I can't post there. I hope technical discussions continue to be crossposted at least until the situation gets clarified.) -- -Peter Schachte pds@quintus.uucp ...!sun!quintus!pds
jimm@amiga.UUCP (Jim Mackraz) (03/15/88)
-- Well, "you're close, you're real close," to paraphrase the psycho with the grenade launcher in Apocalypse Now. You can set up a several "pure" rastports to draw with different offsets into the self-same raster (bitplanes). It is, however, done at the bitmap level. Keeping the BytesPerRows and Rows fields the same (well, maybe not Rows), you can vary the Planes[] addresses and get *something* useful. Problem is, a Window's rastport has a Layer hanging off of it. To do the similar vudu, you need to set up different Layers (which is not at all easy; perhaps never been done). There are some parameters Scroll_X and Scroll_Y which probably apply. It's getting too hard for me, but feel free to pioneer. I think it would be lots easier to put a layer between yourself and graphics that adds a few offsets to each drawing command. E.g.: MyBltBitMapRastPort( ) and so on. Maybe if you figure out a layers trick you can talk at the 1989 Developers' Conference. ;^) jimm -- Jim Mackraz, I and I Computing amiga!jimm BIX:jmackraz Opinions are my own. Comments regarding the Amiga operating system, and all others, are NOT to be taken as Commodore official policy.