Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!ames!amdcad!sun!pepper!cmcmanis
From: cmcmanis%pepper@Sun.COM (Chuck McManis)
Newsgroups: comp.sys.amiga.tech
Subject: Re: FastGraphics on Non-Intuition RastPort
Message-ID: <90124@sun.uucp>
Date: 16 Feb 89 20:27:00 GMT
References: <841@wpi.wpi.edu>
Sender: news@sun.uucp
Reply-To: cmcmanis@sun.UUCP (Chuck McManis)
Organization: Sun Microsystems, Mountain View
Lines: 53

In article <841@wpi.wpi.edu> pawn@wpi.wpi.edu (Kevin Goroway) writes:
> Does anyone know what the fastest way to put graphics on the screen is?
> I have a View/ViewPort/RastPort (no intuition stuff as far as screens/windows)
> and I want to put graphics on it quickly.  I tried DrawImage, which is an
> Intuition Function, and that bombed, even though I had the Image structure
> set up correctly, but I guess that's to be expected.  

I've used DrawImage successfully on Windows, Screens, and little tiny 
RastPorts I create to build image type gadgets. From a first reading
I would guess you may have done one or both of two things. 
	1) The RastPort you have isn't initialized properly, I'm not
		sure if you can initialize the bitmap pointer first
		and then call InitRastPort() or not, but for luck I
		always plug in the bitmap pointer after that step.

	2) You don't have intuition.library open and thus don't have
		IntuitionBase pointing at a valid library. Even if you
		don't "use" Intuition (although technically you are if
		you call DrawImage()) it costs _nothing_ to open it 
		in C programs. Your program neither increases in size
		nor slows in execution. It's "free".

A side comment about DrawImage(), I use it in my Life program to draw the
Cells (mostly because they look like small spheres rather than bits on a 
screen) And the neat thing about DrawImage() is that you can change a couple
of bits in the PlanePick/PlaneOnOff fields and change the colors of your
image while sharing the same image data. But that Plane stuff costs, 
specifially if you don't have the same number of image planes in your Image
that you have in your rastport. This is because DrawImage() seems to allocate
them for you on the fly so that it can use ClipBlit() or something similar
to copy them into your rastport. Anyway, my solution was to preallocate those
planes so that DrawImage wouldn't have to. 

>  I would Use ClipBlit but that coppies from one bitmap to another,
> which is no help if I can't get the graphic onto a bitmap in the first
> place!  As of now the image is stored as an intuition Image, should I
> change the format?  How would I go about writing it directly into the
> bitmap? Should the DrawImage function work even though I'm not using
> intuition, but have a RastPort?

Well, all of the graphics functions will work assuming you have the
graphics.library open. These include such things as Draw, Move, Flood,
AreaXXX, etc. All you need do is give them a pointer to a RastPort to 
talk to. Assuming you have the image data already (as your first comment
seems to indicate), a really workable solution is to build a BitMap 
structure that points at it, and then use BltBitMapRastPort() to 
blit it onto your view/viewport. BBMRP() is documented in the 1.2 autodocs
and the Enhancer manual I believe. Soon to be in the new version of the
A&W Rom Kernel manuals. 

--Chuck McManis
uucp: {anywhere}!sun!cmcmanis   BIX: cmcmanis  ARPAnet: cmcmanis@sun.com
These opinions are my own and no one elses, but you knew that didn't you.