Grayscale works by changing pixels on and off repeatly. you see this as gray.
You can do grayscale this way:
ClrDraw(radians)     >next time, i use (r)
Pause 100   (to prevent the program fron shutting down immediately)
Repeat getKey
ClrDraw(r)
Pt-On(Xpos,Ypos,[FFFFFFFFFFFFFFFF
DispGraph(r)
End
This displays a grayscale square somewhere on the screen (put an X and Y position in)
You can do this for the whole image, but also for a part of it
If you want a part not being gray, simply don't put a (r) after the Pt-On

I hope that this short tutorial is useful for you.

How would I make the entire back buffer black?

Ok. And one last question. How would I draw the text I want to the back buffer, and have it remain black, as the rest is gray?

It shows the text as grayscale too.

Quick Grayscale Tutorial

3 level gray:
Three level grayscale is utilized by using the command DispGraph^r in place of the normal DispGraph command. Three level gray uses the backbuffer (L3) and the front buffer (L6). Everything on the back buffer will show as gray while everything on the front buffer will show as black. The front buffer is drawn over the back buffer, so if a pixel is "on" on both the front and back buffers, it will be shown as black.

You can change the common drawing operations Pt-On, Pt-Off, Pt-Change, Pxl-On, ClrDraw, Rect, Line, DrawInv, etc. to operate on the back buffer by adding the raidan ^r at the end of the command. For example, Pt-On(X,Y,Pic1)^r will draw Pic1 to the backbuffer. If you then look at it with DispGraph, you will see it in gray.

Text, by default is drawn directly to the screen and not to the buffer. For this reason, it can appear as grayscale because it is being erased every time you call DispGraph^r, and then redrawn very quickly. To make it so that text is drawn to the buffer, put a Fix 5 at the beginning of the program (and a Fix 4 at the end). To draw text to the back buffer, you will have to Exch the back and front buffers, write to the front buffer, and switch back:

Code: [Select]

Exch(L3,L6,768): Text(X,Y,"Text") : Exch(L3,L6,768)
4 level gray
With four level gray, the front buffer becomes somewhat transparent. Use the following table to figure out the pixel colors:

Code: [Select]

Front:Back:Color
0    :1   :Light Gray
0    :0   :White
1    :0   :Dark Gray
1    :1   :Black
Buffer operations remain the same. To display in four level gray, use DispGraph^rr

Note: In order for the grayscale to show up, you must put the DispGraph^r or DispGraph^rr in a loop. In monochrome, you can get away with this:

Code: [Select]

:Pt-On(X,Y,Pic1)
:DispGraph
:Repeat getKey
:EndBut with grayscale, you'll have to write the code like this:

Code: (displays Pic1 in dark gray) [Select]

:Pt-On(X,Y,Pic1)
:Repeat getKey
:DispGraph[sup]r[/sup][sup]r[/sup]
:End
edit: 1000 posts

Quote from: ACagliano on February 17, 2011, 11:41:37 am

It shows the text as grayscale too.

Code: [Select]

Rect(0,64,96,64)r
Text(0,0,"This is some black text")
DispGraphr
I tried this:

Code: [Select]

.IMG
Fix 5
Repeat getKey(15)
Rect(0,0,96,64)^r
Text(0,0,"Text
DispGraph^r
End
Fix 4
And I got grey background and in black, 'Text' at coordinates (0,0).

What Axe version are you using? Show me your code please.

I had it set Fix 4 at the beginning, that is why. It works now. Thanks.

Actually the worst thing that can happen is that when you view the mode menu you don't see anything the first time Or similarly if you view the Y= menu or any other menu that uses the small font.  It's so stable that I still haven't bothered putting a Fix 4 at the end of PortalX because I'm too lazy and I know that it won't cause any issues.  That said, it is a good idea for a final release, because people might think you messed up their mode screen or whatever.

It's actually kind of interesting with the lack of a fix 4
I remember playing super mario 2.0 and everything was weird
Also, omnicalc looked interesting...