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Forums > C64 Coding > Text (screen) box drawing algorithm

2003-02-13 13:57

Dr. Jay
Account closed

Registered: Jan 2003
Posts: 32

Text (screen) box drawing algorithm

Anyone have a nice, fast box drawing algorithm for the screen? What I'm trying to do is make a sort of kaleidoscope representation of data.

Let's say I have this sequence: XYXZZ

Then on the screen I would want to render (centered):

ZZZZZZZZZZ
ZZZZZZZZZZ
ZZXXXXXXZZ
ZZXYYYYXZZ
ZZXYXXYXZZ
ZZXYYYYXZZ
ZZXXXXXXZZ
ZZZZZZZZZZ
ZZZZZZZZZZ

I'm assuming I can do it with some mirrorored line-drawing, etc, but I feel like I'm overcomplicating the code. I know how to draw a line, what I'm more interested in is the algorithm to map the sequence to the individual boxes.

Thanks,

Jay

2003-02-13 19:33

WVL

Registered: Mar 2002
Posts: 903

why not RLE encode the data?

so put the data like this in your code :

16 01 02 02 -> 16 times y, then 2 times x etc..

also put in a code for enter/return and just output the data with chrout or something...

Werns

2003-02-13 19:44

Dr. Jay
Account closed

Registered: Jan 2003
Posts: 32

I actually figured it out .. pretty stupid. I'm getting used to it. I just defined the upper left corner. I have a 24 x 24 grid which is really a 12 x 12 quad mirrored over each corner. So by definining the upper left corner, I simply increment in steps of 41 until I hit the middle, then draw the top, bottom, left, and right lines simultaneously - the top, bottom can use an index and the left, right use addition.

Jeremy

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