| From: | |
| Date: | 16 Feb 2001 at 01:07:20 |
| Subject: | Re: Again clipping graphics output |
Hello Sensei
On 15-Feb-01, you wrote:
S>> I've tried to clip graphics output to the rastport with
S>> layers.library help. This works perfectly on AGA, but seems
S>> to cause problems under CGX and Picasso96 on graphics boards.
S> Could you precise what is going on under CGFX and P96? I used this method
Sorry, but I do not own a GFX board. My testers wrote me about this.
All of them wrote that the cursor became "jerky".
S> (or hmmm, I was forced to use it by AmigaOS...) in my BOOPSI scale.gadget
S> and it works fine everywhere... Maybe working example source code will
S> help us a bit... ?
The problem is, that a project is rather big and the source is
messy, so I think it is a bad idea. I could describe the procedure.
I draw a lot of realy changed graphics to a "Shadow Layer", which
is made from a custom bitmap, and then blit the data to the
"Workspace Layer", also made from a custom bitmap. Then I draw a
bit more graphics in it, and finally blit the result to my windows
rastport.
S>> Is there any ability to do the same without layers.library?
S> Yes. You can calculate coordinates so they will fit into bitmap... It
S> could be a problem if you would like to use, for instance, Text()
S> function...
This problem stops me from using this method.
S> Instead calculating coordinates you could allocate bitmap with enought
S> size to hold whole image (you must calculate exactly how big will be this
S> image, if you make mistake of 1 pixel computer will crash...), render to
S> it and blit from this bitmap to destination rastport. This is a more
S> memory consuming method...
The problem in this case is, that I do not know, and can't
calculate the size of future graphics.
Regards
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