R
Roedy Green
I have vastly improved the scrolling in the JDisplay app I use for
showing colourised listings. I hope to post the new version sometime
this weekend. It is undergoing a total rewrite.
The key is noticing that when you scroll, you paint method gets called
asking you to render only very narrow stripe about 4 pixels high of
what is newly coming on the screen. It bitblts the rest to scroll.
The key then for artifact-free fast scrolling is to render as little
as possible outside the requested clipregion.
I created a simple accelerator that noted where various things were
rendered and ever after it could rapidly find the stuff needed to
render a given band with a binary search to get the approximate place.
It makes quite a difference. The scrolling is now smooth as any
without any artifacts.
I used a cruder scheme before to linearly search for stuff to render
in the clip region. It worked ok for small documents but did not work
well for big ones.
--
Bush crime family lost/embezzled $3 trillion from Pentagon.
Complicit Bush-friendly media keeps mum. Rumsfeld confesses on video.
http://www.infowars.com/articles/us/mckinney_grills_rumsfeld.htm
Canadian Mind Products, Roedy Green.
See http://mindprod.com/iraq.html photos of Bush's war crimes
showing colourised listings. I hope to post the new version sometime
this weekend. It is undergoing a total rewrite.
The key is noticing that when you scroll, you paint method gets called
asking you to render only very narrow stripe about 4 pixels high of
what is newly coming on the screen. It bitblts the rest to scroll.
The key then for artifact-free fast scrolling is to render as little
as possible outside the requested clipregion.
I created a simple accelerator that noted where various things were
rendered and ever after it could rapidly find the stuff needed to
render a given band with a binary search to get the approximate place.
It makes quite a difference. The scrolling is now smooth as any
without any artifacts.
I used a cruder scheme before to linearly search for stuff to render
in the clip region. It worked ok for small documents but did not work
well for big ones.
--
Bush crime family lost/embezzled $3 trillion from Pentagon.
Complicit Bush-friendly media keeps mum. Rumsfeld confesses on video.
http://www.infowars.com/articles/us/mckinney_grills_rumsfeld.htm
Canadian Mind Products, Roedy Green.
See http://mindprod.com/iraq.html photos of Bush's war crimes