[OpenJDK 2D-Dev] xrender-pipeline prototype/hack uploaded

Clemens Eisserer linuxhippy at gmail.com
Mon Jul 21 13:55:05 UTC 2008


This week I plan to start with a clean rewrite of the
xrender-pipeline, to factor out  the X11 and XRender specific parts
from the common code base as far as possible and do things the right
The current release is just a prototype/hack where I broke the
existing source, many things are done in a very  ugly or wrong way,
and my goal would be to clean this mess up.
Because of the limited time frame and my lack of prior experience with
Java2D I decided to hack something together instead of flooding the
list with my questions and to clean it up later.

I had problems uploading my code to the repository, as well as to the
java.net project  I created for this purpose (yes, I guess both times
my fault ;) ), so for now I uploaded it to an http-server:

It would be really helpful if you could grab the code and have a look
at it and tell me all the "don'ts" and how I could solve this or that
I also attached a list of questions, if you know maybe one or another
anwer, please let me know the answer :)

Thank you in advance, lg Clemens

1.) I've created a seperate struct to hold the per-surface xrender
data structures, similar to ShmPixmapData.
I initialize it in JX11SD_InitWindow for windows, because initSurface
where I do the xrender-initialization for pixmaps is not called for
Is there a better place to do it for windows, maybe unified for both
windows and pixmaps?

2.) For now I also leak xrender-resources, because
Java_sun_java2d_x11_X11SurfaceData_initOps is also called at
window-resize. Whaht should I do about this?
Should I store xrender-related data in the peers, like its done with
the window-handle?

3.) I am currently using lock/unlock/getrasinfo for MaskFill, is it
worth to write seperate upload-routines because of the overhead those
functions have (JNI calls, Locking, Xsync, ...)?

4.) In X11SD_InitWindow I've currently RGB24 hardcoded, but I guess
this assumption will be wrong once translucent windows are supported
by Java. How can I get the surfacetype of a window?

5.) Currently I set the color by passing SunGraphics2D.pixel down to
the native library, which premultiplies it. I guess this „hardcoded"
way of doing things is not really good.
Is the right way to install an appropriate ColorModel?
For premultiplied surfaces I need to specify a ColorSpace, which one
is the right for me?

6.) Is there a way to get force a BufferedImage to be cached?
For now texturepaints only work when the image has been drawn already,
otherwise its not cached any my pipeline can't handle this case.

7.) In X11PMBlitLoops/X11PMTransformedBlit/Transform I simply use the
inverted transformation on the source. However this means my drawing
area is from 0,0 ->bounds.x/bounds.y.
If I don't do it this way, e.g. the rotation point is moved.
Is there a way to translate the inverted transform, so that I don't
need to composite from 0,0?

8.) I am a bit puzzeled with the problem described at:
Is this a bug, or an unwelcome feature? Any ideas how I can work arround it?
I already do clipping the shape-outline however due to rounding errors
I either cut something away or get a black thin line.

9.) When scaling images e.g. only on the x-axis, the result is also
blurred and smeared over the y-axis.
(One of the screenshots is the wrong one, simply have a look for the
other images in the album of the right image)
Any ideas where this could come from, or how I could avoid it?
Setting RepeatPad helps a bit (at least Nimbus looks right), but seems
to fall back to software.

10.) Just from a quick look at
http://linuxhippy.blogspot.com/2008/07/nimbus_20.html, any ideas what
could cause this artifact?  It quite struggles me for some time ;)

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