[OpenJDK 2D-Dev] X11 uniform scaled wide lines and dashed lines; STROKE_CONTROL in Pisces

[Jim Graham]

Hi Denis,

I took a little break from code reviewing to write up this concept which 
might help simplify the PolyIOHelper stuff in your code (later).  My 
concept was that the attached "transforming PathConsumer" classes would 
be potentially more efficient than putting the coordinates into a buffer 
and then calling a method on AffineTransform.  With the PolyIOHelper 
stuff we have the following flow:

     src calls pc.fooTo()
     pc calls io.readFoo()
     io stores to buffer
     conditionally:
         io calls at.transform()
         at loads values
         at computes values
         at stores values

With these classes, if there is a transform:

     src calls tpc.fooTo(x,y)
     tpc computes values
     tpc calls pc.fooTo(x',y')
     pc stores to buffer as needed

And if the transform was null or identity:

     src calls pc.fooTo()
     pc stores to buffer as needed

And something similar on the output.  The buffering is then entirely at 
the discretion of the eventual consumer (Dasher/Stroker) and the 
information flow is more direct whether or not there is a transform.

There are optimal "TPC" implementations of translate, scale+translate, 
and full transform.  AT further optimizes the cases of scale without 
translate and shears without scales (and/or translates), but I don't 
think those cases happen often enough to worry about spending too much 
to optimize, especially since these classes already win by inlining the 
transform calculations...?

Note that these compile, but I haven't tested them (the implementation 
was pretty straightforward, though)...

			...jim
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: TransformingPathConsumer2D.java
URL: <http://mail.openjdk.java.net/pipermail/2d-dev/attachments/20101013/5978e0c8/TransformingPathConsumer2D.java>