Hi Sergey,
The getClip methods don't claim to return the exact same shape that the
user handed in - it just has to cover the territory covered by the clip.
x,y,-N,-M covers the same territory as x,y,0,0 so it would be fine to
substitute that value in its place. It is arguable whether it matters
if we convert x,y,+N,-M to x,y,+N,0 or x,y,0,0 since both rectangles
cover no ground. Also, preserving the x,y is questionable since any
0-dimensioned rectangle covers no ground and is equally representative
of the fact that the clip is empty.
There isn't even any guarantee that we will hand them back a rectangle
from getClip(). After all, if you end up in the drop through case then
we hand the paths to Area to do intersections and Area will do all sorts
of surgery on the geometry. We could hand them back a hard-coded "I'm
an empty shape" object that isn't any class that they'd recognize and
would return 0,0,0,0 for bounds and a singleton iterator that
immediately claims "isDone()==true".
If it passes tests (meaning our clever optimizations in the
transform/untransform helper methods don't unravel it incorrectly) then
I think simply replacing any negative dimensions with zeros would be the
least surprising result. I'm not sure what value there is in attempting
to return a rectangle that conveys the "same negative dimensions"...
...jim
On 12/20/2012 3:35 PM, Sergey Bylokhov wrote:
21.12.2012 3:26, Sergey Bylokhov пишет:
Hi, Jim.
21.12.2012 1:42, Jim Graham wrote:
Hi Sergey,
Avoiding the transform only works if they read it back in the same
coordinate system that they set it. It will fail if they do:
setClip or clip(...);
scale(5, 5);
getClip();
So, given that we have to deal with the transform/untransform issues
anyway then a user-space clip caching solution isn't going to solve
the immediate problem for all cases.
Yes, right, second solution does not work in this case.
I'd have to look closely at the code to know for sure, but I imagine
that it would be easy enough to ensure that the [un]transform methods
always turn a rectangle with 0 dimensions into another rectangle with
0 dimensions (whether one or both are 0).
Well, I expect that solution from the webrev does this, isn't it?
Approach is simple if we have correct clip from the user, we always
get correct clip after transformation, and vice versa.
The setFFD normalization only hurts us when we have negative
dimensions, but it should be OK with 0 dimensions, no? So, if we
normalize negative dimensions to 0 going in then it might be safe?
Do you mean just change Rectangle(0,0,-100,-100) to (100,100,0,0)?
I just realise that (100,100,0,0) is incorrect here. So the question
more general: Do you mean just change Rectangle(0,0,-100,-100) to ..
"what"?
How we can revert back this operation?
...jim
On 12/20/2012 9:52 AM, Sergey Bylokhov wrote:
20.12.2012 14:12, Sergey Bylokhov пишет:
20.12.2012 13:49, Jim Graham wrote:
More to the point, if you substitute a 0x0 clip when an incoming clip
is an empty rectangle then it will always be empty under any kind of
transform. This could be done by performing a "max(w,0);max(h,0);"
operation on the incoming data. Once a clip is accepted as
non-empty, then I think the current code will adequately deal with
flipped transforms, won't it?
Yes, but with one exception. What to do with getClip:untransformShape
methods in this case, it executes the reverse transformation.
The question is: if the incoming clip is an empty how to store it? If
we did not transform incoming clip, we should change
getClip/clip/untransformShape + some flag which should indicate that
incoming clip(not a result of transformation) was empty.
Another solution: don't use transformShape/untransformShape in the
set/get methods. store usrClip as is, and transform usrClip->usrClipTmp
in validateCompClip().
In this case setters/getters will become much simpler.
...jim
On 12/19/2012 8:47 PM, Jim Graham wrote:
Hi Sergey,
This is all a lot more complicated than I think it needs to be.
Why not
just detect incoming empty rectangles and force an empty
composite clip
in that case? No heuristics necessary...
...jim
On 12/15/2012 9:26 AM, Sergey Bylokhov wrote:
Hi, Jim.
Could you please review the updated version of the fix:
http://cr.openjdk.java.net/~serb/8004859/webrev.01
14.12.2012 0:40, Jim Graham wrote:
This fix breaks other behavior.
You need to use setFrameFromDiagonal on the results of the
transform
because a flip or rotation can cause the transformed points to be
unordered and setFFD will sort them as they need to be. It is the
incoming rectangle that needs to be checked for being empty,
not the
results of the transform.
In the new version I restore coordinates relation, if it were
changed
during transform.
Swap needed:
- If the user provide incorrect rectangle and after
transformation we
get correct rectangle.
- If the user provide correct rectangle and after
transformation we
get incorrect rectangle.
The case that will fail with this fix is setting the clip to a
valid
rectangle in a coordinate system that is rotated by a multiple
of 90
degrees or is flipped horizontally or vertically. Those cases will
result in an empty clip, but the clip was not empty coming in...
...jim
On 12/13/2012 3:08 AM, Sergey Bylokhov wrote:
Hello,
Please review the fix for jdk 8.
Change description:
1 transformShape now symmetric to untransformShape()
(setFrameFromDiagonal was removed).
2 getClipBounds now always uses getBounds2D which does not return
empty
Rectangle if the userclip has negative width or height.
Note that if the userclip has negative width or height, our real
graphic
clip will be empty/no-area. This wasn't true before the fix
for the
scaled graphics.
Bug: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8004859
Webrev can be found at:
http://cr.openjdk.java.net/~serb/8004859/webrev.00
