We should acknowledge that the test case is buggy anyway. It is not computing the scale of a transform correctly,
though that is likely due to the unfortunate naming we chose for our methods.
If you are looking for "the amount by which an X coordinate is stretched or contracted", you have to compute a distance
formula on all of the elements of the X transform equation. We don't have a method to do that for the caller. If we
did, we might call it something very similar to "getScaleX()".
Unfortunately, we have a method named "getScaleX()" which one might think does
that, but it doesn't.
While I think we should prevent a stack overflow here, it's really more of "making sure a program bug is caught early
and with a more sane response", than "fixing a valid test case".
Also, we should consider adding a method to do the right calculation, and document the existing getScaleX() to point out
that it cannot be used to determine "the stretchiness of X coordinates" or something more appropriately worded...
...jim
On 5/20/16 4:27 AM, prasanta sadhukhan wrote:
Hi Phil,
When we call print() it calls RasterPrinterJob#printPage() which sets
peekGraphics.transform([4.16,0,0][0,4.16,0]) as
obtained from xscale=4.16 [getXRes()=300 / 72.0] ,yscale=4.16
It calls SunGraphics2D.transform which was identity transform [1.0, 0.0, 0.0]
[0.0, 1.0, 0.0] calls
transform.concatenate(peekgraphicsTx) and stores as ([4.16,0,0][0,4.16,0])
Then RasterPrinterJob#printPage() again calls peekGraphics.transform(new
AffineTransform(page.getMatrix()));
where page.getMatrix() returns 0.0, -1.0, 1.0, 0.0, 0.0, 841.88 and
peekGraphics transform now becomes [0.0, 1.0, 0.0]
[-1.0, 0.0, 841.88]
which calls SunGraphics2D#transform() where it again does
transform.concatenate(peekgraphicsTx)
so the transform becomes [m00=0, m01=4.16, m02=0][m10=-4.16, m11=0,
m12=3507.873]
Now scaleX obtains value from g2d.getTransform().getScaleX() which returns
SunGraphics2D stored transform.m00 which is 0
and scaleY is m11=0 so scaleX,scaleY becomes 0.
Regards
Prasanta
On 5/19/2016 4:03 AM, Phil Race wrote:
It sounds like scalex & scaley are 0 and are then used in calculations which
results in the NaN ? So why are they zero to begin with ?
-phil.
On 5/16/2016 3:32 AM, prasanta sadhukhan wrote:
Hi All,
Please review a fix for jdk9 whereby it is seen that
A StackOverflowError occurs when printing in landscape orientation with a
scaled and transformed graphics object.
at sun.print.PSPrinterJob.prepDrawing(PSPrinterJob.java:1610)
at sun.print.PSPrinterJob.beginPath(PSPrinterJob.java:1319)
at sun.print.PSPrinterJob.convertToPSPath(PSPrinterJob.java:1793)
at sun.print.PSPrinterJob$GState.emitPSClip(PSPrinterJob.java:1718)
at sun.print.PSPrinterJob.prepDrawing(PSPrinterJob.java:1625)
at sun.print.PSPrinterJob.beginPath(PSPrinterJob.java:1319)
at sun.print.PSPrinterJob.convertToPSPath(PSPrinterJob.java:1793)
at sun.print.PSPrinterJob$GState.emitPSClip(PSPrinterJob.java:1718)
at sun.print.PSPrinterJob.prepDrawing(PSPrinterJob.java:1625)
Bug: https://bugs.openjdk.java.net/browse/JDK-6842011
webrev: http://cr.openjdk.java.net/~psadhukhan/6842011/webrev.00/
StackOverflowError is occuring because the scalex, scaley for landscape
orientation was 0 so when the testcase tries
to scale with these scale factors
using g2d.scale( 1 / scalex, 1 / scaley );
it creates a AffineTransform of NaN transformation. Now, In linux, when the PS
print drawing information is being
prepared, it calls prepDrawing() where it checks
getGState().mTransform.equals(mLastTransform) and since NaN values cannot be compared it
results in "false", causing
erroneous "grestore" postscript command to be issued and remove a GState from
the stack so isOuterGState() becomes
true which causes emitPSClip() to be called which calls
prepDrawing() again via convertToPSPath() , beginPath() and since
isOuterState() returns true due to transform not
being equal it again calls emitPSClip() causing a recursion.
The fix was to check if transform is NaN and do not fill the devicePath if it
is so, so that erroeous drawing is not
done.
So, it will print out a blank page.
In windows, the testcase prints out a blank page. In mac, the testcase prints a
2x2 rectangle.
Regards
Prasanta
