Glad you got it working. FYI here's a good explanation of using the dot product to compute angles:
http://en.wikipedia.org/wiki/Dot_product#Geometric_interpretation On Jan 24, 2008 10:02 AM, Bishop, Michael W. CONTR J9C880 < [EMAIL PROTECTED]> wrote: > Yeah, if I switch my "getRotationAngle" method with yours in my main > application, everything works itself out. This bug's probably been in > my code for a long time; I just never noticed it until I started > smoothly rotating objects on the canvas as opposed to applying a single > rotation angle. > > Thanks for checking that out. > > Michael Bishop > > > -----Original Message----- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > > On Behalf Of Archie Cobbs > > Sent: Wednesday, January 23, 2008 5:16 PM > > To: batik-users@xmlgraphics.apache.org > > Subject: Re: Rendering bug with transforms? > > > > Something is wrong with your logic that computes the angles. > > The reason you are not seeing it with rectangles and circles > > is because they have 180 degree rotational symmetry. > > > > Apply the attached patch to your code to see what the real > > angle is you are rotating by, which bounces around during > > part of the rotation. > > > > Don't know what the exact problem is but you can probably > > figure it out from here... > > > > -Archie > > > > > > On Jan 23, 2008 3:29 PM, Bishop, Michael W. CONTR J9C880 < > > [EMAIL PROTECTED] > > <mailto:[EMAIL PROTECTED]> > wrote: > > > > > > I got snapshots from the original, rotated (flipped) > > and rotated > > (correct) DOMs. Since the transform is in matrix form, > > it's hard to > > discern anything save the fact that all three are > > different. I loaded > > each snapshot in Squiggle; they looked the same as they do in my > > application. > > > > I was able to create a test class that can showcase > > this behavior. It's > > not a specific SVG; it's an application that rotates a > > rect element, > > degree-by-degree a full 360 degrees on a JSVGCanvas > > successfully. Then > > it does the same with a text element and the errors > > occur between 90 and > > 270. > > > > I'll attach the class for those curious; it's a single > > file that just > > needs Batik on the classpath: > > mil.jfcom.cie.whiteboard.TestElementTransform > > > > I guess I should also file a bug unless someone finds > > something wrong > > with the attached code. > > > > > > Michael Bishop > > > > > -----Original Message----- > > > From: [EMAIL PROTECTED] > > <mailto:[EMAIL PROTECTED]> [mailto:[EMAIL PROTECTED] > > > On Behalf Of Archie Cobbs > > > > > Sent: Wednesday, January 23, 2008 2:52 PM > > > To: batik-users@xmlgraphics.apache.org > > > Subject: Re: Rendering bug with transforms? > > > > > > > > I would be interesting to "snapshot" your DOM after the > > > unexpected flip occurs then: > > > > > > - Save it to a file. > > > - Verify relaunching squiggle on the file still shows > > item flipped. > > > - Do analysis to determine whether matrix is incorrect (your > > > bug) or batik is mis-reading it (batik bug). > > > - If Batik is mis-reading matrix, create Bugzilla issue > > > containing simplified counterexample SVG file. > > > > > > One possibility is your computation is broken around the > > > "corner cases" of 90 and 270 degress. Continuous reading and > > > updating of the matrix makes these corner cases more likely > > > to be hit. > > > > > > > > > On Jan 23, 2008 1:36 PM, Bishop, Michael W. CONTR J9C880 > > > <[EMAIL PROTECTED]> wrote: > > > > > > > > > OK, the slider basically reports a degree from 0 to > > > 359. I have a > > > ChangeListener attached that updates the "transform" > > > attribute of the > > > selected element. > > > > > > So what essentially happens: > > > > > > - Retrieve the "transform" (I use the matrix only) > > > attribute as an > > > AffineTransform. > > > - Revert the current rotation angle on the > > AffineTransform. > > > - Apply the new rotation angle to the AffineTransform. > > > - Convert the AffineTransform to a "transform" > > attribute. > > > - Apply the new "transform" attribute to the > > element on the > > > UpdateManager. > > > > > > I don't think static rotation covers it. My old > > > rotation technique was > > > a plain JSlider that would only update the element > > > after the change > > > occurs. This never fails. It only seems to happen > > > when the document is > > > continuously updated as the slider is moving. Another > > > interesting fact > > > is that sometimes an element STAYS flipped; > > when I get back to 0 > > > degrees, I see that a text element might be upside-down. > > > > > > If this behavior was consistant across all elements, > > > I'd be more apt to > > > dig through my code. It only seems to happen with > > > certain elements. > > > Maybe I can write a test case that will draw an element > > > to a canvas, > > > then rotate it through 360 degrees with a for loop. > > > > > > Michael Bishop > > > > > > > > > > -----Original Message----- > > > > From: [EMAIL PROTECTED] [mailto: > > > > > [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> ] > > > > On Behalf Of Archie Cobbs > > > > Sent: Wednesday, January 23, 2008 1:41 PM > > > > To: batik-users@xmlgraphics.apache.org > > > > Subject: Re: Rendering bug with transforms? > > > > > > > > What is your slider actually doing? > > > > > > > > If it's just updating the "transform" > > attribute of a DOM > > > > element, in theory you should be able to > > produce a static > > > > document containing a polygon rotated e.g. > > 120 degrees that > > > > squiggle renders upside down. > > > > > > > > I.e., what's the simplest document or program > > that reproduces > > > > incorrect rendering? I'm sure something > > obvious like an > > > > upside down rotation would be fixed pretty quickly. > > > > > > > > On the other hand, it could be your logic. > > How exactly does a > > > > circular slider position turn into SVG attributes? > > > > > > > > > > > > On Jan 23, 2008 12:31 PM, Bishop, Michael W. > > CONTR J9C880 > > > > < [EMAIL PROTECTED] > > <mailto:[EMAIL PROTECTED]> > wrote: > > > > > > > > > > > > Hello, > > > > I've come across a pretty odd > > problem with Batik. > > > > I'm using the > > > > 1.7 release version. For my application, I've > > > > developed a "circle > > > > slider" which is pretty much a Jslider > > that goes in a > > > > circle. I use it > > > > to rotate elements from 0 degrees to > > 360 degrees. As I > > > > move the slider, > > > > the shape on the JSVGCanvas changes. This works > > > > perfectly for circle, > > > > ellipse, line, and rect elements. On > > other elements > > > > (polygon, polyline, > > > > path, text), the element is rapidly > > flipped 180 degrees > > > > ONLY when the > > > > circle slider is between 90 and 270 degrees. > > > > So I get a smooth rotation from 0 to 90. > > > From 90 to 270 the > > > > element gets flipped upside-down over > > and over again, > > > > oscillating back > > > > and forth. From 270 to 360 (0), I get > > smooth rotation > > > > again. The > > > > reason I think it's Batik is because it > > doesn't occur > > > > with every element > > > > and my application is reporting the > > correct number of > > > > degrees. I think > > > > it's odd that it only happens witin > > that certain range. > > > > Has anyone > > > > experienced this? > > > > > > > > Michael Bishop > > > > > > > > > > > > > > > > > --------------------------------------------------------------------- > > > > To unsubscribe, e-mail: > > > > [EMAIL PROTECTED] > > > > > <mailto: > > [EMAIL PROTECTED] > > <mailto:[EMAIL PROTECTED]> > > > > > > > For additional commands, e-mail: > > > > [EMAIL PROTECTED] > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > Archie L. Cobbs > > > > > > > > > > > > > > > > > > > --------------------------------------------------------------------- > > > To unsubscribe, e-mail: > > > [EMAIL PROTECTED] > > > > > <mailto:[EMAIL PROTECTED]> > > > > > For additional commands, e-mail: > > > [EMAIL PROTECTED] > > > > > > > > > > > > > > > > > > > > > -- > > > Archie L. Cobbs > > > > > > > > > > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: > > [EMAIL PROTECTED] > > For additional commands, e-mail: > > [EMAIL PROTECTED] > > > > > > > > > > > > -- > > Archie L. Cobbs > > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > -- Archie L. Cobbs
