Displaying Java objects on top of JSVGCanvas objects

[Wilkins, Rob]

I've inherited a Java GUI that uses the JSVGCanvas object (through a derived class) inside a JScrollPane. Objects which are derived from JComponent are then added to the JSVGCanvas object using the JSVGCanvas.add() method.   The user can zoom in and out of the SVG. This is implemented by a mouse event handler on the JSVGCanvas derived class which calls JSVGCanvas.getRenderingTransform(), manipulates the AffineTransform then applies it by calling JSVGCanvas.setRenderingTransform().   The objects placed on top of the JSVGCanvas (via calls to add()) are then scaled using the same transform via a code in the gvtRenderingCompleted() event handler (although this code has also been called from gvtRenderingStarted() and also in the mouse handler (where the transform is being manipulated) during attempts to fix the problems we are encountering).   The code all worked in Batik v1.1.1 and as the user zoomed in and out of the SVG the objects on top were also scaled to keep them synchronised with the SVG.   However when we moved to Batik v1.5 (in an effort to reduce the amount of memory that appeared to be leaked when loading new SVGs and zooming them) we noticed that the SVG and the objects were no longer being synchronised when the SVG was being manipulated. After a bit of investigation it appears that the scaling of the objects is causing the SVG to be re-rendered such that the following appears to be happening:   Render the SVG at the new scale. Render the objects at the new scale. Render the SVG at the new scale again.   This also happened in Batik v1.1.1, however the difference between the two versions appears to be that when the above sequence occurs in v1.1.1 the two renderings of the SVG occur at the same scale (say 1.25 times the original). However when this is executed in v1.5 the SVG is first rendered at a scale of 1.25 then at a scale of (1.25 * 1.25). The objects and the SVG are therefore being rendered at different scales (1.25 and 1.25^2) respectively. This can be further shown by setting the scale to 1 which allows the objects and the SVG to be rendered at the same scale since 1^2=1.   Our ideal solution would be to prevent the re-rendering of the SVG (which we presume is being triggered by the rendering of the objects on top of it). However if we should be drawing the objects using some other mechanism we would like to know how to do this. I looked through the archives of this group and I get the impression that I should be rendering all the objects using some form of overlay object. However the objects have context menus and the user can interact with them to move them and resize them so I would need to be able to provide this type of functionality using the alternative object rendering solution if one is suggested.   I've tried some of the methods on JSVGCanvas that would appear to disable it/enable it around the calls to scale the objects but the above sequence still appear to occur.   Thanks in advance,   Rob     ------------------------------------------------------------------- Rob Wilkins, Tandberg Television,  Control & Management Software, Strategic Park, Comines Way, Hedge End, Southampton, Hampshire, SO30 4DA.   Tel: (023) 8057 3116 (Int. Ex 3116) Fax: (023)  8057 3341 E-Mail:  [EMAIL PROTECTED]   *********************************************************************************** This email, its content and any attachments is PRIVATE AND CONFIDENTIAL to TANDBERG Television. If received in error please notify the sender and destroy the original message and attachments. www.tandbergtv.com ***********************************************************************************