Thanks for the reply.
Ok, so here is our theory:
1) Using the SVG view box and the scale factor, figure how many tiles
(at say 100 X 100) will fit into the image.
2) Create a JSVGComponent (workingComp) and set the preferred size to be
the size of our tiles (100 X 100)
3) Set the rendering transform of workingComp to have the scale factor
we want
---
In our paint method for our JComponent (myComp), we will paint the tiles
that are visible in our scrollpane.
For each visible tile
4) translate the rendering transform so that the part of the
tile we want is on the workingComp
5) Draw this to a buffered image and keep it.
6) repaint this tile on myComp
Does this sound OK? Are there any obvious pitfalls or performance
issues that might make this not a practical solution?
Mark
> -----Original Message-----
> From: Thomas DeWeese [mailto:[EMAIL PROTECTED]
> Sent: Friday, August 08, 2003 6:29 PM
> To: Batik Users
> Subject: Re: Lazy rendering and zoom
>
>
> Mark Claassen wrote:
> > Thanks for the reply.
> >
> > As it turns out, we are using a static document already. We went
> > ahead and actually set the state to be static, but we still get the
> > memory problem if we zoom enough. (It seems that we are
> now able to
> > zoom a bit more, although this may just be a coincidence.)
> From your
> > description, we thought it was futile to override the
> > createImageRenderer method as this point.
> >
> > It seems to me that if the tiles are rendered lazily, we could zoom
> > indefinitely and use a relatively constant amount of
> memory. Also, we
> > have never noticed the document being painted as we scroll. If the
> > tiles truley were rendered lazily, I would except to see this.
> >
> > Maybe we are just doing something wrong. We weren't quite
> sure how to
> > get the zoom we wanted using the API directly, so we resize
> the canvas
> > to zoom. To zoom 2X, we:
> >
> > Dimension d = canvas.getSize();
> > d.width = d.width * 2;
> > d.height = d. height * 2;
> > canvas.setPreferredSize(d)
> > canvas.revalidate();
> >
> > Is there a better way?
>
> Yes change the rendering transform, take a look at
> Zoom(In|Out)?Action in JSVGCanvas.java you are actually
> doubling the size of the 'visible' canvas so it creates an
> offscreen that size.
>
>
>
>
> >
> >>-----Original Message-----
> >>From: Thomas DeWeese [mailto:[EMAIL PROTECTED]
> >>Sent: Friday, August 08, 2003 12:10 PM
> >>To: Batik Users
> >>Subject: Re: Lazy rendering and zoom
> >>
> >>
> >>Mark Claassen wrote:
> >>
> >>>I noticed there is a setProgressivePaint(boolean) method in
> >>>JGVTComponent. This seems to display items on the canvas
> >>
> >>as they are
> >>
> >>>rendered, and not just display the whole document at once.
> >>>
> >>>What I was wondering was if there is an option that goes a step
> >>>further, and would restrict rendering to just viewable
> >>
> >>area. This is
> >>
> >>>a common thing in Swing, where, for instance, the rows of a
> >>
> >>table that
> >>
> >>>are not currently visible in a JScrollPane are never rendered.
> >>>
> >>>The default zooming behaviour in Batik seems to render a portion of
> >>>the document while not changing the canvas size. We would like to
> >>>change the canvas size, so that the we can pan to see any
> >>
> >>part of the
> >>
> >>>document we need simply by moving the scrollbars.
> >>
> >>Unfortunately, this
> >>
> >>>causes OutOfMemory errors when the zoom factor gets large.
> >>>
> >>>I know we can increase the JVM heap size, but this can only
> >>
> >>go so far.
> >>
> >>>What I was hoping for was something in the JSVGCanvas that
> >>
> >>would draw
> >>
> >>>just a portion of the document on the canvas, and then when
> >>
> >>a scroll
> >>
> >>>occurred, it would noticed that this area had not been rendered and
> >>>draw that. One could even go so far as to anticipate the
> >>
> >>loading of
> >>
> >>>sections and use SortReferences to hold now longer visible
> sections.
> >>>
> >>>Is there anything like this, or any plans to include something like
> >>>this?
> >>
> >>Hi Mark,
> >>
> >> This is already done for Static Documents. The Static Renderer
> >>keeps a tiled view of the image and when translates happen it tries
> >>to populate the new view from the stored tiles. This is generally
> >>not done for dynamic documents as maintaining the tile store is
> >>expensive for many small changes (the system would widens rendering
> >>requests to tile
> >>boundries) also there were a few bugs in what I will call odd
> >>cases (the size/location of the root SVG changing). However
> >>depending on your context this still might be a win for your
> >>case. It is pretty easy to change this by overiding the
> >>following method in batik.swing.svg.JSVGComponent:
> >>
> >> protected ImageRenderer createImageRenderer() {
> >> if (isDynamicDocument) {
> >> return rendererFactory.createDynamicImageRenderer();
> >> } else {
> >> return rendererFactory.createStaticImageRenderer();
> >> }
> >> }
> >>
> >> So it always returns a static ImageRenderer.
> >>
> >>
> >>
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> >
> >
> >
> >
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>
>
>
>
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