Magic Finger wrote:
I've put some simple checkpoints to the different methods called by
SVGGraphics2D.stream(...) and saw that the methods for writing out the xml
entity *attributes* (writeXml(Attr attr, IndentWriter out) and
writeChildrenXml(Attr attr, IndentWriter out) inside class
org.apache.batik.svggen.XmlWriter) are called very often and slow down the
file writing process mostly.
Well it isn't surprising that the part of the code that writes
most of the output takes most of the time, but looking at the code
it is possible that it could be sped up.
In particular if the writeChildrenXML call was rewritten so
it got a 'char []' from the string and instead of calling
'write(c)' it collected runs of unsubsititued chars and called
'write(chars, start, len)' this might significantly reduce the
overhead. You could also look at alternatives to the 'switch'
so a clever set of 'if' constructs might be quicker in the most
common cases. I know that for C/C++ this is seldom the case.
In my case the xml attributes are the x,y coordinates and the stroke-info
for a 2d line:
<line fill="none" x1="273.5316" x2="231.6523" y1="665.7648" y2="327.1585"
stroke="black" stroke-width="2" />
And I have to store very often more than 20.000 lines.
So I have to wonder a little at this. You might consider
using a 'path' element. If your lines are often 'connected'
(i.e. x2,y2 of one line === x1,y1 of the next) this would
almost certainly be better all around, smaller file, faster
read/write and probably faster render.
If you are using SVGGraphics2D for everything you would
need to use 'java.awt.geom.GeneralPath'.
Best regards,
Maik
----- Original Message -----
From: "Thomas DeWeese" <[EMAIL PROTECTED]>
To: "Batik Users" <[EMAIL PROTECTED]>
Sent: Wednesday, February 11, 2004 11:06 PM
Subject: Re: storing SVG DOM tree contents to a file by method
org.apache.batik.svggen.SVGGraphics2D.stream(...) very slow !
Magic Finger wrote:
Thanks for your help Bibek, but unfortunately no elements were written
out
to SVG file when replacing in my code shown below the statement
This is one of the more common mistakes with the SVGGraphics2D,
the factory document is used as just that - a factory. It does not
append the elements to that document. If you want the document
tree from the SVGGraphics2D you need to use 'getRoot'. Note that this
'clears' the SVGGraphics2D so if you are 'check pointing' the work
you need to store the element returned (not that I think this applies
here).
BTW I don't think it will be much faster. If you are really
concerned about performance you should run a profiler on the code
and see what pops out. Could be simple stuff like not using
StringBuffer where we should, but who knows without profiling you
are generally just "shooting in the dark".
svgGenerator.stream(out, useCSS);
by your alternative suggestion
DOMUtilities.writeDocument(myFactory, out);
It seems that 'myFactory' (which is an instance of org.w3c.dom.Document)
contains no Node elements -- very strange !?
Best regards,
Maik
----- Original Message -----
From: "Bibek Sahu" <[EMAIL PROTECTED]>
To: "Batik Users" <[EMAIL PROTECTED]>
Sent: Friday, February 06, 2004 4:23 PM
Subject: Re: storing SVG DOM tree contents to a file by method
org.apache.batik.svggen.SVGGraphics2D.stream(...) very slow !
Another way is to use
org.apache.batik.dom.util.DOMUtilities.writeDocument(org.w3c.dom.Document
doc, java.io.Writer w)
Don't know whether it's faster or not, but it's worth a shot. It works
pretty well for me, but my SVGs are smaller than yours...
Good luck!
- Bibek
On Fri, 6 Feb 2004, Magic Finger wrote:
Hello,
I have serious performance problems when writing out the SVG DOM tree
by
the
Batik SVG-Generator method
org.apache.batik.svggen.SVGGraphics2D.stream(...).
Writing out ~ 20.000 lines to a SVG file by method
SVGGraphics2D.stream(...)
with BufferedWriter takes ~3 minutes -- that's unbelievable slow.
The resulting size of the SVG file is ~1.3 MB.
Does anybody can tell me how to accelerate file writing, or is it just
a
normal, poor behaviour of Batik's internal SVGGraphics2D.XmlWriter ?
And any idea how to give a "I am working..." feedback to users while
streaming out the DOM tree contents to an SVG file, e.g. by showing a
progressbar ?
The DOM tree contents are just lines and the resulting SVG file looks
like
this:
--------------------------------------------------------------------------
<?xml version="1.0"?>
<!DOCTYPE svg PUBLIC '-//W3C//DTD SVG 1.0//EN'
'http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd'>
<svg fill-opacity="1" xmlns:xlink="http://www.w3.org/1999/xlink";
color-rendering="auto" color-interpolation="auto" text-rendering="auto"
stroke="black" stroke- linecap="square" stroke-miterlimit="10"
shape-rendering="auto" stroke-opacity="1" fill="black"
stroke-dasharray="none" font-weight="normal" stroke-width="1"
xmlns="http://www.w3.org/2000/svg"; font-family="'sansserif'"
font-style="normal" stroke-linejoin="miter" font-size="12"
stroke-dashoffset="0" image-rendering="auto">
<!--Generated by Foo-->
<defs id="genericDefs" />
<g>
<g fill="white" stroke="white">
<rect width="562" x="0" height="378" y="0" stroke="none" />
</g>
<g stroke-linecap="round" fill="rgb(204,255,204)"
text-rendering="optimizeLegibility" stroke-linejoin="round"
stroke="rgb(204,255,204)" stroke- width="0.375">
<line y2="217" fill="none" x1="222" x2="222" y1="217" />
...
<line fill="none" x1="60" x2="61" y1="153" y2="153" stroke="blue"
stroke-width="0.5" />
...
<line fill="none" x1="477" x2="477" y1="258" y2="258"
stroke="black"
stroke-width="2" />
...
</g>
</g>
</svg>
--------------------------------------------------------------------------
The lines were generated for a JPanel by explicetely calling its
paintComponent(Graphics g) method with an instance of SVGGraphics2D as
the
parameter 'g' (please see code snippets below):
--------------------------------------------------------------------------
...
File svgFile;
...
DOMImplementation domImpl =
GenericDOMImplementation.getDOMImplementation();
Document myFactory =
domImpl.createDocument(/*null*/SVGDOMImplementation.SVG_NAMESPACE_URI,
"svg", null);
SVGGeneratorContext ctx =
SVGGeneratorContext.createDefault(myFactory);
ctx.setComment("Generated by Foo");
SVGGraphics2D svgGenerator = new SVGGraphics2D(ctx, false);
...
MyJPanel panel = new MyJPanel();
....
panel.paintComponent(svgGenerator);
....
FileOutputStream fileout = new FileOutputStream(svgFile);
Writer out = new BufferedWriter(new OutputStreamWriter(fileout,
"UTF-8"), 131072/*buffersize=128kB*/);
boolean useCSS = false; // CSS style attribute
svgGenerator.stream(out, useCSS);
...
--------------------------------------------------------------------------
class MyJPanel extends JPanel {
...
BasicStroke strokeLine = new BasicStroke(thicknessLine,
BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND);
...
public void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
int maxX = this.getSize().width;
int maxY = this.getSize().height;
// set white background
g2.setColor(Color.white);
g2.fillRect(0, 0, maxX, maxY);
...
// loop over ~ 20.000 lines with different colors and
strokes
...
g2.setColor(colorLine);
g2.setStroke(strokeLine);
g2.draw(new Line2D.Double(line[i].startX, line[i].startY,
line[i].endX, line[i].endY));
...
}
}
--------------------------------------------------------------------------
Thanks in advance for any help or tips !!!
Maik Diergardt
extreme.soft
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