Trying to draw my overlay

[Lasse Riis]

Hi

I've been looking in to your answers and trying to build my app. But I'm
stuck now. I restructured it to use some methods to build the app, as
oppose to a huge main(). It should be very clear to anyone that I am not
very familiar with Java. So sometimes I have no idea what I'm doing. And
usually just follow my IDE's (eclipse) reccommendations (hence the
'static' methods). So I hope you don't spill your coffee laughing when
looking at my code :). But bare in mind, this is the first thing I've
ever written.

I just need this to draw some simple visible image on top of my SVG and
then later figure out how to move it around. But since I have no clue
where to start, I think I've started out wrong, so maybe you could give
me input on how to restructure this poor thing to make my foundation
proper. Here we go:

import java.awt.*;
import java.awt.Graphics;

import javax.swing.*;

import org.apache.batik.swing.JSVGCanvas;
import org.apache.batik.swing.gvt.GVTTreeRendererAdapter;
import org.apache.batik.swing.gvt.GVTTreeRendererEvent;

public class mapIt {

public static void main(String[] args) {
JFrame frame = buildGUI();

frame.setSize(200, 600);
frame.setVisible(true);

}

public static JSVGCanvas buildCanvas(){
JSVGCanvas canvas = new JSVGCanvas();

canvas.setBackground(Color.green);
canvas.setURI("file:/home/riis/P2/maps/gangen.svg");

canvas.addGVTTreeRendererListener(new GVTTreeRendererAdapter() {
public void gvtRenderingCompleted(GVTTreeRendererEvent e) {
System.out.print("Rendering done");
Graphics box = new Graphics();
paint(box);
}
});

return canvas;
}

public static JFrame buildGUI(){
JFrame f = new JFrame("PANTS - MapIt");

JSVGCanvas svgCanvas = buildCanvas();

JSlider slider = new JSlider();

JPanel panel = new JPanel(new BorderLayout());

panel.add("North", slider);

panel.add("Center", svgCanvas);

f.getContentPane().add(panel);

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
return f;
}

public void paint(java.awt.Graphics g) {
g.setColor(java.awt.Color.RED);
g.fillRect(10,10,100,100);
}

}

[James Shaw]

Post by Lasse Riis
Hi
I've been looking in to your answers and trying to build my app. But
I'm stuck now. I restructured it to use some methods to build the app,
as oppose to a huge main(). It should be very clear to anyone that I
am not very familiar with Java. So sometimes I have no idea what I'm
doing. And usually just follow my IDE's (eclipse) reccommendations
(hence the 'static' methods). So I hope you don't spill your coffee
laughing when looking at my code :). But bare in mind, this is the
first thing I've ever written.

Lasse, you're completely mad! :-P One problem I see with your code is
manually creating a Graphics object and trying to paint to it. I think
you should try doing Component.getGraphics(), but I'm not sure which
component you should choose to paint to. Personally, I would create the
image in the SVG DOM, and use event handlers to move it around.

Hope that helps, at least a little bit!
James Shaw

[Thomas DeWeese]

Post by Lasse Riis
I've been looking in to your answers and trying to build my app. But I'm
stuck now. I restructured it to use some methods to build the app, as

You are close, basically you want to make your class implement
the Overlay interface from Batik, and associate your mapIt instance
with the canvas as an overlay

import org.apache.batik.swing.gvt.Overlay; // Interface

public class mapIt implements Overlay { // Note Overlay!!!!
public static JSVGCanvas buildCanvas(){
JSVGCanvas canvas = new JSVGCanvas();

canvas.setBackground(Color.green);
canvas.setURI("file:/home/riis/P2/maps/gangen.svg");

// It will now call your paint method whenever it
// update the canvas!
canvas.getOverlays().add(new mapIt());

return canvas;
}

public static JFrame buildGUI(){
JFrame f = new JFrame("PANTS - MapIt");
JSVGCanvas svgCanvas = buildCanvas();
JSlider slider = new JSlider();
JPanel panel = new JPanel(new BorderLayout());

panel.add("North", slider);

panel.add("Center", svgCanvas);

f.getContentPane().add(panel);

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
return f;
}

public void paint(java.awt.Graphics g) {
g.setColor(java.awt.Color.RED);
g.fillRect(10,10,100,100);
}

}

[Lasse Riis]

Post by Thomas DeWeese
You are close, basically you want to make your class implement
the Overlay interface from Batik, and associate your mapIt instance
with the canvas as an overlay

Well I guess I'm getting there, but I need more help. Perhaps a good
restructure of my app is in order?


I got this now, and of course it still doesn't work. (I didn't quite
understand James' ideas):

import java.awt.*;
import java.awt.Graphics2D;
import javax.swing.*;

import org.apache.batik.swing.JSVGCanvas;
import org.apache.batik.swing.gvt.GVTTreeRendererAdapter;
import org.apache.batik.swing.gvt.GVTTreeRendererEvent;
import org.apache.batik.swing.gvt.Overlay;

public class mapIt implements Overlay{

public static void main(String[] args) {
JFrame frame = buildGUI();

frame.setSize(200, 600);
frame.setVisible(true);

}

public static JSVGCanvas buildCanvas(){
final JSVGCanvas canvas = new JSVGCanvas();

canvas.setBackground(Color.green);
canvas.setURI("file:/home/riis/P2/maps/gangen.svg");

canvas.addGVTTreeRendererListener(new GVTTreeRendererAdapter() {
public void gvtRenderingCompleted(GVTTreeRendererEvent e) {
System.out.print("Rendering done");
Graphics box = canvas.getGraphics();
paint(box);
}
});

canvas.getOverlays().add(new mapIt());

return canvas;
}

public static JFrame buildGUI(){
JFrame f = new JFrame("PANTS - MapIt");

JSVGCanvas svgCanvas = buildCanvas();

JSlider slider = new JSlider();

JPanel panel = new JPanel(new BorderLayout());

panel.add("North", slider);

panel.add("Center", svgCanvas);

f.getContentPane().add(panel);

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
return f;
}

public static void paint(Graphics g) {
g.setColor(java.awt.Color.RED);
g.fillRect(10,10,100,100);
}

}

[Thomas DeWeese]

Post by Lasse Riis

Post by Thomas DeWeese
You are close, basically you want to make your class implement
the Overlay interface from Batik, and associate your mapIt instance
with the canvas as an overlay

Well I guess I'm getting there, but I need more help. Perhaps a good
restructure of my app is in order?
I got this now, and of course it still doesn't work. (I didn't quite
public static void paint(Graphics g) {

^^^^^^ This wasn't here last time. It won't compile
with this.

[Lasse Riis]

Post by Thomas DeWeese

Post by Lasse Riis
public static void paint(Graphics g) {

^^^^^^ This wasn't here last time. It won't compile
with this.

No, but It won't compile without it either. At least not here. My IDE
tells me to make it static, but i don't understand why.
Someone should do a thorough howto on using an overlay in a jsvgcanvas
and put it in the wiki. At least I think so :)

Lasse

[Thomas DeWeese]

Post by Lasse Riis
No, but It won't compile without it either. At least not here. My IDE
tells me to make it static, but i don't understand why.

But the problem was that you were using 'java.awt.Color.RED'
not 'java.awt.Color.red'. What is below works.

Post by Lasse Riis
Someone should do a thorough howto on using an overlay in a jsvgcanvas
and put it in the wiki. At least I think so :)

Using an overlay is pretty trivial, your problems seem to mostly be
with the Java language. This is not an appropriate forum to learn
Java. There are _lots_ of resources for that.

-----

import java.awt.*;
import java.awt.Graphics2D;
import javax.swing.*;

import org.apache.batik.swing.JSVGCanvas;
import org.apache.batik.swing.gvt.GVTTreeRendererAdapter;
import org.apache.batik.swing.gvt.GVTTreeRendererEvent;
import org.apache.batik.swing.gvt.Overlay;

public class MapIt implements Overlay {
public static void main(String[] args) {
JFrame frame = buildGUI();
frame.setSize(200, 600);
frame.setVisible(true);
}

public static JSVGCanvas buildCanvas(){
final JSVGCanvas canvas = new JSVGCanvas();

canvas.setBackground(Color.green);

canvas.setURI("file:/C:/Apps/cygwin/home/l449433/dev/batik/xml-batik/samples/anne.svg");

canvas.getOverlays().add(new MapIt());
return canvas;
}
public static JFrame buildGUI(){
JFrame f = new JFrame("PANTS - MapIt");
JSVGCanvas svgCanvas = buildCanvas();
JSlider slider = new JSlider();
JPanel panel = new JPanel(new BorderLayout());

panel.add("North", slider);

panel.add("Center", svgCanvas);

f.getContentPane().add(panel);

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
return f;
}

public void paint(Graphics g) {
g.setColor(java.awt.Color.red);
g.fillRect(10,10,100,100);
}

}

[Lasse Riis]

Post by Thomas DeWeese
Using an overlay is pretty trivial, your problems seem to mostly be
with the Java language. This is not an appropriate forum to learn
Java. There are _lots_ of resources for that.

I feared this would come up :)
Yes, I thinks this is the core of my problem; I'm learning OOP, Java and
Batik all at the same time, programming my first GUI app. I apologise If
I've been too annoying with my questions. But I hope to return with
more, once I get my Java straight.

But in order to get that, I'd like to know if anyone has knowledge of
projects that use Batik to do something similar to what I'm trying to
do; using and overlay to draw (and perhaps move) some graphics over an
SVG-image. I'd like to study some source code. I think that would help
me a lot.

Doing all sorts of boring classes using Java tutorials will not help me
getting this GUI done :)

Lasse Riis

[Tonny Kohar]

Hi,

Post by Lasse Riis
But in order to get that, I'd like to know if anyone has knowledge of
projects that use Batik to do something similar to what I'm trying to
do; using and overlay to draw (and perhaps move) some graphics over an
SVG-image. I'd like to study some source code. I think that would help
me a lot.

Try to look at the source code for Batik Squigle/SVGBrowser especially
the Scale/Zoom function, it draw dash-ed rectangle as overlay when you
drag the mouse with ctrl key pressed.

Regards
Tonny Kohar

[Lasse Riis]

Post by Thomas DeWeese
Using an overlay is pretty trivial, your problems seem to mostly be
with the Java language. This is not an appropriate forum to learn
Java. There are _lots_ of resources for that.

I feared this would come up :)
Yes, I thinks this is the core of my problem; I'm learning OOP, Java and
Batik all at the same time, programming my first GUI app. I apologize If
I've been too annoying with my questions. But I hope to return with
more, once I get my Java straight.

But in order to get that, I'd like to know if anyone has knowledge of
projects that use Batik to do something similar to what I'm trying to
do; using and overlay to draw (and perhaps move) some graphics over an
SVG-image. I'd like to study some source code. I think that would help
me a lot.

Doing all sorts of boring classes using Java tutorials will not help me
getting this GUI done :)

Lasse Riis

P.S. Our mailserver went down, and it seems this message didn't reach
the mailinglist. So if this is a duplicate, I apologize.

[Andres Toussaint]

Lasse:

Could you detail what it is you want to do with the overlays. I can
think of two uses for them:

1. Related to the SVG content. to draw Scale-unaware selection objects
(such as a bounding box, a resize or reshape indicator, etc.) or
elements that are not part of the drawing, such as guides. Or you want
to annotate your SVG with Graphics2D objects, for some specific reason.

2. Not related to the SVG. That is, your SVG will be simply the
"background image", for your Java 2D Graphics canvas.

With a little more information as to what it is you want to accomplish
with the overlays, we may be able to help you better.

I have done selection objects both as an overlay and as part of the SVG
document, so, although the overlay seems like a simpler solution, event
handling makes the option of having the selection elements as part of
the SVG a better solution (but you have to make these objects "scale
and pan aware" so they remain the same size regardless of your SVG
scale factor.)

Andres.

Post by Lasse Riis

Post by Thomas DeWeese
Using an overlay is pretty trivial, your problems seem to mostly be
with the Java language. This is not an appropriate forum to learn
Java. There are _lots_ of resources for that.

I feared this would come up :)
Yes, I thinks this is the core of my problem; I'm learning OOP, Java
and Batik all at the same time, programming my first GUI app. I
apologize If I've been too annoying with my questions. But I hope to
return with more, once I get my Java straight.
But in order to get that, I'd like to know if anyone has knowledge of
projects that use Batik to do something similar to what I'm trying to
do; using and overlay to draw (and perhaps move) some graphics over an
SVG-image. I'd like to study some source code. I think that would help
me a lot.
Doing all sorts of boring classes using Java tutorials will not help
me getting this GUI done :)
Lasse Riis
P.S. Our mailserver went down, and it seems this message didn't reach
the mailinglist. So if this is a duplicate, I apologize.
---------------------------------------------------------------------

[Lasse Riis]

Post by Andres Toussaint
Could you detail what it is you want to do with the overlays. I can
2. Not related to the SVG. That is, your SVG will be simply the
"background image", for your Java 2D Graphics canvas.

This is exactly what it's for. The SVG will be a map of the building, we
use SVG because it scales so well on different window/monitor-sizes. So
I'll just be using the overlay to draw some form of position-indicator,
an arrow, or a dot something like that. And then, as new positions are
calculated, probably move it and draw a trail from the previous
position. I think an overlay is the best option for this.

But I need to read up on Java as a whole. So I'd like to see some source
code. Preferrably something that is very similar to what I'm doing.

Lasse Riis

[Andres Toussaint]

Do you want to keep track (i.e. store it) of your overlay information?
or will it be volatile, on a per session basis?

You want to have the position-indicator to remain the same size (on
screen), regardless of the zoom level of your map, right?

You want to indicate access routes, elevator position, etc. Right?

How are the new positions will be calculated? By moving the indicators,
or by modifing the Zoom-pan of the map?

This is important to define the best approach.

Andres.

Post by Lasse Riis

Post by Andres Toussaint
Could you detail what it is you want to do with the overlays. I can
2. Not related to the SVG. That is, your SVG will be simply the
"background image", for your Java 2D Graphics canvas.

This is exactly what it's for. The SVG will be a map of the building,
we use SVG because it scales so well on different
window/monitor-sizes. So I'll just be using the overlay to draw some
form of position-indicator, an arrow, or a dot something like that.
And then, as new positions are calculated, probably move it and draw a
trail from the previous position. I think an overlay is the best
option for this.
But I need to read up on Java as a whole. So I'd like to see some
source code. Preferrably something that is very similar to what I'm
doing.
Lasse Riis
---------------------------------------------------------------------

[Lasse Riis]

Post by Andres Toussaint
Do you want to keep track (i.e. store it) of your overlay information?
or will it be volatile, on a per session basis?

Volatile, I Don't see any reason to embed them in the SVG and/or let it
be "saveable". But if the option can be kept open relatively easy, it
would of course be better. But primarily I want to be able to update the
display often without any slow renders.

Post by Andres Toussaint
You want to have the position-indicator to remain the same size (on
screen), regardless of the zoom level of your map, right?

Undecided. I'd like the coordinate-mapping between the overlay and
the map to stay the same if possible. But I guess a constant-sized
indicator will look better. The problem is, we might have to indicate
areas of the map, if our positioning engine is not precise enough, in
that case, the tranparent circle, rectangle, whatever, will have to
scale with the map

Post by Andres Toussaint
You want to indicate access routes, elevator position, etc. Right?

Not sure I know what you mean by this. But I could imagine indicating
exits, stairs and such with a highlighted area. But I guess that could
be done in the SVG, but having it in the overlay would of course allow
for switching it on and off. And that would be a nice feature.

Post by Andres Toussaint
How are the new positions will be calculated? By moving the
indicators, or by modifing the Zoom-pan of the map?

Not sure what you mean here either. The new positions will arrive as UDP
datagrams from the positioning backend/engine and when they do, the
indicator should move. When it gets closer to the edge of the zoom, the
map should pan. So both I guess. But if one option is terribly complex,
then the simpler might have to do.

Lasse Riis