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RE: Creating bitmaps of SGT plots
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Message from the sgt mail list.
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Hi Bob,
> You misunderstood my original suggestion (see the bottom of this email).
> When you call jPane.draw(graphics2D) with the graphics2D object from
> your BufferedImage, SGT is drawing directly to the BufferedImage. There
> is no middleman (a JComponent).
My apologies. I guess I didn't fully grasp your point. I'll go away and
look at it again.
Thanks, Jon
> -----Original Message-----
> From: Bob Simons [mailto:Bob.Simons@noaa.gov]
> Sent: 14 February 2006 16:45
> To: 'sgt@noaa.gov'
> Subject: Re: Creating bitmaps of SGT plots
>
> *************************************************
> Message from the sgt mail list.
> *************************************************
>
>
>
> Jon Blower wrote:
> > *************************************************
> > Message from the sgt mail list.
> > *************************************************
> >
> > Thanks again Bob,
> >
> > The tip about "headless" looks very useful, I'll try that out! I'm sure
> > that's the simplest way of achieving what I want, thanks.
> >
> >
> >>You could, if you wanted, write your own class which extends Graphics2D
> >>and performs all of the operations by manipulating an array of ints
> >>(each representing a pixel) which can later be converted to an Image.
> >>But that would be a stunningly huge job -- years of work to do it right.
> >
> >
> > I didn't quite mean that - rather I meant that, at some point, SGT must
be
> > using Graphics2D to paint stuff onto a Component (or JComponent).
Surely it
> > would be possible simply to get it to paint onto the graphics context of
an
> > Image instead? With the method you gave me (which is quick and neat to
> > implement) SGT is painting onto a Component, then your method copies the
> > graphics onto an Image. I just thought we could cut out the middle man
and
> > paint directly to an Image. I wasn't thinking of constructing a bitmap
> > completely from scratch by manipulating a set of ints.
>
> You misunderstood my original suggestion (see the bottom of this email).
> When you call jPane.draw(graphics2D) with the graphics2D object from
> your BufferedImage, SGT is drawing directly to the BufferedImage. There
> is no middleman (a JComponent).
>
> >
> > Regards, Jon
> >
> >
> >
> >>-----Original Message-----
> >>From: Bob Simons [mailto:Bob.Simons@noaa.gov]
> >>Sent: 14 February 2006 16:26
> >>To: Jon Blower
> >>Subject: Re: Creating bitmaps of SGT plots
> >>
> >>
> >>
> >>Jon Blower wrote:
> >>
> >>>*************************************************
> >>>Message from the sgt mail list.
> >>>*************************************************
> >>>
> >>>Thanks Bob, that's helpful. It's pretty similar to the way I'd hacked
> >>>together. Unfortunately it still suffers from the disadvantage that
> >
> > there
> >
> >>>needs to be an X server running even for "invisible" drawing of the
> >>>components. This is tricky in my particular setup.
> >>>
> >>>I was wondering if someone could point me in the direction of the bits
> >
> > of
> >
> >>>code that do the actual construction of the bitmap picture that is
> >
> > painted
> >
> >>>on to the components in question? Then I could just adapt these bits
of
> >>>code to paint directly onto an Image. I'm most interested in plotting
> >
> > 2-D
> >
> >>>grids of data (i.e. SGTGrids).
> >>
> >>All SGT calls to draw things ultimately resolve down to the standard
> >>methods of the Java Graphics and Graphics2D classes. Even painting
> >>directly to an Image relies on getting the Graphics/Graphics2D object
> >>from the Image and then calling those methods. Actually, that is what
> >>SGT does when you pass it the Graphics2D object from an Image.
> >>
> >>You could, if you wanted, write your own class which extends Graphics2D
> >>and performs all of the operations by manipulating an array of ints
> >>(each representing a pixel) which can later be converted to an Image.
> >>But that would be a stunningly huge job -- years of work to do it right.
> >> Getting "headless" to work certainly must be an easier task.
> >>
> >>I don't think you need to run an X11 server. Instead, you need to run
> >>your program "headless". For me to get this to work on a Linux computer
> >>running Apache and Tomcat (which serves my JSP program), I had to put
> >>"export JAVA_OPTS=-Djava.awt.headless=true" in
> >><TomcatRoot>/bin/startup.sh . Other seemingly reasonable things (e.g.,
> >>putting
> >> System.setProperty("java.awt.headless", "true");
> >>in the constructor for my main class) don't work because of the nature
> >>of how Tomcat works. See the java.exe documentation for "headless"
> >>information. It took me a long time to figure this out.
> >>
> >>Also, I vaguely remember that some things related to "headless" on
> >>Linux/Unix changed with Java 1.4 or 1.5. See the change logs as
> >>java.sun.com or Google to find that info. I certainly recommend 1.5 for
> >>lots of reasons.
> >>
> >>It is unfortunate that Java makes these "headless" operations difficult.
> >>
> >>Good luck.
> >>
> >>
> >>>Thanks,
> >>>Jon
> >>>
> >>>
> >>>
> >>>>-----Original Message-----
> >>>>From: Bob Simons [mailto:Bob.Simons@noaa.gov]
> >>>>Sent: 13 February 2006 16:21
> >>>>To: sgt@noaa.gov
> >>>>Subject: Re: Creating bitmaps of SGT plots
> >>>>
> >>>>*************************************************
> >>>>Message from the sgt mail list.
> >>>>*************************************************
> >>>>
> >>>>I have modified SGT to work as part of a server program and generate
> >>>>BufferedImages. I hacked the SGT code a little to make this possible.
> >>>>Here are my notes. I am sorry they are a little terse. I hope they are
> >>>>helpful.
> >>>>
> >>>> To allow using the system in a non-GUI way:
> >>>> In sgt.Layer.computeScale, I changed
> >>>> Rectangle bnds = getBounds();
> >>>> to
> >>>> Rectangle bnds = pbnds;
> >>>> In sgt.Pane, I added
> >>>> class field:
> >>>> Rectangle bounds;
> >>>> to constructor:
> >>>> bounds = new Rectangle(0,0, size.width, size.height);
> >>>> new method:
> >>>> public Rectangle getBounds() {
> >>>> return bounds;
> >>>> }
> >>>> In sgt.dm.Collection:
> >>>> change variable "enum" to "en" to allow use with Java 1.5
> >>>> Note about SGT coordinates (at different levels):
> >>>> Graph - uses "user" coordinates (e.g., lat and lon)
> >>>> Layer - uses "physical" coordinates (doubles, 0,0 at lower left)
> >>>> JPane - uses "device" coordinates (ints, 0,0 at upper left)
> >>>> To actually use SGT to draw on a Java Image object,
> >>>> 1) make a BufferedImage
> >>>> Get its graphic2D object.
> >>>> 2) set up SGT
> >>>> * Create a JPane object
> >>>> * For each thing plotted:
> >>>> Create a Graph, placed on a Layer, added to the JPane
> >>>> 3) call jPane.draw(graphics2D) to actually draw
> >>>> the graphs you have set up to the buffered image
> >>>>
> >>>>
> >>>>Jon Blower wrote:
> >>>>
> >>>>
> >>>>>*************************************************
> >>>>>Message from the sgt mail list.
> >>>>>*************************************************
> >>>>>
> >>>>>Dear all,
> >>>>>
> >>>>>I've been trying to use SGT to create graphics on the fly for a web
> >>>>>application. I don't want to use a Java applet: I want to create a
> >>>
> >>>bitmap
> >>>
> >>>
> >>>>>picture (jpg, gif or png) on the server, then serve this to the
client
> >>>
> >>>in a
> >>>
> >>>
> >>>>>web page. I note that a very similar thread has been started on this
> >>>>>mailing list by Leonard Scardino, but there have been no replies.
> >>>>>
> >>>>>I have discovered a rather clunky way of achieving this, which
involves
> >>>>>creating the relevant SGT component (e.g. a JPlotLayout) and grabbing
> >>>
> >>>its
> >>>
> >>>
> >>>>>graphics using ScreenImage.createImage(JComponent com, String
filename)
> >>>>>(http://www.discoverteenergy.com/files/ScreenImage.java). This
works,
> >>>
> >>>but
> >>>
> >>>
> >>>>>it has the disadvantage that the graphics are generated in an X
server
> >>>>>off-screen, then grabbed. This means that I need to run an X server
on
> >>>
> >>>my
> >>>
> >>>
> >>>>>web server, which is not ideal for various local reasons.
> >>>>>
> >>>>>It must be possible to draw the graphics in the graphics context of a
> >>>>>BufferedImage object instead of on a Swing or AWT component. Can
this
> >>>
> >>>be
> >>>
> >>>
> >>>>>done? I'd be happy to hack away at the SGT code if necessary but I'd
> >>>
> >>>like
> >>>
> >>>
> >>>>>some pointers on where to start in the code.
> >>>>>
> >>>>>Thanks in advance for any help,
> >>>>>Jon
> >>>>>
> >>>>>--------------------------------------------------------------
> >>>>>Dr Jon Blower Tel: +44 118 378 5213 (direct line)
> >>>>>Technical Director Tel: +44 118 378 8741 (ESSC)
> >>>>>Reading e-Science Centre Fax: +44 118 378 6413
> >>>>>ESSC Email: jdb@mail.nerc-essc.ac.uk
> >>>>>University of Reading
> >>>>>3 Earley Gate
> >>>>>Reading RG6 6AL, UK
> >>>>>--------------------------------------------------------------
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>*************************************************
> >>>>>To remove yourself from this mailing list,
> >>>>>send mail to <epic-majordomo@noaa.gov> with
> >>>>>"unsubscribe sgt" in the message body.
> >>>>>==========
> >>>>
> >>>>
> >>>>Sincerely,
> >>>>
> >>>>Bob Simons
> >>>>Satellite Data Product Manager
> >>>>Environmental Research Division
> >>>>NOAA Southwest Fisheries Science Center
> >>>>1352 Lighthouse Ave
> >>>>Pacific Grove, CA 93950-2079
> >>>>(831)658-3205
> >>>>bob.simons@noaa.gov
> >>>><>< <>< <>< <>< <>< <>< <>< <>< <><
> >>>>
> >>>>*************************************************
> >>>>To remove yourself from this mailing list,
> >>>>send mail to <epic-majordomo@noaa.gov> with
> >>>>"unsubscribe sgt" in the message body.
> >>>>==========
> >>>
> >>>
> >>>
> >>>*************************************************
> >>>To remove yourself from this mailing list,
> >>>send mail to <epic-majordomo@noaa.gov> with
> >>>"unsubscribe sgt" in the message body.
> >>>==========
> >>
> >>--
> >>Sincerely,
> >>
> >>Bob Simons
> >>Satellite Data Product Manager
> >>Environmental Research Division
> >>NOAA Southwest Fisheries Science Center
> >>1352 Lighthouse Ave
> >>Pacific Grove, CA 93950-2079
> >>(831)658-3205
> >>bob.simons@noaa.gov
> >><>< <>< <>< <>< <>< <>< <>< <>< <><
> >
> >
> >
> > *************************************************
> > To remove yourself from this mailing list,
> > send mail to <epic-majordomo@noaa.gov> with
> > "unsubscribe sgt" in the message body.
> > ==========
>
> --
> Sincerely,
>
> Bob Simons
> Satellite Data Product Manager
> Environmental Research Division
> NOAA Southwest Fisheries Science Center
> 1352 Lighthouse Ave
> Pacific Grove, CA 93950-2079
> (831)658-3205
> bob.simons@noaa.gov
> <>< <>< <>< <>< <>< <>< <>< <>< <><
>
> *************************************************
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> send mail to <epic-majordomo@noaa.gov> with
> "unsubscribe sgt" in the message body.
> ==========
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