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Getting an image with JLink

• To: mathgroup at smc.vnet.net
• Subject: [mg116736] Getting an image with JLink
• From: Rebecca Miller-Webster <rebecca at graciouseloise.com>
• Date: Fri, 25 Feb 2011 06:37:15 -0500 (EST)

Hi,

I am writing a Java program to get an image (or byte array) from a
Mathematica program.

My Java code looks something like this:

ml.evaluate("tmp = renderImageGenericLig[" + sampleFormId + ", noteText," +
sizeX + "," + sizeY + ", margin," + dpi + "," + lineStep + "," + tabStep +
"," + ligatureMatch + "," + maxLigHeightDiff + "," + mmSearch + "," +
highToLowGap + "," + lowToHighGap + "," + wordBaselineVariance + "," +
debugFlag + "]");

ml.discardAnswer();
byte[] res = ml.evaluateToImage("tmp", 0, 0);

try {
                BufferedImage imag = ImageIO.read(new
ByteArrayInputStream(res));
                //BufferedImage imag = ImageIO.read(new InputStream(res));
                if(imag != null) {
                    ImageIO.write(imag, "jpg", new
File("/Users/Rebecca/","test.jpg"));
                }else {
                    System.out.println("image is null");
                }
            } catch (IOException ex) {
                System.out.println("IOException occurred: " +
ex.getMessage());
            }


The renderImageGenericLig function is returning:

Return [ Graphics[Raster[ note1[[1]] ], AspectRatio -> Automatic,
   ImageSize -> 530 ] ];


Note: I've also tried returning just Raster as well as Image[Graphics ...


In debug mode, from a notebook, I can render the image using:

   Print[ Graphics[Raster[ note1[[1]] ], AspectRatio -> Automatic,
   ImageSize -> 530 ]  ];


However, when I check the saved file, it is just a white image with nothing
in it.  When debugging the Java code, I see to be getting data in the byte
array, but when I convert to image with Java, I just end up with 0s or 1s.


I don't know Mathematica very well and I am having a hard time finding
examples of JLink in Java connecting to Mathematica.  Any help would be
appreciated.


Thanks!

Rebecca