This code generates a plot with random values:


(import '(ij.gui Plot))
(let [plot (Plot. "The plot" "The X" "The Y"
                  (float-array (range 30))
                  (float-array (map (fn [x] (rand))
                                    (range 30))))]
  (doto plot
    (setSize 700 300)
    (setLimits 0 30 0 1)
    (setLineWidth 2)                                          
    (show)))


This other block does so but adding a text label: FAILS
(import '(ij.gui Plot))
(let [plot (Plot. "The plot" "The X" "The Y"
                  (float-array (range 30))
                  (float-array (map (fn [x] (rand))
                                    (range 30))))]
  (doto plot
    (setSize 700 300)
    (setLimits 0 30 0 1)
    (setLineWidth 2)
    (addLabel 10 295 "Some label")                                        
    (show)))


... with this exception:

java.lang.IllegalArgumentException: Width (0) and height (0) must be > 0 (NO_SOURCE_FILE:0)
	at clojure.lang.Compiler.eval(Compiler.java:4008)
	at Clojure.Clojure_Interpreter$LispThread.parse(Clojure_Interpreter.java:331)
	at Clojure.Clojure_Interpreter$LispThread.run(Clojure_Interpreter.java:273)
Caused by: java.lang.IllegalArgumentException: Width (0) and height (0) must be > 0
	at java.awt.image.SampleModel.<init>(SampleModel.java:108)
	at java.awt.image.ComponentSampleModel.<init>(ComponentSampleModel.java:128)
	at java.awt.image.PixelInterleavedSampleModel.<init>(PixelInterleavedSampleModel.java:69)
	at java.awt.image.PixelInterleavedSampleModel.createCompatibleSampleModel(PixelInterleavedSampleModel.java:126)
	at ij.process.ImageProcessor.getIndexSampleModel(ImageProcessor.java:1724)
	at ij.process.ByteProcessor.createBufferedImage(ByteProcessor.java:98)
	at ij.process.ByteProcessor.createImage(ByteProcessor.java:82)
	at ij.process.ImageProcessor.drawString2(ImageProcessor.java:1007)
	at ij.process.ImageProcessor.drawString(ImageProcessor.java:978)
	at ij.process.ImageProcessor.drawString(ImageProcessor.java:1045)
	at ij.gui.Plot.addLabel(Plot.java:263)
	at user.eval__2477.invoke(Unknown Source)
	at clojure.lang.Compiler.eval(Compiler.java:3997)
	... 2 more


From outside Clojure, same behaviour.

Trying to add the label after calling 'show' on the plot has the same behaviour.

The trick is to specify x and y between 0 and 1, i.e. relative to the image size.  IOW if you call (addLabel 0.1 0.2 "Some label") it will work.  Yes, this is counterintuitive.  But it is existing ImageJ behavior (http://pacific.mpi-cbg.de/cgi-bin/gitweb.cgi?p=ImageJA.git;a=blob;f=ij/gui/Plot.java;h=b9df08a3cbde564201c48da6e9f69a1e7e268d0b;hb=HEAD#l261), so we cannot change it.