Posted by
Jochen Reichel on
Jul 27, 2015; 6:04pm
URL: http://imagej.273.s1.nabble.com/makeSelection-error-with-decimal-numbers-tp5013768.html
Hallo everyone,
I am writing an imageJ macro. I want to recreate a hand-drawn straight
line selection, that can easily contain not integer coordinates, as can
be seen from this code (if the selection was done at high
magnification/zoomed in):
---------------------
Roi.getCoordinates(x,y);
Array.print(x);
Array.print(y);
---------------------
When trying to create a selection that contains only integers,
everything is fine. But when I try to create a selection that also
contains coordinates with decimal numbers with the following code, I get
an error:
---------------------
newImage("Untitled", "8-bit black", 512, 512, 1);
xCoords1 = newArray(200, 400);
yCoords1 = newArray(200, 400);
xCoords2 = newArray(200.5, 400); //<- this .5 causes the
error lateron
yCoords2 = newArray(200, 400);
makeSelection(5, xCoords1, yCoords1); //5 stands for "straight line"
print("everthing fine");
wait(2000);
makeSelection(5, xCoords2, yCoords2);
---------------------
The error message is the following:
#####################
ImageJ 1.50a; Java 1.6.0_20 [64-bit]; Windows 7 6.1; 55MB of 8192MB (<1%)
java.lang.NullPointerException
at ij.macro.Functions.makeSelection(Functions.java:1972)
at ij.macro.Functions.doFunction(Functions.java:142)
at ij.macro.Interpreter.doStatement(Interpreter.java:227)
at ij.macro.Interpreter.doStatements(Interpreter.java:215)
at ij.macro.Interpreter.run(Interpreter.java:112)
at ij.macro.Interpreter.run(Interpreter.java:82)
at ij.macro.MacroRunner.run(MacroRunner.java:139)
at java.lang.Thread.run(Thread.java:619)
######################
Is this a bug, that the coordinates of a selection can have decimal
numbers when drawn by hand but not when done programmatically? Or am I
missing something here?
I have got a second question: Is there a tool/plugin/macro to easily
measure the width of some long "worm-like" structure along its way?
Thank you in advance for any help,
Jochen (PhD student)
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