Updated ContrastAdjuster.java

[AFMiJ]

I updated the ContrastAdjuster.java file to show the image histogram with the LUT colors of the image (if image has LUT). This is especially useful when dealing with atomic force microscopy images.

See the movie below for more details.

Note: these changes are based in part on code from ThresholdAdjuster.java.

Updated ContrastAdjuster.java:

• If image has LUT the image histogram is rendered using the LUT colors.
• The histogram is rendered with LUT accordingly to the current minimum and maximum values (or Contrast and Brightness and so on).
• Added a checkbox for render the histogram with a logarithmic scale.
• Moreover, the title of the "Color Balance..." window is set to "LUT color" and only one channel ("LUT scale") is available for modification when the active image is GREY8 or GREY16 or GREY32 (and is not composite).
• Corrected a bug when there are no open images, the "Color Balance..." window is open and the channel is changed (e.g. from “Red” to “Green”).
  Start of debug log when this error is triggered:
  ImageJ 1.54p; Java 1.8.0_345 [64-bit]; Mac OS X 10.16; 22MB of 3000MB (<1%)
  java.lang.NullPointerException
  at ij.plugin.frame.ContrastAdjuster.itemStateChanged(ContrastAdjuster.java:1200)
  at java.awt.Choice.processItemEvent(Choice.java:631) …

These changes are useful when dealing with atomic force microscopy images, but may be also of interest for other users.
If this is the case, I can make a pull request.

Lorenzo

ContrastAdjuster.mp4

[lannybroo]

Hi Lorenzo, I like these improvements. My vote: I would use both the histogram LUT coloring and the log scale histogram frequently for my day-to-day analysis. You might want to point out this improvement in the https://list.nih.gov/cgi-bin/wa.exe?A0=IMAGEJ also. Alan

…

On Aug 23, 2025, at 4:26 PM, AFMiJ ***@***.***> wrote: AFMiJ created an issue (imagej/ImageJ#281) <#281> I updated the ContrastAdjuster.java file to show the image histogram with the LUT colors of the image (if image has LUT). This is especially useful when dealing with atomic force microscopy images. ContrastAdjuster.jpg (view on web) <https://github.com/user-attachments/assets/e45f2a68-de73-48e5-a13b-81222de89c03> See the movie below for more details. Note: these changes are based in part on code from ThresholdAdjuster.java. Updated ContrastAdjuster.java: If image has LUT the image histogram is rendered using the LUT colors. The histogram is rendered with LUT accordingly to the current minimum and maximum values (or Contrast and Brightness and so on). Added a checkbox for render the histogram with a logarithmic scale. Moreover, the title of the "Color Balance..." window is set to "LUT color" and only one channel ("LUT scale") is available for modification when the active image is GREY8 or GREY16 or GREY32 (and is not composite). Corrected a bug when there are no open images, the "Color Balance..." window is open and the channel is changed (e.g. from “Red” to “Green”). Start of debug log when this error is triggered: ImageJ 1.54p; Java 1.8.0_345 [64-bit]; Mac OS X 10.16; 22MB of 3000MB (<1%) java.lang.NullPointerException at ij.plugin.frame.ContrastAdjuster.itemStateChanged(ContrastAdjuster.java:1200) at java.awt.Choice.processItemEvent(Choice.java:631) … These changes are useful when dealing with atomic force microscopy images, but may be also of interest for other users. If this is the case, I can make a pull request. Lorenzo https://github.com/user-attachments/assets/fd234748-bd6d-4b0f-8a7e-ec2e8d33e8b3 — Reply to this email directly, view it on GitHub <#281>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AABNOGZNS64N6D2FW3S7MML3PDMA5AVCNFSM6AAAAACEUTHOCWVHI2DSMVQWIX3LMV43ASLTON2WKOZTGM2DQOBTGEZTMOI>. You are receiving this because you are subscribed to this thread.

[rasband]

I also like these improvements. Please send me(rasband@gmail.com) the updated ContrastAdjuster.java so I can test it.

[AFMiJ]

mail sent

[rasband]

These ContrastAdjuster improvements are in the ImageJ 2.54q20 daily build. I changed the histogram plot background to white and, to compensate, set the top pixel in each column.
The commit is at https://github.com/imagej/ImageJ/commits/master/ij.