Feature request #4014

Raster histogram drawing effectively freezes UI for large images

Added by Donkagen2 - over 6 years ago. Updated about 2 years ago.

Status:Closed
Priority:Normal
Assignee:Tim Sutton
Category:GUI
Pull Request or Patch supplied:No Resolution:fixed/implemented
Easy fix?:No

Description

If someone selects the histogram tab (intentionally or by error) with a very large image, they are stuck with waiting a long time while the graph is generated.

For novice users this can be confusing and, for anyone clicking the tab in error, frustrating as there is no way to abort a process that could take several minutes.

If the calculation was started by a specific button click (e.g. Calculate), the frustration would be avoided.

History

#1 Updated by Nathan Woodrow over 6 years ago

  • Assignee set to Tim Sutton
  • Target version set to Version 1.7.1
  • Pull Request or Patch supplied set to No

I agree this can be very frustrating. Clicking it on a 5GB ecw I have freezes QGIS and you have no idea how long it will take.

Suggestion to improve experience:
  • Thread the collection of info from the raster.
  • Only load histogram on demand with a button. Even with demand loading it should still be threaded, no need to make the user wait.
  • Show progress bar with current info collection status.

#2 Updated by Tim Sutton about 6 years ago

  • Target version changed from Version 1.7.1 to Version 1.7.2

#3 Updated by Giovanni Manghi almost 6 years ago

  • Target version changed from Version 1.7.2 to Version 1.7.3

#4 Updated by Giovanni Manghi almost 6 years ago

  • Target version changed from Version 1.7.3 to Version 1.7.4

#5 Updated by Giovanni Manghi over 5 years ago

  • Target version changed from Version 1.7.4 to Version 2.0.0

#6 Updated by Pirmin Kalberer about 5 years ago

  • Target version changed from Version 2.0.0 to Future Release - Nice to have

#7 Updated by Médéric RIBREUX about 2 years ago

Hello, bug triage...

There is now a "Compute Histogram" button on the Histogram tab of raster layer properties. The initial request seems to be fully implemented even if the computation is not threaded and that there is no progress bar as suggested by Nathan.

Feel free to reopen the feature request if the above suggestions need to be kept.

#8 Updated by Médéric RIBREUX about 2 years ago

  • Resolution set to fixed/implemented
  • Status changed from Open to Closed

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