Bug report #7619
Setting a "max" value in Raster Properties Histogram has no effect
|Affected QGIS version:||master||Regression?:||No|
|Operating System:||Easy fix?:||No|
|Pull Request or Patch supplied:||No||Resolution:||fixed|
|Crashes QGIS or corrupts data:||No||Copied to github as #:||16544|
Setting a max value does not change the histogram. It doesn't even affect when I call "recompute histogram".
This is a new functionality which was not available in 1.8.
Tested on Win7.
#2 Updated by Anita Graser over 8 years ago
Thanks for your feedack Pedro. Do you mean that editing the min and max values should not do anything? I was expecting that the histogram would zoom to these bounds. If it shouldn't, then the UI is misleading. The user should not be able to edit these values if it doesn't affect anything. Just turn the fields into read-only then.
#3 Updated by Pedro Venâncio over 8 years ago
I also think it could be implemented the functionality to zoom to histogram bounds.
However, I think we can not say that currently does not affect anything, because when you set the min and max values and click Apply, these values are applied to raster.
#7 Updated by Etienne Tourigny over 8 years ago
- Status changed from Open to Feedback
I see what you mean Anita, I implemented this to be able to manually set the bounds, based on the actual histogram. Going back and forth from the style and histogram tabs is highly tedious. Originally I wanted something like what you have in gimp or Photoshop, with arrows to select the min/max values on the histogram. However, I couldn't find a suitable QT widget and gave up.
How would you improve this? I do not want to remove the ability to set the min/max of the style from histogram.
I could add an option to zoom to these bounds. However, how do you zoom back out? Currently you can right-click after doing a left-click + drag zoom in.
I would suggest the following:
1) always show min/max markers when one of the hands are clicked, regardless of "show min/max markers"
2) add an option (off by default) to zoom to min/max
#8 Updated by Anita Graser over 8 years ago
Hi Etienne! I now understand what was the motivation behind the feature. To communicate to the user what to expect from the dialog, I could imagine having labels such as:
"style Band [band dropdown] using Min [input] and Max [input]"
Just to make clear that these input fields are not meant to modify the histogram but rather are a shortcut to layer styling.