Removes hardcoded background colours and standardized it across the code base by jellybean2004 · Pull Request #3862 · SasView/sasview

jellybean2004 · 2026-02-06T12:34:11Z

Description

This change removes hard-coded background colours from the Qt GUI and centralises them in sas.qtgui.Utilities.BackgroundColor. Widgets now reset to the default Qt theme instead of forcing light backgrounds.

Also, standardised errors/warnings to set the widget background to the respective colours instead of changing the text/border colour.

This is strictly a UI change; functionality should not be affected.

Fixes #3838

How Has This Been Tested?

Manually ran software and inspected changes.

Review Checklist:

Documentation

There is nothing that needs documenting
Documentation changes are in this PR
There is an issue open for the documentation (link?)

Installers

There is a chance this will affect the installers, if so
- Windows installer (GH artifact) has been tested (installed and worked)
- MacOSX installer (GH artifact) has been tested (installed and worked)
- Wheels installer (GH artifact) has been tested (installed and worked)

Licensing

The introduced changes comply with SasView license (BSD 3-Clause)

*Adds BackgroundColor.py *QLineEdit bg change to use these UI constants where it is a simple change

Copilot

Pull request overview

This PR addresses issue #3838 by removing hardcoded background colors that break Dark Mode support and centralizing color management in a new BackgroundColor.py module. The changes aim to make the Qt GUI respect system themes instead of forcing light backgrounds.

Changes:

Created centralized BackgroundColor.py module with constants BG_DEFAULT (""), BG_ERROR, and BG_WARNING
Replaced hardcoded background color strings across 18 files with the new constants
Removed local color constant definitions in favor of the centralized module

Reviewed changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated 12 comments.

Show a summary per file

File	Description
src/sas/qtgui/Utilities/BackgroundColor.py	New module defining centralized color constants for theming
src/sas/qtgui/Utilities/Preferences/PreferencesWidget.py	Updated to use BG_DEFAULT and BG_WARNING for input validation styling
src/sas/qtgui/Utilities/Preferences/PlottingPreferencesWidget.py	Updated to use BG_DEFAULT for field reset
src/sas/qtgui/Utilities/Preferences/DisplayPreferencesWidget.py	Updated to use BG_DEFAULT for field reset
src/sas/qtgui/Utilities/ModelEditors/TabbedEditor/TabbedModelEditor.py	Updated to use BG_DEFAULT and BG_ERROR for editor styling
src/sas/qtgui/Utilities/ModelEditors/ReparamEditor/ReparameterizationEditor.py	Updated to use BG_DEFAULT and BG_ERROR for editor styling
src/sas/qtgui/Utilities/ModelEditors/AddMultEditor/AddMultEditor.py	Removed local color constants, updated to use centralized BG_DEFAULT and BG_ERROR
src/sas/qtgui/Utilities/GuiUtils.py	Updated FormulaValidator to use BG_DEFAULT and BG_WARNING
src/sas/qtgui/Perspectives/Invariant/InvariantPerspective.py	Removed local color constants, updated to use centralized BG_DEFAULT and BG_ERROR
src/sas/qtgui/Perspectives/Fitting/MultiConstraint.py	Updated constraint validation to use BG_DEFAULT and BG_ERROR
src/sas/qtgui/Perspectives/Fitting/FittingWidget.py	Updated button styling to use BG_DEFAULT and BG_ERROR
src/sas/qtgui/Perspectives/Fitting/FittingOptions.py	Updated validation styling to use BG_DEFAULT and BG_WARNING
src/sas/qtgui/Perspectives/Fitting/ConstraintWidget.py	Updated button styling to use BG_DEFAULT and BG_ERROR
src/sas/qtgui/Perspectives/Fitting/ComplexConstraint.py	Updated constraint validation to use BG_DEFAULT and BG_ERROR
src/sas/qtgui/Perspectives/Corfunc/CorfuncPerspective.py	Removed local color constants, updated to use centralized BG_DEFAULT and BG_ERROR
src/sas/qtgui/Calculators/SldPanel.py	Updated validation styling to use BG_DEFAULT, BG_ERROR, and BG_WARNING
src/sas/qtgui/Calculators/ResolutionCalculatorPanel.py	Removed local color constants, updated to use centralized BG_DEFAULT and BG_ERROR
src/sas/qtgui/Calculators/GenericScatteringCalculator.py	Removed local color constants, updated to use centralized BG_DEFAULT, BG_ERROR, and BG_WARNING
src/sas/qtgui/Calculators/DataOperationUtilityPanel.py	Removed local color constants, updated to use centralized BG_DEFAULT and BG_ERROR

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Copilot · 2026-02-06T12:39:23Z

src/sas/qtgui/Calculators/SldPanel.py

                results = neutronSldAlgorithm(str(formula), density, float(neutronWavelength))
            except (ValueError, ParseException, AssertionError, KeyError):
-                self.ui.editMolecularFormula.setStyleSheet("background-color: yellow")
+                self.ui.editMolecularFormula.setStyleSheet(BG_ERROR)


The original code used "background-color: yellow" for this validation error, which is a warning-level color. However, this has been changed to BG_ERROR which is a more severe red/pink color. Based on the context (invalid molecular formula), this seems like it should use BG_WARNING instead of BG_ERROR to maintain the same visual severity level as before.

Copilot · 2026-02-06T12:39:24Z

src/sas/qtgui/Calculators/SldPanel.py

                results = xraySldAlgorithm(str(formula), density, float(xrayWavelength))
            except (ValueError, ParseException, AssertionError, KeyError):
-                self.ui.editMolecularFormula.setStyleSheet("background-color: yellow")
+                self.ui.editMolecularFormula.setStyleSheet(BG_ERROR)


The original code used "background-color: yellow" for this validation error, which is a warning-level color. However, this has been changed to BG_ERROR which is a more severe red/pink color. Based on the context (invalid molecular formula), this seems like it should use BG_WARNING instead of BG_ERROR to maintain the same visual severity level as before.

Suggested change

self.ui.editMolecularFormula.setStyleSheet(BG_ERROR)

self.ui.editMolecularFormula.setStyleSheet(BG_WARNING)

src/sas/qtgui/Perspectives/Fitting/FittingOptions.py

src/sas/qtgui/Utilities/ModelEditors/TabbedEditor/TabbedModelEditor.py

src/sas/qtgui/Calculators/SldPanel.py

Copilot · 2026-02-06T12:39:25Z

src/sas/qtgui/Calculators/SldPanel.py

            return
        if not density and '@' not in formula:
-            self.ui.editMassDensity.setStyleSheet("background-color: yellow")
+            self.ui.editMassDensity.setStyleSheet(BG_ERROR)


The original code used "background-color: yellow" for this validation error, which is a warning-level color. However, this has been changed to BG_ERROR which is a more severe red/pink color. Based on the context (missing density field), this seems like it should use BG_WARNING instead of BG_ERROR to maintain the same visual severity level as before.

Suggested change

self.ui.editMassDensity.setStyleSheet(BG_ERROR)

self.ui.editMassDensity.setStyleSheet(BG_WARNING)

src/sas/qtgui/Utilities/ModelEditors/ReparamEditor/ReparameterizationEditor.py

Copilot · 2026-02-06T12:39:26Z

src/sas/qtgui/Perspectives/Fitting/FittingWidget.py

        """
        # Notify the user that fitting is available
-        self.cmdFit.setStyleSheet('QPushButton {color: black;}')
+        self.cmdFit.setStyleSheet(BG_DEFAULT)


The original code set the text color (color: black), but BG_DEFAULT is designed for background colors. Using an empty string here will clear all styles, which may not preserve the intended behavior. Consider creating separate constants for text color styling, or explicitly set the text color here.

Suggested change

self.cmdFit.setStyleSheet(BG_DEFAULT)

self.cmdFit.setStyleSheet("color: black;")

src/sas/qtgui/Perspectives/Fitting/FittingWidget.py

src/sas/qtgui/Utilities/GuiUtils.py

    def validate(self, input, pos):

-        self._setStyleSheet("")
+        self._setStyleSheet(f"QLineEdit {{ {BG_DEFAULT} }}")


llimeht · 2026-02-07T03:16:02Z

It was previously noted that src/sas/qtgui/Utilities/About/Credits.py didn't seem to obey the CSS setting for dark mode (even though that is in the html file src/sas/system/credits.html (generated by build_tools/compile_licenses.py) and that file renders fine in a standalone browser. Is this related and a similar fix?

jellybean2004 · 2026-02-09T12:25:46Z

It was previously noted that src/sas/qtgui/Utilities/About/Credits.py didn't seem to obey the CSS setting for dark mode (even though that is in the html file src/sas/system/credits.html (generated by build_tools/compile_licenses.py) and that file renders fine in a standalone browser. Is this related and a similar fix?

Hi Stuart!
I found that the problem lies in the QTextBrowser not supporting media queries, so it is a different issue.
I have pushed a commit adding a short snippet to credits.py to identify and use the dark theme. Could you kindly review it? Thank you!

src/sas/qtgui/Utilities/About/Credits.py

jellybean2004 added 4 commits February 6, 2026 12:15

Centralize background colors and simple style swaps

9a2dbb9

*Adds BackgroundColor.py *QLineEdit bg change to use these UI constants where it is a simple change

QLineEdit changes

9a3bcfe

Standardize error display: QLineEdit to use red bg instead of border

ea923d0

QPushButton changes

f55fade

jellybean2004 requested a review from Copilot February 6, 2026 12:34

Copilot started reviewing on behalf of jellybean2004 February 6, 2026 12:34 View session

Copilot AI reviewed Feb 6, 2026

View reviewed changes

Copilot suggestions: simply set BG for QLineEdits

cc81375

llimeht reviewed Feb 9, 2026

View reviewed changes

src/sas/qtgui/Utilities/About/Credits.py Outdated Show resolved Hide resolved

Fixes dark theme in credits

3807514

jellybean2004 force-pushed the fix_bg_color branch from c9519b4 to 3807514 Compare February 10, 2026 09:54

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Removes hardcoded background colours and standardized it across the code base#3862

Removes hardcoded background colours and standardized it across the code base#3862
jellybean2004 wants to merge 6 commits intomainfrom
fix_bg_color

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	self.ui.editMolecularFormula.setStyleSheet(BG_ERROR)
	self.ui.editMolecularFormula.setStyleSheet(BG_WARNING)

	self.ui.editMassDensity.setStyleSheet(BG_ERROR)
	self.ui.editMassDensity.setStyleSheet(BG_WARNING)

	self.cmdFit.setStyleSheet(BG_DEFAULT)
	self.cmdFit.setStyleSheet("color: black;")

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jellybean2004 commented Feb 6, 2026

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