[theme] export .onPrimaryColorNamed() to enable preview in fyne_settings

cmd/fyne_settings/settings/appearance.go

@@ -246,8 +246,11 @@ func (p *previewTheme) Color(n fyne.ThemeColorName, _ fyne.ThemeVariant) color.C
 		variant = theme.VariantLight
 	}
 
-	if n == theme.ColorNamePrimary {
+	switch n {
+	case theme.ColorNamePrimary:
 		return theme.PrimaryColorNamed(p.s.fyneSettings.PrimaryColor)
+	case theme.ColorNameOnPrimary:
+		return theme.OnPrimaryColorNamed(p.s.fyneSettings.PrimaryColor)
 	}
 
 	return p.t.Color(n, variant)

theme/color.go

@@ -275,6 +275,32 @@ func OnPrimaryColor() color.Color {
 	return safeColorLookup(ColorNameOnPrimary, currentVariant())
 }
 
+// OnPrimaryColorNamed returns a theme specific color used for text and icons against the named primary color.
+//
+// Since: 2.5
+func OnPrimaryColorNamed(name string) color.Color {
+	switch name {
+	case ColorRed:
+		return backgroundColorLight
+	case ColorOrange:
+		return backgroundColorDark
+	case ColorYellow:
+		return backgroundColorDark
+	case ColorGreen:
+		return backgroundColorDark
+	case ColorPurple:
+		return backgroundColorLight
+	case ColorBrown:
+		return backgroundColorLight
+	case ColorGray:
+		return backgroundColorDark
+	}
+
+	// We return the “on” value for ColorBlue for every other value.
+	// There is no need to have it in the switch above.
+	return backgroundColorLight
+}
+
 // OverlayBackgroundColor returns the theme's background color for overlays like dialogs.
 //
 // Since: 2.3
@@ -370,29 +396,6 @@ func WarningColor() color.Color {
 	return safeColorLookup(ColorNameWarning, currentVariant())
 }
 
-func onPrimaryColorNamed(name string) color.Color {
-	switch name {
-	case ColorRed:
-		return backgroundColorLight
-	case ColorOrange:
-		return backgroundColorDark
-	case ColorYellow:
-		return backgroundColorDark
-	case ColorGreen:
-		return backgroundColorDark
-	case ColorPurple:
-		return backgroundColorLight
-	case ColorBrown:
-		return backgroundColorLight
-	case ColorGray:
-		return backgroundColorDark
-	}
-
-	// We return the “on” value for ColorBlue for every other value.
-	// There is no need to have it in the switch above.
-	return backgroundColorLight
-}
-
 func safeColorLookup(n fyne.ThemeColorName, v fyne.ThemeVariant) color.Color {
 	col := Current().Color(n, v)
 	if col == nil {

theme/theme.go

@@ -106,7 +106,7 @@ func (t *builtinTheme) Color(n fyne.ThemeColorName, v fyne.ThemeVariant) color.C
 	if n == ColorNamePrimary || n == ColorNameHyperlink {
 		return PrimaryColorNamed(primary)
 	} else if n == ColorNameOnPrimary {
-		return onPrimaryColorNamed(primary)
+		return OnPrimaryColorNamed(primary)
 	} else if n == ColorNameFocus {
 		return focusColorNamed(primary)
 	} else if n == ColorNameSelection {