Do not set focus-related style attributes by default

DESIGN.md

@@ -1,5 +1,10 @@
 This document lists architectural details of cview.
 
+# Focus-related style attributes are unset by default
+
+This applies to all widgets except Buttons, which require a style change to
+indicate focus. See [ColorUnset](https://docs.rocketnine.space/gitlab.com/tslocum/cview#pkg-variables).
+
 # Widgets always use `sync.RWMutex`
 
 See [#30](https://gitlab.com/tslocum/cview/-/issues/30).

box.go

@@ -81,8 +81,8 @@ func NewBox() *Box {
 		innerX:             -1, // Mark as uninitialized.
 		backgroundColor:    Styles.PrimitiveBackgroundColor,
 		borderColor:        Styles.BorderColor,
-		borderColorFocused: Styles.BorderColor,
 		titleColor:         Styles.TitleColor,
+		borderColorFocused: ColorUnset,
 		titleAlign:         AlignCenter,
 		showFocus:          true,
 	}
@@ -441,7 +441,7 @@ func (b *Box) Draw(screen tcell.Screen) {
 			hasFocus = b.focus.HasFocus()
 		}
 
-		if hasFocus {
+		if hasFocus && b.borderColorFocused != ColorUnset {
 			border = SetAttributes(background.Foreground(b.borderColorFocused), b.borderAttributes)
 		}
 

checkbox.go

@@ -66,12 +66,12 @@ func NewCheckBox() *CheckBox {
 	return &CheckBox{
 		Box:                         NewBox(),
 		labelColor:                  Styles.SecondaryTextColor,
-		labelColorFocused:           Styles.SecondaryTextColor,
 		fieldBackgroundColor:        Styles.ContrastBackgroundColor,
-		fieldBackgroundColorFocused: Styles.ContrastBackgroundColor,
 		fieldTextColor:              Styles.PrimaryTextColor,
-		fieldTextColorFocused:       Styles.PrimaryTextColor,
 		checkedRune:                 Styles.CheckBoxCheckedRune,
+		labelColorFocused:           ColorUnset,
+		fieldBackgroundColorFocused: ColorUnset,
+		fieldTextColorFocused:       ColorUnset,
 	}
 }
 
@@ -285,9 +285,15 @@ func (c *CheckBox) Draw(screen tcell.Screen) {
 	fieldBackgroundColor := c.fieldBackgroundColor
 	fieldTextColor := c.fieldTextColor
 	if c.GetFocusable().HasFocus() {
-		labelColor = c.labelColorFocused
-		fieldBackgroundColor = c.fieldBackgroundColorFocused
-		fieldTextColor = c.fieldTextColorFocused
+		if c.labelColorFocused != ColorUnset {
+			labelColor = c.labelColorFocused
+		}
+		if c.fieldBackgroundColorFocused != ColorUnset {
+			fieldBackgroundColor = c.fieldBackgroundColorFocused
+		}
+		if c.fieldTextColorFocused != ColorUnset {
+			fieldTextColor = c.fieldTextColorFocused
+		}
 	}
 
 	// Prepare

dropdown.go

@@ -157,14 +157,14 @@ func NewDropDown() *DropDown {
 		currentOption:               -1,
 		list:                        list,
 		labelColor:                  Styles.SecondaryTextColor,
-		labelColorFocused:           Styles.SecondaryTextColor,
 		fieldBackgroundColor:        Styles.ContrastBackgroundColor,
-		fieldBackgroundColorFocused: Styles.ContrastBackgroundColor,
 		fieldTextColor:              Styles.PrimaryTextColor,
-		fieldTextColorFocused:       Styles.PrimaryTextColor,
 		prefixTextColor:             Styles.ContrastSecondaryTextColor,
 		dropDownSymbol:              Styles.DropDownSymbol,
 		abbreviationChars:           Styles.DropDownAbbreviationChars,
+		labelColorFocused:           ColorUnset,
+		fieldBackgroundColorFocused: ColorUnset,
+		fieldTextColorFocused:       ColorUnset,
 	}
 
 	d.focus = d
@@ -551,9 +551,15 @@ func (d *DropDown) Draw(screen tcell.Screen) {
 	fieldBackgroundColor := d.fieldBackgroundColor
 	fieldTextColor := d.fieldTextColor
 	if hasFocus {
-		labelColor = d.labelColorFocused
-		fieldBackgroundColor = d.fieldBackgroundColorFocused
-		fieldTextColor = d.fieldTextColorFocused
+		if d.labelColorFocused != ColorUnset {
+			labelColor = d.labelColorFocused
+		}
+		if d.fieldBackgroundColorFocused != ColorUnset {
+			fieldBackgroundColor = d.fieldBackgroundColorFocused
+		}
+		if d.fieldTextColorFocused != ColorUnset {
+			fieldTextColor = d.fieldTextColorFocused
+		}
 	}
 
 	// Prepare.

form.go

@@ -20,10 +20,10 @@ type FormItemAttributes struct {
 	BackgroundColor             tcell.Color
 	LabelColor                  tcell.Color
 	LabelColorFocused           tcell.Color
-	FieldTextColor              tcell.Color
-	FieldTextColorFocused       tcell.Color
 	FieldBackgroundColor        tcell.Color
 	FieldBackgroundColorFocused tcell.Color
+	FieldTextColor              tcell.Color
+	FieldTextColorFocused       tcell.Color
 
 	FinishedFunc func(key tcell.Key)
 }
@@ -124,15 +124,15 @@ func NewForm() *Form {
 		Box:                          box,
 		itemPadding:                  1,
 		labelColor:                   Styles.SecondaryTextColor,
-		labelColorFocused:            Styles.SecondaryTextColor,
 		fieldBackgroundColor:         Styles.ContrastBackgroundColor,
-		fieldBackgroundColorFocused:  Styles.ContrastBackgroundColor,
 		fieldTextColor:               Styles.PrimaryTextColor,
-		fieldTextColorFocused:        Styles.PrimaryTextColor,
 		buttonBackgroundColor:        Styles.ContrastBackgroundColor,
-		buttonBackgroundColorFocused: Styles.PrimaryTextColor,
 		buttonTextColor:              Styles.PrimaryTextColor,
-		buttonTextColorFocused:       Styles.ContrastBackgroundColor,
+		buttonBackgroundColorFocused: Styles.PrimaryTextColor,
+		buttonTextColorFocused:       Styles.InverseTextColor,
+		labelColorFocused:            ColorUnset,
+		fieldBackgroundColorFocused:  ColorUnset,
+		fieldTextColorFocused:        ColorUnset,
 	}
 
 	f.focus = f
@@ -580,15 +580,28 @@ func (f *Form) GetAttributes() *FormItemAttributes {
 }
 
 func (f *Form) getAttributes() *FormItemAttributes {
-	return &FormItemAttributes{
-		BackgroundColor:             f.backgroundColor,
-		LabelColor:                  f.labelColor,
-		LabelColorFocused:           f.labelColorFocused,
-		FieldTextColor:              f.fieldTextColor,
-		FieldTextColorFocused:       f.fieldTextColorFocused,
-		FieldBackgroundColor:        f.fieldBackgroundColor,
-		FieldBackgroundColorFocused: f.fieldBackgroundColorFocused,
+	attrs := &FormItemAttributes{
+		BackgroundColor:      f.backgroundColor,
+		LabelColor:           f.labelColor,
+		FieldBackgroundColor: f.fieldBackgroundColor,
+		FieldTextColor:       f.fieldTextColor,
+	}
+	if f.labelColorFocused == ColorUnset {
+		attrs.LabelColorFocused = f.labelColor
+	} else {
+		attrs.LabelColorFocused = f.labelColorFocused
+	}
+	if f.fieldBackgroundColorFocused == ColorUnset {
+		attrs.FieldBackgroundColorFocused = f.fieldBackgroundColor
+	} else {
+		attrs.FieldBackgroundColorFocused = f.fieldBackgroundColorFocused
+	}
+	if f.fieldTextColorFocused == ColorUnset {
+		attrs.FieldTextColorFocused = f.fieldTextColor
+	} else {
+		attrs.FieldTextColorFocused = f.fieldTextColorFocused
 	}
+	return attrs
 }
 
 // Draw draws this primitive onto the screen.

inputfield.go

@@ -141,19 +141,19 @@ func NewInputField() *InputField {
 	return &InputField{
 		Box:                                     NewBox(),
 		labelColor:                              Styles.SecondaryTextColor,
-		labelColorFocused:                       Styles.SecondaryTextColor,
 		fieldBackgroundColor:                    Styles.ContrastBackgroundColor,
-		fieldBackgroundColorFocused:             Styles.ContrastBackgroundColor,
 		fieldTextColor:                          Styles.PrimaryTextColor,
-		fieldTextColorFocused:                   Styles.PrimaryTextColor,
 		placeholderTextColor:                    Styles.ContrastSecondaryTextColor,
-		placeholderTextColorFocused:             Styles.ContrastSecondaryTextColor,
 		autocompleteListTextColor:               Styles.PrimitiveBackgroundColor,
 		autocompleteListBackgroundColor:         Styles.MoreContrastBackgroundColor,
 		autocompleteListSelectedTextColor:       Styles.PrimitiveBackgroundColor,
 		autocompleteListSelectedBackgroundColor: Styles.PrimaryTextColor,
 		autocompleteSuggestionTextColor:         Styles.ContrastPrimaryTextColor,
 		fieldNoteTextColor:                      Styles.SecondaryTextColor,
+		labelColorFocused:                       ColorUnset,
+		fieldBackgroundColorFocused:             ColorUnset,
+		fieldTextColorFocused:                   ColorUnset,
+		placeholderTextColorFocused:             ColorUnset,
 	}
 }
 
@@ -583,9 +583,15 @@ func (i *InputField) Draw(screen tcell.Screen) {
 	fieldBackgroundColor := i.fieldBackgroundColor
 	fieldTextColor := i.fieldTextColor
 	if i.GetFocusable().HasFocus() {
-		labelColor = i.labelColorFocused
-		fieldBackgroundColor = i.fieldBackgroundColorFocused
-		fieldTextColor = i.fieldTextColorFocused
+		if i.labelColorFocused != ColorUnset {
+			labelColor = i.labelColorFocused
+		}
+		if i.fieldBackgroundColorFocused != ColorUnset {
+			fieldBackgroundColor = i.fieldBackgroundColorFocused
+		}
+		if i.fieldTextColorFocused != ColorUnset {
+			fieldTextColor = i.fieldTextColorFocused
+		}
 	}
 
 	// Prepare
@@ -627,7 +633,11 @@ func (i *InputField) Draw(screen tcell.Screen) {
 	text := i.text
 	if text == "" && i.placeholder != "" {
 		// Draw placeholder text.
-		Print(screen, Escape(i.placeholder), x, y, fieldWidth, AlignLeft, i.placeholderTextColor)
+		placeholderTextColor := i.placeholderTextColor
+		if i.GetFocusable().HasFocus() && i.placeholderTextColorFocused != ColorUnset {
+			placeholderTextColor = i.placeholderTextColorFocused
+		}
+		Print(screen, Escape(i.placeholder), x, y, fieldWidth, AlignLeft, placeholderTextColor)
 		i.offset = 0
 	} else {
 		// Draw entered text.

util.go

@@ -11,6 +11,10 @@ import (
 	"github.com/rivo/uniseg"
 )
 
+// ColorUnset represents an unset color. This is necessary because the zero
+// value of color, ColorDefault, results in default terminal colors.
+var ColorUnset = tcell.ColorSpecial | 108
+
 // Text alignment within a box.
 const (
 	AlignLeft = iota