Fix issue 244 (#245)

Co-authored-by: makeworld <25111343+makeworld-the-better-one@users.noreply.github.com>

config/config.go

@@ -349,9 +349,19 @@ func Init() error {
 			if !ok {
 				return fmt.Errorf(`value for "%s" is not a string: %v`, k, v)
 			}
-			color := tcell.GetColor(strings.ToLower(colorStr))
-			if color == tcell.ColorDefault {
-				return fmt.Errorf(`invalid color format for "%s": %s`, k, colorStr)
+			colorStr = strings.ToLower(colorStr)
+			var color tcell.Color
+			if colorStr == "default" {
+				if strings.HasSuffix(k, "bg") {
+					color = tcell.ColorDefault
+				} else {
+					return fmt.Errorf(`"default" is only valid for a background color (color ending in "bg"), not "%s"`, k)
+				}
+			} else {
+				color = tcell.GetColor(colorStr)
+				if color == tcell.ColorDefault {
+					return fmt.Errorf(`invalid color format for "%s": %s`, k, colorStr)
+				}
 			}
 			SetColor(k, color)
 		}

config/default.go

@@ -305,6 +305,8 @@ entries_per_page = 20
 # This section is for changing the COLORS used in Amfora.
 # These colors only apply if 'color' is enabled above.
 # Colors can be set using a W3C color name, or a hex value such as "#ffffff".
+# Setting a background to "default" keeps the terminal default
+# If your terminal has transparency, set any background to "default" to keep it transparent
 
 # Note that not all colors will work on terminals that do not have truecolor support.
 # If you want to stick to the standard 16 or 256 colors, you can get
@@ -323,6 +325,7 @@ entries_per_page = 20
 # EXAMPLES:
 # hdg_1 = "green"
 # hdg_2 = "#5f0000"
+# bg = "default"
 
 # Available keys to set:
 

config/theme.go

@@ -84,5 +84,50 @@ func GetColor(key string) tcell.Color {
 func GetColorString(key string) string {
 	themeMu.RLock()
 	defer themeMu.RUnlock()
-	return fmt.Sprintf("#%06x", theme[key].TrueColor().Hex())
+	color := theme[key].TrueColor()
+	if color == tcell.ColorDefault {
+		return "-"
+	}
+	return fmt.Sprintf("#%06x", color.Hex())
+}
+
+// GetContrastingColor returns ColorBlack if color is brighter than gray
+// otherwise returns ColorWhite if color is dimmer than gray
+// if color is ColorDefault (undefined luminance) this returns ColorDefault
+func GetContrastingColor(color tcell.Color) tcell.Color {
+	if color == tcell.ColorDefault {
+		// color should never be tcell.ColorDefault
+		// only config keys which end in bg are allowed to be set to default
+		// and the only way the argument of this function is set to ColorDefault
+		// is if both the text and bg of an element in the UI are set to default
+		return tcell.ColorDefault
+	}
+	r, g, b := color.RGB()
+	luminance := (77*r + 150*g + 29*b + 1<<7) >> 8
+	const gray = 119 // The middle gray
+	if luminance > gray {
+		return tcell.ColorBlack
+	}
+	return tcell.ColorWhite
+}
+
+// GetTextColor is the Same as GetColor, unless the key is "default".
+// This happens on focus of a UI element which has a bg of default, in which case
+// It return tcell.ColorBlack or tcell.ColorWhite, depending on which is more readable
+func GetTextColor(key, bg string) tcell.Color {
+	themeMu.RLock()
+	defer themeMu.RUnlock()
+	color := theme[key].TrueColor()
+	if color != tcell.ColorDefault {
+		return color
+	}
+	return GetContrastingColor(theme[bg].TrueColor())
+}
+
+// GetTextColorString is the Same as GetColorString, unless the key is "default".
+// This happens on focus of a UI element which has a bg of default, in which case
+// It return tcell.ColorBlack or tcell.ColorWhite, depending on which is more readable
+func GetTextColorString(key, bg string) string {
+	color := GetTextColor(key, bg)
+	return fmt.Sprintf("#%06x", color.Hex())
 }

default-config.toml

@@ -302,6 +302,8 @@ entries_per_page = 20
 # This section is for changing the COLORS used in Amfora.
 # These colors only apply if 'color' is enabled above.
 # Colors can be set using a W3C color name, or a hex value such as "#ffffff".
+# Setting a background to "default" keeps the terminal default
+# If your terminal has transparency, set any background to "default" to keep it transparent
 
 # Note that not all colors will work on terminals that do not have truecolor support.
 # If you want to stick to the standard 16 or 256 colors, you can get
@@ -320,6 +322,7 @@ entries_per_page = 20
 # EXAMPLES:
 # hdg_1 = "green"
 # hdg_2 = "#5f0000"
+# bg = "default"
 
 # Available keys to set:
 

display/bookmarks.go

@@ -41,8 +41,10 @@ func bkmkInit() {
 		form.SetLabelColor(config.GetColor("bkmk_modal_label"))
 		form.SetFieldBackgroundColor(config.GetColor("bkmk_modal_field_bg"))
 		form.SetFieldTextColor(config.GetColor("bkmk_modal_field_text"))
+		form.SetFieldBackgroundColorFocused(config.GetColor("bkmk_modal_field_text"))
+		form.SetFieldTextColorFocused(config.GetTextColor("bkmk_modal_field_bg", "bkmk_modal_field_text"))
 		form.SetButtonBackgroundColorFocused(config.GetColor("btn_text"))
-		form.SetButtonTextColorFocused(config.GetColor("btn_bg"))
+		form.SetButtonTextColorFocused(config.GetTextColor("btn_bg", "btn_text"))
 		frame := m.GetFrame()
 		frame.SetBorderColor(config.GetColor("bkmk_modal_text"))
 		frame.SetTitleColor(config.GetColor("bkmk_modal_text"))

display/display.go

@@ -106,7 +106,7 @@ func Init(version, commit, builtBy string) {
 		browser.SetTabBackgroundColor(config.GetColor("bg"))
 		browser.SetTabBackgroundColorFocused(config.GetColor("tab_num"))
 		browser.SetTabTextColor(config.GetColor("tab_num"))
-		browser.SetTabTextColorFocused(config.GetColor("bg"))
+		browser.SetTabTextColorFocused(config.GetTextColor("bg", "tab_num"))
 		browser.SetTabSwitcherDivider(
 			"",
 			fmt.Sprintf("[%s:%s]|[-]", config.GetColorString("tab_divider"), config.GetColorString("bg")),

display/download.go

@@ -45,7 +45,7 @@ func dlInit() {
 		chm.SetTextColor(config.GetColor("dl_choice_modal_text"))
 		form := chm.GetForm()
 		form.SetButtonBackgroundColorFocused(config.GetColor("btn_text"))
-		form.SetButtonTextColorFocused(config.GetColor("btn_bg"))
+		form.SetButtonTextColorFocused(config.GetTextColor("btn_bg", "btn_text"))
 		frame := chm.GetFrame()
 		frame.SetBorderColor(config.GetColor("dl_choice_modal_text"))
 		frame.SetTitleColor(config.GetColor("dl_choice_modal_text"))
@@ -56,7 +56,7 @@ func dlInit() {
 		dlm.SetTextColor(config.GetColor("dl_modal_text"))
 		form = dlm.GetForm()
 		form.SetButtonBackgroundColorFocused(config.GetColor("btn_text"))
-		form.SetButtonTextColorFocused(config.GetColor("btn_bg"))
+		form.SetButtonTextColorFocused(config.GetTextColor("btn_bg", "btn_text"))
 		frame = dlm.GetFrame()
 		frame.SetBorderColor(config.GetColor("dl_modal_text"))
 		frame.SetTitleColor(config.GetColor("dl_modal_text"))

display/modals.go

@@ -49,7 +49,7 @@ func modalInit() {
 		m.SetTextColor(config.GetColor("info_modal_text"))
 		form := m.GetForm()
 		form.SetButtonBackgroundColorFocused(config.GetColor("btn_text"))
-		form.SetButtonTextColorFocused(config.GetColor("btn_bg"))
+		form.SetButtonTextColorFocused(config.GetTextColor("btn_bg", "btn_text"))
 		frame := m.GetFrame()
 		frame.SetBorderColor(config.GetColor("info_modal_text"))
 		frame.SetTitleColor(config.GetColor("info_modal_text"))
@@ -61,7 +61,7 @@ func modalInit() {
 		m.SetTextColor(config.GetColor("error_modal_text"))
 		form = m.GetForm()
 		form.SetButtonBackgroundColorFocused(config.GetColor("btn_text"))
-		form.SetButtonTextColorFocused(config.GetColor("btn_bg"))
+		form.SetButtonTextColorFocused(config.GetTextColor("btn_bg", "btn_text"))
 		frame = errorModal.GetFrame()
 		frame.SetBorderColor(config.GetColor("error_modal_text"))
 		frame.SetTitleColor(config.GetColor("error_modal_text"))
@@ -78,14 +78,14 @@ func modalInit() {
 		form.SetFieldBackgroundColor(config.GetColor("input_modal_field_bg"))
 		form.SetFieldTextColor(config.GetColor("input_modal_field_text"))
 		form.SetButtonBackgroundColorFocused(config.GetColor("btn_text"))
-		form.SetButtonTextColorFocused(config.GetColor("btn_bg"))
+		form.SetButtonTextColorFocused(config.GetTextColor("btn_bg", "btn_text"))
 
 		m = yesNoModal
 		m.SetButtonBackgroundColor(config.GetColor("btn_bg"))
 		m.SetButtonTextColor(config.GetColor("btn_text"))
 		form = m.GetForm()
 		form.SetButtonBackgroundColorFocused(config.GetColor("btn_text"))
-		form.SetButtonTextColorFocused(config.GetColor("btn_bg"))
+		form.SetButtonTextColorFocused(config.GetTextColor("btn_bg", "btn_text"))
 	} else {
 		m := infoModal
 		m.SetBackgroundColor(tcell.ColorBlack)