Added a Component parameter to theme cases

elements/fun/piano.go

@@ -313,7 +313,7 @@ func (element *Piano) drawFlat (
 ) {
 	state.Pressed = pressed
 	pattern := element.theme.Theme.Pattern (
-		theme.PatternButton, state, theme.C("fun", "flatKey"))
+		theme.PatternButton, state, theme.C("fun", "piano", "flatKey"))
 	pattern.Draw(element.core, bounds)
 }
 
@@ -324,6 +324,6 @@ func (element *Piano) drawSharp (
 ) {
 	state.Pressed = pressed
 	pattern := element.theme.Theme.Pattern (
-		theme.PatternButton, state, theme.C("fun", "sharpKey"))
+		theme.PatternButton, state, theme.C("fun", "piano", "sharpKey"))
 	pattern.Draw(element.core, bounds)
 }

theme/default.go

@@ -210,26 +210,30 @@ func (Default) Pattern (id Pattern, state State, c Case) artist.Pattern {
 	case PatternBackground: return patterns.Uhex(0xaaaaaaFF)
 	case PatternDead:       return defaultTextures[0][offset]
 	case PatternRaised:
-		if c == C("basic", "listEntry") {
+		if c.Match("basic", "listEntry", "") {
 			return defaultTextures[10][offset]
 		} else {
 			return defaultTextures[1][offset]
 		}
-	case PatternSunken:     return defaultTextures[2][offset]
-	case PatternPinboard:   return defaultTextures[3][offset]
+	case PatternSunken:   return defaultTextures[2][offset]
+	case PatternPinboard: return defaultTextures[3][offset]
 	case PatternButton:
-		switch c {
-		case C("basic", "checkbox"): return defaultTextures[9][offset]
-		case C("fun", "flatKey"):    return defaultTextures[11][offset]
-		case C("fun", "sharpKey"):   return defaultTextures[12][offset]
-		default:                     return defaultTextures[4][offset]
+		switch {
+		case c.Match("basic", "checkbox", ""):  
+			return defaultTextures[9][offset]
+		case c.Match("fun", "piano", "flatKey"):
+			return defaultTextures[11][offset]
+		case c.Match("fun", "piano", "sharpKey"):
+			return defaultTextures[12][offset]
+		default:
+			return defaultTextures[4][offset]
 		}
-	case PatternInput:      return defaultTextures[5][offset]
-	case PatternGutter:     return defaultTextures[6][offset]
-	case PatternHandle:     return defaultTextures[7][offset]
-	case PatternLine:       return defaultTextures[8][offset]
-	case PatternMercury:    return defaultTextures[13][offset]
-	default:                return patterns.Uhex(0xFF00FFFF)
+	case PatternInput:   return defaultTextures[5][offset]
+	case PatternGutter:  return defaultTextures[6][offset]
+	case PatternHandle:  return defaultTextures[7][offset]
+	case PatternLine:    return defaultTextures[8][offset]
+	case PatternMercury: return defaultTextures[13][offset]
+	default:             return patterns.Uhex(0xFF00FFFF)
 	}
 }
 
@@ -249,21 +253,21 @@ func (Default) Color (id Color, state State, c Case) color.RGBA {
 func (Default) Padding (id Pattern, c Case) artist.Inset {
 	switch id {
 	case PatternRaised:
-		if c == C("basic", "listEntry") {
+		if c.Match("basic", "listEntry", "") {
 			return artist.Inset { 4, 8, 4, 8 }
 		} else {
 			return artist.Inset { 8, 8, 8, 8 }
 		}
 	case PatternSunken:
-		if c == C("basic", "list") {
+		if c.Match("basic", "list", "") {
 			return artist.Inset { 4, 0, 3, 0 }
-		} else if c == C("basic", "progressBar") {
+		} else if c.Match("basic", "progressBar", "") {
 			return artist.Inset { 2, 1, 1, 2 }
 		} else {
 			return artist.Inset { 8, 8, 8, 8 }
 		}
 	case PatternPinboard:
-		if c == C("fun", "piano") {
+		if c.Match("fun", "piano", "") {
 			return artist.Inset { 2, 2, 2, 2 }
 		} else {
 			return artist.Inset { 8, 8, 8, 8 }

theme/state.go

@@ -1,29 +1,59 @@
 package theme
 
 // Case sepecifies what kind of element is using a pattern. It contains a
-// namespace parameter and an element parameter. The element parameter does not
-// necissarily need to match an element name, but if it can, it should. Both
-// parameters should be written in camel case. Themes can change their styling
-// based on this parameter for fine-grained control over the look and feel of
+// namespace parameter, an element parameter, and an optional component trail.
+// All parameter values should be written in camel case. Themes can change their
+// styling based on the case for fine-grained control over the look and feel of
 // specific elements.
-type Case struct { Namespace, Element string } 
+type Case struct {
+	// Namespace refers to the package that the element comes from. This is
+	// so different element packages can have elements with the same name
+	// while still allowing themes to differentiate between them.
+	Namespace string
+
+	// Element refers to the name of the element. This should (generally) be
+	// the type name of the element. For example: Button, Input, Container,
+	// etc.
+	Element string
+
+	// Component specifies the specific part of the element that is being
+	// referred to. This parameter is entirely optional.
+	Component string
+}
  
-// C can be used as shorthand to generate a case struct as used in State.
-func C (namespace, element string) (c Case) {
+// C can be used as shorthand to generate a case struct. The component parameter
+// may be left out of this argument list for brevity. Arguments passed after
+// component will be ignored.
+func C (namespace, element string, component ...string) Case {
+	if component == nil { component = []string { "" } }
 	return Case {
 		Namespace: namespace,
-		Element: element,
+		Element:   element,
+		Component: component[0],
 	}
 }
 
+// Match determines if a case matches the specified parameters. A blank string
+// will act as a wildcard.
+func (c Case) Match (namespace, element, component string) bool {
+	if namespace == "" { namespace = c.Namespace }
+	if element   == "" { element   = c.Element   }
+	if component == "" { component = c.Component }
+
+	return  namespace == c.Namespace &&
+		element   == c.Element   &&
+		component == c.Component
+}
+
 // State lists parameters which can change the appearance of some patterns and
 // colors. For example, passing a State with Selected set to true may result in
 // a pattern that has a colored border within it.
 type State struct {
 	// On should be set to true if the element that is using this pattern is
 	// in some sort of selected or "on" state, such as if a checkbox is
-	// checked or a switch is toggled on. This is only necessary if the
-	// element in question is capable of being toggled or selected.
+	// checked, a file is selected, or a switch is toggled on. This is only
+	// necessary if the element in question is capable of being toggled or
+	// selected.
 	On bool
 
 	// Focused should be set to true if the element that is using this