Theme roles now have a variant field

event/event.go

@@ -45,6 +45,10 @@ func (broadcaster *Broadcaster[L]) ensure () {
 	}
 }
 
+// NoCookie is a cookie that does nothing when closed.
+type NoCookie struct { }
+func (NoCookie) Close () { }
+
 type cookie[L any] struct {
 	id int
 	broadcaster *Broadcaster[L]

go.mod

@@ -2,4 +2,4 @@ module git.tebibyte.media/tomo/tomo
 
 go 1.20
 
-require golang.org/x/image v0.8.0
+require golang.org/x/image v0.11.0

go.sum

@@ -3,6 +3,8 @@ golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACk
 golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
 golang.org/x/image v0.8.0 h1:agUcRXV/+w6L9ryntYYsF2x9fQTMd4T8fiiYXAVW6Jg=
 golang.org/x/image v0.8.0/go.mod h1:PwLxp3opCYg4WR2WO9P0L6ESnsD6bLTWcw8zanLMVFM=
+golang.org/x/image v0.11.0 h1:ds2RoQvBvYTiJkwpSFDwCcDFNX7DqjL2WsUgTNk0Ooo=
+golang.org/x/image v0.11.0/go.mod h1:bglhjqbqVuEb9e9+eNR45Jfu7D+T4Qan+NhQk8Ck2P8=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
@@ -26,6 +28,7 @@ golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
 golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/text v0.10.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
+golang.org/x/text v0.12.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=

object.go

@@ -104,7 +104,7 @@ type Align int; const (
 // Object is any obscreen object. Each object must be linked to a box, even if
 // it is that box.
 type Object interface {
-	Box () Box
+	GetBox () Box
 }
 
 // Box is a basic styled box.

theme/theme.go

@@ -16,19 +16,42 @@ type Role struct {
 	//   - Dial
 	// This should correspond directly to the type name of the object.
 	Object string
+	
+	// Variant is an optional field to be used when an object has one or
+	// more soft variants under one type. For example, an object "Slider"
+	// may have variations "horizontal" and "vertical".
+	Variant string
 }
 
 // R is shorthand for creating a Role structure.
-func R (pack, object string) Role {
-	return Role { Package: pack, Object: object }
+func R (pack, object, variant string) Role {
+	return Role { Package: pack, Object: object, Variant: variant }
 } 
 
+// Color represents a color ID.
+type Color int; const (
+	ColorBackground Color = iota
+	ColorForeground
+	ColorRaised
+	ColorSunken
+	ColorAccent
+)
+
+// RGBA satisfies the color.Color interface.
+func (id Color) RGBA () (r, g, b, a uint32) {
+	if current == nil { return }
+	return current.RGBA(id)
+}
+
 // Theme is an object that can apply a visual style to different objects.
 type Theme interface {
 	// Apply applies the theme to the given object, according to the given
 	// role. This may register event listeners with the given object;
 	// closing the returned cookie will remove them.
 	Apply (tomo.Object, Role) event.Cookie
+	
+	// RGBA returns the RGBA values of the corresponding color ID.
+	RGBA (Color) (r, g, b, a uint32)
 }
 
 var current Theme
@@ -42,5 +65,7 @@ func SetTheme (theme Theme) {
 // role. This may register event listeners with the given object; closing the
 // returned cookie will remove them.
 func Apply (object tomo.Object, role Role) event.Cookie {
+	if current == nil { return event.NoCookie { } }
 	return current.Apply(object, role)
 }
+