Adding options for global keyboard.

widgets/button/button.go

@@ -28,8 +28,8 @@ import (
 )
 
 // CallbackFn is the function called when the button is pressed.
-// The callback function must be non-blocking, ideally just storing a value and
-// returning, since event processing blocks the redraws.
+// The callback function must be light-weight, ideally just storing a value and
+// returning, since more button presses might occur.
 //
 // The callback function must be thread-safe as the mouse or keyboard events
 // that press the button are processed in a separate goroutine.
@@ -100,10 +100,12 @@ func (*Button) Mouse(m *terminalapi.Mouse) error {
 func (b *Button) Options() widgetapi.Options {
 	// No need to lock, as the height and width get fixed when New is called.
 
+	// TODO calculate width and set MaximumSize too.
 	height := b.opts.height + 1 // One for the shadow.
 	return widgetapi.Options{
 		MinimumSize:  image.Point{b.opts.width, height},
-		WantKeyboard: true,
+		MaximumSize:  image.Point{b.opts.width, height},
+		WantKeyboard: b.opts.keyScope,
 		WantMouse:    true,
 	}
 }

widgets/button/button_test.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/kylelemons/godebug/pretty"
 	"github.com/mum4k/termdash/canvas"
+	"github.com/mum4k/termdash/keyboard"
 	"github.com/mum4k/termdash/terminal/faketerm"
 	"github.com/mum4k/termdash/terminalapi"
 	"github.com/mum4k/termdash/widgetapi"
@@ -150,18 +151,56 @@ func TestMouse(t *testing.T) {
 }
 
 func TestOptions(t *testing.T) {
-	ct := &callbackTracker{}
-	b, err := New("text", ct.callback)
-	if err != nil {
-		t.Fatalf("New => unexpected error: %v", err)
+	tests := []struct {
+		desc string
+		opts []Option
+		want widgetapi.Options
+	}{
+		{
+			desc: "doesn't want keyboard by default",
+			want: widgetapi.Options{
+				MinimumSize:  image.Point{6, 3},
+				WantKeyboard: widgetapi.KeyScopeNone,
+				WantMouse:    true,
+			},
+		},
+		{
+			desc: "registers for focused keyboard events",
+			opts: []Option{
+				Key(keyboard.KeyEnter),
+			},
+			want: widgetapi.Options{
+				MinimumSize:  image.Point{6, 3},
+				WantKeyboard: widgetapi.KeyScopeFocused,
+				WantMouse:    true,
+			},
+		},
+		{
+			desc: "registers for global keyboard events",
+			opts: []Option{
+				GlobalKey(keyboard.KeyEnter),
+			},
+			want: widgetapi.Options{
+				MinimumSize:  image.Point{6, 3},
+				WantKeyboard: widgetapi.KeyScopeFocused,
+				WantMouse:    true,
+			},
+		},
 	}
-	got := b.Options()
-	want := widgetapi.Options{
-		MinimumSize:  image.Point{6, 3},
-		WantKeyboard: true,
-		WantMouse:    true,
-	}
-	if diff := pretty.Compare(want, got); diff != "" {
-		t.Errorf("Options => unexpected diff (-want, +got):\n%s", diff)
+
+	for _, tc := range tests {
+		t.Run(tc.desc, func(t *testing.T) {
+			ct := &callbackTracker{}
+			b, err := New("text", ct.callback, tc.opts...)
+			if err != nil {
+				t.Fatalf("New => unexpected error: %v", err)
+			}
+
+			got := b.Options()
+			if diff := pretty.Compare(tc.want, got); diff != "" {
+				t.Errorf("Options => unexpected diff (-want, +got):\n%s", diff)
+			}
+		})
 	}
+
 }

widgets/button/options.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/mum4k/termdash/cell"
 	"github.com/mum4k/termdash/keyboard"
+	"github.com/mum4k/termdash/widgetapi"
 )
 
 // Option is used to provide options.
@@ -45,6 +46,7 @@ type options struct {
 	height      int
 	width       int
 	key         keyboard.Key
+	keyScope    widgetapi.KeyScope
 }
 
 // validate validates the provided options.
@@ -103,7 +105,7 @@ func ShadowColor(c cell.Color) Option {
 }
 
 // DefaultHeight is the default for the Height option.
-const DefaultHeight = 2
+const DefaultHeight = 3
 
 // Height sets the height of the button in cells.
 // Must be a positive non-zero integer.
@@ -123,13 +125,22 @@ func Width(cells int) Option {
 	})
 }
 
-// DefaultKey is the default value for the Key option.
-const DefaultKey = keyboard.KeyEnter
-
 // Key configures the keyboard key that presses the button.
-// Defaults to DefaultKey.
+// The widget responds to this key only if its container if focused.
+// When not provided, the widget ignores all keyboard events.
 func Key(k keyboard.Key) Option {
 	return option(func(opts *options) {
 		opts.key = k
+		opts.keyScope = widgetapi.KeyScopeFocused
+	})
+}
+
+// GlobalKey is like Key, but makes the widget respond to the key even if its
+// container isn't focused.
+// When not provided, the widget ignores all keyboard events.
+func GlobalKey(k keyboard.Key) Option {
+	return option(func(opts *options) {
+		opts.key = k
+		opts.keyScope = widgetapi.KeyScopeFocused
 	})
 }