Allow options on intermediate containers in the grid.

Fixes #181.

CHANGELOG.md

@@ -13,6 +13,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   executed.
 - The SegmentDisplay widget now has a method that returns the observed character
   capacity the last time Draw was called.
+- The grid.Builder API now allows users to specify options for intermediate
+  containers, i.e. containers that don't have widgets, but represent rows and
+  columns.
 
 #### Breaking API changes
 

container/grid/grid.go

@@ -109,18 +109,19 @@ func build(elems []Element, parentHeightPerc, parentWidthPerc int) []container.O
 
 	switch e := elem.(type) {
 	case *row:
+
 		if len(elems) > 0 {
 			perc := innerPerc(e.heightPerc, parentHeightPerc)
 			childHeightPerc := parentHeightPerc - e.heightPerc
 			return []container.Option{
 				container.SplitHorizontal(
-					container.Top(build(e.subElem, 100, parentWidthPerc)...),
+					container.Top(append(e.cOpts, build(e.subElem, 100, parentWidthPerc)...)...),
 					container.Bottom(build(elems, childHeightPerc, parentWidthPerc)...),
 					container.SplitPercent(perc),
 				),
 			}
 		}
-		return build(e.subElem, 100, parentWidthPerc)
+		return append(e.cOpts, build(e.subElem, 100, parentWidthPerc)...)
 
 	case *col:
 		if len(elems) > 0 {
@@ -128,13 +129,13 @@ func build(elems []Element, parentHeightPerc, parentWidthPerc int) []container.O
 			childWidthPerc := parentWidthPerc - e.widthPerc
 			return []container.Option{
 				container.SplitVertical(
-					container.Left(build(e.subElem, parentHeightPerc, 100)...),
+					container.Left(append(e.cOpts, build(e.subElem, parentHeightPerc, 100)...)...),
 					container.Right(build(elems, parentHeightPerc, childWidthPerc)...),
 					container.SplitPercent(perc),
 				),
 			}
 		}
-		return build(e.subElem, parentHeightPerc, 100)
+		return append(e.cOpts, build(e.subElem, parentHeightPerc, 100)...)
 
 	case *widget:
 		opts := e.cOpts
@@ -186,6 +187,9 @@ type row struct {
 
 	// subElem are the sub Rows or Columns or a single widget.
 	subElem []Element
+
+	// cOpts are the options for the row's container.
+	cOpts []container.Option
 }
 
 // isElement implements Element.isElement.
@@ -204,6 +208,9 @@ type col struct {
 
 	// subElem are the sub Rows or Columns or a single widget.
 	subElem []Element
+
+	// cOpts are the options for the column's container.
+	cOpts []container.Option
 }
 
 // isElement implements Element.isElement.
@@ -244,6 +251,16 @@ func RowHeightPerc(heightPerc int, subElements ...Element) Element {
 	}
 }
 
+// RowHeightPercWithOpts is like RowHeightPerc, but also allows to apply
+// additional options to the container that represents the row.
+func RowHeightPercWithOpts(heightPerc int, cOpts []container.Option, subElements ...Element) Element {
+	return &row{
+		heightPerc: heightPerc,
+		subElem:    subElements,
+		cOpts:      cOpts,
+	}
+}
+
 // ColWidthPerc creates a column of the specified width.
 // The width is supplied as width percentage of the parent element.
 // The sum of all widths at the same level cannot be larger than 100%. If it
@@ -257,6 +274,16 @@ func ColWidthPerc(widthPerc int, subElements ...Element) Element {
 	}
 }
 
+// ColWidthPercWithOpts is like ColWidthPerc, but also allows to apply
+// additional options to the container that represents the column.
+func ColWidthPercWithOpts(widthPerc int, cOpts []container.Option, subElements ...Element) Element {
+	return &col{
+		widthPerc: widthPerc,
+		subElem:   subElements,
+		cOpts:     cOpts,
+	}
+}
+
 // Widget adds a widget into the Row or Column.
 // The options will be applied to the container that directly holds this
 // widget.

container/grid/grid_test.go

@@ -389,6 +389,45 @@ func TestBuilder(t *testing.T) {
 				return ft
 			},
 		},
+		{
+			desc:     "two equal rows with options",
+			termSize: image.Point{10, 10},
+			builder: func() *Builder {
+				b := New()
+				b.Add(RowHeightPercWithOpts(
+					50,
+					[]container.Option{
+						container.Border(linestyle.Double),
+					},
+					Widget(mirror()),
+				))
+				b.Add(RowHeightPercWithOpts(
+					50,
+					[]container.Option{
+						container.Border(linestyle.Double),
+					},
+					Widget(mirror()),
+				))
+				return b
+			}(),
+			want: func(size image.Point) *faketerm.Terminal {
+				ft := faketerm.MustNew(size)
+
+				top, bot := mustHSplit(ft.Area(), 50)
+				topCvs := testcanvas.MustNew(top)
+				botCvs := testcanvas.MustNew(bot)
+				testdraw.MustBorder(topCvs, topCvs.Area(), draw.BorderLineStyle(linestyle.Double))
+				testdraw.MustBorder(botCvs, botCvs.Area(), draw.BorderLineStyle(linestyle.Double))
+				testcanvas.MustApply(topCvs, ft)
+				testcanvas.MustApply(botCvs, ft)
+
+				topWidget := testcanvas.MustNew(area.ExcludeBorder(top))
+				botWidget := testcanvas.MustNew(area.ExcludeBorder(bot))
+				fakewidget.MustDraw(ft, topWidget, &widgetapi.Meta{}, widgetapi.Options{})
+				fakewidget.MustDraw(ft, botWidget, &widgetapi.Meta{}, widgetapi.Options{})
+				return ft
+			},
+		},
 		{
 			desc:     "two unequal rows",
 			termSize: image.Point{10, 10},
@@ -406,6 +445,45 @@ func TestBuilder(t *testing.T) {
 				return ft
 			},
 		},
+		{
+			desc:     "two equal columns with options",
+			termSize: image.Point{20, 10},
+			builder: func() *Builder {
+				b := New()
+				b.Add(ColWidthPercWithOpts(
+					50,
+					[]container.Option{
+						container.Border(linestyle.Double),
+					},
+					Widget(mirror()),
+				))
+				b.Add(ColWidthPercWithOpts(
+					50,
+					[]container.Option{
+						container.Border(linestyle.Double),
+					},
+					Widget(mirror()),
+				))
+				return b
+			}(),
+			want: func(size image.Point) *faketerm.Terminal {
+				ft := faketerm.MustNew(size)
+
+				left, right := mustVSplit(ft.Area(), 50)
+				leftCvs := testcanvas.MustNew(left)
+				rightCvs := testcanvas.MustNew(right)
+				testdraw.MustBorder(leftCvs, leftCvs.Area(), draw.BorderLineStyle(linestyle.Double))
+				testdraw.MustBorder(rightCvs, rightCvs.Area(), draw.BorderLineStyle(linestyle.Double))
+				testcanvas.MustApply(leftCvs, ft)
+				testcanvas.MustApply(rightCvs, ft)
+
+				leftWidget := testcanvas.MustNew(area.ExcludeBorder(left))
+				rightWidget := testcanvas.MustNew(area.ExcludeBorder(right))
+				fakewidget.MustDraw(ft, leftWidget, &widgetapi.Meta{}, widgetapi.Options{})
+				fakewidget.MustDraw(ft, rightWidget, &widgetapi.Meta{}, widgetapi.Options{})
+				return ft
+			},
+		},
 		{
 			desc:     "two equal columns",
 			termSize: image.Point{20, 10},

termdashdemo/termdashdemo.go

@@ -166,6 +166,7 @@ func gridLayout(w *widgets, lt layoutType) ([]container.Option, error) {
 						container.BorderTitle("A rolling text"),
 					),
 				),
+				grid.ColWidthPerc(50,
 					grid.RowHeightPerc(50,
 						grid.Widget(w.spGreen,
 							container.Border(linestyle.Light),
@@ -179,6 +180,7 @@ func gridLayout(w *widgets, lt layoutType) ([]container.Option, error) {
 						),
 					),
 				),
+			),
 			grid.RowHeightPerc(7,
 				grid.Widget(w.gauge,
 					container.Border(linestyle.Light),