Use an interface type to pass the list entries

exhibit/list_widget.go

@@ -4,6 +4,11 @@ import (
 	"sync"
 )
 
+type ListEntry interface {
+	String()   string
+	Attributes() Attributes
+}
+
 type ListWidget struct {
 	Constraints Constraints
 	Attrs       Attributes
@@ -15,7 +20,9 @@ type ListWidget struct {
 	border     bool
 
 	listLock sync.Mutex
-	list     [][]rune
+	list     [][]Cell
+
+	listBuf [][]Cell
 
 	lastSize Size
 }
@@ -56,7 +63,6 @@ func (l *ListWidget) Render() [][]Cell {
 				c.Value = ' '
 				l.cells[y] = append(l.cells[y], c)
 			} else {
-				l.cells[y][x].Attrs = l.Attrs
 				l.cells[y][x].Pos.X = x
 				l.cells[y][x].Pos.Y = y
 			}
@@ -68,21 +74,29 @@ func (l *ListWidget) Render() [][]Cell {
 	return append([][]Cell(nil), l.cells...)
 }
 
-func (l *ListWidget) SetList(list []string) {
+func (l *ListWidget) AddEntry(entry ListEntry) {
-	buf := make([][]rune, len(list))
+	if l.listBuf == nil {
-
+		l.listBuf = make([][]Cell, 1)
-	for i, s := range list {
+	} else {
-		buf[i] = make([]rune, 0)
+		l.listBuf = append(l.listBuf, []Cell{})
-
-		for _, r := range s {
-			buf[i] = append(buf[i], r)
-		}
 	}
 
+	index := len(l.listBuf) - 1
+
+	for _, r := range entry.String() {
+		cell := Cell{}
+		cell.Value = r
+		cell.Attrs = entry.Attributes()
+
+		l.listBuf[index] = append(l.listBuf[index], cell)
+	}
+}
+
+func (l *ListWidget) Commit() {
 	l.listLock.Lock()
-	l.list = buf
+	l.list = append([][]Cell{}, l.listBuf...)
 	l.listLock.Unlock()
-
+	l.listBuf = nil
 	l.recalculateCells()
 }
 
@@ -125,15 +139,15 @@ func (l *ListWidget) recalculateCells() {
 		border = 1
 
 		top := make([]Cell, longest+2)
-		top[0] = Cell{Value: '┏'}
+		top[0] = Cell{Value: '┏', Attrs: l.Attrs}
-		top[longest+1] = Cell{Value: '┓'}
+		top[longest+1] = Cell{Value: '┓', Attrs: l.Attrs}
 		for i := 1; i <= longest; i++ {
-			top[i] = Cell{Value: '━'}
+			top[i] = Cell{Value: '━', Attrs: l.Attrs}
 		}
 
 		bottom := append([]Cell(nil), top...)
-		bottom[0] = Cell{Value: '┗'}
+		bottom[0] = Cell{Value: '┗', Attrs: l.Attrs}
-		bottom[longest+1] = Cell{Value: '┛'}
+		bottom[longest+1] = Cell{Value: '┛', Attrs: l.Attrs}
 
 		cells = append([][]Cell{top}, cells...)
 		cells = append(cells, bottom)
@@ -150,7 +164,7 @@ func (l *ListWidget) recalculateCells() {
 		}
 
 		if l.border {
-			c := Cell{Value: '┃'}
+			c := Cell{Value: '┃', Attrs: l.Attrs}
 			cells[i+border][0] = c
 			cells[i+border][longest+1] = c
 		}
@@ -160,7 +174,7 @@ func (l *ListWidget) recalculateCells() {
 			if j > start+len(s)-1 || j < start {
 				c.Value = ' '
 			} else {
-				c.Value = s[j-start]
+				c = s[j-start]
 			}
 
 			cells[i+border][j+border] = c

list_entry.go

@@ -0,0 +1,18 @@
+package main
+
+import (
+	"git.kevincotugno.com/kcotugno/spectator/exhibit"
+)
+
+type ListEntry struct {
+	Value string
+	Attrs exhibit.Attributes
+}
+
+func (e ListEntry) String() string {
+	return e.Value
+}
+
+func (e ListEntry) Attributes() exhibit.Attributes {
+	return e.Attrs
+}

spectator.go

@@ -81,7 +81,7 @@ func main() {
 	window.Constraints.Bottom = true
 	topAsks.SetBorder(true)
 	topAsks.SetRightAlign(true)
-	topAsks.Attrs.ForegroundColor = exhibit.FGRed
+	topAsks.Attrs.ForegroundColor = exhibit.FGYellow
 
 	topBids = &exhibit.ListWidget{}
 	topBids.SetBorder(true)
@@ -168,7 +168,6 @@ func main() {
 		num := numOfOrderPerSide(sz.Y)
 
 		aIt := asks.Iterator()
-		s := make([]string, num)
 
 		var low, high decimal.Decimal
 		for i := num - 1; i >= 0; i-- {
@@ -177,13 +176,15 @@ func main() {
 			entries := aIt.Value().(Entries)
 			price, size := flatten(entries)
 
-			s[i] = fmt.Sprintf("%v - %v ", price.StringFixed(2), size.StringFixed(8))
+			topAsks.AddEntry(ListEntry{Value: size.StringFixed(8),
+				Attrs: exhibit.Attributes{ForegroundColor:
+				exhibit.FGBlue}})
 
 			if i == num-1 {
 				low = price
 			}
 		}
-		topAsks.SetList(append([]string{}, s...))
+		topAsks.Commit()
 
 		bIt := bids.Iterator()
 		for i := 0; i < num; i++ {
@@ -192,22 +193,20 @@ func main() {
 			entries := bIt.Value().(Entries)
 			price, size := flatten(entries)
 
-			s[i] = fmt.Sprintf("%v - %v ", price.StringFixed(2), size.StringFixed(8))
+			topBids.AddEntry(ListEntry{Value: size.StringFixed(8)})
 
 			if i == 0 {
 				high = price
 			}
 		}
 
-		topBids.SetList(append([]string(nil), s...))
+		topBids.Commit()
 
 		diff := low.Sub(high)
 
-		s = []string{"", fmt.Sprintf("%v  Spread: %v",
+		midPrice.AddEntry(ListEntry{Value: high.Add(diff.Div(decimal.
-			high.Add(diff.Div(decimal.New(2, 0))).StringFixed(3),
+			New(2, 0))).StringFixed(3)})
-			diff.StringFixed(2)), ""}
+		midPrice.Commit()
-
-		midPrice.SetList(append([]string(nil), s...))
 	}
 }