Merge pull request #3 from atomicgo/feat/live-area

README.md

@@ -199,6 +199,37 @@ func UpAndClear(n int)
 ```
 UpAndClear moves the cursor up by n lines, then clears the line.
 
+#### type Area
+
+```go
+type Area struct {
+}
+```
+
+Area displays content which can be updated on the fly. You can use this to
+create live output, charts, dropdowns, etc.
+
+#### func  NewArea
+
+```go
+func NewArea() Area
+```
+NewArea returns a new Area.
+
+#### func (*Area) Clear
+
+```go
+func (area *Area) Clear()
+```
+Clear clears the content of the Area.
+
+#### func (*Area) Update
+
+```go
+func (area *Area) Update(content string)
+```
+Update overwrites the content of the Area.
+
 ---
 
 > [AtomicGo.dev](https://atomicgo.dev)  · 

area.go

@@ -0,0 +1,45 @@
+package cursor
+
+import (
+	"fmt"
+	"runtime"
+	"strings"
+)
+
+// Area displays content which can be updated on the fly.
+// You can use this to create live output, charts, dropdowns, etc.
+type Area struct {
+	height int
+}
+
+// NewArea returns a new Area.
+func NewArea() Area {
+	return Area{}
+}
+
+// Clear clears the content of the Area.
+func (area *Area) Clear() {
+	Bottom()
+	if area.height > 0 {
+		ClearLinesUp(area.height)
+	}
+}
+
+// Update overwrites the content of the Area.
+func (area *Area) Update(content string) {
+	area.Clear()
+	lines := strings.Split(content, "\n")
+	if runtime.GOOS == "windows" {
+		for _, line := range lines {
+			fmt.Print(line)
+			StartOfLineDown(1)
+		}
+	} else {
+		for _, line := range lines {
+			fmt.Println(line)
+		}
+	}
+	height = 0
+
+	area.height = len(lines)
+}

cursor.go

@@ -15,7 +15,7 @@ func Up(n int) {
 // Down moves the cursor n lines down relative to the current position.
 func Down(n int) {
 	fmt.Printf("\x1b[%dB", n)
-	if height-n < 0 {
+	if height-n <= 0 {
 		height = 0
 	} else {
 		height -= n

cursor_windows.go

@@ -15,7 +15,7 @@ func Up(n int) {
 // Down moves the cursor n lines down relative to the current position.
 func Down(n int) {
 	move(0, n)
-	if height-n < 0 {
+	if height-n <= 0 {
 		height = 0
 	} else {
 		height -= n

utils.go

@@ -5,9 +5,11 @@ var height int
 // Bottom moves the cursor to the bottom of the terminal.
 // This is done by calculating how many lines were moved by Up and Down.
 func Bottom() {
-	Down(height)
-	StartOfLine()
-	height = 0
+	if height > 0 {
+		Down(height)
+		StartOfLine()
+		height = 0
+	}
 }
 
 // StartOfLine moves the cursor to the start of the current line.