Stop scrolling when last column is visible (#91)

table/dimensions.go

@@ -14,6 +14,8 @@ func (m *Model) recalculateWidth() {
 	}
 
 	updateColumnWidths(m.columns, m.targetTotalWidth)
+
+	m.recalculateLastHorizontalColumn()
 }
 
 // Updates column width in-place.  This could be optimized but should be called

table/model.go

@@ -66,6 +66,9 @@ type Model struct {
 
 	// How many columns to freeze when scrolling horizontally
 	horizontalScrollFreezeColumnsCount int
+
+	// Calculated maximum column we can scroll to before the last is displayed
+	maxHorizontalColumnIndex int
 }
 
 // New creates a new table ready for further modifications.

table/options.go

@@ -275,6 +275,8 @@ func (m Model) WithFooterVisibility(visibility bool) Model {
 func (m Model) WithMaxTotalWidth(maxTotalWidth int) Model {
 	m.maxTotalWidth = maxTotalWidth
 
+	m.recalculateWidth()
+
 	return m
 }
 
@@ -284,6 +286,8 @@ func (m Model) WithMaxTotalWidth(maxTotalWidth int) Model {
 func (m Model) WithHorizontalFreezeColumnCount(columnsToFreeze int) Model {
 	m.horizontalScrollFreezeColumnsCount = columnsToFreeze
 
+	m.recalculateWidth()
+
 	return m
 }
 

table/scrolling.go

@@ -1,8 +1,7 @@
 package table
 
 func (m *Model) scrollRight() {
-	maxCol := len(m.columns) - 1 - m.horizontalScrollFreezeColumnsCount
-	if m.horizontalScrollOffsetCol < maxCol {
+	if m.horizontalScrollOffsetCol < m.maxHorizontalColumnIndex {
 		m.horizontalScrollOffsetCol++
 	}
 }
@@ -12,3 +11,46 @@ func (m *Model) scrollLeft() {
 		m.horizontalScrollOffsetCol--
 	}
 }
+
+func (m *Model) recalculateLastHorizontalColumn() {
+	if m.horizontalScrollFreezeColumnsCount >= len(m.columns) {
+		m.maxHorizontalColumnIndex = 0
+
+		return
+	}
+
+	if m.totalWidth <= m.maxTotalWidth {
+		m.maxHorizontalColumnIndex = 0
+
+		return
+	}
+
+	const (
+		leftOverflowWidth = 2
+		borderAdjustment  = 1
+	)
+
+	// Always have left border
+	visibleWidth := borderAdjustment + leftOverflowWidth
+
+	for i := 0; i < m.horizontalScrollFreezeColumnsCount; i++ {
+		visibleWidth += m.columns[i].width + borderAdjustment
+	}
+
+	m.maxHorizontalColumnIndex = len(m.columns) - 1
+
+	// Work backwards from the right
+	for i := len(m.columns) - 1; i >= m.horizontalScrollFreezeColumnsCount && visibleWidth <= m.maxTotalWidth; i-- {
+		visibleWidth += m.columns[i].width + borderAdjustment
+
+		if visibleWidth <= m.maxTotalWidth {
+			m.maxHorizontalColumnIndex = i - m.horizontalScrollFreezeColumnsCount
+		}
+	}
+
+	if m.maxHorizontalColumnIndex <= m.horizontalScrollFreezeColumnsCount {
+		m.maxHorizontalColumnIndex = 0
+
+		return
+	}
+}