refactor(table): smart crop logic

examples/table/pokemon/main.go

@@ -69,7 +69,7 @@ func main() {
 		Border(lipgloss.NormalBorder()).
 		BorderStyle(re.NewStyle().Foreground(lipgloss.Color("238"))).
 		Headers(CapitalizeHeaders(headers)...).
-		Width(90).
+		Width(40).
 		Rows(data...).
 		StyleFunc(func(row, col int) lipgloss.Style {
 			if row == 0 {

table/table.go

@@ -274,57 +274,47 @@ func (t *Table) String() string {
 			i = (i + 1) % len(t.widths)
 		}
 	} else if width > t.width && t.width > 0 {
-		// Table is too wide, narrow the columns until it reaches the desired
-		// width. We choose which columns to narrow based on the median
-		// non-whitespace length of each column.
+		// Table is too wide, calculate the median non-whitespace length of each
+		// column, and shrink the columns based on the largest difference.
 		columnMedians := make([]int, len(t.widths))
 		for c := range t.widths {
 			trimmedWidth := make([]int, len(t.rows))
-			for r := range t.rows {
-				renderedCell := t.style(r+btoi(hasHeaders), c).Render(fmt.Sprint(t.rows[r][c]))
-				nonWhitespaceChars := lipgloss.Width(strings.TrimRight(renderedCell, " ")) + 1
-				trimmedWidth[r] = nonWhitespaceChars + 1 // +1 for some padding or truncation character
+			for r, row := range t.rows {
+				renderedCell := t.style(r+btoi(hasHeaders), c).Render(fmt.Sprint(row[c]))
+				nonWhitespaceChars := lipgloss.Width(strings.TrimRight(renderedCell, " "))
+				trimmedWidth[r] = nonWhitespaceChars + 1
 			}
 			columnMedians[c] = median(trimmedWidth)
 		}
 
-		for width > t.width {
-			var largestDiff, largestDiffIndex int
-			for i, median := range columnMedians {
-				difference := (t.widths[i] - median)
-				if median > largestDiff {
-					largestDiff = difference
-					largestDiffIndex = i
-				}
-			}
+		// Find the biggest differences between the median and the column width.
+		// Shrink the columns based on the largest difference.
+		differences := make([]int, len(t.widths))
+		for i := range t.widths {
+			differences[i] = t.widths[i] - columnMedians[i]
+		}
 
-			if largestDiff <= 0 {
+		for width > t.width {
+			index := largest(differences)
+			if differences[index] < 1 {
 				break
 			}
 
-			if width-largestDiff < t.width {
-				largestDiff = width - t.width
-			}
-
-			width -= largestDiff
-
-			// Set column width to the median.
-			newWidth := t.widths[largestDiffIndex] - largestDiff
-			t.widths[largestDiffIndex] = max(newWidth, 1)
-			columnMedians[largestDiffIndex] = 0
+			shrink := min(differences[index], width-t.width)
+			t.widths[index] -= shrink
+			width -= shrink
+			differences[index] = 0
 		}
 
-		minWidth := len(t.widths) + (len(t.widths) * btoi(t.borderColumn)) + btoi(t.borderLeft) + btoi(t.borderRight)
-		if t.width > minWidth {
-			var i int
-			for width > t.width {
-				if t.widths[i] <= 1 {
-					continue
-				}
-				t.widths[i]--
-				width--
-				i = (i + 1) % len(t.widths)
+		// Table is still too wide, begin shrinking the columns based on the
+		// largest column.
+		for width > t.width {
+			index := largest(t.widths)
+			if t.widths[index] < 1 {
+				break
 			}
+			t.widths[index]--
+			width--
 		}
 	}
 
@@ -389,6 +379,14 @@ func max(a, b int) int {
 	return b
 }
 
+// min returns the greater of two integers.
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
 // sum returns the sum of all integers in a slice.
 func sum(n []int) int {
 	var sum int
@@ -411,6 +409,16 @@ func median(n []int) int {
 	return n[len(n)/2]
 }
 
+func largest(n []int) int {
+	var largest int
+	for i := range n {
+		if n[i] > n[largest] {
+			largest = i
+		}
+	}
+	return largest
+}
+
 func (t *Table) constructTopBorder() string {
 	var s strings.Builder
 	if t.borderLeft {

table/table_test.go

@@ -638,16 +638,16 @@ func TestTableWidthSmartCropExtensive(t *testing.T) {
 		Rows(rows...)
 
 	expected := strings.TrimSpace(`
-┏━━━━━┳━━━━━┳━━━━┓
-┃ LAN ┃ FOR ┃ IN ┃
-┣━━━━━╋━━━━━╋━━━━┫
-┃ Chi ┃ 您  ┃ 你 ┃
-┃ Jap ┃ こ  ┃ や ┃
-┃ Ara ┃ أهل ┃ أه ┃
-┃ Rus ┃ Здр ┃ Пр ┃
-┃ Spa ┃ Hol ┃ ¿Q ┃
-┃ Eng ┃ You ┃ Ho ┃
-┗━━━━━┻━━━━━┻━━━━┛
+┏━━━━┳━━━━━┳━━━━━┓
+┃ LA ┃ FOR ┃ INF ┃
+┣━━━━╋━━━━━╋━━━━━┫
+┃ Ch ┃ 您  ┃ 你  ┃
+┃ Ja ┃ こ  ┃ や  ┃
+┃ Ar ┃ أهل ┃ أهل ┃
+┃ Ru ┃ Здр ┃ При ┃
+┃ Sp ┃ Hol ┃ ¿Qu ┃
+┃ En ┃ You ┃ How ┃
+┗━━━━┻━━━━━┻━━━━━┛
 `)
 
 	if table.String() != expected {
@@ -709,13 +709,13 @@ func TestTableWidths(t *testing.T) {
 
 	expected := strings.TrimSpace(`
 ──────────────────────────────
- LANGUAGE   FORMAL    INFORMA 
+ LANGUAGE  FORMAL   INFORMAL  
 ──────────────────────────────
- Chinese   Nǐn hǎo    Nǐ hǎo  
- French    Bonjour    Salut   
- Japanese  こんにち   やあ    
- Russian   Zdravstvu  Privet  
- Spanish   Hola       ¿Qué    
+ Chinese   Nǐn hǎo  Nǐ hǎo    
+ French    Bonjour  Salut     
+ Japanese  こんに   やあ      
+ Russian   Zdravst  Privet    
+ Spanish   Hola     ¿Qué tal? 
 ──────────────────────────────
 `)
 
@@ -745,13 +745,13 @@ func TestTableWidthShrinkNoBorders(t *testing.T) {
 
 	expected := strings.TrimSpace(`
 ──────────────────────────────
- LANGUAGE   FORMAL    INFORMA 
+ LANGUAGE  FORMAL   INFORMAL  
 ──────────────────────────────
- Chinese   Nǐn hǎo    Nǐ hǎo  
- French    Bonjour    Salut   
- Japanese  こんにち   やあ    
- Russian   Zdravstvu  Privet  
- Spanish   Hola       ¿Qué    
+ Chinese   Nǐn hǎo  Nǐ hǎo    
+ French    Bonjour  Salut     
+ Japanese  こんに   やあ      
+ Russian   Zdravst  Privet    
+ Spanish   Hola     ¿Qué tal? 
 ──────────────────────────────
 `)