feat: join borders layout functions

joinborders.go

@@ -0,0 +1,293 @@
+package lipgloss
+
+import (
+	"math"
+	"strings"
+
+	"github.com/charmbracelet/x/ansi"
+)
+
+// JoinBorderVertical is a utility function for vertically joining two
+// potentially multi-lined strings along a horizontal axis with borders.
+// The first argument is the style used for the borders. The second argument
+// is the alignment position, with 0 being all the way to the left and 1 being
+// all the way to the right.
+//
+// If you just want to align to the left, right or center you may as well just
+// use the helper constants Left, Center, and Right.
+//
+// Example:
+//
+//	blockB := "...\n...\n..."
+//	blockA := "...\n...\n...\n...\n..."
+//
+//	// Join 20% from the top
+//	str := JoinBorderVertical(s, 0.2, blockA, blockB)
+//
+//	// Join on the right edge
+//	str := JoinBorderVertical(s, Right, blockA, blockB)
+func JoinBorderVertical(borderStyle Style, pos Position, strs ...string) string {
+	if len(strs) == 0 {
+		return ""
+	}
+	if len(strs) == 1 {
+		return strs[0]
+	}
+
+	var (
+		maxWidth int
+		blocks   = make([][]string, len(strs))
+
+		stt, str, stb, stl = getBorderStyles(borderStyle)
+
+		border, top, right, bottom, left = borderStyle.GetBorder()
+	)
+
+	for i := range strs {
+		var w int
+		blocks[i], w = getLines(strs[i])
+		if w > maxWidth {
+			maxWidth = w
+		}
+	}
+
+	var sb strings.Builder
+
+	if top {
+		var buff strings.Builder
+		if left {
+			buff.WriteString(border.TopLeft)
+		}
+		buff.WriteString(strings.Repeat(border.Top, maxWidth))
+		if right {
+			buff.WriteString(border.TopRight)
+		}
+		sb.WriteString(stt.Render(buff.String()))
+		sb.WriteRune('\n')
+	}
+
+	for i, block := range blocks {
+		for j, line := range block {
+			w := maxWidth - ansi.StringWidth(line)
+
+			if left {
+				sb.WriteString(stl.Render(border.Left))
+			}
+
+			switch pos { //nolint:exhaustive
+			case Left:
+				sb.WriteString(line)
+				sb.WriteString(strings.Repeat(" ", w))
+
+			case Right:
+				sb.WriteString(strings.Repeat(" ", w))
+				sb.WriteString(line)
+
+			default: // Somewhere in the middle
+				if w < 1 {
+					sb.WriteString(line)
+					break
+				}
+
+				split := int(math.Round(float64(w) * pos.value()))
+				right := w - split
+				left := w - right
+
+				sb.WriteString(strings.Repeat(" ", left))
+				sb.WriteString(line)
+				sb.WriteString(strings.Repeat(" ", right))
+			}
+
+			if right {
+				sb.WriteString(str.Render(border.Right))
+			}
+
+			// Write a newline as long as we're not on the last line of the
+			// last block.
+			if !(i == len(blocks)-1 && j == len(block)-1) {
+				sb.WriteRune('\n')
+			}
+		}
+		if i < len(blocks)-1 {
+			var buff strings.Builder
+			if left {
+				buff.WriteString(border.MiddleLeft)
+			}
+			buff.WriteString(strings.Repeat(border.Bottom, maxWidth))
+			if right {
+				buff.WriteString(border.MiddleRight)
+			}
+			sb.WriteString(stt.Render(buff.String()))
+			sb.WriteRune('\n')
+		}
+	}
+
+	if bottom {
+		sb.WriteRune('\n')
+		var buff strings.Builder
+		if left {
+			buff.WriteString(border.BottomLeft)
+		}
+		buff.WriteString(strings.Repeat(border.Bottom, maxWidth))
+		if right {
+			buff.WriteString(border.BottomRight)
+		}
+		sb.WriteString(stb.Render(buff.String()))
+	}
+
+	return sb.String()
+}
+
+// JoinBorderHorizontal is a utility function for horizontally joining two
+// potentially multi-lined strings along a vertical axis. The first argument is
+// the position, with 0 being all the way at the top and 1 being all the way
+// at the bottom.
+//
+// If you just want to align to the top, center or bottom you may as well just
+// use the helper constants Top, Center, and Bottom.
+//
+// Example:
+//
+//	blockB := "...\n...\n..."
+//	blockA := "...\n...\n...\n...\n..."
+//
+//	// Join 20% from the top
+//	str := JoinBorderHorizontal(s, 0.2, blockA, blockB)
+//
+//	// Join on the top edge
+//	str := JoinBorderHorizontal(s, Top, blockA, blockB)
+func JoinBorderHorizontal(borderStyle Style, pos Position, strs ...string) string {
+	if len(strs) == 0 {
+		return ""
+	}
+	if len(strs) == 1 {
+		return strs[0]
+	}
+
+	var (
+		// Groups of strings broken into multiple lines
+		blocks = make([][]string, len(strs))
+
+		stt, str, stb, stl = getBorderStyles(borderStyle)
+
+		border, top, right, bottom, left = borderStyle.GetBorder()
+
+		// Max line widths for the above text blocks
+		maxWidths = make([]int, len(strs))
+
+		// Height of the tallest block
+		maxHeight int
+	)
+
+	// Break text blocks into lines and get max widths for each text block
+	for i, str := range strs {
+		blocks[i], maxWidths[i] = getLines(str)
+		if len(blocks[i]) > maxHeight {
+			maxHeight = len(blocks[i])
+		}
+	}
+
+	// Add extra lines to make each side the same height
+	for i := range blocks {
+		if len(blocks[i]) >= maxHeight {
+			continue
+		}
+
+		extraLines := make([]string, maxHeight-len(blocks[i]))
+
+		switch pos { //nolint:exhaustive
+		case Top:
+			blocks[i] = append(blocks[i], extraLines...)
+
+		case Bottom:
+			blocks[i] = append(extraLines, blocks[i]...)
+
+		default: // Somewhere in the middle
+			n := len(extraLines)
+			split := int(math.Round(float64(n) * pos.value()))
+			top := n - split
+			bottom := n - top
+
+			blocks[i] = append(extraLines[top:], blocks[i]...)
+			blocks[i] = append(blocks[i], extraLines[bottom:]...)
+		}
+	}
+
+	// Merge lines
+	var sb strings.Builder
+
+	// write top border
+	if top {
+		var buff strings.Builder
+		buff.WriteString(border.TopLeft)
+		for j := range blocks {
+			if j > 0 {
+				buff.WriteString(border.MiddleTop)
+			}
+			buff.WriteString(strings.Repeat(border.Top, maxWidths[j]))
+		}
+		buff.WriteString(border.TopRight)
+		sb.WriteString(stt.Render(buff.String()))
+		sb.WriteRune('\n')
+	}
+
+	for i := range blocks[0] { // remember, all blocks have the same number of members now
+		for j, block := range blocks {
+			if left || j > 0 {
+				sb.WriteString(stl.Render(border.Left))
+			}
+			sb.WriteString(block[i])
+
+			// Also make lines the same length
+			sb.WriteString(strings.Repeat(" ", maxWidths[j]-ansi.StringWidth(block[i])))
+		}
+		if right {
+			sb.WriteString(str.Render(border.Right))
+		}
+		if i < len(blocks[0])-1 {
+			sb.WriteRune('\n')
+		}
+	}
+
+	// write bottom border
+	if bottom {
+		sb.WriteRune('\n')
+
+		var buff strings.Builder
+		buff.WriteString(border.BottomLeft)
+		for j := range blocks {
+			if j > 0 {
+				buff.WriteString(border.MiddleBottom)
+			}
+			buff.WriteString(strings.Repeat(border.Bottom, maxWidths[j]))
+		}
+		buff.WriteString(border.BottomRight)
+		sb.Write([]byte(stb.Render(buff.String())))
+	}
+
+	return sb.String()
+}
+
+// getBorderStyles gets the styles for each side of the border
+// returns Top, Right, Bottom, and Left Styles
+func getBorderStyles(borderStyle Style) (Style, Style, Style, Style) {
+	var (
+		styleT = NewStyle().
+			Foreground(borderStyle.GetBorderTopForeground()).
+			Background(borderStyle.GetBorderTopBackground())
+
+		styleR = NewStyle().
+			Foreground(borderStyle.GetBorderRightForeground()).
+			Background(borderStyle.GetBorderRightBackground())
+
+		styleB = NewStyle().
+			Foreground(borderStyle.GetBorderBottomForeground()).
+			Background(borderStyle.GetBorderBottomBackground())
+
+		styleL = NewStyle().
+			Foreground(borderStyle.GetBorderLeftForeground()).
+			Background(borderStyle.GetBorderLeftBackground())
+	)
+
+	return styleT, styleR, styleB, styleL
+}

joinborders_test.go

@@ -0,0 +1,47 @@
+package lipgloss
+
+import "testing"
+
+func TestJoinBorderVertical(t *testing.T) {
+	s := NewStyle().Border(NormalBorder())
+	type test struct {
+		name     string
+		result   string
+		expected string
+	}
+	tests := []test{
+		{"pos0", JoinBorderVertical(s, Left, "A", "BBBB"), "┌────┐\n│A   │\n├────┤\n│BBBB│\n└────┘"},
+		{"pos1", JoinBorderVertical(s, Right, "A", "BBBB"), "┌────┐\n│   A│\n├────┤\n│BBBB│\n└────┘"},
+		{"pos0.25", JoinBorderVertical(s, 0.25, "A", "BBBB"), "┌────┐\n│ A  │\n├────┤\n│BBBB│\n└────┘"},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			if test.result != test.expected {
+				t.Errorf("Got \n%s\n, expected \n%s\n", test.result, test.expected)
+			}
+		})
+	}
+}
+
+func TestJoinBorderHorizontal(t *testing.T) {
+	s := NewStyle().Border(NormalBorder())
+	type test struct {
+		name     string
+		result   string
+		expected string
+	}
+	tests := []test{
+		{"pos0", JoinBorderHorizontal(s, Top, "A", "B\nB\nB\nB"), "┌─┬─┐\n│A│B│\n│ │B│\n│ │B│\n│ │B│\n└─┴─┘"},
+		{"pos1", JoinBorderHorizontal(s, Bottom, "A", "B\nB\nB\nB"), "┌─┬─┐\n│ │B│\n│ │B│\n│ │B│\n│A│B│\n└─┴─┘"},
+		{"pos0.25", JoinBorderHorizontal(s, 0.25, "A", "B\nB\nB\nB"), "┌─┬─┐\n│ │B│\n│A│B│\n│ │B│\n│ │B│\n└─┴─┘"},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			if test.result != test.expected {
+				t.Errorf("Got \n%s\n, expected \n%s\n", test.result, test.expected)
+			}
+		})
+	}
+}