feat: Add multi-line labels and width control with auto-fitting

.gitignore

@@ -15,3 +15,9 @@ mermaid-ascii
 *.tar.gz
 *.tar.zst
 result
+mermaid-ascii-fork
+mermaid-ascii-go
+mermaid-ascii-patched
+
+# Backup files
+*.bak

LICENSE

@@ -1,6 +1,7 @@
 MIT License
 
 Copyright (c) 2023 Alexander Grooff
+Copyright (c) 2026 Gregory R. Warnes
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -1,6 +1,15 @@
 # Mermaid ASCII
 
-Render mermaid diagrams in your terminal:
+Render mermaid diagrams in your terminal.
+
+## Features
+
+This fork adds:
+- **Multi-line node labels**: Use `<br/>` or `<br>` HTML tags in node labels to create multi-line text
+- **Diagram width control**: Use `-w/--maxWidth` to constrain diagram width, with automatic layout fitting
+- **Label alignment control**: Use `--center-multi-line-labels` to control how multi-line labels are centered (default: left-justified block)
+- **Version flag**: Use `--version` to show version information
+- **Enhanced UTF-8 support**: Proper handling of wide characters (CJK, emoji) in node labels
 
 ## Installation
 
@@ -127,6 +136,60 @@ $ mermaid-ascii -f ./test.mermaid
           │   │              
           └───┘              
 
+# Multi-line node labels (using <br/> or <br> tags)
+$ cat test.mermaid
+graph LR
+A["First<br/>Second"] --> B["Line 1<br>Line 2<br>Line 3"]
+$ mermaid-ascii -f ./test.mermaid
+┌────────┐     ┌────────┐
+│ First  │     │ Line 1 │
+│ Second ├────►│ Line 2 │
+│        │     │ Line 3 │
+└────────┘     └────────┘
+
+# Multi-line labels with tree-like structure (default: left-justified)
+$ cat test.mermaid
+graph LR
+A["┌─ TIMER<br/>├─> Step 1<br/>└─> Step 2"]
+$ mermaid-ascii -f ./test.mermaid
+┌────────────┐
+│ ┌─ TIMER   │
+│ ├─> Step 1 │
+│ └─> Step 2 │
+└────────────┘
+
+# Center each line individually with --center-multi-line-labels
+$ cat test.mermaid
+graph LR
+A["┌─ TIMER<br/>├─> Step 1<br/>└─> Step 2"]
+$ mermaid-ascii -f ./test.mermaid --center-multi-line-labels
+┌────────────┐
+│ ┌─ TIMER   │
+│ ├─> Step 1 │
+│ └─> Step 2 │
+└────────────┘
+
+# Control diagram width
+$ cat test.mermaid
+graph LR
+A --> B --> C --> D --> E
+$ mermaid-ascii -f ./test.mermaid -w 50
+┌───┐     ┌───┐     ┌───┐
+│   │     │   │     │   │
+│ A ├────►│ B ├────►│ C │
+│   │     │   │     │   │
+└─┬─┘     └───┘     └───┘
+  │                      
+  │                      
+  │                      
+  │                      
+  ▼                      
+┌───┐     ┌───┐          
+│   │     │   │          
+│ D ├────►│ E │          
+│   │     │   │          
+└───┘     └───┘          
+
 # Top-down layout
 $ cat test.mermaid
 graph TD
@@ -355,13 +418,18 @@ Available Commands:
   web         HTTP server for rendering mermaid diagrams.
 
 Flags:
-  -p, --borderPadding int   Padding between text and border (default 1)
-  -c, --coords              Show coordinates
-  -f, --file string         Mermaid file to parse
-  -h, --help                help for mermaid-ascii
-  -x, --paddingX int        Horizontal space between nodes (default 5)
-  -y, --paddingY int        Vertical space between nodes (default 5)
-  -v, --verbose             Verbose output
+  -a, --ascii                        Don't use extended character set
+  -p, --borderPadding int            Padding between text and border (default 1)
+      --center-multi-line-labels     Center multi-line node labels as a block
+  -c, --coords                       Show coordinates
+  -f, --file string                  Mermaid file to parse (use '-' for stdin)
+      --fit                          Force automatic fitting even without width constraint
+  -h, --help                         help for mermaid-ascii
+  -w, --maxWidth int                 Maximum diagram width in characters (0 = unlimited)
+  -x, --paddingX int                 Horizontal space between nodes (default 5)
+  -y, --paddingY int                 Vertical space between nodes (default 5)
+  -v, --verbose                      Verbose output
+      --version                      Show version information
 
 Use "mermaid-ascii [command] --help" for more information about a command.
 
@@ -509,10 +577,12 @@ Note that with `--coords` enabled, the grid-coords shown show the starting locat
 ### Graphs / Flowcharts ✅
 - [x] Graph directions (`graph LR` and `graph TD`)
 - [x] Labelled edges (like `A -->|label| B`)
+- [x] Multi-line node labels (using `<br/>` or `<br>` tags)
 - [x] Multiple arrows on one line (like `A --> B --> C`)
 - [x] `A & B` syntax
 - [x] `classDef` and `class` for colored output
 - [x] Prevent arrows overlapping nodes
+- [x] Control diagram width (via `-w/--maxWidth` flag)
 - [ ] `subgraph` support
 - [ ] Shapes other than rectangles
 - [ ] Diagonal arrows
@@ -547,9 +617,9 @@ The baseline components for Mermaid work, but there are a lot of things that are
 ### Rendering
 
 - [x] Prevent arrows overlapping nodes
+- [x] Control maximum diagram width (via `-w/--maxWidth` flag)
 - [ ] Diagonal arrows
 - [ ] Place nodes in a more compact way
-- [ ] Prevent rendering more than X characters wide (like default 80 for terminal width)
 
 ### Sequence Diagram Improvements
 

cmd/diagram.go

@@ -84,6 +84,20 @@ func (gd *GraphDiagram) Render(config *diagram.Config) (string, error) {
 	}
 	gd.properties.styleType = styleType
 	gd.properties.useAscii = config.UseAscii
+	if config.GraphDirection != "" {
+		gd.properties.graphDirection = config.GraphDirection
+	}
+	gd.properties.paddingX = config.PaddingBetweenX
+	gd.properties.paddingY = config.PaddingBetweenY
+	gd.properties.boxBorderPadding = config.BoxBorderPadding
+	gd.properties.labelWrapWidth = config.LabelWrapWidth
+	gd.properties.edgeLabelPolicy = config.EdgeLabelPolicy
+	gd.properties.edgeLabelMaxWidth = config.EdgeLabelMaxWidth
+	gd.properties.centerMultiLineLabels = config.CenterMultiLineLabels
+
+	if config.FitPolicy == diagram.FitPolicyAuto && config.MaxWidth > 0 {
+		return fitGraphToWidth(gd.properties, config), nil
+	}
 
 	return drawMap(gd.properties), nil
 }

cmd/direction.go

@@ -45,23 +45,23 @@ func (c drawingCoord) Direction(dir direction) drawingCoord {
 	return drawingCoord{x: c.x + dir.x, y: c.y + dir.y}
 }
 
-func selfReferenceDirection(e *edge) (direction, direction, direction, direction) {
-	if graphDirection == "LR" {
+func (g *graph) selfReferenceDirection(e *edge) (direction, direction, direction, direction) {
+	if g.graphDirection == "LR" {
 		return Right, Down, Down, Right
 	}
 	return Down, Right, Right, Down
 }
 
-func determineStartAndEndDir(e *edge) (direction, direction, direction, direction) {
+func (g *graph) determineStartAndEndDir(e *edge) (direction, direction, direction, direction) {
 	if e.from == e.to {
-		return selfReferenceDirection(e)
+		return g.selfReferenceDirection(e)
 	}
 	d := determineDirection(genericCoord(*e.from.gridCoord), genericCoord(*e.to.gridCoord))
 	var preferredDir, preferredOppositeDir, alternativeDir, alternativeOppositeDir direction
 
 	// Check if this is a backwards flowing edge
 	isBackwards := false
-	if graphDirection == "LR" {
+	if g.graphDirection == "LR" {
 		// In LR mode, backwards flow is when edge goes from right to left (Left direction)
 		isBackwards = (d == Left || d == UpperLeft || d == LowerLeft)
 	} else { // TD mode
@@ -75,7 +75,7 @@ func determineStartAndEndDir(e *edge) (direction, direction, direction, directio
 	// For backwards edges, use special start positions: Down in LR mode, Right in TD mode
 	switch d {
 	case LowerRight:
-		if graphDirection == "LR" {
+		if g.graphDirection == "LR" {
 			preferredDir = Down
 			preferredOppositeDir = Left
 			alternativeDir = Right
@@ -87,7 +87,7 @@ func determineStartAndEndDir(e *edge) (direction, direction, direction, directio
 			alternativeOppositeDir = Left
 		}
 	case UpperRight:
-		if graphDirection == "LR" {
+		if g.graphDirection == "LR" {
 			preferredDir = Up
 			preferredOppositeDir = Left
 			alternativeDir = Right
@@ -99,7 +99,7 @@ func determineStartAndEndDir(e *edge) (direction, direction, direction, directio
 			alternativeOppositeDir = Left
 		}
 	case LowerLeft:
-		if graphDirection == "LR" {
+		if g.graphDirection == "LR" {
 			// Backwards flow in LR mode - start from Down, arrive at Down
 			preferredDir = Down
 			preferredOppositeDir = Down // Edge goes to bottom of destination
@@ -112,7 +112,7 @@ func determineStartAndEndDir(e *edge) (direction, direction, direction, directio
 			alternativeOppositeDir = Right
 		}
 	case UpperLeft:
-		if graphDirection == "LR" {
+		if g.graphDirection == "LR" {
 			// Backwards flow in LR mode - start from Down, arrive at Down
 			preferredDir = Down
 			preferredOppositeDir = Down // Edge goes to bottom of destination
@@ -128,13 +128,13 @@ func determineStartAndEndDir(e *edge) (direction, direction, direction, directio
 	default:
 		// Handle direct backwards flow cases
 		if isBackwards {
-			if graphDirection == "LR" && d == Left {
+			if g.graphDirection == "LR" && d == Left {
 				// Direct left flow in LR mode - start from Down, arrive at Down
 				preferredDir = Down
 				preferredOppositeDir = Down // Edge goes to bottom of destination
 				alternativeDir = Left
 				alternativeOppositeDir = Right
-			} else if graphDirection == "TD" && d == Up {
+			} else if g.graphDirection == "TD" && d == Up {
 				// Direct up flow in TD mode - start from Right, arrive at Right
 				preferredDir = Right
 				preferredOppositeDir = Right // Edge goes to right of destination

cmd/draw.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 
 	"github.com/gookit/color"
+	"github.com/mattn/go-runewidth"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -155,7 +156,14 @@ func drawMap(properties *graphProperties) string {
 	g.setStyleClasses(properties)
 	g.paddingX = properties.paddingX
 	g.paddingY = properties.paddingY
+	g.graphDirection = properties.graphDirection
+	g.boxBorderPadding = properties.boxBorderPadding
+	g.labelWrapWidth = properties.labelWrapWidth
+	g.edgeLabelPolicy = properties.edgeLabelPolicy
+	g.edgeLabelMaxWidth = properties.edgeLabelMaxWidth
 	g.useAscii = properties.useAscii
+	g.centerMultiLineLabels = properties.centerMultiLineLabels
+	g.setLabelLines()
 	g.setSubgraphs(properties.subgraphs)
 	g.createMapping()
 	d := g.draw()
@@ -228,10 +236,81 @@ func drawBox(n *node, g graph) *drawing {
 		boxDrawing[to.x][to.y] = "+"     // Bottom right corner
 	}
 	// Draw text
-	textY := from.y + h/2
-	textX := from.x + w/2 - CeilDiv(len(n.name), 2) + 1
-	for x := 0; x < len(n.name); x++ {
-		boxDrawing[textX+x][textY] = wrapTextInColor(string(n.name[x]), n.styleClass.styles["color"], g.styleType)
+	labelLines := n.labelLines
+	if len(labelLines) == 0 {
+		labelLines = []string{n.name}
+	}
+	innerLeft := from.x + 1
+	innerRight := to.x - 1
+	innerTop := from.y + 1
+	innerBottom := to.y - 1
+	innerWidth := innerRight - innerLeft + 1
+	innerHeight := innerBottom - innerTop + 1
+	startY := innerTop
+	if innerHeight > len(labelLines) {
+		startY = innerTop + (innerHeight-len(labelLines))/2
+	}
+	maxLines := Min(len(labelLines), innerHeight)
+	isMultiLine := len(labelLines) > 1
+
+	// When centerMultiLineLabels is false and we have multiple lines,
+	// pad all lines to the same width before centering as a block
+	linesToDraw := labelLines
+	if isMultiLine && !g.centerMultiLineLabels {
+		// Find max line width accounting for character widths
+		maxLineWidth := 0
+		for _, line := range labelLines[:maxLines] {
+			lineWidth := runewidth.StringWidth(line)
+			if lineWidth > maxLineWidth {
+				maxLineWidth = lineWidth
+			}
+		}
+		// Pad each line to max width with trailing spaces
+		linesToDraw = make([]string, len(labelLines))
+		for i, line := range labelLines {
+			lineWidth := runewidth.StringWidth(line)
+			if lineWidth < maxLineWidth {
+				linesToDraw[i] = line + strings.Repeat(" ", maxLineWidth-lineWidth)
+			} else {
+				linesToDraw[i] = line
+			}
+		}
+	}
+
+	for lineIdx := 0; lineIdx < maxLines; lineIdx++ {
+		line := linesToDraw[lineIdx]
+		runes := []rune(line)
+		// Use display width (accounts for CJK full-width chars, emoji, etc.)
+		lineWidth := runewidth.StringWidth(line)
+
+		startX := innerLeft
+		// Center single-line labels, or multi-line when centerMultiLineLabels is true
+		if (!isMultiLine || g.centerMultiLineLabels) && innerWidth > lineWidth {
+			startX = innerLeft + (innerWidth-lineWidth)/2
+		} else if isMultiLine && !g.centerMultiLineLabels && innerWidth > lineWidth {
+			// Block centering: center the entire padded block
+			startX = innerLeft + (innerWidth-lineWidth)/2
+		}
+
+		// Place characters at display positions - wide chars (CJK, emoji) occupy 2 display columns
+		displayPos := 0
+		for _, r := range runes {
+			charWidth := runewidth.RuneWidth(r)
+			// Check if character will fit in remaining display width
+			if displayPos+charWidth > innerWidth {
+				break
+			}
+			if startX+displayPos > innerRight {
+				break
+			}
+			// Place character at its display position
+			boxDrawing[startX+displayPos][startY+lineIdx] = wrapTextInColor(string(r), n.styleClass.styles["color"], g.styleType)
+			// For wide characters, clear the next cell (the character spans it visually)
+			if charWidth > 1 && startX+displayPos+1 <= innerRight {
+				boxDrawing[startX+displayPos+1][startY+lineIdx] = ""
+			}
+			displayPos += charWidth
+		}
 	}
 
 	return &boxDrawing