Add cli option

d2cli/main.go

@@ -89,6 +89,10 @@ func Run(ctx context.Context, ms *xmain.State) (err error) {
 	if err != nil {
 		return err
 	}
+	fontFlag := ms.Opts.String("FONT", "font", "", "", "the font used to render text (default \"Source Sans Pro\"")
+	if err != nil {
+		return err
+	}
 
 	ps, err := d2plugin.ListPlugins(ctx)
 	if err != nil {
@@ -249,6 +253,7 @@ func Run(ctx context.Context, ms *xmain.State) (err error) {
 			bundle:        *bundleFlag,
 			forceAppendix: *forceAppendixFlag,
 			pw:            pw,
+			font:          *fontFlag,
 		})
 		if err != nil {
 			return err
@@ -259,7 +264,7 @@ func Run(ctx context.Context, ms *xmain.State) (err error) {
 	ctx, cancel := context.WithTimeout(ctx, time.Minute*2)
 	defer cancel()
 
-	_, written, err := compile(ctx, ms, plugin, *sketchFlag, *centerFlag, *padFlag, *themeFlag, darkThemeFlag, inputPath, outputPath, *bundleFlag, *forceAppendixFlag, pw.Page)
+	_, written, err := compile(ctx, ms, plugin, *sketchFlag, *centerFlag, *padFlag, *themeFlag, darkThemeFlag, inputPath, outputPath, *bundleFlag, *forceAppendixFlag, pw.Page, *fontFlag)
 	if err != nil {
 		if written {
 			return fmt.Errorf("failed to fully compile (partial render written): %w", err)
@@ -269,13 +274,19 @@ func Run(ctx context.Context, ms *xmain.State) (err error) {
 	return nil
 }
 
-func compile(ctx context.Context, ms *xmain.State, plugin d2plugin.Plugin, sketch, center bool, pad, themeID int64, darkThemeID *int64, inputPath, outputPath string, bundle, forceAppendix bool, page playwright.Page) (_ []byte, written bool, _ error) {
+func compile(ctx context.Context, ms *xmain.State, plugin d2plugin.Plugin, sketch, center bool, pad, themeID int64, darkThemeID *int64, inputPath, outputPath string, bundle, forceAppendix bool, page playwright.Page, font string) (_ []byte, written bool, _ error) {
 	start := time.Now()
 	input, err := ms.ReadPath(inputPath)
 	if err != nil {
 		return nil, false, err
 	}
 
+	// load custom fonts before initializing ruler
+	fontFamily, err := d2fonts.AddFont(font)
+	if err != nil {
+		return nil, false, err
+	}
+
 	ruler, err := textmeasure.NewRuler()
 	if err != nil {
 		return nil, false, err
@@ -289,6 +300,8 @@ func compile(ctx context.Context, ms *xmain.State, plugin d2plugin.Plugin, sketc
 	}
 	if sketch {
 		opts.FontFamily = go2.Pointer(d2fonts.HandDrawn)
+	} else if fontFamily != "" {
+		opts.FontFamily = go2.Pointer(fontFamily)
 	}
 
 	cancel := background.Repeat(func() {

d2cli/watch.go

@@ -53,6 +53,7 @@ type watcherOpts struct {
 	bundle        bool
 	forceAppendix bool
 	pw            png.Playwright
+	font          string
 }
 
 type watcher struct {
@@ -360,7 +361,7 @@ func (w *watcher) compileLoop(ctx context.Context) error {
 			w.pw = newPW
 		}
 
-		svg, _, err := compile(ctx, w.ms, w.layoutPlugin, w.sketch, w.center, w.pad, w.themeID, w.darkThemeID, w.inputPath, w.outputPath, w.bundle, w.forceAppendix, w.pw.Page)
+		svg, _, err := compile(ctx, w.ms, w.layoutPlugin, w.sketch, w.center, w.pad, w.themeID, w.darkThemeID, w.inputPath, w.outputPath, w.bundle, w.forceAppendix, w.pw.Page, w.font)
 		errs := ""
 		if err != nil {
 			if len(svg) > 0 {

d2renderers/d2fonts/d2fonts.go

@@ -6,7 +6,13 @@ package d2fonts
 
 import (
 	"embed"
+	"encoding/base64"
+	"fmt"
+	"os"
+	"path/filepath"
 	"strings"
+
+	fontlib "oss.terrastruct.com/d2/lib/font"
 )
 
 type FontFamily string
@@ -212,6 +218,43 @@ func init() {
 	}] = b
 }
 
+func AddFont(fontLoc string) (FontFamily, error) {
+	if fontLoc == "" {
+		return "", nil
+	}
+	fontBuf, err := os.ReadFile(fontLoc)
+	if err != nil {
+		return "", fmt.Errorf("failed to read font: %v", err)
+	}
+
+	splitFont := strings.Split(fontLoc, "/")
+	fontFileName := splitFont[len(splitFont)-1]
+	fontName := strings.TrimSuffix(fontFileName, filepath.Ext(fontFileName))
+	fontFamily := FontFamily(fontName)
+	woffFont, err := fontlib.Sfnt2Woff(fontBuf)
+	if err != nil {
+		return "", fmt.Errorf("failed to convert to woff font: %v", err)
+	}
+
+	encodedWoff := fmt.Sprintf("data:application/font-woff;base64,%v", base64.StdEncoding.EncodeToString(woffFont))
+
+	// Encode all styles for now
+	customFont := fontFamily.Font(0, FONT_STYLE_REGULAR)
+	FontFaces[customFont] = fontBuf
+	FontEncodings[customFont] = encodedWoff
+
+	customFont = fontFamily.Font(0, FONT_STYLE_BOLD)
+	FontFaces[customFont] = fontBuf
+	FontEncodings[customFont] = encodedWoff
+
+	customFont = fontFamily.Font(0, FONT_STYLE_ITALIC)
+	FontFaces[customFont] = fontBuf
+	FontEncodings[customFont] = encodedWoff
+
+	FontFamilies = append(FontFamilies, fontFamily)
+	return fontFamily, nil
+}
+
 var D2_FONT_TO_FAMILY = map[string]FontFamily{
 	"default": SourceSansPro,
 	"mono":    SourceCodePro,