accept font input

ci/release/changelogs/next.md

@@ -1,5 +1,6 @@
 #### Features 🚀
 
+- Flags to set a custom font are supported. See [docs](https://d2lang.com/todo). [#1108](https://github.com/terrastruct/d2/pull/1108)
 - `--animate-interval` can be passed as a flag to animate multi-board diagrams. See [docs](https://d2lang.com/todo). [#1088](https://github.com/terrastruct/d2/pull/1088)
 - `paper` is available as a `fill-pattern` option [#1070](https://github.com/terrastruct/d2/pull/1070)
 - fonts are now subsetted to reduce svg file size [#1089](https://github.com/terrastruct/d2/pull/1089)

ci/release/template/man/d2.1

@@ -80,6 +80,15 @@ Renders the diagram to look like it was sketched by hand
 .It Fl -center Ar flag
 Center the SVG in the containing viewbox, such as your browser screen
 .Ns .
+.It Fl -font-regular
+Path to .ttf file to use for the regular font. If none provided, Source Sans Pro Regular is used
+.Ns .
+.It Fl -font-italic
+Path to .ttf file to use for the italic font. If none provided, Source Sans Pro Regular-Italic is used
+.Ns .
+.It Fl -font-bold
+Path to .ttf file to use for the bold font. If none provided, Source Sans Pro Bold is used
+.Ns .
 .It Fl -pad Ar 100
 Pixels padded around the rendered diagram
 .Ns .

d2cli/main.go

@@ -95,6 +95,10 @@ func Run(ctx context.Context, ms *xmain.State) (err error) {
 		return err
 	}
 
+	fontRegularFlag := ms.Opts.String("D2_FONT_REGULAR", "font-regular", "", "", "path to .ttf file to use for the regular font. If none provided, Source Sans Pro Regular is used.")
+	fontItalicFlag := ms.Opts.String("D2_FONT_ITALIC", "font-italic", "", "", "path to .ttf file to use for the italic font. If none provided, Source Sans Pro Regular-Italic is used.")
+	fontBoldFlag := ms.Opts.String("D2_FONT_BOLD", "font-bold", "", "", "path to .ttf file to use for the bold font. If none provided, Source Sans Pro Bold is used.")
+
 	ps, err := d2plugin.ListPlugins(ctx)
 	if err != nil {
 		return err
@@ -114,6 +118,11 @@ func Run(ctx context.Context, ms *xmain.State) (err error) {
 		return nil
 	}
 
+	fontFamily, err := loadFonts(ms, *fontRegularFlag, *fontItalicFlag, *fontBoldFlag)
+	if err != nil {
+		return xmain.UsageErrorf("failed to load specified fonts: %v", err)
+	}
+
 	if len(ms.Opts.Flags.Args()) > 0 {
 		switch ms.Opts.Flags.Arg(0) {
 		case "init-playwright":
@@ -265,6 +274,7 @@ func Run(ctx context.Context, ms *xmain.State) (err error) {
 			bundle:          *bundleFlag,
 			forceAppendix:   *forceAppendixFlag,
 			pw:              pw,
+			fontFamily:      fontFamily,
 		})
 		if err != nil {
 			return err
@@ -275,7 +285,7 @@ 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, renderOpts, *animateIntervalFlag, inputPath, outputPath, *bundleFlag, *forceAppendixFlag, pw.Page)
+	_, written, err := compile(ctx, ms, plugin, renderOpts, fontFamily, *animateIntervalFlag, inputPath, outputPath, *bundleFlag, *forceAppendixFlag, pw.Page)
 	if err != nil {
 		if written {
 			return fmt.Errorf("failed to fully compile (partial render written): %w", err)
@@ -285,7 +295,7 @@ func Run(ctx context.Context, ms *xmain.State) (err error) {
 	return nil
 }
 
-func compile(ctx context.Context, ms *xmain.State, plugin d2plugin.Plugin, renderOpts d2svg.RenderOpts, animateInterval 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, renderOpts d2svg.RenderOpts, fontFamily *d2fonts.FontFamily, animateInterval int64, inputPath, outputPath string, bundle, forceAppendix bool, page playwright.Page) (_ []byte, written bool, _ error) {
 	start := time.Now()
 	input, err := ms.ReadPath(inputPath)
 	if err != nil {
@@ -302,6 +312,7 @@ func compile(ctx context.Context, ms *xmain.State, plugin d2plugin.Plugin, rende
 		Layout:     layout,
 		Ruler:      ruler,
 		ThemeID:    renderOpts.ThemeID,
+		FontFamily: fontFamily,
 	}
 	if renderOpts.Sketch {
 		opts.FontFamily = go2.Pointer(d2fonts.HandDrawn)
@@ -659,3 +670,47 @@ func initPlaywright() error {
 	}
 	return pw.Cleanup()
 }
+
+func loadFont(ms *xmain.State, path string) ([]byte, error) {
+	if filepath.Ext(path) != ".ttf" {
+		return nil, fmt.Errorf("expected .ttf file but %s has extension %s", path, filepath.Ext(path))
+	}
+	ttf, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read font at %s: %v", path, err)
+	}
+	ms.Log.Info.Printf("font %s loaded", filepath.Base(path))
+	return ttf, nil
+}
+
+func loadFonts(ms *xmain.State, pathToRegular, pathToItalic, pathToBold string) (*d2fonts.FontFamily, error) {
+	if pathToRegular == "" && pathToItalic == "" && pathToBold == "" {
+		return nil, nil
+	}
+
+	var regularTTF []byte
+	var italicTTF []byte
+	var boldTTF []byte
+
+	var err error
+	if pathToRegular != "" {
+		regularTTF, err = loadFont(ms, pathToRegular)
+		if err != nil {
+			return nil, err
+		}
+	}
+	if pathToItalic != "" {
+		italicTTF, err = loadFont(ms, pathToItalic)
+		if err != nil {
+			return nil, err
+		}
+	}
+	if pathToBold != "" {
+		boldTTF, err = loadFont(ms, pathToBold)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return d2fonts.AddFontFamily("custom", regularTTF, italicTTF, boldTTF)
+}

d2cli/watch.go

@@ -26,6 +26,7 @@ import (
 	"oss.terrastruct.com/util-go/xmain"
 
 	"oss.terrastruct.com/d2/d2plugin"
+	"oss.terrastruct.com/d2/d2renderers/d2fonts"
 	"oss.terrastruct.com/d2/d2renderers/d2svg"
 	"oss.terrastruct.com/d2/lib/png"
 )
@@ -51,6 +52,7 @@ type watcherOpts struct {
 	bundle          bool
 	forceAppendix   bool
 	pw              png.Playwright
+	fontFamily      *d2fonts.FontFamily
 }
 
 type watcher struct {
@@ -358,7 +360,7 @@ func (w *watcher) compileLoop(ctx context.Context) error {
 			w.pw = newPW
 		}
 
-		svg, _, err := compile(ctx, w.ms, w.layoutPlugin, w.renderOpts, w.animateInterval, w.inputPath, w.outputPath, w.bundle, w.forceAppendix, w.pw.Page)
+		svg, _, err := compile(ctx, w.ms, w.layoutPlugin, w.renderOpts, w.fontFamily, w.animateInterval, w.inputPath, w.outputPath, w.bundle, w.forceAppendix, w.pw.Page)
 		errs := ""
 		if err != nil {
 			if len(svg) > 0 {

d2renderers/d2fonts/d2fonts.go

@@ -245,3 +245,78 @@ var D2_FONT_TO_FAMILY = map[string]FontFamily{
 	"default": SourceSansPro,
 	"mono":    SourceCodePro,
 }
+
+func AddFontStyle(font Font, style FontStyle, ttf []byte) error {
+	FontFaces[font] = ttf
+
+	woff, err := fontlib.Sfnt2Woff(ttf)
+	if err != nil {
+		return fmt.Errorf("failed to encode ttf to woff: %v", err)
+	}
+	encodedWoff := fmt.Sprintf("data:application/font-woff;base64,%v", base64.StdEncoding.EncodeToString(woff))
+	FontEncodings[font] = encodedWoff
+
+	return nil
+}
+
+func AddFontFamily(name string, regularTTF, italicTTF, boldTTF []byte) (*FontFamily, error) {
+	customFontFamily := FontFamily(name)
+
+	regularFont := Font{
+		Family: customFontFamily,
+		Style:  FONT_STYLE_REGULAR,
+	}
+	if regularTTF != nil {
+		err := AddFontStyle(regularFont, FONT_STYLE_REGULAR, regularTTF)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		fallbackFont := Font{
+			Family: SourceSansPro,
+			Style:  FONT_STYLE_REGULAR,
+		}
+		FontFaces[regularFont] = FontFaces[fallbackFont]
+		FontEncodings[regularFont] = FontEncodings[fallbackFont]
+	}
+
+	italicFont := Font{
+		Family: customFontFamily,
+		Style:  FONT_STYLE_ITALIC,
+	}
+	if italicTTF != nil {
+		err := AddFontStyle(italicFont, FONT_STYLE_ITALIC, italicTTF)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		fallbackFont := Font{
+			Family: SourceSansPro,
+			Style:  FONT_STYLE_ITALIC,
+		}
+		FontFaces[italicFont] = FontFaces[fallbackFont]
+		FontEncodings[italicFont] = FontEncodings[fallbackFont]
+	}
+
+	boldFont := Font{
+		Family: customFontFamily,
+		Style:  FONT_STYLE_BOLD,
+	}
+	if boldTTF != nil {
+		err := AddFontStyle(boldFont, FONT_STYLE_BOLD, boldTTF)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		fallbackFont := Font{
+			Family: SourceSansPro,
+			Style:  FONT_STYLE_BOLD,
+		}
+		FontFaces[boldFont] = FontFaces[fallbackFont]
+		FontEncodings[boldFont] = FontEncodings[fallbackFont]
+	}
+
+	FontFamilies = append(FontFamilies, customFontFamily)
+
+	return &customFontFamily, nil
+}

e2etests-cli/main_test.go

@@ -82,6 +82,19 @@ steps: {
 				assert.Testdata(t, ".svg", svg)
 			},
 		},
+		{
+			name: "with-font",
+			run: func(t *testing.T, ctx context.Context, dir string, env *xos.Env) {
+				writeFile(t, dir, "font.d2", `a: Why do computers get sick often?
+b: Because their Windows are always open!
+a -> b: italic font
+`)
+				err := runTestMain(t, ctx, dir, env, "--font-bold=./RockSalt-Regular.ttf", "font.d2")
+				assert.Success(t, err)
+				svg := readFile(t, dir, "font.svg")
+				assert.Testdata(t, ".svg", svg)
+			},
+		},
 		{
 			name: "incompatible-animation",
 			run: func(t *testing.T, ctx context.Context, dir string, env *xos.Env) {