From 9ba1d85d21fb16b3c912931f97b380c9fa48a033 Mon Sep 17 00:00:00 2001
From: Kevin David <git@kevindavid.org>
Date: Tue, 24 Jan 2023 21:20:34 -0500
Subject: [PATCH] d2graph: check that font family is entirely loaded before
 using it

I tested this by removing the changes I added in `d2fonts`, which led to:
```
[21:23:54] info: compiling GetUniqueColumnName-fix.d2...
[21:23:54] err: failed to compile: ruler does not have entire font family SourceCodePro loaded, is a style missing?
```

The error was also rendered in the UI.
---
 d2graph/d2graph.go             |  6 ++++++
 lib/textmeasure/textmeasure.go | 27 +++++++++++++++++++--------
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/d2graph/d2graph.go b/d2graph/d2graph.go
index 28ea03ef9..9a29d6ba1 100644
--- a/d2graph/d2graph.go
+++ b/d2graph/d2graph.go
@@ -1077,6 +1077,12 @@ func appendTextDedup(texts []*d2target.MText, t *d2target.MText) []*d2target.MTe
 }
 
 func (g *Graph) SetDimensions(mtexts []*d2target.MText, ruler *textmeasure.Ruler, fontFamily *d2fonts.FontFamily) error {
+	if ruler != nil && fontFamily != nil {
+		if ok := ruler.HasFontFamilyLoaded(fontFamily); !ok {
+			return fmt.Errorf("ruler does not have entire font family %s loaded, is a style missing?", *fontFamily)
+		}
+	}
+
 	for _, obj := range g.Objects {
 		obj.Box = &geo.Box{}
 
diff --git a/lib/textmeasure/textmeasure.go b/lib/textmeasure/textmeasure.go
index b1facb528..b46cc1711 100644
--- a/lib/textmeasure/textmeasure.go
+++ b/lib/textmeasure/textmeasure.go
@@ -4,7 +4,6 @@
 package textmeasure
 
 import (
-	"fmt"
 	"math"
 	"unicode"
 	"unicode/utf8"
@@ -16,6 +15,7 @@ import (
 )
 
 const TAB_SIZE = 4
+const SIZELESS_FONT_SIZE = 0
 
 // ASCII is a set of all ASCII runes. These runes are codepoints from 32 to 127 inclusive.
 var ASCII []rune
@@ -136,15 +136,26 @@ func NewRuler() (*Ruler, error) {
 	return r, nil
 }
 
-func (r *Ruler) addFontSize(font d2fonts.Font) {
-	sizeless := font
-	sizeless.Size = 0
-	ttf := r.ttfs[sizeless]
-	if ttf == nil {
-		panic(fmt.Errorf("sizeless font %s not found with style %s", font.Family, font.Style))
+func (r *Ruler) HasFontFamilyLoaded(fontFamily *d2fonts.FontFamily) bool {
+	for _, fontStyle := range d2fonts.FontStyles {
+		font := d2fonts.Font{
+			Family: *fontFamily,
+			Style:  fontStyle,
+			Size:   SIZELESS_FONT_SIZE,
+		}
+		_, ok := r.ttfs[font]
+		if !ok {
+			return false
+		}
 	}
 
-	face := truetype.NewFace(ttf, &truetype.Options{
+	return true
+}
+
+func (r *Ruler) addFontSize(font d2fonts.Font) {
+	sizeless := font
+	sizeless.Size = SIZELESS_FONT_SIZE
+	face := truetype.NewFace(r.ttfs[sizeless], &truetype.Options{
 		Size: float64(font.Size),
 	})
 	atlas := NewAtlas(face, ASCII)