From 14300dc9f801851e0530d689e5604d5ba80bc2fd Mon Sep 17 00:00:00 2001
From: Gavin Nishizawa <gavin@terrastruct.com>
Date: Mon, 19 Jun 2023 15:25:14 -0700
Subject: [PATCH] update leading/trailing accounting

---
 d2graph/d2graph.go             | 21 ++++++++++-----------
 d2renderers/d2svg/d2svg.go     |  4 ++--
 lib/textmeasure/textmeasure.go |  1 +
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/d2graph/d2graph.go b/d2graph/d2graph.go
index e39ec27ca..a91c95e12 100644
--- a/d2graph/d2graph.go
+++ b/d2graph/d2graph.go
@@ -1314,29 +1314,28 @@ func GetTextDimensions(mtexts []*d2target.MText, ruler *textmeasure.Ruler, t *d2
 		var h int
 		if t.Language != "" {
 			originalLineHeight := ruler.LineHeightFactor
-			ruler.LineHeightFactor = 1.3
+			ruler.LineHeightFactor = textmeasure.CODE_LINE_HEIGHT
 			w, h = ruler.MeasureMono(d2fonts.SourceCodePro.Font(t.FontSize, d2fonts.FONT_STYLE_REGULAR), t.Text)
 			ruler.LineHeightFactor = originalLineHeight
 
 			// count empty leading and trailing lines since ruler will not be able to measure it
 			lines := strings.Split(t.Text, "\n")
-			leadingLines := 0
-			for _, line := range lines {
-				if strings.TrimSpace(line) == "" {
-					leadingLines++
-				} else {
-					break
-				}
+			hasLeading := false
+			if len(lines) > 0 && strings.TrimSpace(lines[0]) == "" {
+				hasLeading = true
 			}
-			trailingLines := 0
+			numTrailing := 0
 			for i := len(lines) - 1; i >= 0; i-- {
 				if strings.TrimSpace(lines[i]) == "" {
-					trailingLines++
+					numTrailing++
 				} else {
 					break
 				}
 			}
-			h += t.FontSize * (leadingLines + trailingLines)
+			if hasLeading && numTrailing < len(lines) {
+				h += t.FontSize
+			}
+			h += int(math.Ceil(textmeasure.CODE_LINE_HEIGHT * float64(t.FontSize*numTrailing)))
 		} else {
 			style := d2fonts.FONT_STYLE_REGULAR
 			if t.IsBold {
diff --git a/d2renderers/d2svg/d2svg.go b/d2renderers/d2svg/d2svg.go
index 3b4f0650e..a432c6dc3 100644
--- a/d2renderers/d2svg/d2svg.go
+++ b/d2renderers/d2svg/d2svg.go
@@ -1272,9 +1272,9 @@ func drawShape(writer io.Writer, diagramHash string, targetShape d2target.Shape,
 				padding := float64(targetShape.FontSize) / 2.
 				fmt.Fprintf(writer, `<g transform="translate(%f %f)">`, padding, padding)
 
-				lineHeight := 1.3
+				lineHeight := textmeasure.CODE_LINE_HEIGHT
 				for index, tokens := range chroma.SplitTokensIntoLines(iterator.Tokens()) {
-					fmt.Fprintf(writer, "<text class=\"text-mono\" x=\"0\" y=\"%fem\">", 1+lineHeight*float64(index))
+					fmt.Fprintf(writer, "<text class=\"text-mono\" x=\"0\" y=\"%fem\">", 1+float64(index)*lineHeight)
 					for _, token := range tokens {
 						text := svgEscaper.Replace(token.String())
 						attr := styleAttr(svgStyles, token.Type)
diff --git a/lib/textmeasure/textmeasure.go b/lib/textmeasure/textmeasure.go
index 8602a0bed..8df3a346e 100644
--- a/lib/textmeasure/textmeasure.go
+++ b/lib/textmeasure/textmeasure.go
@@ -18,6 +18,7 @@ import (
 
 const TAB_SIZE = 4
 const SIZELESS_FONT_SIZE = 0
+const CODE_LINE_HEIGHT = 1.3
 
 // ASCII is a set of all ASCII runes. These runes are codepoints from 32 to 127 inclusive.
 var ASCII []rune