From 66083e2d98e23c2c369058dff530472b87734852 Mon Sep 17 00:00:00 2001
From: Bernard Xie <bernard@terrastruct.com>
Date: Mon, 27 Feb 2023 16:05:41 -0800
Subject: [PATCH] set root fill as transparent on pdf exports

---
 lib/color/color.go | 5 ++---
 lib/pdf/pdf.go     | 2 +-
 main.go            | 7 ++++++-
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/lib/color/color.go b/lib/color/color.go
index df433b878..d9f18b03a 100644
--- a/lib/color/color.go
+++ b/lib/color/color.go
@@ -6,7 +6,6 @@ import (
 	"regexp"
 	"strconv"
 
-	"github.com/davecgh/go-spew/spew"
 	"github.com/lucasb-eyer/go-colorful"
 	"github.com/mazznoer/csscolorparser"
 )
@@ -161,7 +160,6 @@ func (c *RGB) IsLight() bool {
 
 	hsp := math.Sqrt(0.299*math.Pow(r, 2) + 0.587*math.Pow(g, 2) + 0.114*math.Pow(b, 2))
 
-	spew.Dump(hsp)
 	return hsp > 130
 }
 
@@ -170,9 +168,10 @@ func Hex2RGB(hex string) (RGB, error) {
 	var rgb RGB
 	if hex[0:1] == "#" {
 		hex = hex[1:]
+	} else {
+		return RGB{}, nil
 	}
 	values, err := strconv.ParseUint(hex, 16, 32)
-
 	if err != nil {
 		return RGB{}, err
 	}
diff --git a/lib/pdf/pdf.go b/lib/pdf/pdf.go
index 5aed48d98..1a05ac8a3 100644
--- a/lib/pdf/pdf.go
+++ b/lib/pdf/pdf.go
@@ -34,7 +34,7 @@ func Init() *GoFPDF {
 }
 
 func (g *GoFPDF) GetFillRGB(fill string) (color.RGB, error) {
-	if fill == "" {
+	if fill == "" || strings.ToLower(fill) == "transparent" {
 		return color.RGB{
 			Red:   255,
 			Green: 255,
diff --git a/main.go b/main.go
index e566fb30c..05bb3a02d 100644
--- a/main.go
+++ b/main.go
@@ -458,6 +458,11 @@ func renderPDF(ctx context.Context, ms *xmain.State, plugin d2plugin.Plugin, ske
 	}
 
 	if !diagram.IsFolderOnly {
+		rootFill := diagram.Root.Fill
+		// gofpdf will print the png img with a slight filter
+		// strip out the background fill within the png so that the background is uniform in the exported pdf
+		diagram.Root.Fill = "transparent"
+
 		svg, err = d2svg.Render(diagram, &d2svg.RenderOpts{
 			Pad:    int(pad),
 			Sketch: sketch,
@@ -484,7 +489,7 @@ func renderPDF(ctx context.Context, ms *xmain.State, plugin d2plugin.Plugin, ske
 			return svg, err
 		}
 
-		err = pdf.AddPDFPage(pngImg, currBoardPath, diagram.Root.Fill)
+		err = pdf.AddPDFPage(pngImg, currBoardPath, rootFill)
 		if err != nil {
 			return svg, err
 		}