From 6d31bfac59e8bff86014f7d458ee1a8ace77b92a Mon Sep 17 00:00:00 2001
From: Drahoslav <drahoslav@yo2.cz>
Date: Sun, 24 Dec 2017 16:05:15 +0100
Subject: [PATCH] Use fill-rule attribute in svg context

---
 draw2dsvg/converters.go |  7 +++++++
 draw2dsvg/gc.go         | 16 +++++++++++-----
 draw2dsvg/svg.go        |  4 +++-
 3 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/draw2dsvg/converters.go b/draw2dsvg/converters.go
index 1564f96..7b5c6a3 100644
--- a/draw2dsvg/converters.go
+++ b/draw2dsvg/converters.go
@@ -28,6 +28,13 @@ func toSvgArray(nums []float64) string {
 	return strings.Join(arr, ",")
 }
 
+func toSvgFillRule(rule draw2d.FillRule) string {
+	return map[draw2d.FillRule]string{
+		draw2d.FillRuleEvenOdd: "evenodd",
+		draw2d.FillRuleWinding: "nonzero",
+	}[rule]
+}
+
 func toSvgPathDesc(p *draw2d.Path) string {
 	parts := make([]string, len(p.Components))
 	ps := p.Points
diff --git a/draw2dsvg/gc.go b/draw2dsvg/gc.go
index 1d741b5..3ef6adb 100644
--- a/draw2dsvg/gc.go
+++ b/draw2dsvg/gc.go
@@ -8,6 +8,7 @@ import (
 	"github.com/llgcode/draw2d"
 	"github.com/llgcode/draw2d/draw2dbase"
 	"image"
+	"strings"
 )
 
 const ()
@@ -71,15 +72,17 @@ func (gc *GraphicContext) FillStroke(paths ...*draw2d.Path) {
 func (gc *GraphicContext) drawPaths(drawType drawType, paths ...*draw2d.Path) {
 	paths = append(paths, gc.Current.Path)
 
-	svgPaths := make([]Path, len(paths))
+	svgPath := Path{}
+	group := Group{}
 
-	group := Group{
-		Paths: svgPaths,
-	}
+	svgPathsDesc := make([]string, len(paths))
 
+	// multiple pathes has to be joined to single svg path description
+	// because fill-rule wont work for whole group
 	for i, path := range paths {
-		svgPaths[i].Desc = toSvgPathDesc(path)
+		svgPathsDesc[i] = toSvgPathDesc(path)
 	}
+	svgPath.Desc = strings.Join(svgPathsDesc, " ")
 
 	if drawType&stroked == stroked {
 		group.Stroke = toSvgRGBA(gc.Current.StrokeColor)
@@ -94,8 +97,11 @@ func (gc *GraphicContext) drawPaths(drawType drawType, paths ...*draw2d.Path) {
 
 	if drawType&filled == filled {
 		group.Fill = toSvgRGBA(gc.Current.FillColor)
+		group.FillRule = toSvgFillRule(gc.Current.FillRule)
 	}
 
+	group.Paths = []Path{svgPath}
+
 	gc.svg.Groups = append(gc.svg.Groups, group)
 }
 
diff --git a/draw2dsvg/svg.go b/draw2dsvg/svg.go
index 025847a..ec16e1b 100644
--- a/draw2dsvg/svg.go
+++ b/draw2dsvg/svg.go
@@ -37,7 +37,9 @@ type Text struct {
 /* shared attrs */
 
 type FillStroke struct {
-	Fill             string `xml:"fill,attr,omitempty"`
+	Fill     string `xml:"fill,attr,omitempty"`
+	FillRule string `xml:"fill-rule,attr,omitempty"`
+
 	Stroke           string `xml:"stroke,attr,omitempty"`
 	StrokeWidth      string `xml:"stroke-width,attr,omitempty"`
 	StrokeLinecap    string `xml:"stroke-linecap,attr,omitempty"`