From b943e9f696b511869334654b2fa2830464817ff3 Mon Sep 17 00:00:00 2001
From: Egon Elbre <egonelbre@gmail.com>
Date: Sun, 14 Jan 2018 15:39:18 +0200
Subject: [PATCH] Add code for removing Inkscape Swatches

---
 fix-svg-style.go | 215 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 215 insertions(+)
 create mode 100644 fix-svg-style.go

diff --git a/fix-svg-style.go b/fix-svg-style.go
new file mode 100644
index 0000000..ed3268d
--- /dev/null
+++ b/fix-svg-style.go
@@ -0,0 +1,215 @@
+// fix-svg-style fixes Inkscape palette to be compatible with Affinity Designer
+//
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"regexp"
+
+	"golang.org/x/net/html"
+	"golang.org/x/net/html/atom"
+)
+
+func main() {
+	err := filepath.Walk("vector", func(path string, info os.FileInfo, err error) error {
+		if info.IsDir() {
+			return nil
+		}
+		if filepath.Ext(path) == ".svg" {
+			return ProcessSVGFile(path)
+		}
+		return nil
+	})
+	if err != nil {
+		panic(err)
+	}
+}
+
+func ProcessSVGFile(file string) error {
+	data, err := ioutil.ReadFile(file)
+	if err != nil {
+		return err
+	}
+
+	input := bytes.NewReader(data)
+	context := &html.Node{
+		Type: html.ElementNode,
+	}
+
+	nodes, err := html.ParseFragment(input, context)
+	if err != nil {
+		return err
+	}
+
+	changed := ProcessSVG(nodes)
+
+	output := bytes.NewBuffer(nil)
+	for _, node := range nodes {
+		html.Render(output, node)
+	}
+
+	outdata := output.Bytes()
+	if changed {
+		fmt.Println("Wrinting ", file)
+		err2 := ioutil.WriteFile(file, outdata, 0755)
+		if err2 != nil {
+			return err2
+		}
+	}
+
+	return nil
+}
+
+func ProcessSVG(nodes []*html.Node) bool {
+	changed := false
+
+	getElementByID := map[string]*html.Node{}
+	var process func(node *html.Node)
+
+	rxRemoveStyle := regexp.MustCompile(`(visibility:visible)[;$]`)
+	rxFillStyle := regexp.MustCompile(`fill:url\((#[a-zA-Z0-9\-]+)\)`)
+	rxStrokeStyle := regexp.MustCompile(`stroke:url\((#[a-zA-Z0-9\-]+)\)`)
+	rxStopColor := regexp.MustCompile(`stop-color:([^;]*)[;$]`)
+
+	resolveColorCache := map[string]string{}
+	resolveColor := func(id string) string {
+		if cached, ok := resolveColorCache[id]; ok {
+			return cached
+		}
+
+		node := getElementByID[id]
+		for {
+			xlink := GetAttributeValue(node, "href")
+			if xlink == "" {
+				break
+			}
+			node = getElementByID[xlink[1:]]
+		}
+
+		stops := GetElementsByTagName(node, "stop")
+		if len(stops) == 0 {
+			return "rgba(0,0,0,0)"
+		}
+		if len(stops) >= 2 {
+			return "url(#" + id + ")"
+		}
+
+		stop := stops[0]
+		style := GetAttributeValue(stop, "style")
+		match := rxStopColor.FindStringSubmatch(style)
+
+		resolveColorCache[id] = match[1]
+		return match[1]
+	}
+
+	process = func(node *html.Node) {
+		// build index
+		id := GetAttributeValue(node, "id")
+		if id != "" {
+			getElementByID[id] = node
+		}
+
+		// recurse
+		for child := node.FirstChild; child != nil; child = child.NextSibling {
+			process(child)
+		}
+
+		if style := GetAttribute(node, "style"); style != nil {
+			style.Val = rxRemoveStyle.ReplaceAllString(style.Val, "")
+			style.Val = rxFillStyle.ReplaceAllStringFunc(style.Val, func(attribute string) string {
+				// fill:url(#xyz)
+				colorId := attribute[10 : len(attribute)-1]
+
+				replacement := "fill:" + resolveColor(colorId)
+				changed = changed || (replacement != attribute)
+				return replacement
+			})
+
+			style.Val = rxStrokeStyle.ReplaceAllStringFunc(style.Val, func(attribute string) string {
+				// colore:url(#xyz)
+				colorId := attribute[12 : len(attribute)-1]
+
+				replacement := "stroke:" + resolveColor(colorId)
+				changed = changed || (replacement != attribute)
+				return replacement
+			})
+		}
+	}
+
+	for _, node := range nodes {
+		process(node)
+	}
+
+	// remove all dead gradients
+	for _, node := range nodes {
+		defss := GetElementsByTagName(node, "defs")
+		for _, defs := range defss {
+			toRemove := []*html.Node{}
+			for child := defs.FirstChild; child != nil; child = child.NextSibling {
+				if child.Data == "linearGradient" {
+					id := GetAttributeValue(child, "id")
+					noReplacement := "url(#" + id + ")"
+					if noReplacement != resolveColor(id) {
+						toRemove = append(toRemove, child)
+					}
+				}
+			}
+
+			for _, child := range toRemove {
+				changed = true
+				defs.RemoveChild(child)
+			}
+		}
+	}
+
+	return changed
+}
+
+func GetAttributeValue(node *html.Node, name string) string {
+	for i := range node.Attr {
+		if node.Attr[i].Key == name {
+			return node.Attr[i].Val
+		}
+	}
+	return ""
+}
+
+func GetAttribute(node *html.Node, name string) *html.Attribute {
+	for i := range node.Attr {
+		if node.Attr[i].Key == name {
+			return &node.Attr[i]
+		}
+	}
+	return nil
+}
+
+func GetElementsByTagName(node *html.Node, tagname string) []*html.Node {
+	xs := []*html.Node{}
+
+	dataAtom := atom.Lookup([]byte(tagname))
+	if dataAtom != 0 {
+		tagname = ""
+	}
+
+	for child := node.FirstChild; child != nil; child = child.NextSibling {
+		if child.Type != html.ElementNode {
+			continue
+		}
+		if child.DataAtom == dataAtom && child.Data == tagname {
+			xs = append(xs, child)
+			continue
+		}
+	}
+	return xs
+}
+
+func check(err error) {
+	if err != nil {
+		panic(err)
+	}
+}