diff --git a/_examples/css_classes/main.go b/_examples/css_classes/main.go
index d650e96..5046b72 100644
--- a/_examples/css_classes/main.go
+++ b/_examples/css_classes/main.go
@@ -7,6 +7,8 @@ import (
"net/http"
)
+// Note: Additional examples on how to add Stylesheets are in the custom_stylesheets example
+
func inlineSVGWithClasses(res http.ResponseWriter, req *http.Request) {
res.Write([]byte(
"" +
diff --git a/_examples/custom_stylesheets/inlineOutput.svg b/_examples/custom_stylesheets/inlineOutput.svg
new file mode 100644
index 0000000..fdb2515
--- /dev/null
+++ b/_examples/custom_stylesheets/inlineOutput.svg
@@ -0,0 +1,21 @@
+
\ No newline at end of file
diff --git a/_examples/custom_stylesheets/main.go b/_examples/custom_stylesheets/main.go
new file mode 100644
index 0000000..2432b2d
--- /dev/null
+++ b/_examples/custom_stylesheets/main.go
@@ -0,0 +1,87 @@
+package main
+
+import (
+ "fmt"
+ "github.com/hashworks/go-chart"
+ "log"
+ "net/http"
+)
+
+const style = "svg .background { fill: white; }" +
+ "svg .canvas { fill: white; }" +
+ "svg path.blue { fill: blue; stroke: lightblue; }" +
+ "svg path.green { fill: green; stroke: lightgreen; }" +
+ "svg path.gray { fill: gray; stroke: lightgray; }" +
+ "svg text.blue { fill: white; }" +
+ "svg text.green { fill: white; }" +
+ "svg text.gray { fill: white; }"
+
+func svgWithCustomInlineCSS(res http.ResponseWriter, _ *http.Request) {
+ res.Header().Set("Content-Type", chart.ContentTypeSVG)
+
+ // Render the CSS with custom css
+ err := pieChart().Render(chart.SVGWithCSS(style, ""), res)
+ if err != nil {
+ fmt.Printf("Error rendering pie chart: %v\n", err)
+ }
+}
+
+func svgWithCustomInlineCSSNonce(res http.ResponseWriter, _ *http.Request) {
+ // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/style-src
+ // This should be randomly generated on every request!
+ const nonce = "RAND0MBASE64"
+
+ res.Header().Set("Content-Security-Policy", fmt.Sprintf("style-src 'nonce-%s'", nonce))
+ res.Header().Set("Content-Type", chart.ContentTypeSVG)
+
+ // Render the CSS with custom css and a nonce.
+ // Try changing the nonce to a different string - your browser should block the CSS.
+ err := pieChart().Render(chart.SVGWithCSS(style, nonce), res)
+ if err != nil {
+ fmt.Printf("Error rendering pie chart: %v\n", err)
+ }
+}
+
+func svgWithCustomExternalCSS(res http.ResponseWriter, _ *http.Request) {
+ // Add external CSS
+ res.Write([]byte(
+ ``+
+ ``+
+ ``))
+
+ res.Header().Set("Content-Type", chart.ContentTypeSVG)
+ err := pieChart().Render(chart.SVG, res)
+ if err != nil {
+ fmt.Printf("Error rendering pie chart: %v\n", err)
+ }
+}
+
+func pieChart() chart.PieChart {
+ return chart.PieChart{
+ // Note that setting ClassName will cause all other inline styles to be dropped!
+ Background: chart.Style{ClassName: "background"},
+ Canvas: chart.Style{
+ ClassName: "canvas",
+ },
+ Width: 512,
+ Height: 512,
+ Values: []chart.Value{
+ {Value: 5, Label: "Blue", Style: chart.Style{ClassName: "blue"}},
+ {Value: 5, Label: "Green", Style: chart.Style{ClassName: "green"}},
+ {Value: 4, Label: "Gray", Style: chart.Style{ClassName: "gray"}},
+ },
+ }
+}
+
+func css(res http.ResponseWriter, req *http.Request) {
+ res.Header().Set("Content-Type", "text/css")
+ res.Write([]byte(style))
+}
+
+func main() {
+ http.HandleFunc("/", svgWithCustomInlineCSS)
+ http.HandleFunc("/nonce", svgWithCustomInlineCSSNonce)
+ http.HandleFunc("/external", svgWithCustomExternalCSS)
+ http.HandleFunc("/main.css", css)
+ log.Fatal(http.ListenAndServe(":8080", nil))
+}
diff --git a/vector_renderer.go b/vector_renderer.go
index c154424..71c6a86 100644
--- a/vector_renderer.go
+++ b/vector_renderer.go
@@ -28,6 +28,25 @@ func SVG(width, height int) (Renderer, error) {
}, nil
}
+// SVGWithCSS returns a new png/raster renderer with attached custom CSS
+// The optional nonce argument sets a CSP nonce.
+func SVGWithCSS(css string, nonce string) (func(width, height int)(Renderer, error)) {
+ return func(width, height int) (Renderer, error) {
+ buffer := bytes.NewBuffer([]byte{})
+ canvas := newCanvas(buffer)
+ canvas.css = css
+ canvas.nonce = nonce
+ canvas.Start(width, height)
+ return &vectorRenderer{
+ b: buffer,
+ c: canvas,
+ s: &Style{},
+ p: []string{},
+ dpi: DefaultDPI,
+ }, nil
+ }
+}
+
// vectorRenderer renders chart commands to a bitmap.
type vectorRenderer struct {
dpi float64
@@ -222,12 +241,23 @@ type canvas struct {
textTheta *float64
width int
height int
+ css string
+ nonce string
}
func (c *canvas) Start(width, height int) {
c.width = width
c.height = height
c.w.Write([]byte(fmt.Sprintf(`