src/main/java/org/jfree/graphics2d/svg/SVGGraphics2D.java
private String getClipPathRef() {
        if (this.clip == null) {
            return "";
        }
        if (this.clipRef == null) {
            this.clipRef = registerClip(getClip());
        }
        StringBuilder b = new StringBuilder();
        b.append("clip-path=\"url(#").append(this.clipRef).append(")\"");
        return b.toString();
    }
private String getClipPathRef() {
        if (this.clip == null) {
            return "";
        }
        if (this.clipRef == null) {
            this.clipRef = registerClip(getClip());
        }
        StringBuilder b = new StringBuilder();
        b.append("clip-path=\"url(#").append(this.clipRef).append(")\"");
        return b.toString();
    }
Returns a clip path reference for the current user clip.  This is
written out on all SVG elements that draw or fill shapes or text.

@return A clip path reference.