iTextSharp.text.pdf.RadioCheckField.GetAppearanceRadioCircle C# (CSharp) Метод

        public PdfAppearance GetAppearanceRadioCircle(bool on)
        {
            PdfAppearance app = PdfAppearance.CreateAppearance(writer, box.Width, box.Height);
            switch (rotation) {
                case 90:
                    app.SetMatrix(0, 1, -1, 0, box.Height, 0);
                    break;
                case 180:
                    app.SetMatrix(-1, 0, 0, -1, box.Width, box.Height);
                    break;
                case 270:
                    app.SetMatrix(0, -1, 1, 0, 0, box.Width);
                    break;
            }
            Rectangle boxc = new Rectangle(app.BoundingBox);
            float cx = boxc.Width / 2;
            float cy = boxc.Height / 2;
            float r = (Math.Min(boxc.Width, boxc.Height) - borderWidth) / 2;
            if (r <= 0)
                return app;
            if (backgroundColor != null) {
                app.SetColorFill(backgroundColor);
                app.Circle(cx, cy, r + borderWidth / 2);
                app.Fill();
            }
            if (borderWidth > 0 && borderColor != null) {
                app.SetLineWidth(borderWidth);
                app.SetColorStroke(borderColor);
                app.Circle(cx, cy, r);
                app.Stroke();
            }
            if (on) {
                if (textColor == null)
                    app.ResetGrayFill();
                else
                    app.SetColorFill(textColor);
                app.Circle(cx, cy, r / 2);
                app.Fill();
            }
            return app;
        }