Question

我想要实现的是使用itextsharp隐藏图像（通过不透明度或透明度）。到目前为止，图像显示如下：

  string webURL = "X:/XXXXXX/web.png";
  iTextSharp.text.Image webIcon = iTextSharp.text.Image.GetInstance(webURL);
 webIcon.Annotation = new Annotation(0,0,0,0, "http://www.xxxxx.com");
            webIcon.ScaleAbsolute(35f, 35f);
            webIcon.SetAbsolutePosition(227,23);
            webIcon.Transparency = new int[] {0,0 };
            //state.FillOpacity = 0.2f;
            //webIcon.GrayFill = 0.2f;
            doc.Add(webIcon);

如何更改透明度以使图像的可见性为空？

Answer 1

您需要使用PdfGState。在你的情况下：

var writer = PdfWriter.GetInstance(document, output);
document.Open();

string webURL = "http://www.apache.org/foundation/press/kit/feather.png";
Image webIcon = Image.GetInstance(webURL);
webIcon.Annotation = new Annotation(0, 0, 0, 0, "http://www.google.com");
webIcon.ScaleAbsolute(35f, 35f);
webIcon.SetAbsolutePosition(227, 23);
PdfContentByte canvas = writer.DirectContentUnder;
canvas.SaveState();
PdfGState state = new PdfGState();
state.FillOpacity = 0.6f; // THIS is where you set opacity
canvas.SetGState(state);
canvas.AddImage(webIcon);
canvas.RestoreState();  

document.Close();

希望有所帮助

在itextsharp中隐藏图像

1 个答案: