c# - 图片上没有水印

Question

我遇到了一个错误:无法从具有索引像素格式的图像创建图形对象

所以我将这段代码实现到我的方法中:Solution for "A Graphics Object cannot be Created from an Image that has an Indexed Pixel Format"

但现在我的水印不想在我的图像上绘制。

请任何人提供帮助。

代码:

private Image AddWaterMark(Image original)
{
    Image waterMark = Image.FromFile(ConfigurationManager.AppSettings["GalleryFolder"] + @"\watermark.png");
    Bitmap bm = (Bitmap)original;

    Size waterMarkResize = ResizeFit(new Size(original.Width, original.Height));

    using (Image watermarkImage = new Bitmap(waterMark, waterMarkResize))
    using (Graphics imageGraphics = Graphics.FromImage(new Bitmap(bm.Width, bm.Height)))
    {
        imageGraphics.DrawImage(bm, new Rectangle(0, 0, bm.Width, bm.Height), 0, 0, bm.Width, bm.Height, GraphicsUnit.Pixel);
        using (TextureBrush watermarkBrush = new TextureBrush(watermarkImage))
        {
            int x = (original.Width / 2 - watermarkImage.Width / 2);
            int y = (original.Height / 2 - watermarkImage.Height / 2);
            watermarkBrush.TranslateTransform(x, y);
            imageGraphics.FillRectangle(watermarkBrush, new Rectangle(new Point(x, y), new Size(watermarkImage.Width + 1, watermarkImage.Height)));
        }
    }

    return bm;
}

Answer 1

您正在创建一个新的 Bitmap 以传递给 Graphics.FromImage，然后返回未经编辑的原始 Bitmap。独立创建新的Bitmap，将其传递给FromImage，然后返回新的Bitmap。

var edit = new Bitmap(bm.Width, bm.Height);
// ...
using (Graphics imagesGraphics = Graphics.FromImage(edit))
{
    // draw original
    // draw watermark
}
return edit;