增加水印,在文档之下。

最新推荐文章于 2025-08-18 09:21:08 发布

原创最新推荐文章于 2025-08-18 09:21:08 发布 · 327 阅读

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#文档 #byte #image #button #object #string

本文介绍了一种使用C#进行图像处理的方法，具体为如何在图片上添加带有透明度的文字水印。通过实例代码展示了从创建位图到计算文字尺寸、绘制水印并调整其透明度的全过程。

private void button6_Click(object sender, EventArgs e)
{

DrawWatermark(null, "TEST", new Font("宋体", 64, FontStyle.Bold), new SolidBrush(Color.Black), 10, 10, 0.2);

}

        /// <summary>
        /// 给一个位图绘制水印文字
        /// </summary>
        /// <param name="text">水印文本</param>
        /// <param name="x">起始点</param>
        /// <param name="y">起始点</param>
        /// <param name="opacity">不透明度，0~1</param>
        private Bitmap DrawWatermark(Image image, string text, Font font, Brush brush, int x, int y, double opacity)
        {
            Bitmap bm1 = new Bitmap("e://a.bmp");
            Graphics g1 = Graphics.FromImage(bm1);
            //测量水印文字的大小，然后申请一个新的位图
            SizeF sizef = g1.MeasureString(text, font);
            Bitmap bm2 = new Bitmap((int)sizef.Width, (int)sizef.Height);
            Graphics g2 = Graphics.FromImage(bm2);
            g2.DrawImage(bm1, 0, 0, new Rectangle(x, y, bm2.Width, bm2.Height), GraphicsUnit.Pixel);
            g2.DrawString(text, font, brush, 0, 0);
            BitmapData data1 = bm1.LockBits(new Rectangle(0, 0, bm1.Width, bm1.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
            BitmapData data2 = bm2.LockBits(new Rectangle(0, 0, bm2.Width, bm2.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
            unsafe
            {
                byte* p1 = (byte*)(void*)data1.Scan0;
                byte* p2 = (byte*)(void*)data2.Scan0;
                for (int j = 0; j < bm2.Height; j++)
                {
                    for (int i = 0; i < bm2.Width; i++)
                    {
                        //p1[(y + j) * data1.Stride + (x + i) * 3] = (byte)(p1[(y + j) * data1.Stride + (x + i) * 3] * (1 - opacity) + opacity * p2[j * data2.Stride + i * 3]);
                        //p1[(y + j) * data1.Stride + (x + i) * 3 + 1] = (byte)(p1[(y + j) * data1.Stride + (x + i) * 3 + 1] * (1 - opacity) + opacity * p2[j * data2.Stride + i * 3 + 1]);
                        //p1[(y + j) * data1.Stride + (x + i) * 3 + 2] = (byte)(p1[(y + j) * data1.Stride + (x + i) * 3 + 2] * (1 - opacity) + opacity * p2[j * data2.Stride + i * 3 + 2]);

                        p1[(y + j) * data1.Stride + (x + i) * 3] = (byte)(p1[(y + j) * data1.Stride + (x + i) * 3] * (1 - opacity) + opacity * p2[j * data2.Stride + i * 3]);
                        p1[(y + j) * data1.Stride + (x + i) * 3 + 1] = (byte)(p1[(y + j) * data1.Stride + (x + i) * 3] * (1 - opacity) + opacity * p2[j * data2.Stride + i * 3 + 1]);
                        p1[(y + j) * data1.Stride + (x + i) * 3 + 2] = (byte)(p1[(y + j) * data1.Stride + (x + i) * 3] * (1 - opacity) + opacity * p2[j * data2.Stride + i * 3 + 2]);

                    }
                }
                bm1.UnlockBits(data1);
                bm2.UnlockBits(data2);
            }
            bm1.Save("e://1.bmp");
            return bm1;
        }