c# 创建斜着写字图片

void Main()
{
    using (var bitmap = new Bitmap(3094, 2136，PixelFormat.Format32bppArgb))
    {
        using (Graphics g = Graphics.FromImage(bitmap))
        {
            var msg = "在线考试模板图片(勿删)";
            var font = new Font("微软雅黑", 100);
            var brush = new SolidBrush(Color.FromArgb(30, Color.Black));
            var size = g.MeasureString(msg,font );
            g.ResetTransform();    //重置图像
            g.TranslateTransform(bitmap.Width / 2, bitmap.Height / 2);     //设置旋转中心
            g.RotateTransform(53);    //旋转53度 顺时针
            g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;     //指定文本呈现的质量 解决文字锯齿问题
            g.Clear(Color.White);
            g.DrawString(msg, font , brush, 0 - size.Width /2 , 0- size.Height/2);     //设置文字、字体、大小、颜色、起始位置
            bitmap.Save(@"E:\Desktop\test.TIF", ImageFormat.Tiff);
        }
    }
}

 自动根据图像尺寸倾斜文字：

private Bitmap createEmptyImage(int width, int height)
        {
            var bitmap = new Bitmap(width, height);

            using (Graphics g = Graphics.FromImage(bitmap))
            {
                var msg = "此区域考生未作答";
                var brush = new SolidBrush(Color.FromArgb(30, Color.Black));
                var fontSize = 100;
                var font = new Font("微软雅黑", fontSize);
                var size = g.MeasureString(msg, font);

                while (size.Width > width && fontSize > 1)
                {
                    fontSize--;
                    font = new Font("微软雅黑", fontSize);
                    size = g.MeasureString(msg, font);
                }

                while (size.Height > height && fontSize > 1)
                {
                    fontSize--;
                    font = new Font("微软雅黑", fontSize);
                    size = g.MeasureString(msg, font);
                }

                g.ResetTransform();
                g.TranslateTransform(bitmap.Width / 2, bitmap.Height / 2);
                g.RotateTransform((int)(Math.Asin(height / Math.Sqrt(Math.Pow(width, 2) + Math.Pow(height, 2))) * 180 / Math.PI));
                g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
                g.Clear(Color.White);
                g.DrawString(msg, font, brush, 0 - size.Width / 2, 0 - size.Height / 2);

            }

            return bitmap;
        }