【C#】把TextBox的文字转成图片

通过系统Graphics绘图把文字绘制到位图上，然后显示或保存起来，这里用定义该函数

        /// <summary>
        /// 把文字转换才Bitmap
        /// </summary>
        /// <param name="text"></param>
        /// <param name="font"></param>
        /// <param name="rect">用于输出的矩形，文字在这个矩形内显示，为空时自动计算</param>
        /// <param name="fontcolor">字体颜色</param>
        /// <param name="backColor">背景颜色</param>
        /// <returns></returns>
        private Bitmap TextToBitmap(string text, Font font, Rectangle rect, Color fontcolor, Color backColor)
        {
            Graphics g;
            Bitmap bmp;
            StringFormat format = new StringFormat(StringFormatFlags.NoClip);
            if (rect == Rectangle.Empty)
            {
                bmp = new Bitmap(1, 1);
                g = Graphics.FromImage(bmp);
                //计算绘制文字所需的区域大小（根据宽度计算长度），重新创建矩形区域绘图
                SizeF sizef = g.MeasureString(text, font, PointF.Empty, format);

                int width = (int)(sizef.Width + 1);
                int height = (int)(sizef.Height + 1);
                rect = new Rectangle(0, 0, width, height);
                bmp.Dispose();

                bmp = new Bitmap(width, height);
            }
            else
            {
                bmp = new Bitmap(rect.Width, rect.Height);
            }

            g = Graphics.FromImage(bmp);

            //使用ClearType字体功能
            g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.ClearTypeGridFit;
            g.FillRectangle(new SolidBrush(backColor), rect);
            g.DrawString(text, font, Brushes.Black, rect, format);
            return bmp;
        }

把textbox1文本的内容输出为jpg图片

            //获取文本
            string text = this.textbox1.Text;

            //得到Bitmap(传入Rectangle.Empty自动计算宽高)
            Bitmap bmp = TextToBitmap(text, this.textbox1.Font, Rectangle.Empty, this.textbox1.ForeColor, this.textbox1.BackColor);
            
            //用PictureBox显示
            this.pbTextView.Image = bmp;

            //保存到桌面save.jpg
            string directory = System.Environment.GetFolderPath(System.Environment.SpecialFolder.DesktopDirectory);
            bmp.Save(directory + "\\save.jpg", ImageFormat.Jpeg);