C#长图文（横版实现文字换行）相关实现

效果如上图

代码如下：

/// <summary>
        /// 横版长图文文字从左起
        /// </summary>
        /// <param name="template">底图</param>
        /// <param name="str">文本内容  传入文本段首没有空两格</param>
        /// <param name="font">字体</param>
        /// <param name="color">字色</param>
        /// <param name="top">上边边距</param>
        /// <param name="bottom">下边边距</param>
        /// <param name="left">两边边距</param>
        /// <param name="lineH">列间距</param>
        /// <returns></returns>
        public static Bitmap LongPic_H_left(Bitmap template, string str, Font font, Color color, int top, int bottom, int left, int lineH)
        {
            int h = template.Height;
            int w = CalculateW(str, h, font, top, bottom, left, lineH);
            Bitmap bg = new Bitmap(w, h);
            Graphics g = Graphics.FromImage(bg);
            g.DrawImage(template, 0, 0, w, h);
            Brush c = new SolidBrush(color);
            string[] strs = str.Split(new string[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
            int x = left;
            int y = top;
            int w1 = (int)(Math.Ceiling(font.Size) / 72 * 96) + lineH;//两列字Y的差距
            int row_H = (h - top - bottom);//一列文字可画区域的高度
            int a = font.Height;  //字体高度
            int b = row_H / a;  //一列可容纳的个数
            foreach (string i in strs)
            {
                string s = i.ToString();
                int len = s.Length;
                for (int j1 = 0, j2 = 1; j1 < len; j1++, j2++)
                {
                    if (j2 > b)
                    {
                        x += w1;
                        y = top;
                        j2 = 1;
                    }
                    string s1 = s[j1].ToString();
                    g.DrawString(s1, font, c, x, y);
                    y += font.Height;
                }
                x += w1;
                y = top;
            }
            return bg;
        }
        /// <summary>
        /// 横版长图文文字从右起
        /// </summary>
        /// <param name="template">底图</param>
        /// <param name="str">文本内容  传入文本段首没有空两格</param>
        /// <param name="font">字体</param>
        /// <param name="color">字色</param>
        /// <param name="top">上边边距</param>
        /// <param name="bottom">下边边距</param>
        /// <param name="left">两边边距</param>
        /// <param name="lineH">列间距</param>
        /// <returns></returns>
        public static Bitmap LongPic_H_right(Bitmap template, string str, Font font, Color color, int top, int bottom, int left, int lineH)
        {
            int h = template.Height;
            int w = CalculateW(str, h, font, top, bottom, left, lineH);
            Bitmap bg = new Bitmap(w, h);
            Graphics g = Graphics.FromImage(bg);
            g.DrawImage(template, 0, 0, w, h);
            Brush c = new SolidBrush(color);
            string[] strs = str.Split(new string[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
            int x = w - left;
            int y = top;
            int w1 = (int)(Math.Ceiling(font.Size) / 72 * 96) + lineH;//两列字Y的差距
            int row_H = (h - top - bottom);//一列文字可画区域的高度
            int a = font.Height;  //字体高度
            int b = row_H / a;  //一列可容纳的个数
            foreach (string i in strs)
            {
                string s = i.ToString();
                int len = s.Length;
                for (int j1 = 0, j2 = 1; j1 < len; j1++, j2++)
                {
                    if (j2 > b)
                    {
                        x -= w1;
                        y = top;
                        j2 = 1;
                    }
                    string s1 = s[j1].ToString();
                    g.DrawString(s1, font, c, x, y);
                    y += font.Height;
                }
                x -= w1;
                y = top;
            }
            return bg;
        }
        /// <summary>
        /// 横版长图文计算生成后图片宽度
        /// </summary>
        /// <param name="content">文本内容   传入文本段首没有空两格</param>
        /// <param name="h">底图高度</param>
        /// <param name="font">字体</param>
        /// <param name="top">上边边距</param>
        /// <param name="bottom">底边边距</param>
        /// <param name="left">两边边距</param>
        /// <param name="lineH">列间距</param>
        /// <returns></returns>
        public static int CalculateW(string content, int h, Font font, int top, int bottom, int left, int lineH)
        {
            string[] str = content.Split(new string[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
            int tmp = 0;//累计行数初始为0
            foreach (string i in str)
            {
                string s = i.ToString();
                tmp += RowNum_H(s, h, font, top, bottom);
            }
            int fh = (int)(Math.Ceiling(font.Size) / 72 * 96);//单字的宽度
            int W = tmp * (fh + lineH) + left * 2;
            return W;
        }
        /// <summary>
        /// 横版长图文计算段落的列数
        /// </summary>
        /// <param name="strs">文本内容   传入文本段首没有空两格</param>
        /// <param name="h">图片的高度</param>
        /// <param name="font">字体</param>
        /// <param name="top">上边边距</param>
        /// <param name="bottom">下边边距</param>
        /// <returns></returns>
        public static int RowNum_H(string strs, int h, Font font, int top, int bottom)
        {
            int row = 0;     //初始行数设为0
            int slen = strs.Length;    //段落字符的总个数
            int row_H = (h - top - bottom);//一列文字可画区域的高度
            int a = font.Height;  //字体高度
            int b = row_H / a;  //一列可容纳的个数
            row = (int)Math.Ceiling((double)slen / b);
            return row;
        }

段首空格效果没做出来，失败了