字体大小自动随宽度和内容改变

字体的大小设定可以在开始的时候指定.但是有时候需要根据窗口或者文字的长短来指定.那么这个时候就需要用到时间Paint了. 继承与Control的控件都有这个事件.也可以override OnPaint函数. 主要考虑两个因素,宽度和高度.比方如果字体的长度小于一个比例,则增加字体大小.如果大于一个比例则减小字体.

高度也是同样的道理.控制在一个比例范围以内就可以了

/// <summary>

        /// 标题重绘时候的处理

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void txtTitle_Paint(object sender, PaintEventArgs e)

        {

            var lbl = sender as Label;

            if (lbl == null)

            {

                return;

            }

            var size = MeasureStringWidth(lbl.Text, e.Graphics, lbl.Font);

            float diff = size.Width / lbl.Width;

            var font = lbl.Font;

            while ((diff > 0.6 || diff < 0.4))

            {



                font = new Font(font.Name, diff > 0.5 ? font.Size - 1 : font.Size + 1, font.Style);

                size = MeasureStringWidth(lbl.Text, e.Graphics, font);

                if (size.Height > lbl.Height)

                {

                    font = new Font(font.Name, diff > 0.5 ? font.Size + 1 : font.Size - 1, lbl.Font.Style);

                    break;

                }

                if (font.Size < 5)

                {

                    break;

                }

                diff = size.Width / lbl.Width;

            }

            lbl.Font = font;

        }

        /// <summary>

        /// 获得文字的高宽

        /// </summary>

        /// <param name="text">文字内容</param>

        /// <param name="graphic">绘画</param>

        /// <param name="font">字体</param>

        /// <returns>大小</returns>

        public static SizeF MeasureStringWidth(string text, Graphics graphic, Font font)

        {

            SizeF tmpSize = System.Windows.Forms.TextRenderer.MeasureText(text, font);

            return tmpSize;

        }