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;
}