如何：获取字体规格
更新：2007 年 11 月
FontFamily 类提供了下列方法来检索特定字体/字形组合的各种规格：
GetEmHeight(FontStyle)
GetCellAscent(FontStyle)
GetCellDescent(FontStyle)
GetLineSpacing(FontStyle)
这些方法返回的数字使用的是字体设计单位，因此，它们与特定的 Font 对象的大小和单位无关。
下面的插图显示了各种规格。
.png)
示例
下面的示例显示 Arial 字体系列常规字形的规格。该代码还创建一个大小为 16 像素的 Font 对象（基于 Arial 系列），并显示该特定 Font 对象的规格（以像素为单位）。
下面的插图显示示例代码的输出。
.png)
请注意上面的插图中的前两行输出。Font 对象返回的大小为 16， FontFamily 对象返回的 em 高度为 2,048。这两个数字（16 和 2,048）是在字体设计单位和 Font 对象的单位（在本例中为像素）之间转换的关键。
例如，您可按照以下方法将升高值从设计单位转换为像素：
.png)
下面的代码通过设置 PointF 对象的 Y 数据成员来在垂直方向上定位文本。每新增加一行文本，y 坐标就增加 font.Height。Font 对象的 Height 属性返回该特定 Font 对象的行距（以像素为单位）。在此示例中，Height 返回的数为 19。请注意，这与通过将行距单位转换为像素而得到的数（向上舍入为一个整数）是相同的。
注意 em 高度（也叫大小或 em 大小）不是升高值与降低值之和。升高值与降低值之和称为单元格高度。单元格高度减去内部间隙等于 em 高度。单元格高度加外部间隙等于行距。
Dim infoString As String = "" ' enough space for one line of output
Dim ascent As Integer ' font family ascent in design units
Dim ascentPixel As Single ' ascent converted to pixels
Dim descent As Integer ' font family descent in design units
Dim descentPixel As Single ' descent converted to pixels
Dim lineSpacing As Integer ' font family line spacing in design units
Dim lineSpacingPixel As Single ' line spacing converted to pixels
Dim fontFamily As New FontFamily("Arial")
Dim font As New Font( _
fontFamily, _
16, _
FontStyle.Regular, _
GraphicsUnit.Pixel)
Dim pointF As New PointF(10, 10)
Dim solidBrush As New SolidBrush(Color.Black)
' Display the font size in pixels.
infoString = "font.Size returns " & font.Size.ToString() & "."
e.Graphics.DrawString(infoString, font, solidBrush, pointF)
' Move down one line.
pointF.Y += font.Height
' Display the font family em height in design units.
infoString = "fontFamily.GetEmHeight() returns " & _
fontFamily.GetEmHeight(FontStyle.Regular) & "."
e.Graphics.DrawString(infoString, font, solidBrush, pointF)
' Move down two lines.
pointF.Y += 2 * font.Height
' Display the ascent in design units and pixels.
ascent = fontFamily.GetCellAscent(FontStyle.Regular)
' 14.484375 = 16.0 * 1854 / 2048
ascentPixel = _
font.Size * ascent / fontFamily.GetEmHeight(FontStyle.Regular)
infoString = "The ascent is " & ascent & " design units, " & ascentPixel _
& " pixels."
e.Graphics.DrawString(infoString, font, solidBrush, pointF)
' Move down one line.
pointF.Y += font.Height
' Display the descent in design units and pixels.
descent = fontFamily.GetCellDescent(FontStyle.Regular)
' 3.390625 = 16.0 * 434 / 2048
descentPixel = _
font.Size * descent / fontFamily.GetEmHeight(FontStyle.Regular)
infoString = "The descent is " & descent & " design units, " & _
descentPixel & " pixels."
e.Graphics.DrawString(infoString, font, solidBrush, pointF)
' Move down one line.
pointF.Y += font.Height
' Display the line spacing in design units and pixels.
lineSpacing = fontFamily.GetLineSpacing(FontStyle.Regular)
' 18.398438 = 16.0 * 2355 / 2048
lineSpacingPixel = _
font.Size * lineSpacing / fontFamily.GetEmHeight(FontStyle.Regular)
infoString = "The line spacing is " & lineSpacing & " design units, " & _
lineSpacingPixel & " pixels."
e.Graphics.DrawString(infoString, font, solidBrush, pointF)
string infoString = ""; // enough space for one line of output
int ascent; // font family ascent in design units
float ascentPixel; // ascent converted to pixels
int descent; // font family descent in design units
float descentPixel; // descent converted to pixels
int lineSpacing; // font family line spacing in design units
float lineSpacingPixel; // line spacing converted to pixels
FontFamily fontFamily = new FontFamily("Arial");
Font font = new Font(
fontFamily,
16, FontStyle.Regular,
GraphicsUnit.Pixel);
PointF pointF = new PointF(10, 10);
SolidBrush solidBrush = new SolidBrush(Color.Black);
// Display the font size in pixels.
infoString = "font.Size returns " + font.Size + ".";
e.Graphics.DrawString(infoString, font, solidBrush, pointF);
// Move down one line.
pointF.Y += font.Height;
// Display the font family em height in design units.
infoString = "fontFamily.GetEmHeight() returns " +
fontFamily.GetEmHeight(FontStyle.Regular) + ".";
e.Graphics.DrawString(infoString, font, solidBrush, pointF);
// Move down two lines.
pointF.Y += 2 * font.Height;
// Display the ascent in design units and pixels.
ascent = fontFamily.GetCellAscent(FontStyle.Regular);
// 14.484375 = 16.0 * 1854 / 2048
ascentPixel =
font.Size * ascent / fontFamily.GetEmHeight(FontStyle.Regular);
infoString = "The ascent is " + ascent + " design units, " + ascentPixel +
" pixels.";
e.Graphics.DrawString(infoString, font, solidBrush, pointF);
// Move down one line.
pointF.Y += font.Height;
// Display the descent in design units and pixels.
descent = fontFamily.GetCellDescent(FontStyle.Regular);
// 3.390625 = 16.0 * 434 / 2048
descentPixel =
font.Size * descent / fontFamily.GetEmHeight(FontStyle.Regular);
infoString = "The descent is " + descent + " design units, " +
descentPixel + " pixels.";
e.Graphics.DrawString(infoString, font, solidBrush, pointF);
// Move down one line.
pointF.Y += font.Height;
// Display the line spacing in design units and pixels.
lineSpacing = fontFamily.GetLineSpacing(FontStyle.Regular);
// 18.398438 = 16.0 * 2355 / 2048
lineSpacingPixel =
font.Size * lineSpacing / fontFamily.GetEmHeight(FontStyle.Regular);
infoString = "The line spacing is " + lineSpacing + " design units, " +
lineSpacingPixel + " pixels.";
e.Graphics.DrawString(infoString, font, solidBrush, pointF);
编译代码
前面的示例是为使用 Windows 窗体而设计的，它需要 PaintEventHandler 的参数 PaintEventArgse。