如何：获取字体规格
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 "字体文本")
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）。
下面的插图显示代码示例的输出。
.png "字体文本")
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）对于在字体设计单位和 Font 对象的单位（在本例中为像素）之间进行转换很关键。
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 "字体文本")
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 返回的数值是 19。 请注意，这与通过将行距单位转换为像素而得到的数字（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 PaintEventArgs e。