实例说明

在本实例中，我们制作一个能够显示多种形式文本的应用程序。程序运行后，即在窗体上的不同区域输出不同的文字。程序运行结果如图57-1所示。

图57-1 运行结果

技术要点

l 设定不同的Brush和Font

l 输出字体

实现过程

■ 新建项目

打开Visual Studio.NET，选择"新建项目"，在项目类型窗口中选择"Visual Basic项目"，在模板窗口中，选择"Windows应用程序"，在名称域中输入"GdipText"，然后选择保存路径。单击"确认"。

■ 添加代码

Public Sub New()

MyBase.New()

TextSample = Me

InitializeComponent()

serifFontFamily = New FontFamily(GenericFontFamilies.Serif)

Me.SetStyle(ControlStyles.Opaque,True)

Me.SetStyle(ControlStyles.ResizeRedraw,True)

Dim backgroundImage As Image

'设定背景图片

backgroundImage = New Bitmap(System.Reflection.Assembly.GetExecutingAssembly().

GetManifestResourceStream("colorbars.jpg"))

'新建一个画刷，我们将使用它在背景图片上画图

backgroundBrush = New TextureBrush(backgroundImage)

'设定文本图片

Dim textImage As Image = New Bitmap(System.Reflection.Assembly.GetExecutingAssembly().

GetManifestResourceStream("marble.jpg"))

textTextureBrush = New TextureBrush(textImage)

'设定要使用字体格式

Me.Font = New Font(serifFontFamily,20)

titleFont = New Font(serifFontFamily,60)

textFont = New Font(serifFontFamily,11)

'建立一个阴影画刷

titleShadowBrush = New SolidBrush(Color.FromArgb(70,Color.Black))

'用设定的字体和画刷输出Japanese文本

Try

japaneseFont = New Font("MS Mincho",36)

linearGradBrush = New LinearGradientBrush(New Point(0,0),New Point(0,45),Color.Blue,Color.Red)

Catch ex As Exception

MessageBox.Show("The Japanese font MS Mincho needs be present to run the Japanese part of this sample" & ControlChars.CrLf & "" & ControlChars.CrLf & "" + ex.Message)

doJapaneseSample = False

End Try

End Sub

Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)

Dim g As Graphics = e.Graphics

g.SmoothingMode = SmoothingMode.AntiAlias

'用texture画刷填充背景，并应用到一个白画布上

g.FillRectangle(backgroundBrush,ClientRectangle)

g.FillRectangle(New SolidBrush(Color.FromArgb(180,Color.White)),ClientRectangle)

g.DrawString("欢迎大家来到VB.NET的世界！",Me.Font,New SolidBrush(Color.Black),10,10)

Dim titleText As String = "图形示例"

g.DrawString(titleText,titleFont,titleShadowBrush,15,25)

g.DrawString(titleText,textTextureBrush,20)

Dim textToDraw As String = "银河文化公司"

Dim windowCenter As Double = Me.DisplayRectangle.Width / 2

Dim stringSize As SizeF = g.MeasureString(textToDraw,textFont)

Dim startPos As Double = windowCenter - (stringSize.Width / 2)

g.DrawString(textToDraw,textFont,New SolidBrush(Color.Red),CType(startPos,Single),10)

Dim rectangle1 As RectangleF = New RectangleF(20,150,250,300)

g.FillRectangle(New SolidBrush(Color.Gainsboro),rectangle1)

g.DrawString(flowedText1,New SolidBrush(Color.Blue),rectangle1)

'输出居中文本

Dim rectangle2 As RectangleF = New RectangleF(450,rectangle2)

Dim format As StringFormat = New StringFormat()

format.Alignment = StringAlignment.Center

g.DrawString(flowedText2,rectangle2,Format)

'统计输出的字符数和行数

Dim characters As Integer = 0

Dim lines As Integer = 0

g.MeasureString(flowedText2,rectangle2.Size,format,characters,lines)

Dim whatRenderedText As String = "共输出了" + CType(characters,String) + " 字符和 " + CType(lines,String) + "行"

g.DrawString(whatRenderedText,400,440)

'旋转刚才输出的Japanese文本

If (doJapaneseSample) Then

g.RotateTransform(-30)

g.TranslateTransform(-180,300)

g.DrawString(japaneseText,japaneseFont,linearGradBrush,200,140)

g.ResetTransform()

End If

End Sub

■ 运行程序

单击菜单"调试|启动"或单击 图标运行程序。

小结

本实例使用不同的画刷（Brush）和字体（Font），在不同的区域输出不同的文字，并可以旋转文字，而并不需要使用API函数。