HOW TO：建立縮放效果
更新：2007 年 11 月
下列的範例程式模擬兩個相同大小之點陣圖的縮放效果，其中第二個圖包含第一個圖的縮放中心區段。
範例
' Define bmp and bmpZoom as
' global Bitmap variables for your form.
' Call CreateBitmap and then DefineZoom
' from your form's consructor.
Sub CreateBitmap()
bmp = New Bitmap(75, 75)
Dim g As Graphics = Graphics.FromImage(bmp)
Dim BlueBrush As New SolidBrush(Color.Blue)
Dim RedBrush As New SolidBrush(Color.Red)
Dim OuterRect As New Rectangle(0, 0, 200, 200)
g.FillRectangle(BlueBrush, OuterRect)
Dim InnerRect As New Rectangle(25, 25, 25, 25)
g.FillRectangle(RedBrush, InnerRect)
g.Dispose()
End Sub
Sub ZoomImage()
bmpZoom = New Bitmap(bmp.Width, bmp.Height)
Dim g As Graphics = Graphics.FromImage(bmpZoom)
Dim srcRect As New Rectangle(CInt(bmp.Width / 4), CInt(bmp.Height / 4), _
CInt(bmp.Width / 2), CInt(bmp.Height / 2))
Dim dstRect As New Rectangle(0, 0, bmpZoom.Width, bmpZoom.Height)
g.DrawImage(bmp, dstRect, srcRect, GraphicsUnit.Pixel)
End Sub
Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
e.Graphics.DrawImage(bmp, 0, 0)
e.Graphics.DrawImage(bmpZoom, 125, 0)
bmp.Dispose()
bmpZoom.Dispose()
MyBase.OnPaint(e)
End Sub
// Define bmp and bmpZoom as
// global Bitmap variables for your form.
// Call CreateBitmap and then DefineZoom
// from your form's consructor.
void CreateBitmap()
{
bmp = new Bitmap(75, 75);
Graphics g = Graphics.FromImage(bmp);
SolidBrush BlueBrush = new SolidBrush(Color.Blue);
SolidBrush RedBrush = new SolidBrush(Color.Red);
Rectangle OuterRect = new Rectangle(0, 0, 200, 200);
g.FillRectangle(BlueBrush, OuterRect);
Rectangle InnerRect = new Rectangle(25, 25, 25, 25);
g.FillRectangle(RedBrush, InnerRect);
g.Dispose();
}
private void ZoomImage()
{
bmpZoom = new Bitmap(bmp.Width, bmp.Height);
Graphics g = Graphics.FromImage(bmpZoom);
int new4W = bmp.Width / 4;
int new4H = bmp.Height / 4;
int new2W = bmp.Width / 2;
int new2H = bmp.Height / 2;
Rectangle srcRect = new Rectangle(new4W, new4H, new2W, new2H);
Rectangle dstRect = new Rectangle(0, 0, bmpZoom.Width, bmpZoom.Height);
g.DrawImage(bmp, dstRect, srcRect, GraphicsUnit.Pixel);
}
protected override void OnPaint(PaintEventArgs e)
{
e.Graphics.DrawImage(bmp, 0, 0);
e.Graphics.DrawImage(bmpZoom, 125, 0);
base.OnPaint(e);
}
編譯程式碼
這個範例需要下列命名空間的參考：
請參閱
概念
.NET Compact Framework HOW TO 主題