【TeeChart Pro ActiveX教程】（十三）：圖表面板上的自定義繪圖（上）

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下載TeeChart Pro ActiveX最新版本

TeeChart通過Canvas對象提供廣泛的自定義繪圖工具。使用Canvas，您可以在“Chart Panel”的任何位置添加形狀，線條和文本，并定義其顏色，筆和畫筆樣式。

TeeChart畫布

繪圖順序

使用TeeChart的Canvas方法時，請記住繪圖順序很重要。在圖表上繪制一條線然后添加系列數據點將導致線透支。 有四個主要的圖表繪制事件，按順序排列：

• BeforeDraw事件
• BeforeDrawAxes事件
• BeforeDrawSeries事件
• AfterDraw事件

[C#]

private bool afterDraw; 
private bool beforeDraw; 
private bool beforeDrawAxis; 
private bool beforeDrawSeries; 
 
private void Form1_Load(object sender, System.EventArgs e) {  
     SetFlags(ref beforeDraw); 
     Bar bar1 = new Bar(tChart1.Chart); 
     bar1.FillSampleValues(20); 
     radioButton1.Checked = true; 
} 
private void SetFlags(ref bool Flag) { 
     beforeDraw = false; 
     afterDraw = false; 
     beforeDrawAxis = false; 
     beforeDrawSeries = false; 
     Flag = true; 
} 
private void DrawShape(Steema.TeeChart.Drawing.Graphics3D gg) { 
     gg.Brush.Color = Color.Yellow; 
     gg.Pen.Visible = true; 
     gg.Pen.Style = System.Drawing.Drawing2D.DashStyle.Dash; 
     gg.Brush.Visible = true; 
     gg.Ellipse(1,1,gg.Chart.Width - 1,gg.Chart.Height - 1); 
} 
private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) { 
     if(afterDraw) { 
     DrawShape(g); 
    } 
} 
private void tChart1_BeforeDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) { 
     if(beforeDraw) { 
     DrawShape(g); 
    } 
} 
private void tChart1_BeforeDrawAxes(object sender, Steema.TeeChart.Drawing.Graphics3D g) { 
     if(beforeDrawAxis) { 
     DrawShape(g); 
    } 
} 
private void tChart1_BeforeDrawSeries(object sender, Steema.TeeChart.Drawing.Graphics3D g) { 
     if(beforeDrawSeries) { 
     DrawShape(g); 
    } 
} 
private void radioButton4_Click(object sender, System.EventArgs e) { 
     SetFlags(ref afterDraw); 
     tChart1.Refresh(); 
} 
private void radioButton3_Click(object sender, System.EventArgs e) { 
     SetFlags(ref beforeDrawSeries); 
     tChart1.Refresh(); 
} 
private void radioButton2_Click(object sender, System.EventArgs e) { 
     SetFlags(ref beforeDrawAxis); 
     tChart1.Refresh(); 
} 
private void radioButton1_Click(object sender, System.EventArgs e) { 
     SetFlags(ref beforeDraw); 
     tChart1.Refresh(); 
} 

[VB.Net]

Private BeforeDraw As Boolean 
Private BeforeDrawAxis As Boolean 
Private BeforeDrawSeries As Boolean 
Private AfterDraw As Boolean 
 
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
    SetFlags(BeforeDraw) 
    Dim Bar1 As New Steema.TeeChart.Styles.Bar(TChart1.Chart) 
    Bar1.FillSampleValues(20) 
    RadioButton1.Checked = True 
End Sub 
Private Sub SetFlags(ByRef Flag As Boolean) 
    BeforeDraw = False 
    BeforeDrawAxis = False 
    BeforeDrawSeries = False 
    AfterDraw = False 
    Flag = True 
End Sub 
Private Sub DrawShape(ByVal gg As Steema.TeeChart.Drawing.Graphics3D) 
    gg.Brush.Color = Color.Yellow 
    gg.Pen.Visible = True 
    gg.Pen.Style = Drawing.Drawing2D.DashStyle.Dash 
    gg.Brush.Visible = True 
    gg.Ellipse(1, 1, gg.Chart.Width - 1, gg.Chart.Height - 1) 
End Sub 
Private Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw 
    If AfterDraw = True Then 
     DrawShape(g) 
    End If 
End Sub 
Private Sub TChart1_BeforeDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.BeforeDraw 
    If BeforeDraw = True Then 
     DrawShape(g) 
    End If 
End Sub 
Private Sub TChart1_BeforeDrawAxes(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.BeforeDrawAxes 
    If BeforeDrawAxis = True Then 
     DrawShape(g) 
    End If 
End Sub 
Private Sub TChart1_BeforeDrawSeries(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.BeforeDrawSeries 
    If BeforeDrawSeries = True Then 
     DrawShape(g) 
    End If 
End Sub 
Private Sub RadioButton4_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton4.Click 
    SetFlags(AfterDraw) 
    TChart1.Refresh() 
End Sub 
Private Sub RadioButton3_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton3.Click 
    SetFlags(BeforeDrawSeries) 
    TChart1.Refresh() 
End Sub 
Private Sub RadioButton2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton2.Click 
    SetFlags(BeforeDrawAxis) 
    TChart1.Refresh() 
End Sub 
Private Sub RadioButton1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton1.Click 
    SetFlags(BeforeDraw) 
    TChart1.Refresh() 
End Sub 

確保將自定義繪制的項目保存到Canvas

如果不在其中一個Chart事件中調用Canvas繪制代碼，則自定義繪圖將不會永久保存到Canvas，從而導致在應用程序最小化時丟失任何添加內容或另一個窗口放在它上面。您的代碼不需要直接駐留在Chart事件中; 如果將代碼放在BeforeDrawSeries / AfterDraw中并且檢查運行時設置的標記，則可以在圖表窗口的生命周期中保存用戶繪制的項目。當活動標記為true時，繪制方法因此運行繪制代碼，如上例所示。

繪制線

讓我們添加一個畫布線： 示例（從左上角到右下角對角畫一條線）

[C#]

private void Form1_Load（object sender，System.EventArgs e）{ 
        line1.FillSampleValues（20）; 
        line1.VertAxis = VerticalAxis.Both; 
        line1.HorizAxis = Horizo??ntalAxis.Both; 
        tChart1.Aspect.View3D = false; 
} 
 
private void tChart1_AfterDraw（object sender，Steema.TeeChart.Drawing.Graphics3D g）{ 
        Point s = new Point（tChart1.Axes.Left.Position，tChart1.Axes.Top.Position）; 
        點e =新點（tChart1.Axes.Right.Position，tChart1.Axes.Bottom.Position）; 
        g.MoveTo（一個或多個）; 
        g.LineTo（E，0）; 
} 

[VB.Net]

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
        Line1.FillSampleValues(20) 
        Line1.VertAxis = Steema.TeeChart.VerticalAxis.Both 
        Line1.HorizAxis = Steema.TeeChart.HorizontalAxis.Both 
        TChart1.Aspect.View3D = False 
End Sub 
 
Private Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw 
        Dim S As New Point(TChart1.Axes.Left.Position, TChart1.Axes.Top.Position) 
        Dim E As New Point(TChart1.Axes.Right.Position, TChart1.Axes.Bottom.Position) 
        g.MoveTo(S) 
        g.LineTo(E, 0) 
End Sub

在3D圖表上，由于3D正交位移，軸位置偏離圖表區域。我們可以相應地移動線： 示例（在3D圖表的圖表區域中從左上角到右下角對角繪制一條線）

[C#]

private void Form1_Load(object sender, System.EventArgs e) { 
        line1.FillSampleValues(20); 
        line1.VertAxis = VerticalAxis.Both; 
        line1.HorizAxis = HorizontalAxis.Both; 
        tChart1.Aspect.Chart3DPercent = 50; 
} 
 
private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) { 
        Steema.TeeChart.Drawing.Point3D s = new Steema.TeeChart.Drawing.Point3D(); 
        s.X = tChart1.Axes.Left.Position; 
        s.Y = tChart1.Axes.Top.Position; 
        s.Z = 0; 
 
        Steema.TeeChart.Drawing.Point3D e = new Steema.TeeChart.Drawing.Point3D(); 
        e.X = tChart1.Axes.Right.Position; 
        e.Y = tChart1.Axes.Bottom.Position; 
        e.Z = tChart1.Aspect.Width3D; 
     
        g.MoveTo(s); 
        g.LineTo(e); 
} 

[VB.Net]

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
        Line1.FillSampleValues(20) 
        Line1.VertAxis = Steema.TeeChart.VerticalAxis.Both 
        Line1.HorizAxis = Steema.TeeChart.HorizontalAxis.Both 
        TChart1.Aspect.Chart3DPercent = 50 
End Sub 
 
Private Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw 
        Dim S As New Steema.TeeChart.Drawing.Point3D() 
        S.X = TChart1.Axes.Left.Position 
        S.Y = TChart1.Axes.Top.Position 
        S.Z = 0 
 
        Dim E As New Steema.TeeChart.Drawing.Point3D() 
        E.X = TChart1.Axes.Right.Position 
        E.Y = TChart1.Axes.Bottom.Position 
        E.Z = TChart1.Aspect.Width3D 
 
        g.MoveTo(S) 
        g.LineTo(E) 
End Sub 

畫布筆和畫筆

上面的線是使用為繪制線之前繪制的最后一個對象定義的筆和畫筆繪制的。那可能是也可能不是你想要的筆。相應地更改筆： 示例（在繪制線之前定義筆）

[C#]

private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) { 
        Point p5 = new Point(line1.CalcXPos(5), line1.CalcYPos(5)); 
        Point p15 = new Point(line1.CalcXPos(15), line1.CalcYPos(15)); 
        g.Pen.DashCap = System.Drawing.Drawing2D.DashCap.Triangle; 
        g.Pen.EndCap = System.Drawing.Drawing2D.LineCap.DiamondAnchor; 
        g.Pen.Style = System.Drawing.Drawing2D.DashStyle.DashDotDot; 
        g.Pen.Transparency = 70; 
        g.Pen.Width = 3; 
        g.Pen.Color = Color.BlueViolet; 
        g.MoveTo(p5); 
        g.LineTo(p15, 0); 
} 

[VB.Net]

Private Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw 
        Dim P5 As New Point(Line1.CalcXPos(5), Line1.CalcYPos(5)) 
        Dim P15 As New Point(Line1.CalcXPos(15), Line1.CalcYPos(15)) 
        g.Pen.DashCap = System.Drawing.Drawing2D.DashCap.Triangle 
        g.Pen.EndCap = System.Drawing.Drawing2D.LineCap.DiamondAnchor 
        g.Pen.Style = System.Drawing.Drawing2D.DashStyle.DashDotDot 
        g.Pen.Transparency = 70 
        g.Pen.Width = 3 
        g.Pen.Color = Color.BlueViolet 
        g.MoveTo(P5) 
        g.LineTo(P15, 0) 
End Sub 

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