VB.NET Color.FromArgb方法代码示例

Public Sub FromArgb1(ByVal e As PaintEventArgs)
    Dim g As Graphics = e.Graphics

    ' Transparent red, green, and blue brushes.
    Dim trnsRedBrush As New SolidBrush(Color.FromArgb(120, 255, 0, 0))
    Dim trnsGreenBrush As New SolidBrush(Color.FromArgb(120, 0, _
    255, 0))
    Dim trnsBlueBrush As New SolidBrush(Color.FromArgb(120, 0, 0, 255))

    ' Base and height of the triangle that is used to position the
    ' circles. Each vertex of the triangle is at the center of one of
    ' the 3 circles. The base is equal to the diameter of the circle.
    Dim triBase As Single = 100
    Dim triHeight As Single = CSng(Math.Sqrt((3 * (triBase * _
    triBase) / 4)))

    ' Coordinates of first circle's bounding rectangle.
    Dim x1 As Single = 40
    Dim y1 As Single = 40

    ' Fill 3 over-lapping circles. Each circle is a different color.
    g.FillEllipse(trnsRedBrush, x1, y1, 2 * triHeight, 2 * triHeight)
    g.FillEllipse(trnsGreenBrush, x1 + triBase / 2, y1 + triHeight, _
    2 * triHeight, 2 * triHeight)
    g.FillEllipse(trnsBlueBrush, x1 + triBase, y1, 2 * triHeight, _
    2 * triHeight)
End Sub

Public Sub FromArgb2(ByVal e As PaintEventArgs)
    Dim g As Graphics = e.Graphics

    ' Opaque colors (alpha value defaults to 255 -- max value).
    Dim red As Color = Color.FromArgb(255, 0, 0)
    Dim green As Color = Color.FromArgb(0, 255, 0)
    Dim blue As Color = Color.FromArgb(0, 0, 255)

    ' Solid brush initialized to red.
    Dim myBrush As New SolidBrush(red)
    Dim alpha As Integer

    ' x coordinate of first red rectangle.
    Dim x As Integer = 50

    ' y coordinate of first red rectangle.
    Dim y As Integer = 50

    ' Fill rectangles with red, varying the alpha value from 25 to 250.
    For alpha = 25 To 250 Step 25
        myBrush.Color = Color.FromArgb(alpha, red)
        g.FillRectangle(myBrush, x, y, 50, 100)
        g.FillRectangle(myBrush, x, y + 250, 50, 50)
        x += 50
    Next alpha

    ' x coordinate of first green rectangle.
    x = 50

    ' y coordinate of first green rectangle.
    y += 50


    ' Fill rectangles with green, varying alpha value from 25 to 250.
    For alpha = 25 To 250 Step 25
        myBrush.Color = Color.FromArgb(alpha, green)
        g.FillRectangle(myBrush, x, y, 50, 150)
        x += 50
    Next alpha

    ' x coordinate of first blue rectangle.
    x = 50

    ' y coordinate of first blue rectangle.
    y += 100

    ' Fill rectangles with blue, varying alpha value from 25 to 250.
    For alpha = 25 To 250 Step 25
        myBrush.Color = Color.FromArgb(alpha, blue)
        g.FillRectangle(myBrush, x, y, 50, 150)
        x += 50
    Next alpha
End Sub

Public Sub FromArgb3(ByVal e As PaintEventArgs)
    Dim g As Graphics = e.Graphics

    ' Opaque colors (alpha value defaults to 255 -- max value).
    Dim red As Color = Color.FromArgb(255, 0, 0)
    Dim green As Color = Color.FromArgb(0, 255, 0)
    Dim blue As Color = Color.FromArgb(0, 0, 255)

    ' Solid brush initialized to red.
    Dim myBrush As New SolidBrush(red)
    Dim alpha As Integer

    ' x coordinate of first red rectangle.
    Dim x As Integer = 50

    ' y coordinate of first red rectangle.
    Dim y As Integer = 50

    ' Fill rectangles with red, varying the alpha value from 25 to 250.
    For alpha = 25 To 250 Step 25
        myBrush.Color = Color.FromArgb(alpha, red)
        g.FillRectangle(myBrush, x, y, 50, 100)
        g.FillRectangle(myBrush, x, y + 250, 50, 50)
        x += 50
    Next alpha

    ' x coordinate of first green rectangle.
    x = 50

    ' y coordinate of first green rectangle.
    y += 50

    ' Fill rectangles with green, varying alpha value from 25 to 250.
    For alpha = 25 To 250 Step 25
        myBrush.Color = Color.FromArgb(alpha, green)
        g.FillRectangle(myBrush, x, y, 50, 150)
        x += 50
    Next alpha

    ' x coordinate of first blue rectangle.
    x = 50

    ' y coordinate of first blue rectangle.
    y += 100

    ' Fill rectangles with blue, varying alpha value from 25 to 250.
    For alpha = 25 To 250 Step 25
        myBrush.Color = Color.FromArgb(alpha, blue)
        g.FillRectangle(myBrush, x, y, 50, 150)
        x += 50
    Next alpha
End Sub

Public Sub FromArgb4(ByVal e As PaintEventArgs)
    Dim g As Graphics = e.Graphics

    ' Transparent red, green, and blue brushes.
    Dim trnsRedBrush As New SolidBrush(Color.FromArgb(&H78FF0000))
    Dim trnsGreenBrush As New SolidBrush(Color.FromArgb(&H7800FF00))
    Dim trnsBlueBrush As New SolidBrush(Color.FromArgb(&H780000FF))

    ' Base and height of the triangle that is used to position the
    ' circles. Each vertex of the triangle is at the center of one of
    ' the 3 circles. The base is equal to the diameter of the circle.
    Dim triBase As Single = 100
    Dim triHeight As Single = CSng(Math.Sqrt((3 * (triBase * _
    triBase) / 4)))

    ' Coordinates of first circle
    's bounding rectangle.
    Dim x1 As Single = 40
    Dim y1 As Single = 40

    ' Fill 3 over-lapping circles. Each circle is a different color.
    g.FillEllipse(trnsRedBrush, x1, y1, 2 * triHeight, 2 * triHeight)
    g.FillEllipse(trnsGreenBrush, x1 + triBase / 2, y1 + triHeight, _
    2 * triHeight, 2 * triHeight)
    g.FillEllipse(trnsBlueBrush, x1 + triBase, y1, 2 * triHeight, _
    2 * triHeight)
End Sub

' 导入命名空间
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Windows.Forms

public class ColorCreation
   public Shared Sub Main
        Application.Run(New Form1)
   End Sub
End class

public class Form1
  Inherits System.Windows.Forms.Form

  Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
        Dim g As Graphics = Me.CreateGraphics()

        Dim redColor As Color = Color.FromArgb(120, 255, 0, 0)

        Dim blueColor As Color = Color.FromName("Blue")

        Dim greenColor As Color = Color.FromKnownColor(KnownColor.Green)

        Dim tstColor As Color = Color.Empty

        If greenColor.IsEmpty Then
            tstColor = Color.DarkGoldenrod
        End If

        Dim redBrush As New SolidBrush(redColor)
        Dim blueBrush As New SolidBrush(blueColor)
        Dim greenBrush As New SolidBrush(greenColor)
        Dim greenPen As New Pen(greenBrush, 4)

        g.FillEllipse(redBrush, 10, 10, 50, 50)
        g.FillRectangle(blueBrush, 60, 10, 50, 50)
        g.DrawLine(greenPen, 20, 60, 200, 60)

        Console.WriteLine("Color Name :" + blueColor.Name + ", A:" + blueColor.A.ToString() + ", R:" + blueColor.R.ToString() + ", B:" + blueColor.B.ToString() + ", G:" + blueColor.G.ToString())

        redBrush.Dispose()
        blueBrush.Dispose()
        greenBrush.Dispose()
        greenPen.Dispose()
        g.Dispose()
  End Sub

  Public Sub New()
   
    MyBase.New()
    Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
    Me.ClientSize = New System.Drawing.Size(292, 273)
    Me.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen

  End Sub

End Class

' 导入命名空间
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Windows.Forms

public class GDIObjectsCreateGraphicColorFromRGBAlpha
   public Shared Sub Main
        Application.Run(New Form1)
   End Sub
End class

Public Class Form1
    Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
        Dim canvas As Graphics = e.Graphics
        Dim colorBackground As Color =  Color.FromArgb(127, 0, 255, 123)
        canvas.Clear(colorBackground)
        
        canvas = Nothing
    End Sub
End Class


<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Partial Class Form1
    Inherits System.Windows.Forms.Form

    'Form overrides dispose to clean up the component list.
    <System.Diagnostics.DebuggerNonUserCode()> _
    Protected Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing AndAlso components IsNot Nothing Then
            components.Dispose()
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.SuspendLayout()
        '
        'Form1
        '
        Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
        Me.ClientSize = New System.Drawing.Size(610, 328)
        Me.Name = "Form1"
        Me.Text = "Creating Graphics Objects (Color, Pen, Font, Brush)"
        Me.ResumeLayout(False)

    End Sub

End Class