Question

我是初学程序员，我正在学习使用VB在大学（英国）编写代码。

我在一个图片框的中心绘制了一个位图，这是一个箭头朝右的图像。旋转我用;

RAD = Math.Atan2(MOUSE_Y - CENTRE_Y, MOUSE_X - CENTRE_X) 
ANG = RAD * (180 / Math.PI)

正如您所看到的，我正在尝试使用MousePosition.Y＆amp; X使用鼠标位置旋转图像，使箭头指向鼠标，但箭头的角度关闭，因为它使用X和Y的整个显示器尺寸，而我喜欢它仅使用表单大小（640x480）

这是Picturebox1_Paint子;

Private Sub PictureBox1_Paint(sender As Object, e As PaintEventArgs) Handles PictureBox1.Paint
    Dim MOUSE_X As Integer
    Dim MOUSE_Y As Integer
    Dim CENTRE_X As Integer
    Dim CENTRE_Y As Integer
    Dim BMP As Bitmap
    Dim ANG As Integer = 0
    Dim RAD As Double
    Dim GFX As Graphics = e.Graphics
    BMP = New Bitmap(My.Resources.ARROWE)

    MOUSE_X = (MousePosition.X)
    MOUSE_Y = (MousePosition.Y)
    CENTRE_X = PictureBox1.Location.X + PictureBox1.Width / 2
    CENTRE_Y = PictureBox1.Location.Y + PictureBox1.Height / 2

    RAD = Math.Atan2(MOUSE_Y - CENTRE_Y, MOUSE_X - CENTRE_X)
    ANG = RAD * (180 / Math.PI)

    GFX.TranslateTransform(PictureBox1.Height / 2, PictureBox1.Width / 2)
    GFX.RotateTransform(ANG)
    GFX.DrawImage(BMP, -30, -30, 60, 60)
    GFX.ResetTransform()

End Sub

任何帮助将不胜感激

Answer 1

在paint事件之外使鼠标变量全局化并以mousemove事件的形式捕获它们：

Private MOUSE_X As Integer
Private MOUSE_Y As Integer

Private Sub Form1_MouseMove(sender As Object, e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove
    MOUSE_X = e.X
    MOUSE_Y = e.Y
    PictureBox1.Refresh()
End Sub    

Private Sub PictureBox1_Paint(sender As Object, e As PaintEventArgs) Handles PictureBox1.Paint
    Dim CENTRE_X As Integer
    Dim CENTRE_Y As Integer
    Dim BMP As Bitmap
    Dim ANG As Integer = 0
    Dim RAD As Double
    Dim GFX As Graphics = e.Graphics
    BMP = New Bitmap(My.Resources.ARROWE)

    CENTRE_X = PictureBox1.Location.X + PictureBox1.Width / 2
    CENTRE_Y = PictureBox1.Location.Y + PictureBox1.Height / 2

    RAD = Math.Atan2(MOUSE_Y - CENTRE_Y, MOUSE_X - CENTRE_X)
    ANG = RAD * (180 / Math.PI)

    GFX.TranslateTransform(PictureBox1.Height / 2, PictureBox1.Width / 2)
    GFX.RotateTransform(ANG)
    GFX.DrawImage(BMP, -30, -30, 60, 60)
    GFX.ResetTransform()

End Sub

使用鼠标位置旋转图像 - Visual Studio 2015

1 个答案: