VB.Net背景渐变使用LinearGradientBrush并显示图像

Question

我尝试用渐变背景色绘制表单并用透明度重叠图像。

这可能吗？

我想使用具有透明背景的平铺背景图像并使用自定义线性渐变绘制背景。

Answer 1

我做到了！我想和你分享我的解决方案（很简单）：

外部帮助：Tile a Shape with an Image

Private Sub BackgroundGradient(ByRef Control As Object, _
                                ByVal Color1 As Drawing.Color, _
                                ByVal Color2 As Drawing.Color)

    Dim vLinearGradient As Drawing.Drawing2D.LinearGradientBrush = _
        New Drawing.Drawing2D.LinearGradientBrush(New Drawing.Point(Control.Width, Control.Height), _
                                                    New Drawing.Point(Control.Width, 0), _
                                                    Color1, _
                                                    Color2)

    Dim vGraphic As Drawing.Graphics = Control.CreateGraphics
    ' To tile the image background - Using the same image background of the image
    Dim vTexture As New Drawing.TextureBrush(Control.BackgroundImage)

    vGraphic.FillRectangle(vLinearGradient, Control.DisplayRectangle)
    vGraphic.FillRectangle(vTexture, Control.DisplayRectangle)

    vGraphic.Dispose() : vGraphic = Nothing : vTexture.Dispose() : vTexture = Nothing
End Sub

Answer 2

这里是如何绘制渐变背景。除非您使用 Windows API 或其他工具，否则平铺图像会很慢。

Imports System.Drawing

Public Class frmBG

  Private Sub frmBG_Paint(sender As Object, e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
    Dim g As Graphics = e.Graphics
    Dim p1 As Point = Me.ClientRectangle.Location
    Dim p2 As Point = New Point(Me.ClientRectangle.Right, Me.ClientRectangle.Bottom)
    Using brsGradient As New System.Drawing.Drawing2D.LinearGradientBrush(p1, p2, Color.Red, Color.Blue)
      g.FillRectangle(brsGradient, e.ClipRectangle)
      g.DrawImage(My.Resources.demoImage, Me.ClientRectangle.Location)
    End Using

  End Sub

  Private Sub frmBG_ResizeEnd(sender As Object, e As System.EventArgs) Handles Me.ResizeEnd
    Me.Invalidate()
  End Sub
End Class