VB.Net 使用线性渐变画笔的背景渐变并显示图像

Question

我尝试实现用渐变背景颜色绘制表单并与透明度重叠图像。

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！，我想与您分享我的解决方案（这很容易）：

外部帮助：使用图像平铺形状

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

下面介绍如何绘制渐变背景。平铺图像会很慢，除非你使用Windows API或其他东西。

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