vb.net 更改图片框中的不透明度
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Change opacity in picturebox
提问by user3709879
I use this function
我用这个功能
Public Shared Function ChangeOpacity(ByVal img As Image, ByVal opacityvalue As Single) As Bitmap
Dim bmp As New Bitmap(img.Width, img.Height)
Dim graphics__1 As Graphics = Graphics.FromImage(bmp)
Dim colormatrix As New colormatrix
colormatrix.Matrix33 = opacityvalue
Dim imgAttribute As New ImageAttributes
imgAttribute.SetColorMatrix(colormatrix, ColorMatrixFlag.[Default], ColorAdjustType.Bitmap)
graphics__1.DrawImage(img, New Rectangle(0, 0, bmp.Width, bmp.Height), 0, 0, img.Width, img.Height, _
GraphicsUnit.Pixel, imgAttribute)
graphics__1.Dispose()
Return bmp
End Function
I use this command
我用这个命令
picturebox.Image = ChangeOpacity(picturebox.Image, 0.3)
picturebox.Image = ChangeOpacity(picturebox.Image, 0.3)
This is work ,The picturebox's opacity is fade out. but when I try this
这是工作，图片框的不透明度淡出。但是当我尝试这个时
picturebox.Image = ChangeOpacity(picturebox.Image, 1.0)
picturebox.Image = ChangeOpacity(picturebox.Image, 1.0)
It is nothing happen , The picture is still fade out I want to return picture into default How to fix this ? Thank you very much
什么都没有发生，图片仍然淡出我想将图片恢复为默认值如何解决这个问题？非常感谢
采纳答案by Sathish
Load the image form file like this
像这样加载图像表单文件
PictureBox1.Image = Image.FromFile("C:\Documents and
Settings\User3\Desktop\Sathish\image\calendar-icon-reportdate.png")
And use the call opacity like this
并像这样使用通话不透明度
PictureBox1.Image.Dispose()
PictureBox1.Image = ChangeOpacity(Image.FromFile("C:\Documents and
Settings\User3\Desktop\Sathish\image\calendar-icon-reportdate.png"), 0.3)
PictureBox1.Image.Dispose()
PictureBox1.Image = ChangeOpacity(Image.FromFile("C:\Documents and
Settings\User3\Desktop\Sathish\image\calendar-icon-reportdate.png"), 1)
回答by Ahmed
The second parameter in ChangeOpacity()function is the Opacity Percentage or factor of the picture in first parameter.
ChangeOpacity()函数中的第二个参数是第一个参数中图片的不透明度百分比或系数。
So (1.0) will not change the Opacity, it will return the picture without changes.
所以 (1.0) 不会改变不透明度，它会返回没有改变的图片。
You have to multiply the previous opacity value to have (1) and return the picture into default OR reload your image from the source with the default opacity to first parameter.
您必须乘以先前的不透明度值以获得 (1) 并将图片返回到默认值或从具有默认不透明度到第一个参数的源重新加载图像。
In your example The_Current_Opacity * Opacity_Factor = 1
在您的示例中 The_Current_Opacity * Opacity_Factor = 1
0.3 * Opacity_Factor = 1
0.3 * Opacity_Factor = 1
use: picturebox.Image = ChangeOpacity(picturebox.Image, 3.3)
用： picturebox.Image = ChangeOpacity(picturebox.Image, 3.3)
I prefer the division (1/0.3). It's more accurate than ( 3.3).
我更喜欢除法(1/0.3)。它比 更准确( 3.3)。
Here is the code and you can do the math
这是代码，你可以做数学
dim OpacityPercentage as Single
OpacityPercentage = 0.3
'To fade out the picturebox's opacity
picturebox1.Image = ChangeOpacity(picturebox1.Image, OpacityPercentage )
'To return picture into default
picturebox1.Image = ChangeOpacity(picturebox1.Image, 1/OpacityPercentage )
