I've got a panel in windows forms (Visual Studio 2008) which has a background image (A book shelf).
When scrolling the image flickers and does not redraw so looks awfully - I've tried creating a new object to use double buffering but this has no effect, any suggestions?
Public Class DoubleBufferPanel
Inherits Panel
Public Sub New()
Me.DoubleBuffered = True
SetStyle(ControlStyles.AllPaintingInWmPaint Or _
ControlStyles.DoubleBuffer Or ControlStyles.ResizeRedraw Or ControlStyles.UserPaint, True)
UpdateStyles()
End Sub
End Class
That seems to happen when the BackgroundImageLayout is set to Zoom. If you set it to Stretch, that might fix the problem. If necessary, you can resize the image to fit the panel at load time and whenever the panel size changes.
I have used a docked picturebox, rather than labels I added the text directly to the image.
Related
I'm having a problem when it comes to images with white background. How can I remove the white background or make the image transparent?
For now I'm using this code
Dim _ms3 As New System.IO.MemoryStream()
pbSignCapture.Image.Save(_ms3, System.Drawing.Imaging.ImageFormat.Png)
Dim _arrImage3() As Byte = _ms3.GetBuffer()
_ms3.Close()
Also saving the image using the _arrImage3.
I want to convert the image in the PictureBox to turn the White Background into transparent.
Consider using the Bitmap class to open your image files.
Dim myImage as new Bitmap("C:\Image file.bmp")
And then you can use the MakeTransparent() or MakeTransparent(Color) methods:
Get the color of a background pixel.
Dim backColor As Color = myImage.GetPixel(1, 1)
Make backColor transparent for myBitmap.
myImage.MakeTransparent(backColor)
EDIT:
As I understand from the new details you want to have a PictureBox to be transparent where the source image is transparent. Unfortunately this is not possible using WinForms because the transparency system is not cascading. You can set the BackgroundColorproperty of pictureBox to transparent, but this is going to act differently from what you may think. The free pixels of the PictureBox control will show the content of the parent control.
It means that if you have, for example, a label below your picurebox and set transparent background to the image; the label won't be shown because it is not theparent control of the picturebox.
A workaround is to manually draw the image in the paint event of the destination control.
Let's assume that you have a form with many controls and you want to draw ad image over a button (named btn). You'll have to override the form's paint event this way:
Private Sub form_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles form.Paint
Dim g As Graphics = e.Graphics
g.DrawImage(Image.FromFile("C:/yourimage.png", btn.Location.X, btn.Location.Y)
End Sub
I have an application where I am dynamically changing form font types and sizes at runtime. The forms and controls resize proportionally when the controls are added to the form itself but not when they are added to containers such as panel or group controls where they tend to overlap or not grow to accommodate larger text. Any pointers as to why this might be?
For changing the font and size you use this:
Me.Font = New Font("Verdana", 12)
Me.Size = New Size(20, 20)
I have discovered that this was an issue specific to the DevExpress XtraForm. I resolved it by adding this to the form's constructor:
Font = (New Form()).Font
So my form's constructor looks like this:
Public Sub New()
Font = (New Form()).Font
' This call is required by the designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
End Sub
I have a 1080p touchscreen application. When a modal pops up, i want to emphasize that by darkening the main form.
Right now i use a second form, the size of the main form, that is black and has 50% opacity. Whenever a modal needs to appear, i open the opaque form, and then open the desired modal.
I feel this is a bit devious for my purpose. Its also not asshole-proof that when the user alt tabs, the forms will glitch out of sequence.
Is there a better way to achieve the darkening effect. Perhaps by darkening the main form from within itself?
Solved it myself by doing the following:
Place a hidden picturebox with dock:fill on the main form,
Take a screenshot of the current screen and darken it
assign the image to the picturebox and make it visible
open the modal in a new win
when the modal is dismissed
hide the picturebox
It really stupid that VB.net doesn't have this function built into it. Here's what you do to get around it:
Make a new form and call it Shade. I'm going to assume your main form is called frmMain. For the sake of clarity, lets assume the form you're launching is called dlgX.
Add the following lines in the Load event of dlgX (that's the sub with dlgX.Load or Me.Load or MyBase.Load):
Shade.Opacity = 0.001
Shade.Show()
Shade.Location = frmMain.Location ' Form location will only update if the form is visible.
Shade.Hide()
Shade.FormBorderStyle = Windows.Forms.FormBorderStyle.None 'This gets rid of the windows Titlebar and window border.
Shade.Size = frmMain.Size
Shade.BackColor = Color.Black
Shade.Opacity = 0.5
Shade.Show() ' Form size will only update the next time you show it.
Shade.TopMost = True ' Puts Shade over main form
Me.TopMost = True ' Puts current form over shade
Under all events that dismiss the form dlgX (OK.click, Cancel.click, etc), add the following lines:
Shade.Close
Or you can even make your own sub that handles all events where the form is closed:
Private Sub DispelShades(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Me.FormClosed
Shade.Close()
End Sub
This is way simpler than the PictureBox scenario and you don't have to mess with layering issues and having to ensure that the PictureBox renders on top of everything (for example, tabs really do not like having things rendered above them and they will not let you render a picture box above them). Rendering a black semi transparent form above your main form gets around all these headaches.
If you have multiple forms to shade, just make a Shad1, Shade2, Shade3 etc.
This is pretty obvious but it's worth stating: if you're shading the main form, you'll also want to make it unclickable by opening dlgX via dlgX.ShowDialog and not dlgX.Show
Here is some code, very similar to the method in Thomas's answer. Note to use the Darkness property in a Try...Finally block, to make sure you never leave the form in the dark state.
Public Class Form1
Private _PB As PictureBox
Public WriteOnly Property Darkness
Set(value)
If value Then
Dim Bmp = New Bitmap(Bounds.Size.Width, Bounds.Size.Height)
Me.DrawToBitmap(Bmp, New Rectangle(Point.Empty, Bounds.Size))
Using g = Graphics.FromImage(Bmp)
Dim Brush As New SolidBrush(Color.FromArgb(125, Color.Black))
g.FillRectangle(Brush, New Rectangle(Point.Empty, Bmp.Size))
End Using
_PB = New PictureBox
Me.Controls.Add(_PB)
_PB.Size = Bounds.Size
_PB.Location = Bounds.Location - PointToScreen(Point.Empty)
_PB.Image = Bmp
_PB.BringToFront()
Else
If _PB IsNot Nothing Then
Me.Controls.Remove(_PB)
_PB.Dispose()
End If
End If
End Set
End Property
Private Sub btnDialog_Click(sender As Object, e As EventArgs) Handles btnDialog.Click
Try
Darkness = True
MsgBox("Modal dialog")
Finally
Darkness = False
End Try
End Sub
End Class
i want to control my tab pages with custom buttons...now i want to hide my tabs from tab controls...how can i do that...
This is possible, the native tab control implemented by Windows sends the TCM_ADJUSTRECT message to allow the client to override the size of the tabs. Add a new class to your project and paste the code shown below. Compile. Drop the new control from the top of the toolbox onto your form. At design time it still has the tabs so you can easily switch between the pages. But they'll be gone at runtime.
Public Class MyTabControl
Inherits TabControl
Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
'--- Hide tabs by trapping the TCM_ADJUSTRECT message
If m.Msg = &H1328 AndAlso Not DesignMode Then
m.Result = CType(1, IntPtr)
Else
MyBase.WndProc(m)
End If
End Sub
End Class
I do not believe you can hide the tab buttons so to solve your problem don't use tab pages at all - instead use the Panel control.
You will be forced to do a little bit more work but you will get the effect you are after.
To get the same effect as using tabs, use the .visible property to either true or false on each panel.
Rather than having the pain of laying the panels all out nicely in the designer, design with one panel and then when setting .visible = true, also set the .top, .left, .width and .height to the values you need.
Hope this makes sense.
I am struggling to get my form to have a transparent background in vb.net
Currently in the form New I set
Me.SetStyle(ControlStyles.SupportsTransparentBackColor, true)
But still the form shows up as having the default grey background
Can anyone help??
EDIT: I need the controls on the form to be visible so I don't think setting the opacity to 0 will work
EDIT: I tried the transparency key solution but it doesn't work. I have a circular image with a black background. OnPaint I set the transparency key to the img pixel at 0,0, this then leaves me with circular image (which I want ) It hides the black background but I am still left with the default grey rectangle of the form.
below is the code I have -
Public Sub New()
Me.SetStyle(ControlStyles.SupportsTransparentBackColor, True)
Me.BackColor = Color.Transparent
' This call is required by the Windows Form Designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
Me.Timer1.Start()
End Sub
Private Sub frmWoll_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
Dim img As Bitmap = CType(Me.BackgroundImage, Bitmap)
img.MakeTransparent(img.GetPixel(2, 2))
Me.TransparencyKey = img.GetPixel(2, 2)
End Sub
Use TransparencyKey for transparent form.
eg.
TransparencyKey = Color.Red
Button1.BackColor = Color.Red
Now run the form you will find that the button1 has a hole in it.
So using this method you can create a mask image in paint for which part has to be transparent and apply that image to form and voila the form is now transparent.
Edit:
Sorry for late reply.
Following is your code modified to suit your requirement
Public Sub New()
Me.SetStyle(ControlStyles.SupportsTransparentBackColor, True)
Me.BackColor = Color.Transparent
' This call is required by the Windows Form Designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
Dim img As Bitmap = CType(Me.BackgroundImage, Bitmap)
'img.MakeTransparent(img.GetPixel(2, 2))
Me.FormBorderStyle = Windows.Forms.FormBorderStyle.None
Me.TransparencyKey = img.GetPixel(2, 2)
End Sub
Set Form's TransparencyKey color property same as form's Background color property
There are a few methods you could use.
Use the forms TransparencyKey
Override OnPaintBackground (WM_ERASEBKGND)
Override WndProc and handle the paint messages (WM_NCPAINT, WM_PAINT, etc)
I recommend overriding the window procedure to get optimal results.
Me.Opacity = 0
Be warned that:
This is for the entire form, rather than just the background. There are work-arounds to make certain parts more opague.
It's only psuedo-transparency where it takes a snapshot of what's behind it. It's smart enough to know when you move the form, but not when you move other transparent objects on top of the form.