I am making a program that constantly sends the key "{PRTSC}" and then sets PictureBox1.BackgroundImage = My.Computer.Clipboard.GetImage.
At first it works fine but after a min or two the picturebox goes blank and no error is given.
My code is:
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
If Not My.Computer.Clipboard.ContainsImage Then
SendKeys.Send("{PRTSC}")
Else
PictureBox1.BackgroundImage = My.Computer.Clipboard.GetImage
My.Computer.Clipboard.Clear()
End If
End Sub
I have tried:
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
'SendKeys.Send("{PRTSC}")
'If My.Computer.Clipboard.ContainsImage Then PictureBox1.BackgroundImage = My.Computer.Clipboard.GetImage
Dim bounds As New Rectangle
Dim screenshot As System.Drawing.Bitmap
Dim graph As Graphics
bounds = Screen.PrimaryScreen.Bounds
screenshot = New System.Drawing.Bitmap(bounds.Width, bounds.Height) ', System.Drawing.Imaging.PixelFormat.Format32bppRgb)
graph = Graphics.FromImage(screenshot)
graph.CopyFromScreen(0, 0, 0, 0, bounds.Size, CopyPixelOperation.SourceCopy)
PictureBox1.BackgroundImage = screenshot
graph.Dispose()
'screenshot.Save("d:\\dcap.jpg", Imaging.ImageFormat.Bmp)
End Sub
But attempting to dispose the screenshot yields an instant error. I don't know why.
{PRTSC} grabs the active window, when it has focus, and the screen otherwise.
It's a good idea to disable the timer at the beginning of the tick event, and start it at the end. This prevents re-entry, and, depending on the type of timer (there is the timer control, system.timers.timer, and system.threading.timer, each of which is a little different), you may be required to restart the timer each tick event.
It's normal to assign an image to a picturebox image instead of the backgroundimage. If something in the application is assigning a bitmap to picturebox1.image or blanking picturebox1.image, it will overwrite the screen shot in picturebox1.backgroundimage.
Related
I'm doing a project for my kitten who died...
I would like to know how I make it flip (look at the right side) when it comes to the left side of the screen, I'll leave an example in the print
Here's some code you can use to start with a single image file and display it in its original form or flipped horizontally depending on the horizontal position of its PictureBox on the screen.
'The Image to display on the left side of the screen.
Private leftImage As Image
'The Image to display on the right side of the screen.
Private rightImage As Image
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'Assume that the original image is the one to display on the left.
leftImage = Image.FromFile("file path here")
'Create a mirror image to display on the right.
rightImage = leftImage.Clone()
rightImage.RotateFlip(RotateFlipType.RotateNoneFlipX)
End Sub
Private Function IsPictureBoxOnLeftSideOfScreen() As Boolean
Dim screenMiddle = Screen.PrimaryScreen.WorkingArea.Width \ 2
Dim pictureBoxMiddle = PictureBox1.PointToScreen(Point.Empty).X + PictureBox1.Width \ 2
Return screenMiddle > pictureBoxMiddle
End Function
Private Sub SetImage()
PictureBox1.Image = If(IsPictureBoxOnLeftSideOfScreen(), leftImage, rightImage)
End Sub
Private Sub Form1_FormClosed(sender As Object, e As FormClosedEventArgs) Handles Me.FormClosed
rightImage.Dispose()
leftImage.Dispose()
End Sub
Where you call that SetImage method depends on exactly how you're moving the PictureBox, which you never showed us. If you're moving the form then you might do so in the LocationChanged event handler of the form. If you're moving the PictureBox then you might do so in the LocationChanged event handler of the PictureBox.
I have created a form and imported two square images saved as PNG files in resources. when I run the code below the black box which is drawn will only go about 200 pixels in the x coordinate and 150 pixels in the Y coordinate from where the image is drawn, after that the background remains white, and it seems I am unable to draw anything and anything I do draw stops around this point.
I have tried redrawing the image in a completely different location on the screen and It will not be visible if it is not within the region to the top left of the form, I have also tried drawing other images, but they also cease to exist when not in the top left of my form.
What I want is for the black box/other images to be drawn across the whole form, and not just in the top left corner, which something is preventing me from doing.
Public Class Form1
Dim gameGraphics As System.Drawing.Graphics = Me.CreateGraphics
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
'Draws black square which I have saved as resource
gameGraphics.DrawImage(My.Resources.black_Background, 0, 80, 1600, 600)
'Draws green square which I have saved as resource
gameGraphics.DrawImage(My.Resources.greenSquare, 2, 82, 40, 40)
End Sub
'makes the form fullscreen
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Me.FormBorderStyle = FormBorderStyle.None
Me.WindowState = FormWindowState.Maximized
End Sub
'closes form if quitbutton is clicked
Private Sub QuitButton_Click(sender As Object, e As EventArgs) Handles QuitButton.Click
Me.Close()
End Sub
End Class
Thanks for your time!
The Graphics Object cannot be stored. It's Erased/Updated constantly. You'll end up with an invalid one. It's really useless and, you could say, a mistake.
You can use a Graphics Object created with Control.CreateGraphics(), but you have to remember that it's not persistent; it will be erased when the Control you have painted it on needs to re-Paint() itself (e.g. you drag something over it, if it's a Form, when it's minimized etc.).
Those Properties, Me.FormBorderStyle = FormBorderStyle.None and Me.WindowState = FormWindowState.Maximized are better set in the designer. There's no reason to set them on a Form.Load() event. Their state is not even subject to a condition. In general, leave the Load event of a Form as lightweight as possible and avoid setting properties that can cause cascading events.
An example:
Define an object to store your images:
(The DrawBitmaps flag is used to let your Form know when to draw those Bitmaps).
Public Class MyBitmap
Public Property Image As Bitmap
Public Property Position As Point
Public Property Size As Size
End Class
Public MyBitmaps As List(Of MyBitmap)
Public DrawBitmaps As Boolean = False
Somewhere (even in Form.Load()), fill the list with you bitmaps:
(Here, the bitmap size is set to original size, but you can set it to whatever dimension you see fit).
MyBitmaps = New List(Of MyBitmap)
MyBitmaps.Add(New MyBitmap With {.Image = My.Resources.black_Background,
.Position = New Point(0, 80),
.Size = New Size(My.Resources.black_Background.Width,
My.Resources.black_Background.Height)})
MyBitmaps.Add(New MyBitmap With {.Image = My.Resources.greenSquare,
.Position = New Point(2, 82),
.Size = New Size(My.Resources.greenSquare.Width,
My.Resources.greenSquare.Height)})
The Paint() event e.Graphics of the Form performs all the painting:
(Note that it will not paint its surface unless the DrawBitmaps flag is set to True => It will not paint those Bitmaps when it's loading/showing. The other condition is a basic fail-safe.
Private Sub Form1_Paint(sender As Object, e As PaintEventArgs) Handles MyBase.Paint
If DrawBitmaps = True AndAlso MyBitmaps.Count > 0 Then
For Each _Item As MyBitmap In MyBitmaps
e.Graphics.DrawImage(_Item.Image, New Rectangle(_Item.Position, _Item.Size))
Next
End If
End Sub
When Button1 is clicked, the Form will draw your list of Bitmaps:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
DrawBitmaps = True
Me.Invalidate()
End Sub
Somewhere in your code, add a new Bitmap and tell the Form to Invalidate only a region of the size of this new Bitmap:
MyBitmaps.Add(New MyBitmap With {.Image = My.Resources.[AnotherBitmap],
.Position = New Point(50, 50),
.Size = New Size(200, 200)})
Me.Invalidate(New Rectangle(MyBitmaps.Last().Position, MyBitmaps.Last().Size))
Remove a Bitmap from the list and repaint:
MyBitmaps.RemoveAt(0)
Me.Invalidate()
I am using a worker thread to load .png images (from a path string) into a global PictureBox2 object, and then exit the _RunWorkerCompleted to use the PictureBox2's width and height for additional work in the method called processpic2. Everything works fine until about the 5th or 6th images were added to the PB. A this point, in the processpic2 method, an exception is thrown since the image property of the PictureBox2 evaluates to nothing.
Why would a PB stop taking images after a while?
Public Class Form1
Public WithEvents BackgroundWorker1 As New System.ComponentModel.BackgroundWorker
Private Sub BackGroundworker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
Dim args As ArgumentType = e.Argument
PictureBox2.Image = Nothing
PictureBox2.Invalidate()
Dim img As Image
Using str As Stream = File.OpenRead(args._pathstr)
img = Image.FromStream(str)
End Using
PictureBox2.Image = img
e.Result = "done"
End Sub
Private Sub BackgroundWorker1_RunWorkerCompleted(ByVal sender As System.Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) _Handles BackgroundWorker1.RunWorkerCompleted
'Called when the BackgroundWorker is completed.
processpic2()
End Sub
Sub btnLoadPicture(pathstr)
Dim args As ArgumentType = New ArgumentType()
args._pathstr = pathstr
BackgroundWorker1.RunWorkerAsync(args)
End Sub
Sub processpic2()
If PictureBox2.Image Is Nothing Then MsgBox("Image is Nothing")
End Sub
The whole point of a BackgroundWorker is to do background work. Making changes to the UI is the exact opposite of background work. It is foreground work. If your task is to clear the current contents of a PictureBox, load an image from a file and then display that image, only the middle step is background work so only the middle step should be done in the DoWork event handler. The first step should be done before you call RunWorkerAsync and the last step should be done in the RunWorkerCompleted event handler.
Having said all that, why use a BackgroundWorker at all in this case? Why not simply call the LoadAsync method of the PictureBox itself?
SOLUTION - thanks to the suggestions received, and what I found on MSDN regarding the LoadAsync method of PictureBox the following code solved the issue:
PictureBox2.Image = Nothing
PictureBox2.WaitOnLoad = False
' Load the image asynchronously.
PictureBox2.LoadAsync(pathstr)
I've encountered a very bizarre problem when trying to get a screenshot of a TableLayoutPanel in my form.
I have this code (taken from another question (How to get a screenshot, only for a picturebox); code courtesy of user "Chase Rocker"):
Dim s As Size = TableLayoutPanel1.Size
Dim memoryImage = New Bitmap(s.Width, s.Height)
Dim memoryGraphics As Graphics = Graphics.FromImage(memoryImage)
Dim ScreenPos As Point = Me.TableLayoutPanel1.PointToScreen(New Point(0, 0))
memoryGraphics.CopyFromScreen(ScreenPos.X, ScreenPos.Y, 0, 0, s)
Form3.PictureBox1.SizeMode = PictureBoxSizeMode.AutoSize
Form3.PictureBox1.BringToFront()
Form3.PictureBox1.Image = memoryImage
Now, here comes my problem. This code gives me a blank picture. It takes the screenshot apparently, but all I can see is white. Now, I was trying to see if the size was correct, so I was messing with MsgBox. I add this line to the code:
MsgBox("Random Message")
Getting
Dim s As Size = TableLayoutPanel1.Size
MsgBox("Random Message")
Dim memoryImage = New Bitmap(s.Width, s.Height)
Dim memoryGraphics As Graphics = Graphics.FromImage(memoryImage)
Dim ScreenPos As Point = Me.TableLayoutPanel1.PointToScreen(New Point(0, 0))
memoryGraphics.CopyFromScreen(ScreenPos.X, ScreenPos.Y, 0, 0, s)
Form3.PictureBox1.SizeMode = PictureBoxSizeMode.AutoSize
Form3.PictureBox1.BringToFront()
Form3.PictureBox1.Image = memoryImage
By some reason I don't know, the screenshot now works. I don't see white anymore, but the actual screenshot of the TableLayoutPanel. For me is very weird that the code only works with a MsgBox. Maybe I'm missing something. Does anyone know why this happens? Thank you!
How about if you try to make the TableLayoutPanel draw itself to a bitmap instead? This can be done using the Control.DrawToBitmap() method.
Dim s As Size = TableLayoutPanel1.Size
Dim memoryImage As New Bitmap(s.Width, s.Height)
TableLayoutPanel1.DrawToBitmap(memoryImage, New Rectangle(New Point(0, 0), s))
Form3.PictureBox1.Image = memoryImage
If the TableLayoutPanel fill happens in the same event handler where you grab the image then Windows has not draw the UI for the elements added to the TableLayoutPanel. Only when you exit from the event handler, the winforms engine has the opportunity to draw everything.
Adding a MessageBox changes everything because calling Show (a modal call that interrupts your code and pass control back to window) allows the Winform engine to draw the pending updates and your code works.
You can add a Timer control and put the code that execute the ScreenShoot in the Timer event.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
......
' code that fills the TableLayoutPanel
......
Dim tim1 = new System.Windows.Forms.Timer()
tim1.Interval = 1
AddHandler tim1.Tick, AddressOf tim1Ticked
tim1.Start()
End Sub
Private Sub tim1Ticked(sender As Object, e As EventArgs)
......
' Code that execute the screenshoot.
......
Dim t = DirectCast(sender, System.Windows.Forms.Timer)
t.Stop()
End Sub
I have a Picture Box called BGImage. I hope that when the user clicks on this I can capture the position of the mouse relative to BGImage.
I've tried using MousePosition, only to find it gives the mouse location on the screen, not on the PictureBox.
So I also tried using PointToClient:
Dim MousePos As Point = Me.PointToClient(MousePosition)
But this gives me the location {X=1866,Y=55} whereas I actually clicked on the PictureBox at around {X=516,Y=284}.
I think the problem arises because I have full-screened my program and set the position of the PictureBox to be at the centre of the screen (BGImage.Location = New Point((My.Computer.Screen.WorkingArea.Width / 2) - (1008 / 2), ((My.Computer.Screen.WorkingArea.Height / 2) - (567 / 2))))
I should also mention that the size of the PictureBox is 1008 By 567 pixels and my screen resolution is 1366 by 768.
Is there any way I can get the mouse position relative to BGImage's position?
Add a mouse click event to your picture box
Then use the MouseEventArgs to get the mouse position inside the picture box.
This will give you the X and the Y location inside the picture box.
Dim PPoint As Point
Private Sub PictureBox1_MouseClick(sender As Object, e As MouseEventArgs) Handles PictureBox1.MouseClick
PPoint = New Point(e.X, e.Y)
MsgBox(Convert.ToString(PPoint))
End Sub
I have before the same problem and just solved with the help of some friends.
Give a look Here mouse position is not correct
Here its the code that give you the correct position of the Mouse Based On A Picture.
Tanks to #Aaron he have give a final solution to this problem.
This will put a red dot on the exact point you click. I wonder how useful setting the cursor position will be though, as they will almost certainly move the mouse after clicking the button (inadvertently or not).
Setting the Cursor position needs to be in Screen coordinates - this converts back to client coordinates for drawing. I don't believe the PointToClient is necessary for the cursor position. In the below code, it is an unnecessary conversion, as you just go back to client coordinates. I left it in to show an example of each conversion, so that you can experiment with them.
Public Class Form1
Private PPoint As Point
Public Sub New()
' This call is required by the designer.
InitializeComponent()
PictureBox1.BackColor = Color.White
PictureBox1.BorderStyle = BorderStyle.Fixed3D
AddHandler PictureBox1.MouseClick, AddressOf PictureBox1_MouseClick
AddHandler Button8.Click, AddressOf Button8_Click
' Add any initialization after the InitializeComponent() call.
End Sub
Private Sub Button8_Click(sender As Object, e As EventArgs)
Dim g As Graphics = PictureBox1.CreateGraphics()
Dim rect As New Rectangle(PictureBox1.PointToClient(PPoint), New Size(1, 1))
g.DrawRectangle(Pens.Red, rect)
End Sub
Private Sub PictureBox1_MouseClick(sender As Object, e As MouseEventArgs)
PPoint = PictureBox1.PointToScreen(New Point(e.X, e.Y))
Label8.Text = PPoint.X.ToString()
Label9.Text = PPoint.Y.ToString()
End Sub
End Class
Instead of using:
Dim MousePos As Point = Me.PointToClient(MousePosition)
You should be using:
Dim MousePos As Point = BGImage.PointToClient(MousePosition)
It will give you mouse position in BGImage coordinates, whereas the first code gives you the mouse position in the Form's coordinates.