draw coordinate Two dimensions graph of (x-y) visual basic - vb.net

hey every one I want to make a program that able to draw coordinate graph of Two dimensions of (x-y).when I enter a value in (x) text box and (y) text box and hit draw button it well draw the graph in the blue picture box . I searched in web sit but I found only one method that draw using the mouse and this not what I want .This is the image of the program and and it supposed to draw in white line like this image
Private Sub PictureBox2_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox2.MouseMove
Static last As Point
If e.Button = Windows.Forms.MouseButtons.Left Then
PictureBox2.CreateGraphics.DrawLine(Pens.White, last.X, last.Y, e.X, e.Y)
End If
last = e.Location
End Sub
this is the code that I found that draw using the mouse

You should use the Graphic class inside the panel's Paint event
Private Sub Panel1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs)
' Create pen.
Using blackPen As New Pen(Color.Black, 3)
' Create points that define line.
Dim point1 As New Point(100, 100)
Dim point2 As New Point(500, 100)
' Draw line to screen.
e.Graphics.DrawLine(blackPen, point1, point2)
End Using
End Sub
Then call Panle1.Invalidate() to fire the Paint event

It would be good to have a bit more details of your code, especially how and in what class you store the X and Y coordinate. By the way you draw a line between 2 points so you would need two sets of X and Y coordinate boxes on your form.
After that it is as easy as what you found on the internet using the DrawLine method (https://msdn.microsoft.com/en-us/library/system.drawing.graphics.drawline(v=vs.110).aspx), you just needs to fire it from the Click event of your "draw" button.
Hi again Ahmed
Here is a simple sample of a form that would draw a line when button is clicked. Of course it would need more bootstrapping to make sure user only enter integer value for the number of pixels and in its basic form, (0,0) is the top left of the panel but it can easily be converted for a bottom left approach...
and
Class Form1
Private Sub cmdDraw_Click(sender As Object, e As EventArgs) Handles cmdDraw.Click
Dim x1 As Integer = Integer.Parse(txtX1.Text)
Dim y1 As Integer = Integer.Parse(txtY1.Text)
Dim x2 As Integer = Integer.Parse(txtX2.Text)
Dim y2 As Integer = Integer.Parse(txtY2.Text)
pnlMap.CreateGraphics.DrawLine(New Pen(Color.Black), x1, y1, x2, y2)
End Sub
End Class

Related

How to resize form while keeping it at the centre of the screen?

I have a vb.net form.
I used the following tutorial to add shadow and moving/resizing feature to my form.
Metro-UI-Zune-like-Interface-form
It is working fine but my problem is that i want that whenever my form is resized,
it should remain at the centre of the screen (or, if i resize it from bottom, it resizes from the top & bottom both half-half).
I have used this :
Private Sub Form1_SizeChanged(sender As Object, e As EventArgs) Handles Me.SizeChanged
Top = (Screen.PrimaryScreen.WorkingArea.Height - Height) / 2
Left = (Screen.PrimaryScreen.WorkingArea.Width - Width) / 2
End Sub
But whenever i resize it, after the resizing, the form moves to the position of the mouse pointer.
The mouse pointer is outside the form window since it resizes half half in both opposite directions.
It causes flickering and it changes the position of the form.
Any ideas how i can implement this smoothly ? Thanks in advance.
Declare 2 variables to keep the desktop screen resolutions
Dim dx, dy As Integer
on form load get the screen resolutions and them in dx & dy
dx = My.Computer.Screen.Bounds.Width
dy = My.Computer.Screen.Bounds.Height
and finally, on a resize event do the following
Private Sub Form1_ResizeEnd(sender As Object, e As EventArgs) Handles MyBase.ResizeEnd
Dim x, y As Integer
x = Me.Width / 2
y = Me.Height / 2
Me.Location = New Point(dx / 2 - x, dy / 2 - y)
End Sub
You could use the Form.CenterToScreen() method:
Private Sub Form1_SizeChanged(sender As Object, e As EventArgs) Handles Me.SizeChanged
Me.CenterToScreen()
End Sub
Read more: https://msdn.microsoft.com/en-us/library/system.windows.forms.form.centertoscreen(v=vs.110).aspx?cs-save-lang=1&cs-lang=vb#code-snippet-1
Yes, I know the article says that it's not intended to be used from your code, but I've seen other professional programmers use it without a problem. :)

Find position of mouse relative to control, rather than screen

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.

How to show a grid on picturebox control?

I want to display a image on picturebox and also i want to show grid on picturebox.So if i zoom the image then i can easily identify the pixel size on picturebox.Can any one help me to do this?For eg.
This normal display of image on picturebox
But i want to display image like this on picturebox
Here's the code to draw grid lines using the Graphics.DrawLine():
Public Class Form1
Private Sub PictureBox1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles PictureBox1.Paint
Dim g As Graphics = e.Graphics
Dim pn As New Pen(Color.White) '~~~ color of the lines
Dim x As Integer
Dim y As Integer
Dim intSpacing As Integer = 10 '~~~ spacing between adjacent lines
'~~~ Draw the horizontal lines
x = PictureBox1.Width
For y = 0 To PictureBox1.Height Step intSpacing
g.DrawLine(pn, New Point(0, y), New Point(x, y))
Next
'~~~ Draw the vertical lines
y = PictureBox1.Height
For x = 0 To PictureBox1.Width Step intSpacing
g.DrawLine(pn, New Point(x, 0), New Point(x, y))
Next
End Sub
End Class
To test this, create a new project and add a picturebox (name = PictureBox1). Then select an image for it(you could use the property window to set the image). Then copy-paste the above code and run it. You will see grid lines. We have written the code to draw the gridlines on the paint event of the Picturebox. So, these grids will be redrawn when you set an image on the picturebox at runtime too.
Hope it will give you an idea. BTW, the above was coded and tested using VB.Net.
Wish you good luck...

How to dynamically create an overlay over a VB.Net PictureBox

I have a VB.Net PictureBox floorPlanImage on a form form1.
I load a picture into the picturebox:
floorPlanImage.image = my.resources.ResourceManager.GetObject("level8") 'this is actually dynamic, and this part works
I am trying to create an overlay to highlight a region of the image:
Public Sub highlightPrintArea(ByVal x1 As Integer, ByVal y1 As Integer, ByVal x2 As Integer, ByVal y2 As Integer)
'**** DOES NOT WORK
Dim g As Graphics = Me.CreateGraphics
Dim r As Rectangle = New Rectangle(x1, y1, x2 - x1, y2 - y1) 'these are args passed in to the function
Dim pen As Pen = New Pen(Color.FromArgb(128, 32, 100, 200), 1) 'semi-transparent
Dim b As Brush = New SolidBrush(pen.Color)
g.FillRectangle(b, r)
end sub
I need to do this dynamically at runtime, say, on button click. The above function does not seem to draw the rectangle.
However, if I have a function that Handles floorPlanImage.Paint like follows, then the rectangle is drawn as I expect it to:
Private Sub floorPlanImage_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles floorPlanImage.Paint
'**** Works, but does not suit my workflow
Dim g As Graphics = e.Graphics
Dim r As Rectangle = New Rectangle(100, 100, 100, 100)
Dim pen As Pen = New Pen(Color.FromArgb(128, 32, 100, 200), 1)
Dim b As Brush = New SolidBrush(pen.Color)
g.FillRectangle(b, r)
End Sub
The Question (finally)
How can I modify my onclick function to correctly overlay the rectangle over my PictureBox?
In the onclick event you need to save the location/point to a member variable and set a flag so app knows you have a location saved. To update the picture box call Invalidate and Update.
floorPlanImage.Invalidate()
floorPlanImage.Update()
In the onpaint event test the flag that you have a point then use the saved point to draw the overlay.
Private Sub floorPlanImage_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles floorPlanImage.Paint
If hasPoint
'Draw with saved point
End If
End Sub

Determining what objects fall within a selection rectangle (marquee)

I'm writing a program that (amongst other things) provides an IDE-like environment for the user where they can select one or more objects with a rectangualr selection tool.
All selections will be a simple rectangle, and all selectable objects will be simple rectangles as well.
I already have the code (VB.Net) to create the rubber-banding effect visually - what I need is an efficient algorithm that will tell me what objects have at least a portion of their area within the final selection rectangle.
If it helps to visualize, what I want to do would be identical to dragging a selection box over icons on the Windows desktop... whichever icons have even a portion of their areas located within that selection marquee are highlighted (selected).
Any help would be appreciated... thank you in advance
Dim Rect1 As New Rectangle(10, 10, 20, 20)
Dim Rect2 As New Rectangle(5, 5, 20, 20)
Debug.Print(Rect1.IntersectsWith(Rect2))
IntersectsWith works as BigFunger already has mentioned. But aditionally you should check if a rectangle contains another rectangle(intersectsWith only checks for intersection).
A small sample-form that demonstrates it:
Public Class SelectionRectangle
Private first As Point
Private allRectangles As New List(Of RectangleF)
Private Sub form_MouseDown(ByVal sender As Object, ByVal e As MouseEventArgs) Handles Me.MouseDown
first = New Point(e.X, e.Y)
End Sub
Private Sub form_MouseUp(ByVal sender As Object, ByVal e As MouseEventArgs) Handles Me.MouseUp
Dim p As New Pen(Brushes.Black, 2)
Dim g As Graphics
Dim second As New Point(e.X, e.Y)
Dim x, y, w, h As Int32
x = DirectCast(IIf(first.X > second.X, second.X, first.X), Int32)
y = DirectCast(IIf(first.Y > second.Y, second.Y, first.Y), Int32)
w = Math.Abs(second.X - first.X)
h = Math.Abs(second.Y - first.Y)
Dim nextRec As New RectangleF(x, y, w, h)
Dim intersects As Boolean = False
For Each rec As RectangleF In allRectangles
If rec.Contains(nextRec) OrElse rec.IntersectsWith(nextRec) Then
intersects = True
Exit For
End If
Next
If Not intersects Then
p.DashStyle = System.Drawing.Drawing2D.DashStyle.Dot
g = Me.CreateGraphics()
g.DrawLine(p, first.X, first.Y, second.X, first.Y)
g.DrawLine(p, second.X, second.Y, first.X, second.Y)
g.DrawLine(p, first.X, first.Y, first.X, second.Y)
g.DrawLine(p, second.X, second.Y, second.X, first.Y)
allRectangles.Add(nextRec)
Else
Beep()
End If
End Sub
End Class
UPDATE: changed this code to 1.first check in both directions and 2. and more important for you: checks also if one rectangle not only intersects another but additionally if it contains another.