[RESOLVED] Not getting proper X1 and Y1 co-ordinates of Square parallel to Square PictureBox

[nkvb]

Hello

If you observe the image the gap is more on Right and Bottom Side of Square Drawn in Square of Picturebox

First of all would like to know the Location of Image drawn in picture box.
Is the Img position from Left of PictureBox or position from Left of the Form ?
As per the below trial It seems location of image starts from Left of Form and not the Picture box

PictureBox1 Design Form Properties
PictureBox1.Location = 288, 3
PictureBox1.Size = 720, 720

Public Class Square

Private SqImg As New Bitmap(700, 700)

Private Sub Square_Load(sender As Object, e As EventArgs) Handles MyBase.Load

  DrawSquare(gr, New Point(0, 0), 700, New Pen(Brushes.Blue))
  PictureBox1.Image = SqImg

End Sub

Public Sub DrawSquare(ByVal g As Graphics, ByVal center As Point, ByVal SqEdgeSize As Integer, ByVal pen As Pen)
  
        Dim sqEdges As Integer = 700 

        Dim pointXPicbox As Integer = PictureBox1.Location.X   '288
        Dim pointYPicbox As Integer = PictureBox1.Location.Y   '3

        Dim sizeXPbox As Integer = PictureBox1.Width '720
        Dim SizeYPbox As Integer = PictureBox1.Height 

        Dim diffofXpoint As Integer = (PictureBox1.Width - SqEdgeSize)
        Dim diffofYpoint As Integer = (PictureBox1.Height - SqEdgeSize)

        Dim RectNewXLoc As Integer = diffofXpoint / 2
        Dim RectNewYLoc As Integer = diffofYpoint / 2

        Dim RectNewX1Loc As Integer = PictureBox1.Width - RectNewXLoc - 21 'RectNewXLoc
        Dim RectNewY1Loc As Integer = PictureBox1.Height - RectNewYLoc - 21 '20

        Dim square As Rectangle = New Rectangle(RectNewXLoc, RectNewYLoc, RectNewX1Loc, RectNewY1Loc)

        g.DrawRectangle(pen, square)

End Sub

Any appropriate calculation or Formula to draw the square of any size LESS THAN Square Picturebox Size to derive the X1 and Y1 positions which are respectively mentioned as RectNewX1Loc, RectNewY1Loc in above code. if you see value 21 had to be manually incorporated. Would liked to avoid entering the values of difference of Square PictureBox Size to Img Square Size.

Thanks
nkvb

[nkvb]

FordPrefect

Thank you so much. Indeed this was very useful

Except there were two errors which has been modified and corrected in Blue

' Form1 with PictureBox1 and Button1
Public Class Form1
	Dim r As New Random
	Private SqImg As New Bitmap(700, 700)
	Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
		With PictureBox1
			.Location = New Point(288, 3)
			.Size = SqImg.Size
		End With

		DrawSquare(SqImg, New Size(400, 400), New Pen(Brushes.Blue, 12))
	End Sub

	Public Sub DrawSquare(im As Bitmap, sz As Size, pen As Pen)
		Dim g As Graphics = Graphics.FromImage(im)
		'Dim loc As New PointF((im.Width - sz.Width) \ 2, (im.Height - sz.Height) \ 2)
		Dim loc As New Point((im.Width - sz.Width) \ 2, (im.Height - sz.Height) \ 2)

                Using p As New Pen(pen.Color, pen.Width)
			'g.DrawRectangle(pen, New RectangleF(loc, sz))
                  	g.DrawRectangle(pen, New Rectangle(loc, sz))
                End Using
         End Sub

	Private Sub PictureBox1_Paint(sender As Object, e As PaintEventArgs) Handles PictureBox1.Paint
		e.Graphics.DrawImage(SqImg, 0, 0)
	End Sub
	Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
		Dim x As Integer = r.Next(0, SqImg.Width)
		Dim c As Color = Color.FromArgb(r.Next(100, 256), r.Next(0, 256), r.Next(0, 256))
		DrawSquare(SqImg, New Size(x, x), New Pen(c, 12))
		PictureBox1.Invalidate()
	End Sub
End Class

Thanks nkvb

[.paul.]

PointF and RectangleF take coordinates of Type Single, as opposed to Point and Rectangle which take coordinates of Type Integer. As screen coordinates are all Integers, it makes sense not using the Single options, but beware of rounding errors.

[nkvb]

.Paul. Sir,
Thank you for pointing it out.

PointF and RectangleF take coordinates of Type Single, as opposed to Point and Rectangle which take coordinates of Type Integer. As screen coordinates are all Integers, it makes sense not using the Single options, but beware of rounding errors.

After your above comment I retained the original code posted by FP and failed in handling the error
Will really appreciate if one can correct it retaining the original code

.......
	Dim loc As New PointF((im.Width - sz.Width) \ 2, (im.Height - sz.Height) \ 2)
       .......          
            g.DrawRectangle(pen, New RectangleF(loc, sz))
    
ERROR: BC30311 Value of RectangleF cannot be converted to Rectangle 

Thanks
nkvb

[.paul.]

Here's the documentation for the Graphics.DrawRectangle Method

https://learn.microsoft.com/en-us/do...owsdesktop-9.0

[nkvb]

FordPrefect

Hi

You also failed to tell us what the 'two errors' were!

However, both versions work fine here, the code as posted above and the code below. I assume we are on different versions of VB, mine is:
VS Community 2022 (64bit) Preview
Version 17.13.0 Preview 2.1
.NET v4.8 09032

Thank you so much for the clarification. FYI Whenever I post the thread I choose the prefix as VS2019

You also failed to tell us what the 'two errors' were!

Later on I realized when .Paul. Sir posted his comments in #5. It seemed that I had to mark the Error Nos.

Thanks Once More

nkvb