Selection rectangle that can go backwards

General
1

How can I make a selection rectangle? Basically, my only problem is getting the rectangle to work when the mouse is dragged to the left from the selection point or to the top from the selection point.

I wrote this:

    SelectionRectangle.Top = Min(SelectionPoint.Y, Y)
    SelectionRectangle.Bottom = Max(SelectionPoint.Y, Y)
    
    SelectionRectangle.Left = Min(SelectionPoint.X, X)
    SelectionRectangle.Right = Max(SelectionPoint.X, X)

It does not look great. So I tried this:

    SelectionRectangle.Top = SelectionPoint.Y
    SelectionRectangle.Bottom = Y
    
    SelectionRectangle.Left = SelectionPoint.X
    SelectionRectangle.Right = X

This worked fine, but only if I am extending the rectangle to the right. The first one looks shaky around the starting point.

2

The code for the ‘Bottom’ property is:

Bottom As Integer
Get
  return me.Top + me.height
End Get
Set
  me.height = value - me.top
End Set

And ‘Right’:

Right As Integer

Get
  return me.Left + me.width
End Get
Set
  me.width = value - me.left
End Set

Thanks

3

I had to solve this same problem some time ago. Here’s my method for converting screen coordinates into a Realbasic.Rect object whose Left/Top/Width/Height can be passed directly to Graphics.DrawRect.

Function GetSelectionRect(StartX As Integer, StartY As Integer, EndX As Integer, EndY As Integer) As REALbasic.Rect
  Dim r As New REALbasic.Rect
  If EndX < StartX Then
    r.Left = EndX
    r.Width = StartX - EndX
  Else
    r.Left = StartX
    r.Width = EndX - StartX
  End If
  If EndY < StartY Then
    r.Top = EndY
    r.Height = StartY - EndY
  Else
    r.Top = StartY
    r.Height = EndY - StartY
  End If
  Return r
End Function
4 
Function GetSelectionRect(StartX As Integer, StartY As Integer, EndX As Integer, EndY As Integer) As REALbasic.Rect
  Dim r As New REALbasic.Rect
 r.left=Min(StartX,EndX)
 r.top=Min(StartY,EndY)
 r.width=Max(StartX,EndX)-r.left
 r.height=Max(StartY,EndY)-r.top
  Return r
End Function

No IF/THEN required

5

Not very readable, but you could also utilize realbasic.rect.union

return REALbasic.Rect( new REALbasic.Rect( startx, starty, 0, 0).union( new REALbasic.Rect( endx, endy, 0, 0))

6

[quote=162477:@Dave S] Function GetSelectionRect(StartX As Integer, StartY As Integer, EndX As Integer, EndY As Integer) As REALbasic.Rect Dim r As New REALbasic.Rect r.left=Min(StartX,EndX) r.top=Min(StartY,EndY) r.width=Max(StartX,EndX)-r.left r.height=Max(StartY,EndY)-r.top Return r End Function

No IF/THEN required[/quote]
I believe I tried something similar and it did not look good enough but I will give it a try.

Thanks

7

[quote=162471:@Andrew Lambert]I had to solve this same problem some time ago. Here’s my method for converting screen coordinates into a Realbasic.Rect object whose Left/Top/Width/Height can be passed directly to Graphics.DrawRect.

Function GetSelectionRect(StartX As Integer, StartY As Integer, EndX As Integer, EndY As Integer) As REALbasic.Rect Dim r As New REALbasic.Rect If EndX < StartX Then r.Left = EndX r.Width = StartX - EndX Else r.Left = StartX r.Width = EndX - StartX End If If EndY < StartY Then r.Top = EndY r.Height = StartY - EndY Else r.Top = StartY r.Height = EndY - StartY End If Return r End Function [/quote]
THANKS

8

[quote=162519:@jim mckay]Not very readable, but you could also utilize realbasic.rect.union

return REALbasic.Rect( new REALbasic.Rect( startx, starty, 0, 0).union( new REALbasic.Rect( endx, endy, 0, 0)) [/quote]
THANKS

9

Oliver which function worked best for you? Thanks

10

All of the above functions return the exact same answer… so I don’t understand your statement “doesn’t look good enough”