Need help with resizing at an angle

Question

Hi guys I could really do with some help from a GDI+ expert. I am coding a little app that can draw shapes on the screen. The user can move, resize, and rotate. I have got most of this working pretty good and the project is coming on very well but I am very new to GDI+. The problem I have is letting the user rotate a shape and then resize. I have got selecting and rotating working fine but resizing the shape at an angle is proving very tricky for me. I am able to resize at 0 degrees perfectly with my simple code. If the shape is at an angle then I start getting funny results. One method I have seen is to draw an outer bounds rectangle around the shape with handles. When the outer bound rectangle is stretched the shape is resized to fit. I am really looking for some help and guidance on how I can rotate and resize. Thanks for any help if you can. This is the last major missing piece in the puzzle for me. Mike

mwallett · Answer

Hi Thanks for your reply. Here is my current code that handles resizing for a rectangle. I pass in the current mouse position and handle number that was selected by the user. Public Overrides Sub MoveHandle(ByVal pt As Point ByVal handleNumber As Integer) Dim left As Integer = Me.Rectangle.Left ' x Dim top As Integer = Me.Rectangle.Top ' y Dim right As Integer = Me.Rectangle.Right ' x Dim bottom As Integer = Me.Rectangle.Bottom ' y Select Case handleNumber Case 1 ' Top left left = pt.X top = pt.Y Case 2 ' Top top = pt.Y Case 3 ' Top right right = pt.X top = pt.Y Case 4 ' Right right = pt.X Case 5 ' Bottom right right = pt.X bottom = pt.Y Case 6 ' Bottom bottom = pt.Y Case 7 ' Bottom left left = pt.X bottom = pt.Y Case 8 ' Left left = pt.X End Select Me.Rectangle = New Rectangle(left top right - left bottom - top) End Sub I perform the actual rotation when drawing the shape and handles. ... If Me.Rotation 0 Then Dim m As Matrix = New Matrix m.RotateAt(Me.Rotation New PointF(Me.CenterPoint.X Me.CenterPoint.Y) MatrixOrder.Append) g.Transform = m End If ... Dim pen As New pen(Me.LineColour Me.LineWeight) g.DrawRectangle(pen Me.Rectangle) In the code I haven’t taken into account the rotation during resize this is where I am struggling with what to do.

mibuyt · Answer

Hi Why not like this? You show some snippets code which you think that is the cause of the problems of resizing in different angles! Snippets will do. At least it is easier to identify the problems. Cheers.