GDI+ for twinBASIC

This is a very early preview of a higher-level GDI+ interface for twinBASIC. It is modeled after the C++ wrapper that is the official GDI+ API from Microsoft.

To get the .twinpack package file, open the project and build it.

TO DO:

• + more glue/convenience code

The window above is produced by the following code:

Class Form1
    Dim gdiPlus As GdiPlusUser
    
    Sub Form_Load()
        ScaleMode = vbPixels
        Set gdiPlus = GdiPlusUser()
    End Sub
            
    Sub Paint() Handles Form.Paint, Form.Resize
        Dim gr As Any = Graphics(hDC)
        Dim rect As Any = GpRectF(0, 0, ScaleWidth, ScaleHeight)
        Dim br As Any = LinearGradientBrush(rect, vbCyan, vbBlue)
        Dim ft As Any = Font("Segoe UI", 20)
        Dim fbr As Any = SolidBrush(vbBlack)
                        
        gr.FillRectangle(br, rect)
        gr.DrawLine(Pen(vbGreen, 3.0), rect)
        gr.DrawString("Welcome to GDI+", ft, GpPointF(50, 50), fbr)
    End Sub
End Class

Note:

• An instance of GdiPlusUser must exist while GDI+ objects are used. An arbitrary number of instances can exist at one time, as long as any exist, the GDI+ library is kept active. Since GDI+ is typically used to render forms, or is triggered by actions in the form-based UI, it is sufficient to add an instance of GdiPlusUser to any Form or other class whose code used GDI+.
• All classes can be instantiated either with New AClass(...) or using a convenience "constructor" function with the same signature, i.e. AClass(...). This reduces verbosity in the user code.
• UDTs such as GpPointF, GpRectF etc. also have constructor functions.