Win32 API/GDI

[humate]

Whats the easiest way to get a large number of Win 32 API declarations into a VB.NET project? Ive got a VB6 program that uses lots and lots of GDI functions, which was very easy to do, by just referencing Win.tlb. I dont want to wrap it all in GDI+ which will probably make it slower anyway, I just want to be able to use all the functions inside GDI32.DLL from VB.NET. Do I have to declare them all one by one? Thatd take years!

 

[dynamic_sysop]

why not just use the in-built graphics in .net? System.Drawing.Graphics

 

[humate]

because it would involve completely rewriting the whole project!
And because it uses BitBlts and memory DCs, etc, i.e. not just lines and circles.

 

[Volte]

If you really want to port it to .NET, rewriting the whole project will be largely necessary. Otherwise, leaving it in VB6 would be wisest.

Also, I suggest you take a closer look at GDI+ - it can do far more natively than GDI32 can. Its far more flexible, and more imporantly, object oriented.

 

[humate]

Given time and money, we would re-write it all, to take advantage of the cool things that GDI+ can do. But at the moment I just want to have it working from a .NET environment and assumed that thered be a file or something out there that effectively includes declarations for all the Win32 API calls, in whatever wrappers are necessary. For example, if you want to use OpenGL in VB.NET, you can, you just have to reference a special wrapper DLL first.

The graphics have to run as fast as possible and redraw themselves at a high frame rate. From some of the other threads in this forum Im not convinced that GDI+ will be an improvement in that respect. An object orientated approach is clearly better, but how does it help if I just want to blast lines and polygons onto the screen in a set order, fast? Probably the program lends itself more to a C++ type thing but it all worked great in VB6 and was very readable and easy to maintain.

I dont want to use VB6 for ever, that cant be right...

 

[AndreRyan]

Microsoft is trying to get everyone to switch to GDI+. It does have many more features and some features compare to line drawing funtions in Direct3D. You can get a reasonable speed out of GDI+ if you only draw when you have to rather than constant looping, just override PAINT.

There is no DLL for wrapping GDI32 the only one avaliable is System.Drawing for GDI+. If you want GDI32 you have to use the declaration statements as these are still applicable.

To use OpenGL you have to import the VB6 COM wrapper after running it through the wrapper program, so you end up with OpenGL32.DLL>OpenGL COM Wrapper>.Net Wrapper for the COM Wrapper>.Net program using OpenGL
You could get past this with direct declartions though.

BitBlt:

Declare Function BitBlt Lib "gdi32.dll" (ByVal hDestDC As Int32, ByVal x As Int32, ByVal y As Int32, ByVal nWidth As Int32, ByVal nHeight As Int32, ByVal hSrcDC As Int32, ByVal xSrc As Int32, ByVal ySrc As Int32, ByVal dwRop As Int32) As Int32

Or the better method:

<DLLImport("gdi32.dll")>Public Function BitBlt(ByVal hDestDC As Int32, ByVal x As Int32, ByVal y As Int32, ByVal nWidth As Int32, ByVal nHeight As Int32, ByVal hSrcDC As Int32, ByVal xSrc As Int32, ByVal ySrc As Int32, ByVal dwRop As Int32) As Int32
End Function

.Net forms no longer are tyed to GDI(at least noticably) so there is no hDC or ForeColor of BackColor properties so youll need GetDC and ReleaseDC APIs to use GDI32 functions or the Get DC function in Drawing.Graphics

GDI+ will get faster, its slower than GDI32 because of all the new graphics effects that arent easily achievable in GDI32