Comments on: VB Graphics Programming: Part 2 (Beginning API)

By: Tanner

Tanner — Tue, 24 May 2011 14:14:41 +0000

Thanks for the comments, Devant. However, AutoRedraw does not need to be set to true for the examples to work. In fact, when AutoRedraw is set to false, the image will be updated every time SetPixelV is used (which isn't ideal for performance, but is useful for checking to see if your code is working). If you set AutoRedraw to true, please note that any changes made by SetPixelV are made to the picture box's .Image property, not the .Picture property. So, when you're done running SetPixelV, you will need to add a line like Picture1.Picture = Picture1.Image followed by Picture1.Refresh to force an update to the screen. You can check this very easily on the downloadable code for this article - simply change the picture box's .AutoRedraw property to false and watch what happens.

By: Devant

Devant — Tue, 24 May 2011 08:55:29 +0000

I found the solution to the problem. Picture1 had Autoredraw set to False. It worked when I set it to True.

Maybe you would like to point out that Autoredraw has to be set to True for the examples to work. Thanks for the excellent tutorial.

By: Devant

Devant — Tue, 24 May 2011 08:51:18 +0000

Greetings,

It seems that I can’t load the GDI32.dll

Things I did:

Public Declare Function SetPixelV Lib “GDI32″ (…)

Public Declare Function SetPixelV Lib “C:\Windows\System32\GDI32.dll” (…)

Didn’t produce any error, but they wouldn’t effect the Picture1 too.

(with

SetPixelV Picture1.hDC, i, j, RGB(255, 0, 0)

)

Trying to put a reference to GDI32.dll (Project->References) produced a “Can’t add a reference to the specified file.” error.

Trying to repair the GDI32.dll with a fresh copy didn’t change anything.

Trying to put a fresh copy on another directory, and referencing/declaring the function from there, produced a “File not found” error.

By: leveleditor6680

leveleditor6680 — Thu, 29 Jul 2010 16:45:49 +0000

Never mind, I figured it out!
Here’s the code in case your wondering…
Code is Visual Basic 2008:
' get hdc... Dim g As Graphics = Graphics.FromImage(ThePicturebox.Image) Dim dc As System.IntPtr = g.GetHdc() ' do something with the hdc... Dim SomeNameHere As Image = Image.FromHbitmap(dc)

'release... g.ReleaseHdc(dc) g.Dispose()

By: leveleditor6680

leveleditor6680 — Thu, 29 Jul 2010 00:25:36 +0000

Hello,

I would like to know how to use something similar to the “.hdc” in visual basic 2008!

Even links are helpful!

By: Tanner

Tanner — Mon, 04 Jan 2010 21:29:36 +0000

Hi MRFARAG. The following link should provide what you need: http://www.planet-source-code.com/vb/scripts/ShowCode.asp?txtCodeId=38582&lngWId=1

By: MrFarag

MrFarag — Mon, 04 Jan 2010 00:31:58 +0000

plese
i want to draw a very smooth line or circle by vb6 can i ?
the line is bad in vb6 but in microsoft word it is smooth
and i want to write a word text like that in microsoft word
I cant do ?
I think i must to go another langauge
can you help
thanks