Solved

BitBlt in VB

Posted on 2002-04-30
4
314 Views
Last Modified: 2010-07-27
I have the following bit of code in my application:
    Set picSource.Picture = LoadPicture(sFile)
    Const PIXEL = 3
    picSource.ScaleMode = PIXEL
    picDest.ScaleMode = PIXEL
    hDestDC = picDest.hDC
    x = 0
    y = 0
    ' Assign information of the source bitmap.
    hSrcDC = picSource.hDC
    lReturn = BitBlt(hDestDC, _
                     0, _
                     0, _
                     iWidth, _
                     iHeight, _
                     hSrcDC, _
                     iLeft, _
                     iTop, _
                     &HCC0020)


The picture loads into picSource okay, and the DCs appear to be set up correctly. But after the BitBlt, picDest.picture is always empty (ie., 0). The idea of the exercise is to copy a section (bounded by iLeft, iTop, iWidth, iHeight) of the picture in picSource to picDest. But, obviously, it's not working. Why not?
0
Comment
Question by:toff_in_sydney
  • 3
4 Comments
 
LVL 3

Expert Comment

by:n_narayanan
ID: 6980028
Look at this Excellent Code

http://www.freevbcode.com/ShowCode.Asp?ID=3677

Narayanan
0
 
LVL 15

Expert Comment

by:ameba
ID: 6980044
Drawing on the picturebox (or form) doesn't change its Picture property.
What will be different is picDest.Image, not picDest.Picture.
Use  "picDest.Picture = picDest.Image", or, after drawing, use "picDest.AutoRedraw = False", e.g.:

Private Sub Form_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
    AutoRedraw = True
   
    ' draw something
    Me.Line -(X, Y)
   
    AutoRedraw = False   ' make permanent picture
End Sub
0
 
LVL 15

Accepted Solution

by:
ameba earned 300 total points
ID: 6980058
picDest.Image will have the size of the control, so you'll have to set dimensions of picDest.

Instead of BitBlt, you can directly produce the picture using PaintPicture method.
0
 
LVL 15

Expert Comment

by:ameba
ID: 7137404
Explanation to EE (No, I am not asking you to change the grade)

I correctly answered the question, not with one solution, but with all practical solutions, and all with the required code.
solution 1:
Use  "picDest.Picture = picDest.Image"

solution 2:
is a complete drawing program which shows how to make permanent picture using AutoRedraw

I have also given the alternative to BitBlt:

>Instead of BitBlt, you can directly produce the picture using PaintPicture method.

It seems user have jumped to the alternative, without reading or understanding the first part of my post, and instead of posting feedback in this question, he posts a new question about PaintPicture.
http://www.experts-exchange.com/visualbasic/Q_20295350.html
0

Featured Post

Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

The debugging module of the VB 6 IDE can be accessed by way of the Debug menu item. That menu item can normally be found in the IDE's main menu line as shown in this picture.   There is also a companion Debug Toolbar that looks like the followin…
Background What I'm presenting in this article is the result of 2 conditions in my work area: We have a SQL Server production environment but no development or test environment; andWe have an MS Access front end using tables in SQL Server but we a…
Get people started with the process of using Access VBA to control Excel using automation, Microsoft Access can control other applications. An example is the ability to programmatically talk to Excel. Using automation, an Access application can laun…
Get people started with the utilization of class modules. Class modules can be a powerful tool in Microsoft Access. They allow you to create self-contained objects that encapsulate functionality. They can easily hide the complexity of a process from…

828 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question