I have been trying to make a program in VB where several images need to be overlapped and dragged around the screen, I have tried using a PictureBox and a panel. However, when using a PNG with transparency, it does not seem to work correctly. It simply shows the background rather than being transparent and showing the pictures below. I can make the "flag" a child of one of the pictures which will result in this: But this cuts off the flags, so that won't work. Alternatively, I tried using Graphics to draw the images. This solves the problem of transparency so it looks as it should. But this requires me to redraw the images every time they are dragged, which causes a lot of flickering. I don't need to manipulate the images or anything, simply to be able to load them and drag them around. Is there really no easy way to do that in Visual Studio? or am I forced to use DirectX or some other means of doing this, because it kind of feels like shooting flies with cannons? It seems like a very strange way Visual Studio handles transparency in general and have a difficult time understanding why anyone would ever choose to use a transparent image and then not want it to be truly transparent.

I just uploaded a simple class from UserControl, to be improved : https://github.com/castorix/VB_TransparentControl

How do you use true transparency in .Net (VB)?

Zac Mckraken 25

I have been trying to make a program in VB where several images need to be overlapped and dragged around the screen, I have tried using a PictureBox and a panel. However, when using a PNG with transparency, it does not seem to work correctly.

Pic_1

It simply shows the background rather than being transparent and showing the pictures below.

I can make the "flag" a child of one of the pictures which will result in this:

pic_2

But this cuts off the flags, so that won't work.

Alternatively, I tried using Graphics to draw the images. This solves the problem of transparency so it looks as it should.

Drawimage

But this requires me to redraw the images every time they are dragged, which causes a lot of flickering.

I don't need to manipulate the images or anything, simply to be able to load them and drag them around. Is there really no easy way to do that in Visual Studio? or am I forced to use DirectX or some other means of doing this, because it kind of feels like shooting flies with cannons?

It seems like a very strange way Visual Studio handles transparency in general and have a difficult time understanding why anyone would ever choose to use a transparent image and then not want it to be truly transparent.

Castorix31 81,636 Reputation points

2023-05-08T18:20:22.45+00:00

I have been trying to make a program in VB where several images need to be overlapped and dragged around the screen,

There are several methods but it depends if you really need to drag images over controls or not.

For example, if other images can be drawn on client area (instead of inside controls), a way is with ImageList APIs (I had posted a test in C++ in this thread https://social.msdn.microsoft.com/Forums/en-US/8078ff63-d2ff-439b-aad4-8219534670a2/how-to-drag-and-drop-an-image-not-included-in-imagelist-using-win32-api-c?forum=windowsgeneraldevelopmentissues)
Castorix31 81,636 Reputation points

2023-05-09T08:37:52.1566667+00:00

Or a better method seems to be with Layered child windows :
Zac Mckraken 25 Reputation points

2023-05-10T19:24:42.7566667+00:00

Are those layered child windows these: https://learn.microsoft.com/en-us/windows/win32/winmsg/window-features#overlapped-windows

So if I understand it correctly, it is basically just a window holding an image you are using in that example?

Also if it is not too much of a hassle, could you post the code?

Accepted answer

Castorix31 81,636 Reputation points

2023-05-10T21:46:28.87+00:00

I just uploaded a simple class from UserControl, to be improved : https://github.com/castorix/VB_TransparentControl
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1 person found this answer helpful.
Zac Mckraken 25 Reputation points

2023-05-10T23:18:09.0266667+00:00

Thanks a lot for that, really appreciate you taking the time to make it.

I have to admit that it is beyond my current abilities to understand the code and what is going on. But it does what I need. :)

I'm a bit surprised about the huge amount of code required to obtain something which, at least to me, ought to be a standard functionality of Visual Studio when using PNG images, given how common a format it is.

I can't help feeling the design choice behind it working as it does, is somewhat similar to them making an audio functionality, but if the audio file is a Wave file, then the bass won't be included by default without you writing a whole lot of code.

I don't see why anyone by default using a PNG, wouldn't want the transparency functionality turned on by default and then given the option to turn it off instead. To me, it is a very odd design choice :)

LRP 0 Reputation points

2023-12-01T17:43:18.6066667+00:00

I love this control, but have a problem positioning an object once created. The reason is probably the object is suppose to be dragged, but sometime the location is somewhere off the screen and dragging is impossible. Is there anyway to correct the problem of the graphic being out of bounds of the parent?

Castorix31 81,636 Reputation points

2023-12-02T09:06:56.7933333+00:00

If I add, at the end of Form1_Load, for example :

TransparentControl1.Location = New Point(0, 0) TransparentControl2.Location = New Point(0, 0) TransparentControl3.Location = New Point(0, 0)

the 3 controls are correctly positioned at Top/Left
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How do you use true transparency in .Net (VB)?

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