Overlapping transparent gifs bug in C# windows forms

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I use C# Windows Forms and i have the following problem:
I have a program with a background picture in the form (not in picturebox)and there are 2 picture boxes over it, with 2 transparent Gifs, and they overlapping, but the gif in front opens a hole with his transparent area to the gif below and in that area appearing the background picture of the form, is there a way the display those 2 gifs overlapping without open a hole the one to the other? or it's a weakness of C#?

Thanks

What I have tried:

I have no code to post because I did everything with the mouse drag and drop.

Posted 13-Mar-19 12:17pm

tool__

Updated 13-Mar-19 14:29pm

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Dave Kreskowiak · Accepted Answer · 2019-03-13T14:29:00

You're not going to like this. It's not a bug, at least not in Windows Forms or the controls.

It's a bug in your understanding of how controls work in Windows Forms.

First, controls are not transparent. But I hear you saying "I set the background of the PictureBox to Transparent!" Yeah, but Transparent doesn't mean what you think it means.

Setting the background of a control to Transparent just tells the control to take on the Background properties of the container the control sits in, namely, your Form. So, Transparent gives the illusion of being transparent if the background of the control matches the background of it's container, but only under certain conditions.

In one of those conditions, the illusion of transparency is broken when your top (in Z-Order terms) PictureBox overlaps a lower level PictureBox. The pixels occupied by the lower level PictureBox are overdrawn by the higher level one. Since the background of the higher level PictureBox matches the background of the Form, it gives the illusion your lower level picturebox is disappearing, or has a hole in it.

So how do you get around this? There's a variety of tricks to doing this. What is applicable depends on what you're doing with your images.

One method is to not use PictureBoxes at all. Instead, you handle drawing the images on the surface of the Form yourself with your own drawing code. How complicated this gets depends on your application though.