I guess this is about understanding or "transparency". In raw effect, nothing is transparent: you just have different colors for different pixels, and the pixel is always 100% opaque.
The effect of transparency comes up (rather as a metaphor), when you move some object over non-uniform background. Then the background behave as some see-through pattern; the resulting pixels are composed of the combination of colors of background and foreground. On a uniform background, "transparency" is undetectable. There is no a way to spot the difference between the semi-transparent image, or some 100% opaque image tinted with the background color in certain proportion depending on some opaqueness value.
Now: two recommendations which may come at surprise:
- Almost never use
PictureBox. This control is totally redundant and won't give you any benefits (but may add a lot of troubles), except the simplest possible cases. Transparency is already not the simple case. Instead, render some Image on some Control yourself. Showing some semi-transparent image is quite trivial.
- Never use MDI. Don't torture yourself and scare off you customers. You will see what I recommend to do in some of the past answers referenced below.
Some references to my past answers:
Append a picture within picturebox[
^],
draw a rectangle in C#[
^],
How do I clear a panel from old drawing[
^],
What kind of playful method is Paint? (DataGridViewImageCell.Paint(...))[
^],
capture the drawing on a panel[
^],
Drawing Lines between mdi child forms[
^],
How to Create MDI Parent Window in WPF? [
Solution 2],
Question on using MDI windows in WPF[
^],
MDIContainer giving error[
^],
How to set child forms maximized, last childform minimized[
^].
Good luck.
—SA
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