How to have different opacity for multiple controls? - c#

I have a problem with the opacity of some controls.
So I set the form opacity to 0.3, when the form is loaded, and the problem is that it makes the other controls as tranparent as the form. Here is the code.
private void Form1_Load(object sender, EventArgs e)
{
this.Opacity = 0.3;
}
By doing this, all my controls are as transparent as the form. Is there any way to have different opacity for the controls inside the form ? I don't want the other to be transparent at all.

My first recommandation would be to avoid that. Having a semi-transparent background with opaque controls will look somewhat weird. Instead, consider changing the opacity when the form is active say from 0.3 to 0.7 so that it is easier to read.
Also another problem if some controls are opaque and the background is almost transparent, then your UI might not work well on some background. For example, if the background is really dark, then dark text (control) will be hard to see. If the background is white, then white controls like edit box would be the same color as the background.
You can get a few idea from other people comments. Even though some comment are for WPF, you might be able to take some idea for WinForms. And if you don't get the expected result, you might also consider using WPF for that part of the UI.
Having said that, a possible workaround to get what you want is to create two top-level windows at the same position (and move/resize them as appropriate). That way, you can have one window with a transparency key and the desired background for opaque area that will be used to have opaque and semi-transparent area. The other window will use the opacity so that it would be semi-transparent. This is the window that will contain your UI controls (and the one that would be on the top).
I have used that technic in the past to have a semi-transparent client area with a fully opaque frame in one application where I want to be able to see through client area (adjustable opacity) so that I could "draw" in my window using the image in another application as a reference.
Another comment is that you might need actual control with windows handle and direct Win32 API access for some customization that are not available in WinForms and/or WPF. In my application, I was handling activation in a way that if I click on the bottom level windows, the top-level window still appears as the active one (caption bar color). If one has no standard caption bar (either the frame is custom or no frame at all), then you would not have that problem.
As suggested by some links in the comment section, it might also be possible to get what you want using a single top-level windows. I have not tried that. In fact, when I try the above solution, I think that my application was still supported on Windows XP and as such you are more limited in options and the behavior is somewhat different essentially because XP more or less write directly to screen while Vista and later use bitmaps (buffers) for each windows.
I have also used combined transparency key and opacity for splash screen (on a single window) and it works on most system but sometime I got black background instead of desired background on some system (probably some XP machine with specific configuration).

Related

Getting Pixel Values "Under" Current Window

I'm trying to make, essentially, a screen capture program, that captures the pixel values under the current window. (I'm working in C#, in Visual Studio 2015.) However, for various reasons, the window itself needs to be opaque (for filters and such). How can I best achieve this?
It is possible to find the window below yours and get a screenshot of it even if it is hidden with the method: PrintWindow (see PInvoke.net as well)
See Copying content from a hidden or clipped window in XP?
It is very simple to do in Winforms. Just set the form's Opacity value to 99%. Now Graphics.CopyFromScreen() will not see your window anymore.
Except when the window underneath yours is also a layered window, then it also won't be visible to CopyFromScreen() for the same reason. Then you have to set Opacity to 0, copy and set it back to 0.99. Very quick, probably good enough for what you want to do.

Blinking Form when background Image set to it c#

When I fix a Background to my winform, It is getting blink on form load. I have a table layout panel on my form and I kept all my controls on the table layout panel.
I set the backcolor of tablelayout panel to Transparent and Set the Image to the background. Why am I getting blink on my form load?
WinForms doesn't handle transparency very well (As I'm sure you may have noticed, not all WinForms controls even support it). The blink is caused because as your TableLayoutPanel is loaded, as well as all its items, the Form has to find the correct 'image' (Because the control doesn't support transparency in the same way as WPF or a game does, it instead uses an image of the controls behind it) to display. It must go through this process as each of your controls are loaded, hence the blinking. You can try enabling DoubleBuffering on your Form, however, if I recall correctly, this can cause issues with transparency.
If you find that you are using a lot of transparency and/or want to customise your Form a lot more, I suggest you take a look at WPF. It offers far greater control over your Form (Window in WPF) as well as supporting transparency on every single control.

Adding components to a transparent form

I used this code from the code project in order to display a .png image (with transparency). At line 87 I tried to add a label in which I succeeded but somehow It won't appear on the form. I tried Refresh, Invalidate but none of them worked. Maybe someone can point me into the right direction.
I think, since you're using UpdateLayeredWindow the "normal" painting mechanism is disabled, i.e. no WM_PAINT messages are sent to the window, and the WinForms library has no chance to render the Label Controls.
I found this article about using layered windows on MSDN stating:
Note that when using UpdateLayeredWindow the application doesn't need to respond to WM_PAINT or other painting messages, because it has already provided the visual representation for the window and the system will take care of storing that image, composing it, and rendering it on the screen. UpdateLayeredWindow is quite powerful, but it often requires modifying the way an existing Win32 application draws.
So I'm afraid that WinForms isn't able to work together with your approach. Even if it would, you would likely get unpleasant results since "real" transparency is not easily done with winforms (i.e. the labels wouldn't show up transparently but would be drawn the parent forms background color)

Build turns partially transparent image pixels black

I'm very new to C# and I've run into a problem and haven't been able to solve it. I have a row of buttons that have .png images assigned to them. The images are in .png format to allow transparency, and smoothing the edges in GIMP leaves some semi-transparent pixels. I've set the Image List Toolbar (imglToolbar)'s properties to recognize "Transparent" as the designated color to show up as transparent. I'm working in Visual Studio 2005.
The strange thing is that everything looks great when I'm viewing the Visual C# form preview window. The icons look exactly as they should. However, once I actually build the project, the buttons treat every semi-transparent pixel near the edge of the image as if it's black. It seems like it can't handle one that's both transparent and has color.
Image of it via the Visual C# form editor:
alt text http://img5.imageshack.us/img5/2577/whatiwanted.jpg
Image of what it looks like when built:
alt text http://img690.imageshack.us/img690/7241/whatigot.jpg
Any ideas as to why this is happening?
I just found the answer, at least to my specific situation.
The form I'm dealing with is a top-level MDI container. For whatever reason, having the icons set to 32 bit color doesn't allow for these semi-transparent pixels to be properly interpreted. Setting it to 24-bit, on a whim, completely solved the problem. Not sure if this is some situation that has come up as a result of some unseen factor, but the color depth change fixed my problem.
Also for those who may come here with a similar problem, make sure the window isn't a child of an MDI container. While looking for information, I found MDI children don't support TransparencyKeys at all.
I ran into this problem as well; changing the form's IsMdiContainer property to false solved it.

Display Form non-maximized with borders on Windows Mobile

I need to create a status dialog for a Windows Mobile application (C# 2.0) that needs to be updated, so MessageBox is out. I tried to just create a new Form class, change the size and call ShowDialog, but it always comes up full screen (minus the title bar of course). The only way I could figure out how to display it small is to set FormBorderStyle to None, but then it really does have no border or title bar at all!
I want it to still look like a message box (with title bar and borders) but, I need to actually use a Form so I can update it.
Any ideas of how to do this?
The challenge here is the WinMo shell itself. What's not apparent is that the caption on the form (at the top of the screen) is actually not the caption of the Form you see - it's a completely different application. So to get your Form to "float" requires subverting the way the shell handles Form display. A quick and dirty way is to set the Form BorderStyle to none, but then you lose your caption bar. An option then is to manually draw it in with a FillRect and DrawString in OnPaint. Not too difficult and doesn't require any P/Invoke shenanigans, but it does require that you take the new header into consideration when you layout your controls.
Another option is to use P/Invoke and manipulate the Form's style bits yourself. This works well, but take care that you do it in the right location in code, as some bits have to be set on Window creation. Also beware the shell, as it might want to change the bits back on you - so this mechanism requires more testing and attention to detail. IMO this is a better route, and I've blogged about it in more detail here. That blog entry isn't specifically about floating forms, but it covers style manipulation well. For more specifically on non-fullscreen Forms, see my other blog entry here.

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