We have a mapping form in our application that needs a Google Earth background image, and as you can't use the Google Earth plugin in a browser that is under a panel, we use a second form to show the background image. We have a transparent panel on the mapping form that the drawing is done on while Google Earth is drawn on a form held in sync below.
We achieve transparency by giving the form a transparency key of 255, 250, 250 and setting the panel background to this color before drawing on it. Although now after looking at the information available online it appears that the panel shouldn't ever get cursor events.
This works perfectly in most cases, but on one or two customers machines (one is definatly Windows 7) the cursor will not work correctly on the panel where it is transparent. If the cursor is placed over a drawn area of the map then it all work fine.
I think the issue is due to transparancy click through but as it works in most cases I'm not sure what is exactly going on. We've updated all of the graphics drivers to see if there is a custom setting on the customers machine but this hasn't helped.
Does someone have a definative description of what the transparency key does? Is there a way to absolutly set that the panel should recieve the mouse events?
EDIT
Added detail about transparency key.
Try intercepting the WM_HITTEST message in the WndProc for the Form window and when you know it is over the client area return the appropriate HTCLIENT value. It could be that the default window processing is sometimes returning a different value.
Stevo - Have you ever figured out an answer to this? I had the same problem and figured out to change the transparency key of the main form to some odd color. May or may not help you. I had a custom control with transparency but the forms key color was also my drawing color, thus allowing it to click through (strangely). I changed it and it worked!
Related
I'm trying to place a transparent and borderless child (WinForm) form on top of another child (WinForm) form that is opaque, but I'd like to retain the ability to directly click on the transparent form. There are a few answers on the web regarding making a transparent form that can be clicked through, but I want to make one that I can click on.
I've found this answer, which shows that setting my transparent form's BackColor and TransparencyKey to something specific like Color.Red achieves the desired behavior. However based on this answer, it seems this behavior between certain Colors and TransparencyKey may actually be a long-running bug.
Ideally I don't want to rely on a bug to achieve a desired effect. What would be a more "appropriate" approach for making a clickable, transparent, and borderless (WinForm) form?
Update (Additional Context):
I'm basically creating a screen pixel previewer for color data extraction.
Overlay forms containing captured bitmap(s) of the screen area.
Another form that gives a visual indicator for the pixel area being previewed (small black box in the below snapshot). This form is placed above the bitmap forms. I have this form as transparent (to see through to the below bitmaps), but I still want to be able to click on it for event processing.
Without the TransparencyKey = BackColor = Color.Red trick, clicking within the small black box causes focus to move to the below bitmap form, which then covers up the small box form and the preview window showing the zoomed view. The purpose of the click is to capture the cursor position for additional processing. I can work around this by immediately giving focus back to the small box + preview forms, but that occasionally causes flicker.
It seams to be a bug, if you change a Form size to a previously transparent region, mouse events will no longer be detected on it.
How to reproduce it:
Create a new Windows form project
Set Form1 TransparencyKey to Magenta
Add a Panel to Form1 and config it as:
Dock fill
BackColor to Magenta
Run, now try to change the Form size, if you reduce it (enough so the new border will be placed over a current transparent region), the mouse will no longer "detect" the window border on that side. If you minimize/restore the window, it will work again. How can I fix that? I tried Refresh on Form Layout/Resize event, but it didn't work.
Just to confirm, yes this is a bug in the current Aero implementation on Windows 8.1. Possibly before. Been around for quite a while, seems like it is a pretty structural problem. It is part of a set of bugs related to layered windows with the transparency key set, and getting the mouse to be transparent to such a window, it also doesn't work properly with certain color selections for the key. In this specific case, it inappropriately makes the frame transparent to clicks as well.
Hard to give specific advice, this does require calling Microsoft Support to get ahead. Technically you can take advantage of another bug, the window is never transparent to mouse clicks when you pick, say, Red as the transparency key:
public Form1() {
InitializeComponent();
this.TransparencyKey = panel1.BackColor = Color.Red;
}
Solves the bug you are dealing with, but of course disables mouse transparency completely. A workaround you almost definitely won't like is:
protected override void OnResizeEnd(EventArgs e) {
base.OnResizeEnd(e);
this.RecreateHandle();
}
Too noticeable. Programmers are starting to take advantage of these bugs, sometimes they want such lack of transparency intentionally. Makes you wonder how Microsoft is ever going to get this fixed without breaking some program. Not pretty.
When a form loads, I'd like it to show a loading image (within a Picture Box) and a standard Windows label with some text. However, all I see are white boxes, or sometimes I see another form underneath. How do I get the image and label to display properly.
I've tried setting AllowTransparency to false when the form loads, and also setting the Transparency Key of the form to some other colour, but nothing has worked.
The project is C# .Net v3.5 (also tried v4 and v4.5).
Any ideas?
First, you can't display an image, busy-wait, and then change the image - this will never redraw anything, leading to the symptoms you describe. To "wait" you will need to return control to your main application loop so it can continue to process messages (e.g. to handle redraw requests for your window). One way to do what you want is to display your initial state (splash screen) and then use a timer to call you back later to change the display to your second state.
The next problem you face is using forms controls with transparency. Most controls treat "transparent" as "fill your background with your parent controls color", which is not what you want. An easy way around this is to implement a Paint handler and draw the image and text for yourself - this gives you much more control of how your display looks, and will also allow you to get a cleaner redraw (no flicker or other problems caused by the display being built up but by bit in several controls)
Lastly, consider implementing your splash screen display as a separate control/form that you show above your main form during loading, as that makes it easy to "overlay" on your main form without having to change its design at all.
Just write formObjectName.Refresh() after formObjectName.Show()
I've created a semi-transparent form (60% opacity with black background color) that my app launches, maximized, over the entire screen. Basically, it casts a gray color on the entire desktop.
When the user mouses-over a window on the desktop, I want to get that window's handle (hWnd).
The easy way to do this, which is working for me, is:
Temporarily hide my form (OR, temporarily set my form's opacity to 0.0)
Call [GetCursorPos][1]
Call [WindowFromPoint][2]
Show my form again
The problem with this approach is that my form / the screen blinks, which I don't like.
I've tried to fix this in two ways:
I figure there should be a way to get the hWnd of the window directly underneath my form by calling ChildWindowFromPointEx (passing-in the hWnd of the desktop and CWP_SKIPTRANSPARENT), but it doesn't seem to work. I also played with [ChildWindowFromPoint][4] and [RealChildWindowFromPoint][5] with no success. (P.S. Raymond Chen discusses the differences between these calls, here and it seems to me that ChildWindowFromPointEx is designed to do exactly what I need)
I tried preventing the entire desktop from refreshing (kind of "freezing" the screen momentarily) by using (1) SendMessage(GetDesktopWindow(), WM_SETREDRAW, false, 0) before I hide my form and (2) SendMessage(GetDesktopWindow(), WM_SETREDRAW, true, 0) after I hide my form. This didn't work quite right: some areas of the screen would freeze, some weird black blocks would appear, etc. I do know, however, that (1) does work, because one time I called (1) and didn't call (2) and my desktop appeared completely frozen (had to reboot, even TaskMgr didn't render correctly). I also tried using SuspendLayout and ResumeLayout on my form, but I don't think they are meant to handle my case.
Any help would be greatly appreciated.
You can do the checking yourself since your need to customise beyond that what the standard functions offer.
Call EnumWindows() to get a list of top-level windows.
Remove your semi-transparent window from this list.
For each window in the list use PtInRegion() to determine whether or not the mouse is over the window. Remove any windows that don't fit the bill.
Use GetNextWindow(), starting from one of the remaining windows to walk the z-order and find out which of the candidates is at the top.
I'm pasting an image from the game im building.
the matrix of empty cells you see are made of PictureBox[][].
I wan't whenever I drop a coin to one of the columns... I want it to go down but the purple stuff will hide the falling coin and the gray color you see wont hide it.
How do I make this effect?
please notice that in each PictureBox control I have set the BG Image as you can see
Don't do it like that.
Create custom control. In custom control, override Paint, and then draw COIN sprite first, then draw mask over it. Be sure that you use double-buffered painting here.
It will work like a charm, trust me!
And, since you are (I gueess) building 5-in-a-row game here, your custom control will be able to paint occupied slots as well.
By designing custom control, you'll be able to hide all the animation and graphics stuff away from your main form.
I don't think it is possible like that. Controls in WinForms cannot be transparent, that is the problem
I would think in three directions:
Forgetting about controls and
painting everything OnPaint event of
the form. It is not too complicated
(well it would be more complicated
to detect some mouse events like you
did now, as you wouldn't know which
graybox is hit, but rather just
mouse coordinates)
Experimenting with coin as a form
(forms can be transparent)
Possibly using WPF with same logic
you did, as controls can be
transparent there
Controls in Windows Forms can be transparent. You need to set the TransparencyKey of the Form to some color that you never plan on using (many people seem to love/hate Magenta for this), and then set the BackgroundColor of each PictureBox to the same color. The result should be a transparent PictureBox with its Image drawn over it. I'm pretty sure this won't work with the BackgroundImage property, mind you- just the Image property.
One potentially unwanted side effect of this method is that you'll be able to see whatever's behind your form (the desktop, other application windows, etc.) through the transparent places in the PictureBox.