We use Windows Forms and custom user controls, and I would like to be able to rotate the panel hosting the userControl in a particular form. I have seen similar functionnalities with WPF, but I can't use it for the moment. Is it possible to achieve the rotation of a panel and its children using possibly built-in .NET methods or GDI+?
I have seen some pretty cool visual effect with menus that are displayed in game development, so I was wondering if it would be possible to create similar effects using Windows Forms.
Rotating a panel and its children in Windows Forms is not something directly supported, and I think it will end up being a buggy headache that could easily suck up lots of time. It's especially painful to think about when you could do this in WPF with zero lines of C# code and only a tiny bit of XAML.
You can use rotations in GDI+ by calling the RotateTransform method on a Graphics object.
However, rotating an entire control is not so simple, and will depend heavily on how the control is implemented.
If it's a composite UserControl that has other controls inside of it, you're out of luck.
If it's a sinlge control that paints itself, try inheriting the control, overriding the OnPaint method, and calling RotateTransform on the Graphics object. However, you will probably have trouble with it. In particular, you will probably need to override all of the mouse events and call the base control's events with rotated coordinates.
You can get halfway there by calling the DrawToBitmap method on your panel, then rotating the bitmap and displaying it e.g. in a PictureBox:
var bitmap = new Bitmap(panel.Width, panel.Height);
panel.DrawToBitmap(bitmap, new Rectangle(Point.Empty, panel.Size));
bitmap.RotateFlip(RotateFlipType.Rotate270FlipNone);
var pictureBox = new PictureBox();
pictureBox.Location = panel.Location;
pictureBox.SizeMode = PictureBoxSizeMode.AutoSize;
pictureBox.Image = bitmap;
Controls.Remove(panel);
Controls.Add(pictureBox);
Rotation angles other than 90-degree increments are also possible, if you draw the bitmap into another bitmap using GDI:
var bitmap2 = new Bitmap(bmp.Width + 75, bmp.Height + 100);
var graphics = Graphics.FromImage(bmp2);
graphics.TranslateTransform(bitmap2.Width / 2, bitmap2.Height / 2);
graphics.RotateTransform(-15f);
graphics.TranslateTransform(-bitmap.Width / 2, -bitmap.Height / 2);
graphics.DrawImageUnscaled(bitmap, Point.Empty);
graphics.Dispose();
The problem of course is that you're only displaying an image of your panel, and not the panel itself, so it's no longer possible to interact with the controls inside.
That could probably be done as well, but you would have to mess with window messages, which gets quite a bit more complicated. Depending on your needs you might also be able to get away with handling click and key events on the PictureBox, manipulating the controls in the panel, and then updating the image.
Related
I have wpf project with one Window (MainWindow). Depending upon the config file it shows one of two UserControl's as Content. It may be a horizontal (1920x1080) control or vertical (1080x1920) control. It's fine with horizontal screen, but when vertical is loaded I would like to do:
1) rotate window/control by 270 degrees
2) change primary screen orientation
I would prefer to just rotate application and don't interact with windows API. I can't change orientation manually, because I have only remote access to this computer.
You can not rotate the Window object itself, as it is positioned by the window management system built in Windows. You can, however, transform (and thus rotate) any FrameworkElement inside the window. This includes, but is not limited to, the Grid, the Button and the TextBox elements.
All you need to do is edit the LayoutTransform property on the element you want to rotate, which is most likely the root element in your window. Set the rotation to 270/-90 degrees and WPF will automatically rotate your UI.
Because you are using the LayoutTransform property, the layout system will also scale you UI correctly. The RenderTransform property causes the control to first be rendered, then be rotated.
YES WE CAN CHANGE SCCREEN ORIENTATION USING
DEVMODE & using System.Runtime.InteropServices;
its bit late to reply but I am replaying for the new ones , if someone com across this article for change screen rotation in C# or VB .
Please use the link given below to get help Mr. Hannes Completely write an article to change screen rotation and luckily its working fine for me (Windows 11) as now of..
https://www.codeguru.com/dotnet/creating-a-screen-rotator-in-net/
I could begin by asking the question outright or by citing my sources (this, this, this, and this) descriptively, but I'll walk you ll through what I'm trying to do instead.
Let's start with a main window. It has its own window class whose hbrBackground is set to COLOR_BTNFACE + 1. Now let's do
EnableThemeDialogTexture(hwnd, ETDT_ENABLE | ETDT_USETABTEXTURE)
so the tab control we're about to add will be drawn with visual styles. (Try Windows XP with the standard Luna theme for best results.) Now let's add a tab control and two tabs.
On the first tab, we create an instance (let's call it container) of a new window class. This window class is going to hold various controls. I could set hbrBackground to COLOR_BTNFACE + 1, but then it will draw over the tab background. So I want this new child window to be transparent. So what I do is
set the class hbrBackground to GetStockObject(HOLLOW_BRUSH)
set container's extended style to WS_EX_TRANSPARENT
set the class WM_ERASEBKGND handler to do SetBkMode((HDC) wParam, TRANSPARENT); return 0; to set the device context and have Windows draw the transparent background.
So far so good, right? I'm not sure if I'm really doing all this correctly, and I'd like this to also be flicker-free, which doesn't seem to happen: when I resize the window (at least in wine) I get either flicker or garbage drawn (even in child controls, somehow!). Windows XP in a VM just shows flicker. I tried tweaking some settings but to no avail.
But wait, now I want to have another control, one that just draws some bitmap data. On the next tab, create another container, then have a third window class area as a child of that. area only draws in the upper-left 100x100 area and has scrollbars; the rest of the window area should be transparent.
Right now, what I have for area is:
the window class hbrBackground set to NULL and styles CS_HREDRAW and CS_VREDRAW set
the extended window style being 0
the WM_ERASEBKGND simply doing return 1;
the WM_PAINT filling the entire update rect with COLOR_BTNFACE + 1 before drawing, and rendering all of it
This is flicker-free, but obviously not transparent. NOW I'm really not sure what to do, because I want the area to be transparent in such a way that it shows the tab control background. Again, I tried tweaking settings to bring them closer to what I tried above with container, but I got either flicker or invalidation leftovers when I tried.
So how do I get both of these custom control types (the container and the drawing area) to be both flicker-free and transparent?
I presently must target Windows XP at a minimum, though if the solution would be easier with Vista+ only I'd be happy to keep that solution on the side in case I ever drop XP support (unfortunately Stack Overflow doesn't let me hand out silver medals...).
Thanks!
To paint your window in a manner that is "flicker free", you will need to paint your window to a bitmap, then copy the bitmap to the destination device context. On Windows XP, you will need to create a bitmap, adjust the origin of the drawing DC and then paint your window. On Vista and later you can use BeginBufferedPaint and its associated routines to do the buffering for you.
Once you have buffered painting working, you can then use WM_PRINTCLIENT to paint your window's parent window into the your drawing DC before you do any actual drawing. Unfortunately, not all windows will support WM_PRINTCLIENT.
You could consider using DrawThemeParentBackground, rather than WM_PRINTCLIENT directly.
Combining these two methods together will leave you with transparent flicker-free drawing.
I think I must be missing something obvious, but I'm unable to find this after several hours of searching. Is there no way to use a PictureBox or other control to contain an image with partial transparent/alpha-blended pixels, and place that over another image and have the blending be based on the image under it?
For example, this produces the results I want:
Place a panel on a form.
Add an OnPaint handler.
In the OnPaint handler draw 1 PNG, then draw another PNG over it, using Graphics.DrawImage for both.
This does not:
Place a PictureBox on a form and set it to a PNG.
Place another PictureBox on the form and set it to a PNG.
Place the 2nd picture box over the first.
...even if the 2nd picture box is just empty and has a background color of Transparent, it still covers the picture below it.
I've read this stems from all winform controls being windows, so by nature they aren't transparent.
...but even the 15 year old platform I'm migrating from, Borland's VCL, had several windowless controls, so it's hard to imaging winforms doesn't at least have some easy solution?
My first example above is one answer, true, but that adds a lot of work when you can only use one big panel and draw all of your "controls" inside of it. Much nicer if you can have separate controls with separate mouse events/etc. Even if not an image control, and a control I have to draw myself, that would be fine, as long as I can just put one image in each control. In VCL they called this a "paint box", just a rectangle area you could place on a form and draw whatever you want on it. Has it's own mouse events, Bounds, etc. If you don't draw anything in it, it is like it's not even there (100% transparent) other than the fact it still gets mouse events, so can be used as a "hot spot" or "target" as well.
The PictureBox control supports transparency well, just set its BackColor property to Transparent. Which will make the pixels of its Parent visible as the background.
The rub is that the designer won't let you make the 2nd picture box a child of the 1st one. All you need is a wee bit of code in the constructor to re-parent it. And give it a new Location since that is relative from the parent. Like this:
public Form1() {
InitializeComponent();
pictureBox1.Controls.Add(pictureBox2);
pictureBox2.Location = new Point(0, 0);
pictureBox2.BackColor = Color.Transparent;
}
Don't hesitate to use OnPaint() btw.
Sorry, I just found this... once I decided to Google for "winforms transparent panel" instead of the searches I was doing before, the TransPictureBox example show seems to do exactly what I need:
Transparency Problem by Overlapped PictureBox's at C#
Looks like there are 2 parts to it:
Set WS_EX_TRANSPARENT for the window style
Override the "draw background" method (or optionally could probably make the control style Opaque).
I have to draw a lot of Shape (about 1/2 hundred thousand) as [Canvas][2]'s childrens. I make this in my WPF application dividing work in two parts: first thing I create shapes by setting the properties of each of them (like Margin, Fill, Width, etc...), after I add shapes as Canvas's children.
MyCanvas.Children.Add(MyShape)
Now i want to improve the performance of the second part, because when i draw the shapes my application is blocked for a long period of time. So i tried to use the Dispatcher and its method [BeginInvoke][4] with different [priorities][5]: only if I use the Background priority the main application does not block, otherwise the application remains blocked and the "picture" is not displayed until all shapes are added to my Canvas, but if I use the Background priority obviously everything is slower. I also tried to create a new thread instead of using the Dispatcher, but there was no significant change.
How can I fix this problem, and generally improve the performance of my application when I add my shapes to Canvas?
Thanks.
Need to use Visual objects instead of Shape; in particular, as suggested, DrawingVisual: a visual object that can be used to render vector graphics. In fact, as written in the MSDN library:
DrawingVisual is a lightweight drawing class that is used to render shapes, images, or text. This class is considered lightweight because it does not provide layout, input, focus, or event handling, which improves its performance. For this reason, drawings are ideal for backgrounds and clip art.
So, for example, to create a DrawingVisual that contains a rectangle:
private DrawingVisual CreateDrawingVisualRectangle()
{
DrawingVisual drawingVisual = new DrawingVisual();
// Retrieve the DrawingContext in order to create new drawing content.
DrawingContext drawingContext = drawingVisual.RenderOpen();
// Create a rectangle and draw it in the DrawingContext.
Rect rect = new Rect(new System.Windows.Point(160, 100), new System.Windows.Size(320, 80));
drawingContext.DrawRectangle(System.Windows.Media.Brushes.LightBlue, (System.Windows.Media.Pen)null, rect);
// Persist the drawing content.
drawingContext.Close();
return drawingVisual;
}
In order to use DrawingVisual objects, you need to create a host container for the objects. The host container object must derive from the FrameworkElement class, which provides the layout and event handling support that the DrawingVisual class lacks. When you create a host container object for visual objects, you need to store the visual object references in a VisualCollection.
public class MyVisualHost : FrameworkElement
{
// Create a collection of child visual objects.
private VisualCollection _children;
public MyVisualHost()
{
_children = new VisualCollection(this);
_children.Add(CreateDrawingVisualRectangle());
// Add the event handler for MouseLeftButtonUp.
this.MouseLeftButtonUp += new System.Windows.Input.MouseButtonEventHandler(MyVisualHost_MouseLeftButtonUp);
}
}
The event handling routine can then implement hit testing by invoking the HitTest method. The method's HitTestResultCallback parameter refers to a user-defined procedure that you can use to determine the resulting action of a hit test.
Agreed that if you want to draw millions of elements, you simply can't do it in WPF. WriteableBitmapEx as mentioned is a good alternative.
See this related question which goes into depth on high performance graphics in WPF and the alternatives available.
If you simply must use Canvas, check out this ZoomableApplication2 - A million items. This is a Canvas based demo which makes heavy use of Virtualization to get reasonable performance with 1,000,000 UIElements on a Canvas.
That's a lot of UIElements and probably isn't going to give the kind of performance you're looking for. Do you need to be able to interact with each of the elements you're rendering? If not, I would highly recommend looking into using WriteableBitmap instead. If you need to draw shapes and don't want to create all that logic yourself (who would want to?), check out the WriteableBitmapEx project over on CodePlex.
This may be somewhat unrelated, and I apologize if you feel this way, but in the hopes that it can shed some light for other users, I'll share this tidbit.
We had some performance issues with a Canvas control used for capturing signatures. The capture was very jagged, and we couldn't draw curved lines as a result. It turned out to be related to a style was was generating drop-shadows on the UI elements. Disabling the drop-shadow effect solved our problem.
Imagine a document window in a MDI application which contains a child WPF window, say a sidebar for example. How can one get a bitmap containing both the WPF pixels AND the GDI (non-wpf) pixels?
I've discovered that when making my thumbnail preview for the Win7 taskbar app icon hover, I get black in the parts of the preview where the WPF pixels should be. My current method simply grabs a bitmap capture of the document window. Then I get a DC for the preview, make a memory DC from it and select my bitmap into it. Then I do some size adjustments and bitblt the memory dc to the real dc. I'm guessing that the BitBlt operation doesn't take into account the fact that the WPF pixels are hardware accelerated and therefore need to be grabbed from the graphics hardware. All the stuff in GDI is managed just fine, though and when there's no WPF child windows, the preview image looks fine.
I'm wondering if it's at all possible to grab a bitmap of the WPF window from native C++. Then I can blt that onto the black area of the previous preview.
Maybe I'm not understanding your current approach correctly, but could you do a BitBlt() from the screen DC to your memory DC? You'd need to get the screen rect of your window, but that shouldn't be too bad.
To solve this, I had to create an abstract class in native code containing a virtual method to get the bitmap that was implemented in C++/CLI. In the managed implementation, I used .NET's RenderTargetBitmap class to get a bitmap capture of the WPF window and then I filled up the passed in CBitmap object (see How to get an BITMAP struct from a RenderTargetBitmap in C++/CLI?). In the unmanaged caller routine, I used the virtual method to obtain the Bitmap.
In short, there was no way to get the bitmap by simply using unmanaged C++ since WPF and GDI really don't work together for all practical purposes.