I just started to use Gtk# today, and I'm astonished how few Documentation and exampleprojects are out there. Anyways I wanted to ask, does anybody know how to add a backgroundimage to a window or a widget?
Or I don't know is it possible to stack multiple widgets over each other beacause, because then it would be quite easy.
Gtk.Window is for the GUI, for background images you need to use Graphics i.e you need to access the underlying GdkWindow . In Gtk# simply use
Gtk.Window mwin = new Gtk.Window();
Gdk.Window gwin = mwin.GdkWindow;
then use Gdk.Pixbuf to set the background image. Here's a link that may be helpful, it is in PHP-GTK, but it shouldn't be too hard to convert to C#.
http://www.kksou.com/php-gtk2/articles/place-a-background-image-in-GtkWindow.php
Does anyone know how to make labels, or text, smoother? At the moment they look quite jagged. As I want to make the label dynamic, I can't just insert the text from Photoshop.
You'll have to dynamically generate images representing your text if you want to anti-alias it. Here is an example on msdn: http://msdn.microsoft.com/en-us/library/a619zh6z.aspx
EDIT: Editing per comment below.
The link describes using the OnPaint event of your control to use a different TextRenderingHint. If you're wanting something a little more re-useable what you can do is create a Custom Label class that extends the Label class, and use this in your forms:
public partial class CustomLabel : Label
{
private TextRenderingHint _hint = TextRenderingHint.SystemDefault;
public TextRenderingHint TextRenderingHint
{
get { return this._hint; }
set { this._hint = value; }
}
protected override void OnPaint(PaintEventArgs pe)
{
pe.Graphics.TextRenderingHint = TextRenderingHint;
base.OnPaint(pe);
}
}
Add a new Custom Control called CustomLabel (or whatever you want to call it) and use the code above. Rebuild your project and you should then see the CustomLabel control appear in your toolbox at the top, under the "MyProject Components" category. In the properties pane for this custom label you'll see the new TextRenderingHint property. Set this to "AntiAlias." Add another label to your form and compare how they look.
If you want to default it to AntiAlias simply change the default value of the private variable.
Are you referring to ClearType? Then ClearType has to be enabled in Windows, and you must use a modern font, such as Tahoma or Segoe UI, not MS Sans Serif.
Update
You posted an example of the problem. I magnified it to 400 %. Clearly ClearType subpixel antialiasing is enabled. Personally I do not think the text looks jagged. If you want higer quality on-screen text you could buy a screen with a higher physical resolution (pixels per inch), and then draw the text at a (correspondingly) larger size. Then the text will have the same size on your screen, but will look much more smooth.
You could also give up on ClearType and use some other font-smoothing algorithm, but that is far from trivial, because ClearType is the font-smoothing system on Windows.
Update 2
If you are running Windows 7, you can fine-tune ClearType. Just open the start menu, write "ClearType" and start the guide. I think there are guides for Vista and XP too, but perhaps not installed by default, but available as PowerToys or something like that...
Make sure you have ClearType enabled.
Install MacType program, it smoothes your Windows font like MacOS, I don't know why Microsoft don't fix its Windows smoothness font?
If Microsoft fixed its fonts, I don't need to install third party app to such things like that which is fundamental for Windows.
I have seen many other samples out there that draw smooth text on glass. But I can't use them. I need every single label that gets added at runtime to be smooth. I can't just "draw" text onto the screen.
Is this at all possible, and are there and sources around?
Thank you
Take a long at this article http://msdn.microsoft.com/en-us/magazine/cc163435.aspx#S6
It's a bit long but it answers alot of your question and alore more in regards to glass.
but the relevant part for you directly is
One particular gotcha is that
rendering a GDI item in black uses the
bit pattern 0x00000000-which also
happens to be a completely transparent
black if you are using an alpha
channel. This means that if you draw
with a black GDI brush or pen you'll
get a transparent color, not a black
one. The biggest problem this presents
is when you try to use the default
text color in a control of a text
label that sits on the glass area.
Since the default text color is
usually black, the DWM will consider
this to be transparent and the text
will be written in the glass
incorrectly. An example can be seen in
Figure 10. The first line is written
with GDI+, the second is a text label
control using the default color. As
you can see, it's nearly illegible
because it's actually incorrectly
rendered text that shows up as gray,
not black.
Happily, there are a number of ways
around this problem. Using owner-draw
controls is one. Rendering to a bitmap
that has an alpha channel is another.
Fortunately, the easiest way to get
text on controls is to let the .NET
Framework 2.0 use GDI+ for you. This
is easily accomplished by setting the
UseCompatibleTextRendering property on
your controls. By default, this
property is set to false so that
controls written for previous versions
of the .NET Framework will render the
same. But if you set it to true, your
text will come out looking correct.
You can set the property globally with
the
Application.SetUseCompatibleTextRenderingDefault
method.
He also provides example code you can place in your Main()
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(true);
Application.Run(new GlassForm());
}
But I recommend reading the article, It'll clear up alot of what's going on with Aero/Glass
Cheers,
Phyx
I'm making a .NET 3.5 app with a form that draws a partially transparent black background. I'm overriding OnPaintBackground to accomplish this:
protected override void OnPaintBackground( PaintEventArgs e )
{
using ( Brush brush = new SolidBrush( Color.FromArgb( 155, Color.Black ) ) )
{
e.Graphics.FillRectangle( brush, e.ClipRectangle );
}
}
It works, but occasionally the form draws over itself without clearing the screen, making the transparency darker than it should be. I've tried playing with Graphics.Flush() and Graphics.Clear(), but it either doesn't help or completely removes transparency. Any suggestions?
Edit:
Here's what it looks like, after starting the app on the left, and after the form redraws itself a few times (in response to tabbing from one control to another) on the right:
Transparency Issue http://www.quicksnapper.com/files/5085/17725729384A10347269148_m.png
Edit 2:
I was trying a few things out this morning and noticed that when the desktop behind the transparent portions change, it's not actually being redrawn. For example, if I open Task Manager and put it behind the window, you don't see it refreshing itself. This makes sense with what I've been seeing with the transparency levels. Is there a function to make Windows redraw the area behind your window?
Edit 3:
I've tried changing a few properties on the form, but they all result in the form drawing non-transparent black:
this.AllowTransparency = true;
this.DoubleBuffered = true;
this.Opacity = .99;
I'm going to try creating a separate window for the transparent portion as overslacked mentioned, but any other ideas are still welcome.
I think I would call this expected behavior, actually. What I would do is render my background to an in-memory bitmap and, in the paint event, copy that to the form (basic double-buffering).
If I'm way off base, could you post a screenshot? I don't know that I'm imagining what you're describing correctly.
EDIT:
I'm wondering about your use of OnPaintBackground... pre-.NET, if you were doing double-buffering you'd catch and ignore the WM_ERASKBKGND message (to prevent flicker), render your image to an offscreen buffer, and copy from the buffer to the screen on WM_PAINT. So, try changing from the OnPaintBackground to OnPaint.
I haven't done too much of this kind of thing in .NET, but I had a pretty good handle on it before; I just don't know if it'll translate well or not!
EDIT 2:
Marc, the more I think about what you're trying to do, the more problems appear. I was going to suggest creating a background thread dedicated to capturing the screen and rendering it darkened; however, in order to remove your own form you'd have to set the visibility to false which would create other problems....
If you're unwilling to give up, I would suggest creating two windows and "binding" them together. Create a semi-opaque window (by setting opacity) for your background window, and create a second "normal" window for the foreground. Use SetWindowRgn on the foreground window to cut away the background and position them on top of each other.
Good luck!
Is Graphics.CompositingMode set to CompositingMode.SourceCopy? That should cause painting the background twice to be equivalent to painting it once, since it will replace the existing alpha/color data instead of compositing over it.
I have a library of a few "custom controls". Essentially we have our own buttons, rounder corner panels, and a few groupboxes with some custom paint. Despite the "math" in the OnPaint methods, the controls are pretty standard. Most of the time, all we do is draw the rounded corners and add gradient to the background. We use GDI+ for all that.
These controls are ok (and very nice looking according to our customers), however and despite the DoubleBuffer, you can see some redrawing, especially when there are 20++ buttons (for example) on the same form. On form load you see the buttons drawing… which is annoying.
I'm pretty sure that our buttons are not the fastest thing on earth but my question is: if double buffer is "on", shouldn't all that redraw happen in background and the Windows subsystem should show the results "instantly" ?
On the other hand, if there's "complex" foreach loop that will create labels, add them to a panel (double buffered) and change their properties, if we suspendlayout of the panel before the loop and resume layout of the panel when the loop is over, shouldn't all these controls (labels and buttons) appear "almost instantly"? This doesn't happen like that, you can see the panel being filled.
Any idea why this is not happening? I know it's hard to evaluate without sample code but that's hard to replicate too. I could make a video with a camera, but trust me on this one, it's not fast :)
We've seen this problem too.
One way we've seen to "fix" it is to completely suspend drawing of the control until we're ready to go. To accomplish this, we send the WM_SETREDRAW message to the control:
// Note that WM_SetRedraw = 0XB
// Suspend drawing.
UnsafeSharedNativeMethods.SendMessage(handle, WindowMessages.WM_SETREDRAW, IntPtr.Zero, IntPtr.Zero);
...
// Resume drawing.
UnsafeSharedNativeMethods.SendMessage(handle, WindowMessages.WM_SETREDRAW, new IntPtr(1), IntPtr.Zero);
One of the things you should look at is whether you have set BackColor=Transparent on any of the child controls of your panels. The BackColor=Transparent will significantly degrade rendering performance especially if parent panels are using gradients.
Windows Forms does not use real transparency, rather it is uses "fake" one. Each child control paint call generates paint call on parent so parent can paint its background over which the child control paints its content so it appears transparent.
So if you have 50 child controls that will generate additional 50 paint calls on parent control for background painting. And since gradients are generally slower you will see performance degradation.
Hope this helps.
I'll approach your problem from a performance angle.
foreach loop that will create labels,
add them to a panel (double buffered)
and change their properties
If that's the order things are done, there's room for improvement. First create all your labels, change their properties, and when they are all ready, add them to the panel: Panel.Controls.AddRange(Control[])
Most of the time, all we do is draw
the rounded corners and add gradient
to the background
Are you doing the same thing over and over again? How are your gradients generated? Writing an image can't be that slow. I once had to create a 1680x1050 gradient in-memory, and it was really fast, like, too fast for Stopwatch, so drawing a gradient can't be so hard.
My advice would be to try and cache some stuff. Open Paint, draw your corners and save to disk, or generate an image in-memory just once. Then load (and resize) as needed. Same for the gradient.
Even if different buttons have different colors, but the same motif, you can create a bitmap with Paint or whatever and at runtime load it and multiply the Color values by another Color.
EDIT:
if we suspendlayout of the panel before the
loop and resume layout of the panel when the loop is over
That's not what SuspendLayout and ResumeLayout are for. They suspend the layout logic, that is, the automatic positioning of the controls. Most relevant with FlowLayoutPanel and TableLayoutPanel.
As for doublebuffering, I'm not sure it applies to custom draw code (haven't tried). I guess you should implement your own.
Doublebuffering in a nutshell:
It's very simple, a couple lines of code. On the paint event, render to a bitmap instead of rendering to the Graphics object, and then draw that bitmap to the Graphics object.
In addition to the DoubleBuffered property, also try adding this to your control's constructor:
SetStyle(ControlStyles.OptimizedDoubleBuffer |
ControlStyles.AllPaintingInWmPaint, true);
And if that ends up not being enough (which I'm gonna go out on a limb and say it isn't), consider having a look at my answer to this question and suspend/resume the redraw of the panel or Form. This would let your layout operations complete, then do all of the drawing once that's done.
You may want to look at the answer to my question, How do I suspend painting for a control and its children? for a better Suspend/Resume.
It sounds like what you are looking for is a "composited" display, where the entire application is drawn all at once, almost like one big bitmap. This is what happens with WPF applications, except the "chrome" surrounding the application (things like the title bar, resize handles and scrollbars).
Note that normally, unless you've messed with some of the window styles, each Windows Form control is responsible for painting itself. That is, every control gets a crack at the WM_ PAINT, WM_ NCPAINT, WM_ERASEBKGND, etc painting related messages and handles these message independently. What this means for you is that double buffering only applies to the single control you are dealing with. To get somewhat close to a clean, composited effect, you need to concern yourself not just with your custom controls that you are drawing, but also the container controls on which they are placed. For example, if you have a Form that contains a GroupBox which in turn contains a number of custom drawn buttons, each of these controls should have there DoubleBuffered property set to True. Note that this property is protected, so this means you either end up inheriting for the various controls (just to set the double buffering property) or you use reflection to set the protected property. Also, not all Windows Form controls respect the DoubleBuffered property, as internally some of them are just wrappers around the native "common" controls.
There is a way to set a composited flag if you are targeting Windows XP (and presumably later). There is the WS_ EX_ COMPOSITED window style. I have used it before to mix results. It doesn't work well with WPF/WinForm hybrid applications and also does not play well with the DataGridView control. If you go this route, be sure you do lots of testing on different machines because I've seen strange results. In the end, I abandoned used of this approach.
Maybe first draw on a control-only 'visible' (private) buffer and then render it:
In your control
BufferedGraphicsContext gfxManager;
BufferedGraphics gfxBuffer;
Graphics gfx;
A function to install graphics
private void InstallGFX(bool forceInstall)
{
if (forceInstall || gfxManager == null)
{
gfxManager = BufferedGraphicsManager.Current;
gfxBuffer = gfxManager.Allocate(this.CreateGraphics(), new Rectangle(0, 0, Width, Height));
gfx = gfxBuffer.Graphics;
}
}
In its paint method
protected override void OnPaint(PaintEventArgs e)
{
InstallGFX(false);
// .. use GFX to draw
gfxBuffer.Render(e.Graphics);
}
In its resize method
protected override void OnSizeChanged(EventArgs e)
{
base.OnSizeChanged(e);
InstallGFX(true); // To reallocate drawing space of new size
}
The code above has been somewhat tested.
I had the same problem with a tablelayoutpanel when switching usercontrols that I wanted displayed.
I completely got rid of the flicker by creating a class that inherited the table, then enabled doublebuffering.
using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
namespace myNameSpace.Forms.UserControls
{
public class TableLayoutPanelNoFlicker : TableLayoutPanel
{
public TableLayoutPanelNoFlicker()
{
this.DoubleBuffered = true;
}
}
}
I've had a lot of similar issues in the past, and the way I resolved it was to use a third-party UI suite (that is, DevExpress) rather than the standard Microsoft controls.
I started out using the Microsoft standard controls, but I found that I was constantly debugging issues which were caused by their controls. The problem is made worse by the fact that Microsoft generally does not fix any of the issues which are identified and they do very little to provide suitable workarounds.
I switched to DevExpress, and I have nothing but good things to say. The product is solid, they provide great support and documentation and yes they actually listen to their customers. Any time I had a question or an issue, I got a friendly response within 24 hours. In a couple of cases, I did find a bug and in both instances, they implemented a fix for the next service release.
I have seen bad winforms flicker on forms where the controls referred to a missing font.
This is probably not common, but it's worth looking into if you've tried everything else.