Develop Reference

WinForms Control Alpha Blending [duplicate]

TL;DR: Look at the picture below
So I'm trying to make a little picture, and I and people around me are kinda out of ideas.
I have a table (the sitting+eating one) in the middle (seen from above), and people sitting around it. Those people are round, as isthe table.
Every person has their own picturebox, I just use one picture, rotate it, and set it as image in the next box.
Thep roblem now is: The PictureBoxes of people on corners overlap the table with empty corner, in the image there is transparency there. It should show the table below it, but instead it shows the background of the Form :(
Edit: All backgrounds are set to transparent, the Form has the marble as background and white ("Window") as background colour.
I put one person in the back and one in the front, so it's easy to see:
Edit 2 (same as ocmment):
In the last two days I read this question about 10 times, and not one that described this exact problem has had an actual answer. When trying to push one of those, I was told I should post a new question.
Example: How to make picturebox transparent?

Transparency in winforms is kind of misleading, since it's not really transparency.
Winforms controls mimic transparency by painting the part of their parent control they would hide instead of their own background.
However, they will not paint the other controls that might be partially covered by them.
This is the reason your top most picture boxes hides your big picture box.
You can overcome this by creating a custom control that inherits from PictureBox and override its OnPaintBackground method (taken, with slight adjustments, from this code project article):
protected override void OnPaintBackground(PaintEventArgs e)
{
base.OnPaintBackground(e);
Graphics g = e.Graphics;
if (this.Parent != null)
{
var index = Parent.Controls.GetChildIndex(this);
for (var i = Parent.Controls.Count - 1; i > index; i--)
{
var c = Parent.Controls[i];
if (c.Bounds.IntersectsWith(Bounds) && c.Visible)
{
using (var bmp = new Bitmap(c.Width, c.Height, g))
{
c.DrawToBitmap(bmp, c.ClientRectangle);
g.TranslateTransform(c.Left - Left, c.Top - Top);
g.DrawImageUnscaled(bmp, Point.Empty);
g.TranslateTransform(Left - c.Left, Top - c.Top);
}
}
}
}
}
Microsoft have published a Knowledge base article to solve this problem a long time ago, however it's a bit out-dated and it's code sample is in VB.Net.
Another option is to paint the images yourself, without picture boxes to hold them, by using Graphics.DrawImage method.
The best place to do it is probably in the OnPaint method of the form.

Make Picture boxes transparent, each overlapping the other with a corner?

TL;DR: Look at the picture below
So I'm trying to make a little picture, and I and people around me are kinda out of ideas.
I have a table (the sitting+eating one) in the middle (seen from above), and people sitting around it. Those people are round, as isthe table.
Every person has their own picturebox, I just use one picture, rotate it, and set it as image in the next box.
Thep roblem now is: The PictureBoxes of people on corners overlap the table with empty corner, in the image there is transparency there. It should show the table below it, but instead it shows the background of the Form :(
Edit: All backgrounds are set to transparent, the Form has the marble as background and white ("Window") as background colour.
I put one person in the back and one in the front, so it's easy to see:
Edit 2 (same as ocmment):
In the last two days I read this question about 10 times, and not one that described this exact problem has had an actual answer. When trying to push one of those, I was told I should post a new question.
Example: How to make picturebox transparent?

Transparency in winforms is kind of misleading, since it's not really transparency.
Winforms controls mimic transparency by painting the part of their parent control they would hide instead of their own background.
However, they will not paint the other controls that might be partially covered by them.
This is the reason your top most picture boxes hides your big picture box.
You can overcome this by creating a custom control that inherits from PictureBox and override its OnPaintBackground method (taken, with slight adjustments, from this code project article):
protected override void OnPaintBackground(PaintEventArgs e)
{
base.OnPaintBackground(e);
Graphics g = e.Graphics;
if (this.Parent != null)
{
var index = Parent.Controls.GetChildIndex(this);
for (var i = Parent.Controls.Count - 1; i > index; i--)
{
var c = Parent.Controls[i];
if (c.Bounds.IntersectsWith(Bounds) && c.Visible)
{
using (var bmp = new Bitmap(c.Width, c.Height, g))
{
c.DrawToBitmap(bmp, c.ClientRectangle);
g.TranslateTransform(c.Left - Left, c.Top - Top);
g.DrawImageUnscaled(bmp, Point.Empty);
g.TranslateTransform(Left - c.Left, Top - c.Top);
}
}
}
}
}
Microsoft have published a Knowledge base article to solve this problem a long time ago, however it's a bit out-dated and it's code sample is in VB.Net.
Another option is to paint the images yourself, without picture boxes to hold them, by using Graphics.DrawImage method.
The best place to do it is probably in the OnPaint method of the form.

SplitContainer Panel Resize Issue

The General Problem
The application is C# WinForms .Net 4.0.
I have a SplitContainer that takes up most of the form, it is set to Anchor in all directions so it re-sizes along with the form. The left panel (Panel1) has a simple menu, no problems here. The right panel (Panel2) is more complex and contains a number of nested tab controls (with lots of controls) - it is painfully complex, but it's not changing.
The problem is that re-sizing the form doesn't work so well. In fact, if you resize by dragging the edges slowly then it works ok, but drag quickly or use the "restore" button (top-right of form) then the issue occurs.
My Control Hierarchy
The following is a simple example of my control hierarchy, its definitely a cut down version but does highlight the nested tab control which may help with replication:
Form
Split Container (anchor: top, left, bottom, right)
SC Panel1 (min width: 300)
TreeViewControl (forget what it is called)
SC Panel2
Panel (anchor: top, left, bottom, right)
Tab Control (anchor: top, left, bottom, right)
Tab Control w/ lots of pages that overflow screen and require the navigation buttons to show in top right corner (anchor: top, left, bottom, right)
Debug Details
After some debugging it appears that it is in fact Panel2 (a child of the split container) that doesn't resize properly, and the actual SplitContainer itself resizes fine.
Here are the debug values that show this...
Full width form, before resize:
splitContainerMain.Width: 1479
splitContainerMain.Panel2.Width: 1206
panelCenter.Width: 1203
tabControlMain.Width: 1215
All as expected, splitContainerMain.Panel2.Width is smaller than splitContainerMain.Width.
After resize where the issue occurs:
splitContainerMain.Width: 815
splitContainerMain.Panel2.Width: 1206
panelCenter.Width: 1203
tabControlMain.Width: 1215
As can be seen, the splitContainerMain.Width has resized as desired, but the splitContainerMain.Panel2.Width and subsequently its children have not.
NOTE: Please remember, the width updates correctly if I manually resize the form slowly - this is not a problem with me not correctly setting any anchors.
My Efforts So Far
What I have tried to do is use various Form resize events and try to set the widths manually, but to no avail. I think what I would like to try is to set the Panel2.Width value from within an event of some sort.
What I Am Looking For
Is there anyway to force splitContainerMain.Panel2.Width to resize correctly when the splitContainerMain size changes?
Alternatively, how can I calculate what the Panel2.Width should be? And how can I set that value from the Form.Resize event? (or another event?)

Though the question is about 6 years old, I opted to answer this because I was in the same situation as the opening post. Unfortunately, the orientation was not specified. So, my answer would address the ones with Horizontal orientation.
Please translate to C# as this code is in VB.
Private Sub splitContainerMain_Resize(sender As Object, e As EventArgs) Handles splitContainerMain.Resize
'/* This is a work around about panels being left out when SplitContainer is resized */
Dim pnl1Height As Single = splitContainerMain.SplitterDistance '/* Get upper panel height */
Dim pnl2Height As Single = splitContainerMain.Height - splitContainerMain.SplitterDistance '/* Get lower panel height */
splitContainerMain.Panel1.SetBounds(0, 0, splitContainerMain.Width, pnl1Height) '/* Set Upper panel bounds */
'/* Set lower panel bounds, with a top of upper panel height plus splitter width */
splitContainerMain.Panel2.SetBounds(0, pnl1Height + splitContainerMain.SplitterWidth, splitContainerMain.Width, pnl2Height)
End Sub

From what I see u should set anchor to none for controls that are creating problem including splitcontainer pannels.
Also I would suggest to use dock fill property to best use the splitcontainers.
If need further help please provide designer file so can have a better look.

So on each Change event you are creating a new thread, that thread will then wait 100 ms and then do the recize??? thats stupid. You can have a thread created at the constructor, then calling Start() on your thread which could have the following:
private void resizeMe()
{
this.BeginInvoke((Action)() => {
splitContainer.Height = tableBorder.Height;
splitContainer.Width = tableBorder.Width;
}
}

Exactly the same problem, below code worked for me:
Surround splitContainer in a panel "tableBorder"
On tableBorder
Dock = DockStyle.Fill;
On split Container, (no anchoring)
Dock = DockStyle.None;
On tableBorder SizeChanged event
private void tableBorder_SizeChanged(object sender, EventArgs e)
{
new Thread(() => { resizeMe(); }).Start();
}
private void resizeMe()
{
Thread.Sleep(100);
this.BeginInvoke((Action)(() => {
doIt();
}));
}
private void doIt()
{
splitContainer.Height = tableBorder.Height;
splitContainer.Width = tableBorder.Width;
}
There is a small lag, but works

Windows Forms Custom Control not painting correctly

So i'm trying to make a nice rounded switch that when clicked it will slide either left or right to basically turn something on or off (it could be used for other things). I have a rectangle version working somewhat ok (i have a few tweaks in mind that I want to make for it) but the problem I'm running into is by using rounded rectangles. I made a few classes to help my self in this. I have one called RoundRectanglePath. Using the Create method I give it a Rectangle (or x,y,w,h) and a radius for the corners and it returns a closed GraphicsPath that I can then use Graphics.[Fill|Draw]Path with. I then have a RoundRectangle class which is a just a control that acts very similar to a Label. I found that if I override the OnPaintBackground and not send the event to the base, but instead paint a rectangle the same color as it's Parent.BackColor than I get the illusion that the control is really round. (as a related side note I allow transparent)
For my RoundMovableSwitch class I use 2 RoundRectanglePaths to split the Control in half. The left is a green Color and the right is Pink (thinking about it now I could have just used a horizontal LinearGradient brush...ooops oh well) I then draw the string On and Off on opposing sides. To that control I add a RoundRectangle. When the user clicks on either the RoundRectangle or the MoveableSwitch the Control then moves the RoundRectangle left or right 1 pixel at a time. The movement works great. The problem I am having is this. The outside Edge of the RoundRectangle is the correct Transparent color. The inside edge is the wrong color. See RoundMovingSwitch 1 and 2 in picture below. Once I get the code working correctly I'll go back and reorganize the code a bit more.
The code is hosted on GitHub: Here

"The problem I am having is this. The outside Edge of the RoundRectangle is the correct Transparent color. The inside edge is the wrong color."
Not sure I understand the problem...
Are you trying to get rid of the blue corners that are outside the rounded edges?
If so, then try this in RoundRectangle:
public RoundRectangle()
{
this.ResizeRedraw = true;
this.VisibleChanged += new EventHandler(RoundRectangle_VisibleChanged);
}
private bool RegionSet = false;
void RoundRectangle_VisibleChanged(object sender, EventArgs e)
{
if (this.Visible && !RegionSet)
{
RegionSet = true;
var r = new RectangleEx(this.ClientRectangle);
var path = RoundRectanglePath.Create(r.ToRectangle(), this.Radius, this.Corners);
this.Region = new Region(path);
}
}
*If the size of the control changes then you should reset the Region() property to the new size.
Edit: To make it reset the Region when the size changes:
protected override void OnSizeChanged(EventArgs e)
{
base.OnSizeChanged(e);
var r = new RectangleEx(this.ClientRectangle);
var path = RoundRectanglePath.Create(r.ToRectangle(), this.Radius, this.Corners);
this.Region = new Region(path);
}

How to make a UserControls BackColor transparent in C#?

I created a simple stick man in a Windows Form User-Control (consisting of a radio button and three labels and one progress bar).
I set the back-color of the new user-control to transparent so that when I drag it onto my form, it blends with other colors and drawings on the form.
I am not getting what I'm trying to achieve.
Here is the picture:

UserControl already supports this, its ControlStyles.SupportsTransparentBackColor style flag is already turned on. All you have to do is set the BackColor property to Color.Transparent.
Next thing you have to keep in mind in that this transparency is simulated, it is done by asking the Parent of the control to draw itself to produce the background. So what is important is that you get the Parent set correctly. That's a bit tricky to do if the parent is not a container control. Like a PictureBox. The designer will make the Form the parent so you will see the form's background, not the picture box. You'll need to fix that in code, edit the form constructor and make it look similar to this:
var pos = this.PointToScreen(userControl11.Location);
userControl11.Parent = pictureBox1;
userControl11.Location = pictureBox1.PointToClient(pos);

In constructor set style of control to support a transparent backcolor
SetStyle(ControlStyles.SupportsTransparentBackColor, true);
and then set Background to transperent color
this.BackColor = Color.Transparent;
From MSDN
A more complex approach (and possibly working one) is described here - with overrding of CreateParams and OnPaint.

Why all those things?
UserControl class has property Region.
Set this to what ever shape you like and no other adjustments are needed.
public partial class TranspBackground : UserControl
{
public TranspBackground()
{
InitializeComponent();
}
GraphicsPath GrPath
{
get
{
GraphicsPath grPath = new GraphicsPath();
grPath.AddEllipse(this.ClientRectangle);
return grPath;
}
}
protected override void OnPaint(PaintEventArgs e)
{
// set the region property to the desired path like this
this.Region = new System.Drawing.Region(GrPath);
// other drawing goes here
e.Graphics.FillEllipse(new SolidBrush(ForeColor), ClientRectangle);
}
}
The result is as in the image below:
No low level code, no tweaking, simple and clean.
There is however one issue but in most cases it can go undetected, the edges are not smooth and anti-aliasing will not help either.
But the workaround is fairly easy. In fact much easier than all those complex background handling..