This might be a little techie, but I think most people here are familiar with Delphi to understand the difference between a TWinControl and TGraphicControl.  

I was trying to create a C# Winform project based on a Delphi prototype and ran into this problem which I posted to some Winform forums ... 

This led me to an *obvious* deficiency in Winforms programming. I'd like to hear your thoughts.

My question to the Winforms forums describing the problem is copied below:

<snip>

Hi, I mostly do Delphi development but would like to start my next small work project in Visual Studio using C# and Winforms.

Right away I see that there is something so easy to do in Delphi and potentially difficult to do in WinForms. I am hoping maybe someone could explain to me how this UI design task could be accomplished easily with WinForms.

Here is my design goal:

I would like to design screens with graphical elements (controls positioned at design time) which overlap each other. These graphical elements do not accept user input, but usually convey some text, image, background, shape, or other drawn item. The key though is this: these items are not rectangles, they are words or shapes and colors that may overlap one anther.

Here is a screenshot from my Delphi prototype which uses GraphicControl classes (standard in Delphi) to accomplish my goal:

http://imagebot.org/snapshops/overlapping.jpg

Above we have an  image control, two text label control, and a infobox control (rounded edged, interior gradient fill). Notice that the infobox is in the back, the text on top of it, and the image (globe with people) is to the left.

Now I can easily create these layouts in the form design using Delphi, but with Winforms there is a problem; all controls are windows and thus rectangular. They will clip the drawing of the controls behind them and not give me the composited per pixel transparency I am going for. See a closer look of of the screen above an notice the controls are blended together:

http://imagebot.org/snapshops/closer.jpg

Notice the variable per pixel level alpha blending. So my question is, how can I create this same layout in the Winforms visual designer where controls have variable levels of alpha blending per pixel and are all layered together on on top of another?

I can think of one solution, which is to have a control that requests controls underneath it to paint themselves in it (typically by sending WM_PAINT with your DC and the origin offset).

Is this already handled by the Winforms framework?
Is there a simple method I can call to compisite controls together?
Have other people tackled this problem and solved it in a form that can be downloaded?

</snip>

"Anthony Walter" wrote: .
>
>
> Here is my design goal:
>
> I would like to design screens with graphical elements (controls 
> positioned at design time) which overlap each other. These graphical 
> elements do not accept user input, but usually convey some text, image, 
> background, shape, or other drawn item. The key though is this: these 
> items are not rectangles, they are words or shapes and colors that may 
> overlap one anther.
>
....
>
> Is this already handled by the Winforms framework?
> Is there a simple method I can call to compisite controls together?
> Have other people tackled this problem and solved it in a form that can be 
> downloaded?

Have you considered the Winforms designer that is included with .NET 2.0? 
You can find example code on how to host the designer in a Winforms form if 
you do a Google on "hosting winforms designer".

I'm no C# developer but I believe you can do this by:

1. Setting the overlapping controls BackColor as Color.Transparent
2. Setting the overlapping controls parent as the control its on top of, e.g.:

http://www.climsystems.com/misc/Untitled-2.jpg

// pictureBox1 is the blue swirl
// hello world
label1.BackColor = System.Drawing.Color.Transparent;
label1.Parent = pictureBox1;

// the blue/green circle with the semi-transparent 'reflection' (PNG file)
pictureBox2.BackColor = System.Drawing.Color.Transparent;
pictureBox2.Parent = pictureBox1;

Perhaps not as robust as TGraphicControl but it can be done. 

--
Climate change and adaptation software and services - http://www.climsystems.com/

Edited by: Matthew Dooley on Oct 21, 2009 2:20 PM

> {quote:title=John Cash wrote:}{quote}
> "Anthony Walter" wrote: .
> >
> >
> > Here is my design goal:
> >
> > I would like to design screens with graphical elements (controls 
> > positioned at design time) which overlap each other. These graphical 
> > elements do not accept user input, but usually convey some text, image, 
> > background, shape, or other drawn item. The key though is this: these 
> > items are not rectangles, they are words or shapes and colors that may 
> > overlap one anther.
> >
> ...
> >
> > Is this already handled by the Winforms framework?
> > Is there a simple method I can call to compisite controls together?
> > Have other people tackled this problem and solved it in a form that can be 
> > downloaded?
> 
> Have you considered the Winforms designer that is included with .NET 2.0? 
> You can find example code on how to host the designer in a Winforms form if 
> you do a Google on "hosting winforms designer".
 
I have Visual Studio installed. Why would I need "the Winforms designer"?

> {quote:title=Matthew Dooley wrote:}{quote}
> I'm no C# developer but I believe you can do this by:
> 
> 1. Setting the overlapping controls BackColor as Color.Transparent
> 2. Setting the overlapping controls parent as the control its on top of, e.g.:
> 
> http://www.climsystems.com/misc/Untitled-2.jpg
> 
> // pictureBox1 is the blue swirl
> // hello world
> label1.BackColor = System.Drawing.Color.Transparent;
> label1.Parent = pictureBox1;
> 
> // the blue/green circle with the semi-transparent 'reflection' (PNG file)
> pictureBox2.BackColor = System.Drawing.Color.Transparent;
> pictureBox2.Parent = pictureBox1;
> 
> Perhaps not as robust as TGraphicControl but it can be done. 

Okay, that did make some difference, and I didn't know you could do that with Winforms. Kudos!

*But*, your solution is not without its own problems..

http://imagebot.org/snapshops/some-clipping.jpg

Child controls still clip each other and the parent control clips the children. In my original example if I were to parent the image and labels to the infobox control, the image would be clipped because it lays 50% inside the left edge of the infobox and 50% outside the left edge of the infobox.

> Okay, that did make some difference, and I didn't know you could do that with Winforms. Kudos!
> 
> *But*, your solution is not without its own problems..
> 
> http://imagebot.org/snapshops/some-clipping.jpg
> 
> Child controls still clip each other and the parent control clips the children. In my original example if I were to parent the image and labels to the infobox control, the image would be clipped because it lays 50% inside the left edge of the infobox and 50% outside the left edge of the infobox.

Ah yes I see.  The best solution at this point would be to create a custom control and draw everything yourself, or use your WM_PAINT idea (which I can only guess comes with its own set of hassles). 
--
Climate change and adaptation software and services - http://www.climsystems.com/

"Anthony Walter" wrote:
>> {quote:title=John Cash wrote:}{quote}
>> "Anthony Walter" wrote: .
>> >
>> >
>> > Here is my design goal:
>> >
>> > I would like to design screens with graphical elements (controls
>> > positioned at design time) which overlap each other. These graphical
>> > elements do not accept user input, but usually convey some text, image,
>> > background, shape, or other drawn item. The key though is this: these
>> > items are not rectangles, they are words or shapes and colors that may
>> > overlap one anther.
>> >
>> ...
>> >
>> > Is this already handled by the Winforms framework?
>> > Is there a simple method I can call to compisite controls together?
>> > Have other people tackled this problem and solved it in a form that can 
>> > be
>> > downloaded?
>>
>> Have you considered the Winforms designer that is included with .NET 2.0?
>> You can find example code on how to host the designer in a Winforms form 
>> if
>> you do a Google on "hosting winforms designer".
>
> I have Visual Studio installed. Why would I need "the Winforms designer"?

Because it will provide the design surface in your application that allows 
you to place elements on it and move them around - plus a lot more.

> {quote:title=John Cash wrote:}{quote}
> Because it will provide the design surface in your application that allows 
> you to place elements on it and move them around - plus a lot more.

And this has something to do with the problem I described how?

> {quote:title=Matthew Dooley wrote:}{quote}
> > Okay, that did make some difference, and I didn't know you could do that with Winforms. Kudos!
> > 
> > *But*, your solution is not without its own problems..
> > 
> > http://imagebot.org/snapshops/some-clipping.jpg
> > 
> > Child controls still clip each other and the parent control clips the children. In my original example if I were to parent the image and labels to the infobox control, the image would be clipped because it lays 50% inside the left edge of the infobox and 50% outside the left edge of the infobox.
> 
> Ah yes I see.  The best solution at this point would be to create a custom control and draw everything yourself, or use your WM_PAINT idea (which I can only guess comes with its own set of hassles). 


What might work is a container control which specifically renders the children in z-order inside of itself and then ...

well this is another problem with .NET ... I can't easily view base library the source code and step through it to learn how it works. And even when you do get the source code to the control framework, it's not nearly as nicely designed around known knowns and known unknowns (the Windows API) as the VCL controls. There is no Windows.pas in .NET, which is all Winforms is anyways ... a layer on top of the Windows API.

"Anthony Walter" wrote in message news:175429@forums.codegear.com...
>> {quote:title=John Cash wrote:}{quote}
>> Because it will provide the design surface in your application that 
>> allows
>> you to place elements on it and move them around - plus a lot more.
>
> And this has something to do with the problem I described how?

> Here is my design goal:
>
> I would like to design screens with graphical elements (controls
> positioned at design time) which overlap each other. These graphical
> elements do not accept user input, but usually convey some text, image,
> background, shape, or other drawn item. The key though is this: these
> items are not rectangles, they are words or shapes and colors that may
> overlap one anther.

I've cancelled multiple personal attacks (and replies to same) in this
thread. Please keep it civil.

-- 
Craig Stuntz · Vertex Systems Corp. · Columbus, OH
Delphi/InterBase Weblog : http://blogs.teamb.com/craigstuntz/

"Craig Stuntz" wrote:
> I've cancelled multiple personal attacks (and replies to same) in this
> thread. Please keep it civil.
> 

Thanks...