Develop Reference

Is a single pass dropshadow pixel shader possible?

I've been working on a project, in WPF/C#, at work which uses quite a few animations. As a whole the project is going very well, and we've managed to make the animations efficient and impressive.
The problem is, we had to remove drop shadows to make that a reality. This has been met with a bit of resistance, as drop shadows on our title text generally look nicer. Now that we are getting close to the wrap-up stage I was asked to take another look at drop shadows and see if I can't make a workable solution. I tried the standard drop shadow effect, which is notoriously bad, and the Windows.Themes.x.DropShadowChrome effect which is more lightweight but still not great.
I am currently approaching the issue by trying to make a custom control which is using a template selector to basically remove the drop shadows during animation, and things are going well enough but I was curious about making my own pixel shader. Once upon a time I learned HLSL, and I have made a few shaders before but try as I might I cannot seem to make a single pass (a requirement of wpf) drop shadow.
I'm honestly not even sure such a shader is possible and I couldn't find a definitive yes or no online. Anyone have any insight to the possibility/method of doing something like this?

How to draw animations on top of winforms controls?

I'd like to create some animations to make my (old) winforms app look a little nicer. The basic premise would be something like this:
I have a button I can press, and when I do, a random letter appears on top of the button and "flies" over to a textbox. Once the letter arrives at its destination, the letter vanishes and is appended to the text in the textbox.
This should be async, meaning there can be multiple letters on the way at the same time.
My problem is that I do not really know how to accomplish this. I know I can draw things on top of my controls by creating a graphics -object and drawing with it, but unless I force a redraw (Invalidate, or something else), the previous drawing is not cleared. However, if I do force the redraw, things tend to go all flickery (with or without DoubleBuffered set to true).
So I'm a bit at a loss in here, and despite my best efforts at googling, I wasn't able to find a suitable solution. Probably because drawing animations on winforms isn't all that popular (wpf would probably suit this ten times better), but I'd still like to at least learn if it is possible to accomplish.

What if you first draw it on a bitmap, then bitblt it to the screen/form. Look at the accepted answer in: Simple Game in C# with only native libraries

C# PictureBox control flickering / performance issues

I am currently working in Windows Form Apps and am making what will essentially be a map editor for a game. The way i have gone about this is by having a central TabControl where each TabPage contains a custom PictureBox control and all the other UI controls are around this central TabControl. The PictureBox uses its Paint event to draw everything that is placed on the map, and therefore draws multiple images of many sizes, rotations and scales etc to the single PictureBox. This has all gone well so far. The TabPage is essentially used as a view window for the PictureBox and is of size (1280x720).
The problem is with the scale to which the maps are being produced. The avg (and also maximum) map size on screen is around 19200x10800px and can be made up of hundreds of items at any one point. When drawing just a backdrop image of size 19200x10800px the PictureBox starts to flicker when it redraws and makes the program unusable. As the map is so big you are able to pan around them and this is where the flickering really shows. Also i do not want to use a 19200x10800px image source if possible for the sake of file sizes and the scaled image quality isn't an issue at all.
I have done heaps of reading on why this might be and feel like I have tried everything up until this point. So far ive tried:
Having the background image only 1920x1080 and scaling it up by 10x
Starting with a 1920x1080 image, programatically resizing it and drawing this image
Slicing the background into multiple segments (i tried many different amounts) and drawing only the ones that the view window can see (tried this for both a small(1080p) and large(10800p) images)
Using graphics clipping so that only the things on screen would be drawn
Used Double Buffering on both the picturebox and the form that the picturebox is on
Converting the image at initialisation to an "optimised bitmap" with faster formatting and then drawing the bitmap
I've probably tried a couple other things along with minor optimisations but its taken me so long ive forgotten the rest. From what i've read its most likely something to do with the control redrawing too slowly for some sort of performance reason or a limitation with picturebox's, however exactly what is going on i cannot tell due to lack of experience with form apps controls.
Currently to draw the background in the Paint event i have either:
g.DrawImage(image, new Rectangle(0, 0, (int)(image.Size.Width * levelScale), (int)(image.Size.Height * levelScale)));
or
g.ScaleTransform(levelScale, levelScale);
g.DrawImage(image, new Rectangle(0, 0, (int)(image.Size.Width), (int)(image.Size.Height)));
Where g is the Graphics object.
Have I hit the limit of Win form apps capabilities or is there something i may be missing?
Any and all help appreciated,
Thanks in advance.

Just for formality I though id answer my own question just in case anyone else would like to know the outcome.
Based off the overwhelming consensus that winforms was just not made to do the things I was trying to do with it I decided I had to move to some other platform. Suggested to me was WPF, DirectX and OpenGL but after some extensive searching around I found what I think is the optimal solution.
In order to utilise the power of DirectX hardware acceleration MS has made it so that you can embed XNA graphics devices into a winforms application. Essentially you can create custom controls that run in the normal winform style that have access to a much higher caliber of graphics control. In this manner (with a bit of extra work) I have replaced the picturebox I was using with a custom graphics control which handles all of the drawing. This has worked very well, and on the up side i havent had to take too much of a hit to my development time.
For those looking for more info refer to this question which has further links that should help. Once again thanks to all those who gave their advice!

This is a quoted answer from the URL at the bottom. There are code examples at the link at the bottom. Hope this is helpful; not sure if you tried this yet and maybe it'll help you get a little more juice out of the existing picturebox control. As explain in the other answers, it sounds like you will be forced to a more powerful solution in the near future regardless (DirectX/OpenGL or WPF)
** Partial quote from http://social.msdn.microsoft.com/Forums/en-US/68ecd1f6-2eeb-45ce-a881-24c62145ab0e/c-picturebox-problems
"I'd guess the real problem is that it takes too long to redraw the images. GDI+ is pretty slow, it doesn't use any video hardware acceleration. To speed it up, be sure to avoid rescaling the drawing and to use the Format32PArgb format. It is about 10 times faster than any other format. Load the images into a Bitmap with the right format first."

If you have a LOT of items (Maybe realized as controls), forget about the standard event mechanism of Windows Forms. Some time ago, i've written a logic gate editor/simulator which supported lots of thousands of gates in the editor and was really fast. There, I've used the canvas and draw the gates as custom "images" instead of putting them as controls. You'll have to write a custom GetUnderlyingGate function which resolves the current gate / tile (Is your editor a tilemap editor?) from a coordinate array. Also, there were some visible area optimizations.
Maybe, when i'm back home, I'll upload some sourcecode and notify you.

Bigger is better, but how do I make sure my PictureBoxes are resized relative to resolution?

We have a bunch of forms with alot of PictureBoxes on them. They're basically a representation of an engineering system with pipes connected to pumps and whatever. Each element is it's own picturebox, so there's a few hundred.
The problem we have is that when we take the app to a large 40"+ TV, there's too much space everywhere and it doesn't look the way it does on the developer's screen. So we designed it for these large TV's but when we look at it on a normal computer screen it's all wrong.
So how do we design the form with pictureboxes for the actual images to resize and reposition the controls relative to the size of the resolution it's being viewed on? If we simply anchor everything then the image sizes themselves are not relative to the display it's seen on.
Much appreciated!

In a Winforms solution you will have to do at least some of the resize calculations if anchoring and docking do not provide you with the required results.
If it is really important to you to be able to design the UI in Visual Studio I recommend writing custom controls that expose the desired resize properties and resize behavior and perhaps even a custom designer to support the design time features.
It might not be feasible but you could consider having a look at WPF, it has a ViewBox control that might simply be the answer to your needs.

Rotate Windows form upside down

I have a C# application that has an existing WinForm that I now need to display upside down.
The application will be displayed on a touchscreen Windows 7 device. If two people are using the device, one person is viewing it right-side-up while another user will be simultaneously viewing it upside-down. I will need to have one control displayed right-side-up while another control is displayed upside-down, each duplicate forms. Both need to be functional. It is not necessary for the title bar and Windows close, maximize, and minimize to be rotated.
Is there a way to easily rotate this Form and all of its contents without having to rewrite it from scratch?

Unfortunately, rotating controls is not directly possible in WinForms.
At least, not if you want them to retain their functionality. It would be relatively simple to draw the control into a bitmap, rotate the bitmap, and then draw that back to the desired location on the form. But you would obviously lose the ability to interact with the controls. They would just be static representatives of their original selves.
But making functional upside-down controls just isn't going to happen. I mean, you could try to write a bunch of custom drawing code for owner-drawn controls, but you'll still run into a bunch of bugs, corner cases, and compatibility problems. The Win32 controls that WinForms is based on just don't support this. No big surprise, really, considering they were invented some 20–25 years before anyone thought of computer screens that you could carry around in your pocket and rotate in any direction. There is a good reason that UI technologies like WPF came out around the time that touch screens and tablets did.
There are some possibilities that can be explored when it comes to flipping the entire screen, but that's not going to help when you want different controls going different directions. (And I guess it betrays my vantage point as a desktop app guy when I say this, but that just sounds like an incredibly confusing UI.)
If you absolutely have to have this, someone else is going to have to give you another route to hack it, perhaps along the lines of Dhawalk's comment: hosting the WinForms control inside of a WPF app that does provide built-in support for rotated controls. I don't know enough about this to make any concrete suggestions down that path. From a few minutes of searching, it appears that WindowsFormsHost does not actually support rotation transforms, so this may be a non-starter anyway.