I was the functionality of a UserControl but I want it to look like a bitmap. How can I do this in WPF?
What about the Image control? What exactly do you want? How does a bitmap look like? Can you write more than one sentence?
You can do the following
Download source of the Bitmap class that will snap to device pixels from here
Rewrite it a little bit.
a. Set UserControl instead of UIElement as it's parent
b. Rename MeasureCore to MeasureOverride
I hope that will become the thing you need.
Related
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'm currently looking to achieve a gradient effect a bit like the rectangle in http://pjnicholson.com/Fireworks/fillgradients.htm
If I compromise a little I can get close to this using RadialGradientBrush... but is there any (not too painful) way to achieve the rectangular effect?
Use an ImageBrush instead and use this image (or a similar image generated using some image editor) for the background of your rectangle.
One solution a colleague and I came with was to derive a new Panel that used a WriteableBitmap as the source for its background.
The panel will give you the dimensions you need to make your WriteableBitmap. Using whatever algorithm you want you can fill it appropriately. In our case, we needed a radial or cone gradient, but the same concept applies.
Additionally, you can create several properties on your new control to specify the colors for the gradient. We adapted a LinearGradientBrush for our needs, but if you're working on just two colors, simple properties may suffice.
I don't have the code handy but will try to find it and post an update later. But the above should get you going.
How can I programmatically draw a bitmap to a WPF Canvas? (or should I do something else entirely?) I will have about 40 moving images.
If you need to dynamically create and modify bitmaps, then use a WritableBitmap. You can place these on a canvas.
I did something similar, but I wanted some logic on each image(object) so I created a UserControl with an image and just add the UserControl to the canvas.
I'd like to ask if there is any possibility to draw on WPF Canvas with some kind of a Graphics type providing methods like: DrawLine, DrawPath etc.. (as it was in .NET 2).
I know there's a lot of stuff like storyboards etc.. but I'm planning to do all the drawing in code behind and to have just 1 Canvas in WPF without any child elements.
Do you think it is a good idea? will it be smooth ?
I'd like to ask if there is any possibility to draw on WPF Canvas with some kind of a Graphics type providing methods like: DrawLine, DrawPath etc.. (as it was in .NET 2).
Yes, you need to use the DrawingContext class
Do you think it is a good idea? will it be smooth ?
That's hard to tell, depending on your exact needs... If the canvas doesn't have any child items, I think a better solution would be to create a custom control and override the OnRender method. Regarding smoothness, it all depends on how you implement it...
I want to put an image on a button, but I want part of the image to be transparent. How do I do this?
Try the Image.OpacityMask property. You can give it a brush that specifies the region you want to be transparent.
EDIT: From MSDN:
There is no direct support for
color-keying a bitmap in WPF.
However, it is fairly easy to
implement on your own. Dwayne has
implemented a ColorKeyBitmap on his
blog:
http://blogs.msdn.com/dwayneneed/archive/2008/06/20/implementing-a-custom-bitmapsource.aspx
I believe it links to the code on
Codeplex as well. You could also
accomplish this simply by reading your
bitmap into system memory, iterating
through all the pixels and setting
their values yourself, and
constructing a new bitmap out of that
array.
Use a paint program (I use Paint.Net) to change the area you want transparent to an alha=0 color. Then save the image (mine was JPG) as a PNG. Seemed to work fine for me in the WPF Image control.