Question
How can I scale an image in XAML quickly without anti-aliasing applied?
Background
I am trying to make a pixel editor as a Windows 8 XAML/C# app. I'm using c#/XAML because most of my experience is with c#/WPF.
Method 1: WriteableBitmap + Image control. Originally, I used a WriteableBitmap to store and edit an image. That image is displayed in a resized XAML Image control. The problem is that the image does not get scaled properly because of anti-aliasing. (XAML does not seem to provide the BitmapScalingOptions that are available in WPF)
Method 2: Redrawn WriteableBitmap + Image control. Next I tried writing my own scaling, where I take my original image and write to a larger WriteableBitmap so that the scaled image is pixelated. The scaled image is then presented inside a XAML Image control. This process is slow and inefficient.
Method 3: SharpDX + Direct2d ?? I am pretty sure a solution exists somewhere between SharpDx, SurfaceImageSource, and Direct2d. Event still, I can't quite figure out how to display a SharpDx.WIC.Bitmap inside a Windows.UI.Xaml Image control, and am generally getting lost in the documentation.
What exactly is a recommended setup for achieving my desired end? Are there c# samples available which might point me in the right direction?
I don't know if you mean by scaling it by resizing it with the mouse or just with a button click to auto scale to a predetermined size.
But the thing you can do is to use an Image panel and then, just set it to image.Stretch = Stretch.Fill; so if you override and create a method for the Resize event of the Image Panel, your image will take the size to fill the Image panel.
Related
I am trying to create an animated sprite from a spritesheet in wpf. The current technique I am using is breaking down an image of containing all the frames of the animation into separate images and just swapping them out.
However this is costly on memory and was wondering if there is a way to just draw a section of an image (specify the source rectangle) rather than splitting the image up.
You can definitely do this. In order for this to be supported by WPF's built-in animation system you need to animate a dependency property. In your case it seems you want to animate the SourceRect property of a CroppedBitmap using a RectAnimationUsingKeyFrames with the DiscreteRectKeyFrame class.
If you're displaying the image using an Image element then you would set it's Source property to a CroppedBitmap, then the cropped bitmap would have its Source property set to a BitmapImage. The cropped bitmap wraps the standard bitmap and adds cropping functionality.
I want to know how to overlay one image over the over in Windows Phone. I did some search online, a lot of people suggest put two images into one grid and adjust the margin. However, my case is a little different. I'm making the background image of the secondary tile, I want to integrate the two images, store it locally and make the tile. So I can't put them into a grid. So what should I do in this case? Thanks!
You can create UserControl with any layout you wish (173x173px). Then, when you need to generate a tile, put this control to a page (probably out of the screen) and make and image from it with new WriteableBitmap(YourTile, null);. Than save these image to the /Shared/ShellContent/ and you are done
Probably there are better solutions for this task but this works fine too
I made this work using Ku6opr method using the following
WriteableBitmap bmp = new WriteableBitmap(173, 173);
bmp.Render(renderRoot, new TranslateTransform());
bmp.Invalidate();
where renderRoot is the usercontrol containing the Grid and the Image. I then save the bmp to the /Shared/ShellContent folder in Isolated storage.
I've got a large image in memory which I convert to an System.Windows.Media.ImageBrush and use it as the Fill for a System.Windows.Shapes.Rectangle. You can move this rectangle around with your cursor.
Basically I want to use the rectangle as a "viewport". Thus I need to change which parts of the image get displayed within the rectangle, i.e., define a rectangular subsection of the image.
How can I do that?
I see ImageBrush.Viewport but that doesn't seem to mean the same thing.
I'm open to alternative solutions that don't involve a rectangle, such as drawing directly on a canvas or something, but AFAIK WPF doesn't let you access pixel data directly (at least not easily).
To achieve this your going to have to create your own rectangle user control to allow the user to create/resize a rectangle. Then I would create a CroppedBitmap of the image in the rectangle portion Cropped Bitmap MSDN Stackoverflow example
Edit
No, no, no #Mark, You dont turn the CroppedBitmap into a UserControl. You create a USerControl that exposed the CroppedBitmap. Basically, you create a UserControl with the following DependencyProperties
The Image
The Width of he cropped portion
The Height of the cropped portion
The Left of the cropped portion
Top of the cropped portion
Then as soon as any of these properties your DP callback will do a RenderTargetBitmap Crop of the new region.
How can I show something on screen wihtout using forms?
Actually, I want to show some text and images popping on screen.
EDIT: just like i said HERE
What you can do is to create a alphatransparent form that draws the PNG and position it at the correct location and bind move etc.
http://www.codeproject.com/KB/GDI-plus/perpxalpha_sharp.aspx
PerPixelAlphaForm transparentImageForm = new PerPixelAlphaForm();
transparentImageForm.SetBitmap(<IMAGE GOES HERE>,<OPACITY GOES HERE>);
//opacity is the opacity that the image will be drawn with, a value of 255 = all transparent parts will be alpha/transparent just as much as the original PNG etc..
and you can put a timer that calls SetBitmap and changes the Opacity to fade in/out the image on the screen
And you can generate the text (on the fly) in a nice way with code from THIS article
and pass that image to the SetBitmap of the AlphaTransparent form.
EDIT: OR GO TO WPF.
I don't think you can: a form is equivalent to a window, and Windows applications draw into a window and not directly onto the screen (unless perhaps it's the backgroun/wallpaper, which I don't know about).
I think that's overdoing it but XNA will allow you to draw to the screen, but it is meant to be used for games so you will have trouble fitting it to a normal application.
In normal C# it is easy to draw to a bitmap using the Grpahics.DrawString() method. Silverlight seems to have done away with Bitmap objects and Graphics is no longer available either. So...How am I meant to manipulate/create a bitmap when using Silverlight? If it helps, I am using Silverlight 3.
Let me tell you what I am doing. I am being given a template, basically a pre-rendered image. The user is then able to select from multiple images and enter the deisred text. I then render it to the image, adjusting size etc... within bounds and centering it in the pre-defined area of the image. If I can calculate the size (as in the MeasureString method) and then draw the string (as in the Graphics.DrawString method) that would be fine. The real question, no matter why I want to be able to do this, is can it be done?
The question is: why do you want to? Why not just use a TextBlock?
If you are trying to dynamically generate an image, use standard Silverlight/WPF controls (including TextBlock) and render them to a WritableBitmap.
Edit:
Ok, you've updated and expanded, which gives me more to go on. Unfortunately, you're not going to like the answer. First, keep in mind that Silverlight and WPF in general are vector based, and intended to be used as such. Although the Canvas allows you to do pseudo-pixel manipulations, you cannot be nearly as pixel-accurate as old-school GDI. This is a factor of your medium. If you absolutely have to measure things the way you want to measure them, I suggest you build your images on a remote server and transmit them to your Silverlight app.
You can calculate the size on-screen of the text rendered via a TextBlock using the ActualWidth and ActualHeight properties. But it only works on an already rendered control. Something like MeasureString is simply not available in Silverlight. Based on your description of your app, some user interaction could accomplish what you want. The user selects the image, enters the text, and is shown a preview. The user can then adjust the width and height of the various text areas until satisfied, at which point you can take a snapshot using the render method I liked to above.
The following may work, its a bit nebulous because I haven't tried yet myself.
The object you are looking for is the WritableBitmap.
You create a Visual tree, for example create your self a Grid or Canvas (you're not adding this to the UI). Add to it the selected image and a TextBlock positioned and sized as you prefer.
Create a new WritableBitmap either of a specific size or using the selected image to initialize it.
Use the WritableBitmap Render method passing the above root Grid or Canvas to it.
Now you have a bitmap which you should able to use to do whatever its you needed to do that required all this hoop jumping in the first place.