I'm working with C# WinForms app and using custom control for displaying bitmap images. The problem is, when zooming images I'm using MouseWheel event and, creating new Bitmap image, based on new width and height properties.
On small and average images that works fine, but when size of image is about 3000*3000 pixels or greater, I have serious performance problems in line
scaledImage = new Bitmap(baseImage, size);
Where size - new size of image and baseImage - my original .png image.
So, maybe exists some another solution for such scaling?
Also I must mention that I'm limited with .net 3.5
Related
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.
In my winform app, i am adding images to listview using ImageList.
but when i increase the Image size (i.e. height & width) small images(ex. bmp images) got blurred.
is there any way to prevent imgs from blurring ??
Thanks in advance.
In .NET ListView, you probably have to wrap the image in standard-sized bitmap and then put the whole bitmap in the item:
Bitmap bmp = new Bitmap(64, 64);
Graphics grfx = Graphics.FromImage(bmp);
grfx.DrawImage(
myImage,
(bmp.Width - myImage.Width) / 2,
(bmp.Height - myImage.Height) / 2);
listView.Items[0].Image = bmp;
You may try Better ListView Express or Better ListView. It supports images of arbitrary sizes out of the box. When the image is small, it puts it on center without resizing and prevents the blurring:
enter link description here
If those are small images then obviously it will be blurred. If you want bigger images and you cant find them on Internet then try to create your own images by outlining the small images in photoshop or gimp(free product).
No there isn't. If you're making images bigger than their original size they always lose quality. Try using bigger images at first.
I was wondering if it was possible to change the size of a WriteableBitmap in WP7. I have noticed that the default size is 640x480, and my windows phone application is in Portrait mode, so I would like the height of my writeablebitmap (which I am using to overylay a live grayscale camera image) could be increased accordingly (while ofcourse keeping the same aspect ratio). I have not been able to find anything regarding this anywhere?
Why not instead create a bitmap of the desired size using the relevant constructor?
My application is used to design airports for a flight simulator. Users can add one or more images as background. The image(s) can be sized accurately and then used as a template to lay down features such as runways, aprons and so on.
I use a third party graphics library (Piccolo) which has an image class (as far as I can see it is a simple wrapper for System.Drawing.Image).
So far I have done little except allow the user to add an image, size it and so on. It will be no surprise that users sometimes complain of poor performance. We tell them not to load large images (up to 100k seem OK) but don't stop them and 100Mb bitmaps have been used with horrible results.
I need to fix this in a couple of ways. First by converting any image they use to an efficient format (size vs definition) and second by ensuring that the loaded image is suitably sized for the dimensions - at the moment I don't do anything specific to deal with the resizing of say a 2000 x 2000 image to fit a 500 x 500 area of the display.
The default 1:1 display of the application represents 1m per pixel. Once the user has resized the image to fit accurately would I be right in thinking that the best resoultion for the image would be to resample it to that size? I am aware that if the user zooms in way past 1:1 which they will probably do then the clarity of the image will fall.
My ignorance of handling images is complete. I have looked at some image manipulation libraries (ImageMagick and the free version of dotIamge) first for converting the input image to a standard one and second for resizing -resampling. The truth is that they do far more than I need.
Any pointer much appreciated.
Yes, resampling so that the bitmap doesn't constantly have to be rescaled for every paint should make a big difference. The default Graphics.InterpolationMode makes pretty images but is not cheap.
Another biggie is the pixel format of the bitmap. Format32bppPArgb is 10 times faster than any of the others on most video adapters.
private static Bitmap Resample(Image img, Size size) {
var bmp = new Bitmap(size.Width, size.Height, System.Drawing.Imaging.PixelFormat.Format32bppPArgb);
using (var gr = Graphics.FromImage(bmp)) {
gr.DrawImage(img, new Rectangle(Point.Empty, size));
}
return bmp;
}
The ImageList has a method named "Draw":
imageList.Draw(graphics, bounds.X, bounds.Y, bounds.Width, bounds.Height, imgIndex);
I use this method to draw an image on a graphics object of a PrintDocument. When using the original image size (16 x 16 pixels), the image is drawn correct. If however, I change the bounds size, nothing is drawn. Even changing the size to 32 x 32 (double size) has no effect. Nothing is drawn. I need to change the drawn size because of the different dpi ... Where am I gong wrong ?
Edit: The solution seems to be simply to use the g.DrawImage method instead. Why imageList.Draw() doesn't draw is still a mistery to me ...
g.DrawImage(imageList.Images[imgIndex], bounds);
ImageList.Draw() is a bit unusual, it takes advantage of the built-in support that the native image list code inside of Windows has for rendering an image in the list. This is an optimization, it avoids the cost of converting the internal image as stored in the native image list back to a managed Image object.
One side-effect however is that this drawing happens without regard for any of the transforms that were applied to the Graphics object. A 16x16 image in the list is going to be rendered as 16x16 pixels on paper. Which is indeed a bit hard to find back, printers have very high resolution (600 dots per inch is typical), that image turns into a decimal point.
Image lists were really meant to be the source of images for the TreeView and ListView controls, it is not a good general purpose collection object for images. Like a List<Image>. Your workaround is good, the Image property converts the internal bitmap back to a managed Image, Graphics.DrawImage() will then scale it appropriately to get a size on paper that's close to the size on the screen. However with the graininess you get from making an image 6 times larger. Note that you should Dispose() that object.