I had ImageResizer set up for years in my app and it is serving/resizing JPGs fine (I use presets) but today I wanted to resize a spacer.gif and it did not do anything. I then tried with spacer.png and it also doesn't touch it (no resize, image rendered at 1x1 pixels).
What could be going on here?
As covered in Basic Usage, ImageResizer does not upscale by default. You will need to specify ?scale=both&width=200 to upscale tiny images.
This is unlikely to have anything to do with the image format (namely gif/png).
Related
I have converted one of my Windows Store applications to a universal application and added a Windows Phone project to it.
When rendering the graphics (Image and Rectangles with ImageBrushes) the graphics always gets scaled even if I set it to not scale which is not how expect it to work.
Example:
I have an image that is named test.scale-100.png which is 27*27 pixles.
The same image exists as a 32*32 pixel sized image named test.scale-140.png and another named test.scale-240.png which is 59*59 pixles
I use this image in my default layout the following way:
<Image x:Name="imgTest" Source="/Assets/test.png" Stretch="None"/>
When I start my app with the Windows Phone 8.1 WVGA 4 inch emulator the 32*32 image is shown with the correct bounds, but the actual image is scaled (I can see that quite simple because the content gets blurred).
The same happens when I start the app with the Windows Phone 8.1 1080p 6inch emulator; The image is 59*59 pixles but the image is a bit blurred.
How can I force scaling to not be performed?
Thanks in advance for any help!
I am not sure. I am looking for a solution right now too. But I found that scaling is not supported in Windows Phone 8.1. Only Windows Store apps are working with scaling. Take a look at link below.
http://msdn.microsoft.com/en-us/library/windows/apps/dn263244.aspx
So, the way how to scale images is to use height/width propreties to force size of image or you can use BitmapImage and its property DecodePixelHeight/DecodePixelWidth together with Height/Width properties to decode the image.
Hope it helps ;)
I have the same issue, I think this is an OS bug:
Test 1
test.scale-100.png +
test.scale-140.png +
test.scale-240.png
= Blurry result
Test 2
test.scale-240.png
= Blurry result, again
Test 3
test.scale-240.png renamed to test.png
= Sharp result!
The problem occurs only with certain assets, not all. In my case only in some DataTemplates. I think that in some situations the system scale the image incorrectly, with an horrible blurry result. If you leave only the "scale-240" image, it is blurry. If you rename it removing "scale-240", it becomes sharp!
In summary, name the image as test.png and stop.
As MSDN says:
Don't use images that aren't sized to multiples of 5px. Units that aren't multiples of 5px can experience pixel shifting when scaled to 140%, 180%, and 240%.
https://msdn.microsoft.com/en-us/library/windows/apps/xaml/hh465362.aspx
Your Width="53" Height="53" could be the issue of incorrect behavior
I'm using a 40 x 40 sized image as a search result suggestion image in Windows 8 search. Only advice about the image format I can find is to have correct size for it (http://msdn.microsoft.com/en-us/library/windows/apps/Hh700542.aspx: "Windows will scale or crop smaller or larger images").
However, the correctly sized image blurs annoyingly. The same thing happens whether I use jpg or png. Original image looks fine, but the result suggestion in the search charm is very ugly, being still of same size! Is Windows converting the image somehow, and how could I get the image to stay crisp?
I haven't noticed blurring with photo-like images, but this image contains clear lines and areas which are vulnerable to any scaling etc.
Update Sep 24:
Here is the test image I used when trying to figure out the problem. I also created different scale versions, but in my case the 100% version was used (that's why the "100" marking) - as I supposed because the resulting image really is 40x40. As you can see, the resulting image (right) is of same size as original (left), but blurry.
it does not happen that often but it seems the right solution in this case was simply to wait ;) I haven't done anything new regarding result suggestion images in my solution and today I realized that the images became crisp. Probably fixed by any of the windows updates.
[Took a stab at answering what seems the related question mentioned in the comments, so I'm posting here as well.]
It sounds like this could be related to automatic scaling of the images. Windows will automatically scale up/down based on pixel density, and you can help things scale well by either using vector-based images or, for bitmap images, supplying scale-specific versions.
For example, to scale an image referenced in markup as "AppLogo.jpg", you'd include these images:
AppLogo.scale-100.jpg
AppLogo.scale-140.jpg
AppLogo.scale-180.jpg
You can also use folders, e.g. "\scale-140\AppLogo.jpg".
For search result images, the 100% image is the 40x40 pixel version, 140 is 56x56, and 180 is 72x72. Just reference the image as "AppLogo.jpg" and the appropriate version will be used automatically. (You can also detect scale with DisplayProperties.ResolutionScale and manually choose an image.)
Here's a couple of articles with more examples/details:
"Guidelines for scaling to pixel density"
"Quickstart: Using file or image resources"
There's also some scaling discussion in the forums (general, not specific to search) here and here.
I'm currently optimizing my iOS app for the new iPad. Unfortunately by adding launch images for the iPad retina display the size of my ipa grows from 1.2MB to 5.5MB, mainly because of the two PNG images in 1536 x 2008 (portrait) and 2048 x 1496 (landscape). The size of these images are respectivly 1.9MB and 1.7MB.
The portrait can be seen here: http://uploads.demaweb.dk/iPadPortrait.png.
As you may notice, the background is a fixed pattern but sadly it seems that this is not very compressible. I've further tried to compress the images using ImageOptim, but it does not make any difference after Xcode has compressed the images during the archive. Searching the web I've noticed, that some people are dissuading to turn off PNG compressing in Xcode.
Are there anything I can do? It is not a solution to change the pattern in the image to a solid color, as it should look like the background in my iOS view. But it seems odd, that supporting the new iPad increase the size by ~4MB.
I was able to get it down to 633KB with pngquant (64 colors with slight dithering, which is barely noticeable on regular screen, and should be absolutely invisible at Retina resolution) and ImageOptim.
Yes, you will need to disable Xcode's conversion to avoid Xcode inflating files by converting them to ARGB.
NB: the article quoted in the accepted answer provides no benchmarks at all for the claimed speed difference.
It also contains correction that it is possible to optimize images with ImageOptim for iOS apps.
I'm using a great tool called ImageOptim
It incorporates a number of tools inside which crush your png files significantly (in my case it was between 25% to 50%).
One thing to remember is to disable Xcode's PNG optimization (as explained on the website)
EDIT:
Simply drag the images to the imageOptim window and the optimization will start automatically
Ive struggled with this too, unfortunately not much can be done.
In an effort to dramatically increase drawing performance of iOS apps,
Xcode re-compresses PNG files as it builds. It premultiplies the alpha
channel and byte swaps the red, green and blue channels to be
sequenced blue, green and red. The result is optimised for iOS’s
purpose, but as a side effect, ImageOptim’s work gets undone…
Source
My app downloads images from a website. These images are all manner of sizes, from 800x600 up to 1800x1600. I analyze the image using facial recognition, and then want to resize and crop the image. However, it's important that the detected CGRect be visible on the cropped image.
I was using the excellent UIImage+Resize code and using UIViewContentModeScaleAspectFill, but it doesn't seem to have a programatic way of specifying an arbitrary location that needs to be visible in the final image. So if a face is located at the 1600px range of an 1800x1600 image, it'll get cut off.
Is there an easy solution to this, or do I need to dig around in the depths of UIImage+Resize? Any guidance would be appreciated!
I need to take some images from the iPhone / iPad photo library from within my app and store them in a Core Data entity, and display them as small thumbnail images (48x48 pixels) in a UITableViewCell, and about 80x80 pixels in a detail UIView. I've followed the Recipes sample app, where they use UIImageJPEGRepresentation(value, 0.1) to convert to NSData and store the bytes inside Core Data, and it doesn't end up taking much space, which is good. But when retrieve the data, using UIImage *uiImage = [[UIImage alloc] initWithData:value]; and display it as a thumbnail image with "Aspect Fit", it looks terrible and grainy. I tried changing the image quality variable in the JPEG compression, but even setting it to 0.9 doesn't help.
Is that normal? Is there a better way to compress the image that doesn't cause so much grainee-ness? Since I just want to show a small thumbnail, and then a slightly bigger thumbnail, I feel Core Data would be great for storing this, since it should (theoretically) also support iCloud. But if it's going to look terrible, then I'll have to reconsider.
Two things, are you resizing the image to the right size? Have you tried UIImagePNGRepresentation()? That should compress it without losing quality.
If UIImagePNGRepresentation (which is lossless) is giving you bad images, then the problem is in your image resizing code. Core Data is just giving you what you back what you put in, so if you get bad images out, it's because you put bad images in.
Is one of your iPhone/iPad retina and the other isn't? If so, perhaps the problem is that you don't really want 48x48 pixel images, you want 48x48 point (which means you'll need 2x images 96x96 for retina quality display).