I use vector graphics in my app and would like the image to be bigger. Unfortunately all posts I found on this just scaled the image, not using the through vector graphics available higher resolution.
photoButton = [[UIButton alloc] initWithFrame:CGRectMake(width/3.0*2.0-15,
15,
width/3.0,
height/3.0)];
[photoButton setImage:[UIImage imageNamed:#"Photo"] forState:UIControlStateNormal];
[photoButton addTarget:self action:#selector(photo) forControlEvents:UIControlEventTouchUpInside];
Any ideas?
Ah, what you're seeing is a result of how the vector images are used in ios and os x. They are not stored as vector images in the compiled bundle. The vector image is used, at compile time, to create all the required standard and retina versions of the image. These are then stored as png files in the bundle and the png file for the screen resolution (standard, 2x, 3x retina) are used to display them.
What you probably want is to use a resizable image. For this you can't use vector images you have to provide a png. Then you can "slice" the image into resizable and non-resizable sections.
For instance you can create a button background image that will resize to the button dimensions and keep the corners nice and rounded by making sure the corners are not distorted.
Take a look at the "show slicing" options in the asset catalog in Xcode.
Related
I am having difficulties with retina images.
The screenshot below shows the UICollectionView with a UIImageView contained within each UICollectionViewCell.
Within the app I have a large image 512x512 pixels called travel.png.
The green circle shows what is displayed on the app when I name this file: travel.png. The blue circle shows what I see when I update the image name to be travel#2x.png (i.e. retina naming).
I was hoping due to the large size of the image (512x512) that simply adding the #2x suffix would be enough to convert it to twice the definition (i.e. retina) but as you can see from the two screenshots, both version images show as non-retina.
How can I update the image so that it will display in retina?
travel.png:
travel#2x.png:
* Updated *
Following request in comments below:
I load this image by calling the following function:
// Note - when this method is called: contentMode is set to .scaleAspectFit & imageName is "travel"
public func setImageName(imageName: String, contentMode: ContentMode) {
self.contentMode = contentMode
if let image = UIImage(named: imageName) {
self.image = image
}
}
Here is how the image appears in Xcode before the app renders it (as you can see it is high enough definition):
The reason why you see the low quality image is anti-aliasing. When you provide images bigger then an actual frame of UIImageView (scaleAspectFit mode) the system will automatically downscale them. During scaling some anti-aliasing effects can be added at curve shapes. To avoid the effect you should provide the exact image size you want to display on the screen.
To detect if UIImageView autoscale the image you can switch on Debug->Color Misaligned Images at Simulator menu:
Now all scaled images will highlight at simulator with yellow color. Each highlighted image may have anti-aliasing artifacts and affect CPU usage for scaling algorithms:
To resolve the issue you should use exact sizes. So the system will use them directly without any additional calculations. For example, if your button have 80x80px size you should add three images to assert catalog with following sizes and dpi: 80x80px (72 dpi), 160x160px (144 dpi) and 240x240px (216 dpi):
Now the image will be drawn at the screen without downscaling with much better visual quality:
If your intention is to have just one image for all the sizes, I would suggest it having under Assets.xcassets. It is easy to create the folder structures and manage media assets here.
Steps
On clicking + icon, you will displayed a list of actions. Choose to create a New folder.
Choosing the new folder that is created, click on the + icon again and click on New Image Set.
Choose the imageset. And choose the attributes inspector.
Select Single Scale, under Scales.
Drag and drop the image.
Rename the image name and folder names as you wish.
Now you can use this image using the image name for all the screen sizes.
TL;DR;
Change the view layer's minificationFilter to .trilinear
imageView.layer.minificationFilter = .trilinear
as illustrated by the device screenshot below
As Anton's answer correctly pointed out, the aliasing effet you observe is caused by the large difference in dimensions between the source image and the image view it's displayed in. Adding the #2x suffix won't change anything if you do not change the dimensions of the source image itself.
That said there is an easy way to improve the situation without resizing the original image: CALayer offers some control over the method used by the graphics back-end to resize images : minificationFilter and magnificationFilter. The first one is relevant in your case since the image size is being reduced. The default value is CALayerContentsFilter.linear, just switch to .trilinear for a much better result (more info on those wikipedia pages). This will require more GPU power (thus battery), especially if you apply it on many images.
You should really consider resizing the images before displaying them, either statically or at run-time (and maybe cache the resized versions). In addition to the bad visual quality, using such large images in quantities in your UI will decrease performance and waste lots of memory, leading to potentially other issues.
I have fixed, #DarshanKunjadiya issue.
Make sure (if you are already using assets):
Make sure images are not un-assigned
Now use images in storyboard or code without extensions. (e.g. "image" NOT "image.png")
If you are not using images from assets, move them to assets.
Demo Projects
Hope it helps.
Let me know of your feedback.
I think images without the #2x and #3x are rendered for devices with low resolutions (like the iphone 4 an 3G).
The solution I think is to always use the .xcassets file or to add the #2x or #3X in the names of your images.
In iOS, content is placed on the screen based on the iOS coordinate system. for displaying an image on a standard resolution system having 1:1 pixel density we should supply image at #1x resolution. for higher resolution displays the pixel density will be a scale factor of 2.0, 3.0 which refers in the iOS system as #2x and #3x respectively. That is high-resolution displays demands images with higher density.
For example, if you want to display an image of size 128x128 in standard resolution. You have to supply the #2x and #3x size image of the same. ie., 256x256 at #2x version and 384x384 image at #3x version.
In the following screenshot, I have supplied an image of size 256x256 for 2x version to display a 128x128 pixel image in iPhone 6s. iPhone 6s render images at #2x size. Using the three version of images such as 1x, 2x and 3x with asset catalogue will resolve your issues. So the iPhone will automatically render the correct sized image automatically with the screen resolution.
I'm trying to use a PDF/SVG Image as the SKTexture for an SKSpriteNode.
I know that this can be done for a UIImageView by ticking "Preserve Vector Data", setting Scaled to "Single Scale" and configuring the UIImageView to
imageView.adjustsImageSizeForAccessibilityContentSizeCategory = true
Is this possible to do when using the UIImage in an SKTexture? This would prevent the creation of #2x & #3x images.
Thanks
You cannot use vector images for an SKTexture
A SKTexture doesn't have a vector format, it's simply a bitmap image.
So when you add a PDF vector image to your asset catalog and then you create a SKTexture out of it, you get a bitmap image (also if you selected Preserve Vector Format and Single scale)
The good part of this procedure is that you don't need to create the 1x, 2x and 3x sized images since Xcode will do it for you at build time. But the generated texture is still going to be in bitmap format.
I can't get my UIButton image to not end up pixelated. The original image is 432X417 and my button size is 18X17. I'm setting up the button in interface builder and setting the content mode to aspect fit.
You absolutely should NOT try to install a 432x417 pixel images into a 18x17 point button.
You should create your image at the target size(s) in an image editor (e.g. Photoshop) and install that into your asset catalog. Remember that for most devices an 18x17 point images will need to be 36x34 pixels for 2x retina, and 54x51 pixels for the #3x scaled needed for the 6+ and 7+ devices.
If the image is a vector PDF then it should scale well, although 18x17 points is quite small and hard to show much detail.
So I've done lots of reading on how to achieve perfect image quality on UIButton's .imageView property in iOS. Here's my example ->
I've got an UIButton 24x24 points as per the following line:
myButton = [UIButton buttonWithType:UIButtonTypeCustom];
myButton.frame = CGRectMake(82, 8, 24, 24);
myButton.contentMode = UIViewContentModeCenter;
buttonImage = [UIImage imageNamed:#"myImage.png"];
ogImage = [buttonImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
I then have the original image sized to 46x46 pixels (twice 23x23, 24x24 on button for even size to prevent iOS auto-aliasing), then the image#2x at 92x92 pixels. Im testing on an iPhone 6s (obviously retina display) and am still seeing some jaggedness on my UIButton's image. What am I doing wrong here? Am I still not understanding how to achieve perfect retina quality?
Here's an image, Im hoping it displays well for example:
Not sure if this is going to help, but this is my personal preference. If for example, I have a UIButoon of size 24x24, I always generate 24x24, 48x48, and 72x72 images. I rely on my Adobe Illustrator to creat pixel perfect images. Always check your images in pixel preview mode and make sure edges are aligned with the pixels. If not, it can produce artifacts that you see in xCode.
If it's what you want in Illustrator then it's what you get in xCode.
Apologies for posting an image-related question as a new user, I need more reputation in order to include pics in my post :)
I am trying to resize an image without scaling its corners. I tried using resizableImageWithCapInsets as well as slicing through an asset catalog (although the latter only supports a deployment target of iOS 7+, which really does not make it a solution option...). I am using an image named "ViewHeaderTest.png" which is 44x100 pixels. The caps/insets should be a 16x16 pixel square in each corner.
This is the code:
UIImageView *headerTest = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"ViewHeaderTest.png"]];
headerTest.image = [headerTest.image resizableImageWithCapInsets:UIEdgeInsetsMake(8, 8, 8, 8) resizingMode:UIImageResizingModeStretch];
headerTest.frame = CGRectMake(0, 0, 22, 50);
Code as well as asset catalog slicing produce the same result for me, which, oddly, does not appear mentioned anywhere else on stackoverflow: The caps / insets work fine, but they are scaled to double their original size. Basically it appears that resizableImageWithCapInsets takes returns an image of twice its original proportions.
Any takers? :)
Solution found:
As suspected, this is a retina issue. To avoid xcode confusing retina and non-retina images when using cap insets,
Specity image name without file extension, i.e. #"FileName" instead of #"FileName.png"
Have retina AND "normal" version of the file in corresponding resolutions in your project. I.e. have FileName.png (100px x 100 px) AND FileName#2x.png (200px x 200px) in the project.
I'm happy that it works, so I have not checked if either of these is redundant :)