问题
I'm trying to add my own image as a bar button item, but I don't know how to get the image to scale properly. Apple's Human Interface guidelines recommends that my image be 44x44 px, but when I use a 44x44 px image, it is too large for the toolbar, as you can see:
When I use a smaller version of the image, it looks pixellated on the Retina display. What am I supposed to do here?
回答1:
In images.xcassets, you can add the images as 1x, 2x and 3x. Xcode will use the appropriate image size depending on the device.
回答2:
You need to follow apple guidelines for designing you can find it from this link https://developer.apple.com/library/ios/documentation/UserExperience/Conceptual/MobileHIG/LayoutandAppearance.html#//apple_ref/doc/uid/TP40006556-CH54-SW1
You can find the attached screenshot image for correct sizing for the UIBarButtonItem image size as par the apple guidelines you have to use 44X44 for ratina (@2x) and 22X22 for normal (@1x) for UIBarButtonItem
回答3:
width 22 pixels X height 22 pixels - ideal for left or right BarButtonItem.
You can resize any image to custom sizes using online tools, one such I used is
http://www.picresize.com/
来源：https://stackoverflow.com/questions/32815490/ios-how-to-set-the-proper-image-scale-for-a-bar-button-item