App Development Combat 6-app work

2.2APP Cut-chart work

Ideally, designers are designing two sets of images for the iOS app and Android app, and in reality, most of the designers use the iphone, not the Android phone, and to conserve resources, designers usually only provide design cuts and dimensioning as required by the iOS app.

Here is the screen size and pixel density of the iphone:

Equipment	Screen size	Reader	Resolution (PX)	Pixel density value
IPhone 3GS	3.5 inch	@1x	320x480	163
IPhone 4/4s	3.5 inch	@2x	640x960	330
IPhone 5/5s/5c	4.0 inch	@2x	640x1136	326
IPhone 6	4.7 inch	@2x	750x1334	326
IPhone6 Plus	5.5 inch	@3x	1242x2208	401

The minimum resolution of the iphone is 320x480, which is set as the reference interface size (baseline), the base size of the icon is set to 1 time times the figure (@1x), the rest of the model used by the pixel density value and the base size of the pixel density value of multiples of twice and 3 times times the graph.

Screen pixel density refers to the number of pixels per inch, DPI, is the abbreviation of "Dot per inch", the PPI is "Pixel per inch" abbreviation, pixels per inch, dpi=ppi for the design of the display.

The calculation method is the length and width of the pixels of the square of the sum of the root, divided by the diagonal length (in inches), such as the iphone 5 dpi is √ (640^2 + 1136^2)/4 =326.

Android divides the screen size into four levels:

small--screen size less than 3 inches or so

normal--screen size less than 4.5 inches or so

large--screen size between 4 "-7"

xlarge--screen size between 7-10 inches

(http://developer.android.com/guide/practices/screens_support.html)

Screen pixel density is related to screen size and screen resolution: the smaller the screen size, the higher the resolution, the greater the pixel density, and the smaller the inverse.

The screen size and pixel density of Android are shown in the following table:

	Low density (+), ldpi	Medium density (), mdpi	High Density (hdpi),	Extra-high-density (XHDPI),
SmallScreen	QVGA (240x320)		480x640
Normalscreen	WQVGA400 (240x400)	HVGA (320x480)	WVGA800 (480x800)	640x960
	WQVGA432 (240x432)		WVGA854 (480x854)
			600x1024
Largescreen	wvga800** (480x800)	wvga800* (480x800)		720x1280
	wvga854** (480x854)	wvga854* (480x854)
		600x1024
Extra-largescreen	1024x600	WXGA (1280x800)?	1536x1152	2048x1536
		1024x768	1920x1152	2560x1536
		1280x768	1920x1200	2560x1600

(where the xhdpi is calculated as a screen size of 4.5 inches, dpi is √ (720^2 + 1280^2)/4.5 = 326, and the DPI value of approximately 320;xxhdpi is 480)

The IOS app usually contains two sets of images @2x and @3x, while the Android app usually contains only a set of xhdpi images, and the xhdpi corresponds to the resolution of the IPhone5 series the closest (pixel density) So designers can press the IPHONE5 series resolution to do a set of @2x transduction, in the Android app to put @2x pictures in the drawable-xhdpi folder (on the 4.5-inch 720x1280 on the phone with the best, pixel density).

App Development Combat 6-app work