xdpi.markdown

device.xdpi

Type	Number
Library	device.*
Keywords	xdpi, dpi
See also	Sample code, ydpi, refreshDpi

Overview

This property is the dpi (dots per inch) resolution of the device running the application, along the x-axis.

This property can be used with ydpi to have display objects appear as the same size, regardless of device being used to run the application (e.g. to create a ruler app), and to avoid stretching display objects with a stretched application display (see examples below).

Example

local device = require 'plugin.device'

print( device.xdpi )

To have display objects appear as the same size, regardless of device:

local device = require 'plugin.device'

-- Create a rectangle 0.4 inches wide by 0.6 inches tall
local rect = display.newRect(0, 0, 0.4 * device.xdpi * (display.contentWidth / display.pixelWidth), 0.6 * device.ydpi * (display.contentHeight / display.pixelHeight))

To avoid stretching display objects, when the application runs with a stretched display:

local device = require 'plugin.device'

-- Create a rectangle with a width to height ratio of 2:3
local rectWidth = 200
local rectHeight = rectWidth * (3 / 2) * (device.ydpi / device.xdpi) * ((display.contentHeight / display.pixelHeight) / (display.contentWidth / display.pixelWidth))

local rect = display.newRect(0, 0, rectWidth, rectHeight)