dart - Flutter 如何计算不同分辨率的像素？

Question

Flutter 应用可以在各种硬件、操作系统和外形尺寸上运行。不同分辨率的“像素”是如何计算的？

Answer 1

来自 https://api.flutter.dev/flutter/dart-ui/FlutterView/devicePixelRatio.html :

The number of device pixels for each logical pixel. This number mightnot be a power of two. Indeed, it might not even be an integer. Forexample, the Nexus 6 has a device pixel ratio of 3.5.

Device pixels are also referred to as physical pixels. Logical pixelsare also referred to as device-independent or resolution-independentpixels.

By definition, there are roughly 38 logical pixels per centimeter, orabout 96 logical pixels per inch, of the physical display. The valuereturned by devicePixelRatio is ultimately obtained either from thehardware itself, the device drivers, or a hard-coded value stored inthe operating system or firmware, and may be inaccurate, sometimes bya significant margin.

The Flutter framework operates in logical pixels, so it is rarelynecessary to directly deal with this property.