flutter - 如何将真实像素值转换为抖动逻辑像素(密度无关像素)

Question

我正在使用flutter-ffmpeg包将图像叠加到视频上，叠加后我在该图像上绘制一个矩形，但问题是，ffmpeg使用真实像素数据覆盖图像并使用逻辑像素 flutter 绘制矩形，所以我怎么能将 ffmpeg 的真实像素转换为 flutter 的逻辑像素，以便我可以更改图像的叠加尺寸以匹配矩形。

Answer 1

您可以使用devicePixelRatio .这是 Flutter 文档中的定义:

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

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

所以， devicePixels / WidgetsBinding.instance.window.devicePixelRatio应该给你逻辑像素。