what is FractionalTranslation in flutter? - flutter

Question

I am learning flutter for some time. But I do not seem to understand fully what is FractionalTranslation class despite docs and some examples.
Documentation says: FractionalTranslation class applies a translation transformation before painting its child.
But what does it mean? Could you explain it to me in more detail?

Answer 1

FractionalTranslation class is essentially a type of Transform, and it is also used to do The difference of translation transformation is that its translation unit is a multiple of the width and height of the control. It is defined as follows
FractionalTranslation({
Key key,
#required Offset translation,
bool transformHitTests: true,
Widget child })
It can be seen that its definition is the Transform.translatesame. The difference is translation the understanding of parameters. Let’s use a few examples to explain the use of FractionalTranslation
FractionalTranslation use
The translation distance of the Text control to the right is 0.5 times the width of the Text control
Container(
color: Colors.amberAccent,
alignment: Alignment.center,
child: FractionalTranslation(
translation: Offset(0.5, 0),
child: Text("Hello world")),
),
The distance to translate the Text control to the right is 2 times the width of the Text control
Container(
color: Colors.amberAccent,
alignment: Alignment.center,
child: FractionalTranslation(
translation: Offset(2, 0),
child: Text("Hello world")),
),
Move the Text control to the right and down. The right translation distance is 1 times the Text width, and the downward translation distance is 1.5 times the Text height.
Container(
color: Colors.amberAccent,
alignment: Alignment.center,
child: FractionalTranslation(
translation: Offset(1, 1.5),
child: Text("Hello world")),
),
Complete example
import 'package:flutter/material.dart';
import 'dart:math' as math;
class TransformDemo extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
theme: ThemeData(primaryColor: Colors.blue),
home: HomeWidget(),
);
}
}
class HomeWidget extends StatefulWidget {
#override
State createState() {
return HomeState();
}
}
class HomeState extends State<HomeWidget> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text("TransformDemo"),),
body: Container(
color: Colors.amberAccent,
alignment: Alignment.center,
child: FractionalTranslation(
translation: Offset(1, 0),
child: Text("Hello world")),
),
);
}
}