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Scrolling Panel - by Simon Lightfoot - 20/10/2020
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// MIT License | |
// | |
// Copyright (c) 2020 Simon Lightfoot | |
// | |
// Permission is hereby granted, free of charge, to any person obtaining a copy | |
// of this software and associated documentation files (the "Software"), to deal | |
// in the Software without restriction, including without limitation the rights | |
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
// copies of the Software, and to permit persons to whom the Software is | |
// furnished to do so, subject to the following conditions: | |
// | |
// The above copyright notice and this permission notice shall be included in all | |
// copies or substantial portions of the Software. | |
// | |
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
// SOFTWARE. | |
// | |
import 'package:flutter/cupertino.dart'; | |
import 'package:flutter/material.dart'; | |
import 'package:flutter/rendering.dart'; | |
import 'package:flutter/scheduler.dart'; | |
void main() { | |
runApp(MaterialApp( | |
debugShowCheckedModeBanner: false, | |
home: Material( | |
color: Colors.black, | |
child: ScrollingPanel( | |
imageUrls: imageThumbUrls, | |
), | |
), | |
)); | |
} | |
/// | |
/// This are PicasaWeb thumbnail URLs and could potentially change. Ideally the PicasaWeb API | |
/// should be used to fetch the URLs. | |
/// | |
/// Credit to Romain Guy for the photos: | |
/// http://www.curious-creature.org/ | |
/// https://plus.google.com/109538161516040592207/about | |
/// http://www.flickr.com/photos/romainguy | |
/// | |
List<String> imageThumbUrls = [ | |
"https://lh6.googleusercontent.com/-55osAWw3x0Q/URquUtcFr5I/AAAAAAAAAbs/rWlj1RUKrYI/s240-c/A%252520Photographer.jpg", | |
"https://lh4.googleusercontent.com/--dq8niRp7W4/URquVgmXvgI/AAAAAAAAAbs/-gnuLQfNnBA/s240-c/A%252520Song%252520of%252520Ice%252520and%252520Fire.jpg", | |
"https://lh5.googleusercontent.com/-7qZeDtRKFKc/URquWZT1gOI/AAAAAAAAAbs/hqWgteyNXsg/s240-c/Another%252520Rockaway%252520Sunset.jpg", | |
"https://lh3.googleusercontent.com/--L0Km39l5J8/URquXHGcdNI/AAAAAAAAAbs/3ZrSJNrSomQ/s240-c/Antelope%252520Butte.jpg", | |
"https://lh6.googleusercontent.com/-8HO-4vIFnlw/URquZnsFgtI/AAAAAAAAAbs/WT8jViTF7vw/s240-c/Antelope%252520Hallway.jpg", | |
"https://lh4.googleusercontent.com/-WIuWgVcU3Qw/URqubRVcj4I/AAAAAAAAAbs/YvbwgGjwdIQ/s240-c/Antelope%252520Walls.jpg", | |
"https://lh6.googleusercontent.com/-UBmLbPELvoQ/URqucCdv0kI/AAAAAAAAAbs/IdNhr2VQoQs/s240-c/Apre%2525CC%252580s%252520la%252520Pluie.jpg", | |
"https://lh3.googleusercontent.com/-s-AFpvgSeew/URquc6dF-JI/AAAAAAAAAbs/Mt3xNGRUd68/s240-c/Backlit%252520Cloud.jpg", | |
"https://lh5.googleusercontent.com/-bvmif9a9YOQ/URquea3heHI/AAAAAAAAAbs/rcr6wyeQtAo/s240-c/Bee%252520and%252520Flower.jpg", | |
"https://lh5.googleusercontent.com/-n7mdm7I7FGs/URqueT_BT-I/AAAAAAAAAbs/9MYmXlmpSAo/s240-c/Bonzai%252520Rock%252520Sunset.jpg", | |
"https://lh6.googleusercontent.com/-4CN4X4t0M1k/URqufPozWzI/AAAAAAAAAbs/8wK41lg1KPs/s240-c/Caterpillar.jpg", | |
"https://lh3.googleusercontent.com/-rrFnVC8xQEg/URqufdrLBaI/AAAAAAAAAbs/s69WYy_fl1E/s240-c/Chess.jpg", | |
"https://lh5.googleusercontent.com/-WVpRptWH8Yw/URqugh-QmDI/AAAAAAAAAbs/E-MgBgtlUWU/s240-c/Chihuly.jpg", | |
"https://lh5.googleusercontent.com/-0BDXkYmckbo/URquhKFW84I/AAAAAAAAAbs/ogQtHCTk2JQ/s240-c/Closed%252520Door.jpg", | |
"https://lh3.googleusercontent.com/-PyggXXZRykM/URquh-kVvoI/AAAAAAAAAbs/hFtDwhtrHHQ/s240-c/Colorado%252520River%252520Sunset.jpg", | |
"https://lh3.googleusercontent.com/-ZAs4dNZtALc/URquikvOCWI/AAAAAAAAAbs/DXz4h3dll1Y/s240-c/Colors%252520of%252520Autumn.jpg", | |
"https://lh4.googleusercontent.com/-GztnWEIiMz8/URqukVCU7bI/AAAAAAAAAbs/jo2Hjv6MZ6M/s240-c/Countryside.jpg", | |
"https://lh4.googleusercontent.com/-bEg9EZ9QoiM/URquklz3FGI/AAAAAAAAAbs/UUuv8Ac2BaE/s240-c/Death%252520Valley%252520-%252520Dunes.jpg", | |
"https://lh6.googleusercontent.com/-ijQJ8W68tEE/URqulGkvFEI/AAAAAAAAAbs/zPXvIwi_rFw/s240-c/Delicate%252520Arch.jpg", | |
"https://lh5.googleusercontent.com/-Oh8mMy2ieng/URqullDwehI/AAAAAAAAAbs/TbdeEfsaIZY/s240-c/Despair.jpg", | |
"https://lh5.googleusercontent.com/-gl0y4UiAOlk/URqumC_KjBI/AAAAAAAAAbs/PM1eT7dn4oo/s240-c/Eagle%252520Fall%252520Sunrise.jpg", | |
"https://lh3.googleusercontent.com/-hYYHd2_vXPQ/URqumtJa9eI/AAAAAAAAAbs/wAalXVkbSh0/s240-c/Electric%252520Storm.jpg", | |
"https://lh5.googleusercontent.com/-PyY_yiyjPTo/URqunUOhHFI/AAAAAAAAAbs/azZoULNuJXc/s240-c/False%252520Kiva.jpg", | |
"https://lh6.googleusercontent.com/-PYvLVdvXywk/URqunwd8hfI/AAAAAAAAAbs/qiMwgkFvf6I/s240-c/Fitzgerald%252520Streaks.jpg", | |
"https://lh4.googleusercontent.com/-KIR_UobIIqY/URquoCZ9SlI/AAAAAAAAAbs/Y4d4q8sXu4c/s240-c/Foggy%252520Sunset.jpg", | |
"https://lh6.googleusercontent.com/-9lzOk_OWZH0/URquoo4xYoI/AAAAAAAAAbs/AwgzHtNVCwU/s240-c/Frantic.jpg", | |
"https://lh3.googleusercontent.com/-0X3JNaKaz48/URqupH78wpI/AAAAAAAAAbs/lHXxu_zbH8s/s240-c/Golden%252520Gate%252520Afternoon.jpg", | |
"https://lh6.googleusercontent.com/-95sb5ag7ABc/URqupl95RDI/AAAAAAAAAbs/g73R20iVTRA/s240-c/Golden%252520Gate%252520Fog.jpg", | |
"https://lh3.googleusercontent.com/-JB9v6rtgHhk/URqup21F-zI/AAAAAAAAAbs/64Fb8qMZWXk/s240-c/Golden%252520Grass.jpg", | |
"https://lh4.googleusercontent.com/-EIBGfnuLtII/URquqVHwaRI/AAAAAAAAAbs/FA4McV2u8VE/s240-c/Grand%252520Teton.jpg", | |
"https://lh4.googleusercontent.com/-WoMxZvmN9nY/URquq1v2AoI/AAAAAAAAAbs/grj5uMhL6NA/s240-c/Grass%252520Closeup.jpg", | |
"https://lh3.googleusercontent.com/-6hZiEHXx64Q/URqurxvNdqI/AAAAAAAAAbs/kWMXM3o5OVI/s240-c/Green%252520Grass.jpg", | |
"https://lh5.googleusercontent.com/-6LVb9OXtQ60/URquteBFuKI/AAAAAAAAAbs/4F4kRgecwFs/s240-c/Hanging%252520Leaf.jpg", | |
"https://lh4.googleusercontent.com/-zAvf__52ONk/URqutT_IuxI/AAAAAAAAAbs/D_bcuc0thoU/s240-c/Highway%2525201.jpg", | |
"https://lh6.googleusercontent.com/-H4SrUg615rA/URquuL27fXI/AAAAAAAAAbs/4aEqJfiMsOU/s240-c/Horseshoe%252520Bend%252520Sunset.jpg", | |
]; | |
// ------------------------------------------------ | |
@immutable | |
class ScrollingPanel extends StatefulWidget { | |
const ScrollingPanel({ | |
Key key, | |
this.speed = 25.0, | |
@required this.imageUrls, | |
}) : super(key: key); | |
final double speed; | |
final List<String> imageUrls; | |
@override | |
_ScrollingPanelState createState() => _ScrollingPanelState(); | |
} | |
class _ScrollingPanelState extends State<ScrollingPanel> { | |
Future<void> _preload; | |
double _opacity = 0.0; | |
@override | |
void didChangeDependencies() { | |
super.didChangeDependencies(); | |
_preload ??= Future.wait([ | |
for (int i = 0; i < widget.imageUrls.length; i++) | |
precacheImage(NetworkImage(widget.imageUrls[i]), context), | |
]).then((_) { | |
if (mounted) { | |
setState(() => _opacity = 1.0); | |
} | |
}); | |
} | |
@override | |
Widget build(BuildContext context) { | |
final mediaQuery = MediaQuery.of(context); | |
final size = mediaQuery.size * 1.1; // zoom level | |
return AnimatedOpacity( | |
opacity: _opacity, | |
duration: const Duration(seconds: 3), | |
curve: Curves.decelerate, | |
child: FutureBuilder( | |
future: _preload, | |
builder: (BuildContext context, AsyncSnapshot<dynamic> snapshot) { | |
if (snapshot.connectionState != ConnectionState.done) { | |
return SizedBox(); | |
} | |
return OverflowBox( | |
minWidth: size.width, | |
maxWidth: size.width, | |
minHeight: size.height, | |
maxHeight: size.height, | |
child: _ScrollingPanelLayout( | |
speed: widget.speed, | |
children: [ | |
for (final url in widget.imageUrls) | |
Image.network( | |
url, | |
fit: BoxFit.cover, | |
), | |
], | |
), | |
); | |
}, | |
), | |
); | |
} | |
} | |
@immutable | |
class _ScrollingPanelLayout extends MultiChildRenderObjectWidget { | |
_ScrollingPanelLayout({ | |
Key key, | |
this.speed, | |
List<Widget> children, | |
}) : assert(speed != null), | |
super(key: key, children: children); | |
final double speed; | |
@override | |
_RenderScrollingPanel createRenderObject(BuildContext context) { | |
return _RenderScrollingPanel(speed: speed); | |
} | |
@override | |
void updateRenderObject(BuildContext context, _RenderScrollingPanel renderObject) { | |
renderObject..speed = speed; | |
} | |
} | |
class _ScrollingPanelParentData extends ContainerBoxParentData<RenderBox> {} | |
class _RenderScrollingPanel extends RenderBox | |
with | |
ContainerRenderObjectMixin<RenderBox, _ScrollingPanelParentData>, | |
RenderBoxContainerDefaultsMixin<RenderBox, _ScrollingPanelParentData> { | |
_RenderScrollingPanel({ | |
@required double speed, | |
}) : _speed = speed; | |
Ticker _ticker; | |
double _dy = 0.0; | |
double _segmentHeight = 0.0; | |
double _speed; | |
double get speed => _speed; | |
set speed(double value) { | |
if (_speed != value) { | |
_speed = value; | |
markNeedsPaint(); | |
} | |
} | |
@override | |
bool get alwaysNeedsCompositing => true; | |
@override | |
void setupParentData(RenderBox child) { | |
if (child.parentData is! _ScrollingPanelParentData) { | |
child.parentData = _ScrollingPanelParentData(); | |
} | |
} | |
_ScrollingPanelParentData _childParentData(RenderBox child) => | |
child.parentData as _ScrollingPanelParentData; | |
@override | |
void attach(PipelineOwner owner) { | |
super.attach(owner); | |
_ticker = Ticker(_onTick); | |
_ticker.start(); | |
} | |
void _onTick(Duration elapsed) { | |
_dy = speed * (elapsed.inMicroseconds / Duration.microsecondsPerSecond); | |
markNeedsPaint(); | |
} | |
@override | |
void detach() { | |
_ticker.dispose(); | |
_ticker = null; | |
super.detach(); | |
} | |
@override | |
void performLayout() { | |
assert(constraints.hasBoundedWidth); | |
final childWidthConstraint = constraints.maxWidth / 5.0; | |
final childConstraints = BoxConstraints( | |
minWidth: childWidthConstraint, | |
maxWidth: childWidthConstraint, | |
minHeight: childWidthConstraint * 1.5, | |
maxHeight: childWidthConstraint * 1.5, | |
); | |
final children = getChildrenAsList(); | |
for (int i = 0; i < children.length; i++) { | |
final child = children[i]; | |
child.layout(childConstraints, parentUsesSize: true); | |
} | |
final childSize = firstChild.size; | |
for (int i = 0; i < children.length; i++) { | |
final x = (i % 5) * childSize.width; | |
final y = (i ~/ 5) * childSize.height; | |
_childParentData(children[i]).offset = Offset(x, y); | |
} | |
_segmentHeight = (children.length / 5) * childSize.height; | |
size = constraints.biggest; | |
} | |
@override | |
void paint(PaintingContext context, Offset offset) { | |
final _top = (_dy % _segmentHeight); | |
for (int i = 0; i < 2; i++) { | |
context.pushLayer( | |
OffsetLayer(offset: Offset(0.0, -_top + (i * _segmentHeight))), | |
defaultPaint, | |
offset, | |
); | |
} | |
} | |
@override | |
bool hitTestChildren(BoxHitTestResult result, {Offset position}) { | |
return defaultHitTestChildren(result, position: position); | |
} | |
} |
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