In their example https://flutter.dev/docs/cookbook/plugins/picture-using-camera we can take pictures using the camera plugin.
I modified the code and move into a separate widget. My main goal is to try to implement a picture area (like QRCode style) and take the picture and if necessary tell the user to corp the image or my be app will do it automatically. There is a barcode_scan plugin. It shows an area to scan the barcode. I like to implement that part to take pictures of an item.
https://codecanyon.net/item/qr-code-barcode-scanner-and-generator-for-ios-swift-with-admob/screenshots/20280521?index=1 screenshot2 has a 4 half square bracket on 4 edges. I like to make it similar but capture images only.
I am new to this plugin and corp idea. How can I create a picture area in Flutter so the user can center the item in that area and take a picture.?
Widget _buildPictureArea(BuildContext context) {
return new Container(
width: 200,
height: 200,
child: FutureBuilder<void>(
future: _initializeControllerFuture,
builder: (context, snapshot) {
if (snapshot.connectionState == ConnectionState.done) {
// If the Future is complete, display the preview
return CameraPreview(_controller);
} else {
// Otherwise, display a loading indicator
return Center(child: CircularProgressIndicator());
}
},
),
);
}
Related
I am trying to build a layout explicit for Windows and Web. If the App becomes to small there will be another Layout.
The basic Idea is this Layout:
The green and the blue part are potential to big for the screen. And the red part is a header with some selection options.
My goal is, that the user can scroll the complete page down to the end of the green part. So that the red header will be disappear through scrolling down, the green part will be continued to be scrollable. So far I'd just use a Column in a SingleChildScrollView.
The tricky part is the blue part. I want it to get scrolled with the header to the top of the screen but then stays pinned there while the green part continues to be scrolled. Ideally it uses the complete height of the screen when the header is out of view.
Has somebody an idea how to achieve this?
Is there a ready solution I just don't know or would I need to exchange the layout when the header disappears?
If it helps. here is the code to make the basic layout:
#override
Widget build(BuildContext context) {
return SingleChildScrollView(
child: Column(
children: [
//hides when scrolled down
_buildHeader(),
//some small divider
Container(height: 5, color: Colors.black,),
_mainContent(),
],
),
);
}
Widget _mainContent(){
return Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
//Container on the left is Fixed under header if header visible and uses complete screen if header is not visible
Expanded(child: _buildLeftContainer()),
//a Container with unknown hieght
Expanded(child: _buildRightContainer())
],
);
}
Widget _buildHeader(){
//some Content
return Container(
height: 150,
color: Colors.red,
);
}
Widget _buildRightContainer(){
//could be any height from not shown to 5 times the screens
return Container(
height: 1000,
color: Colors.green,
);
}
Widget _buildLeftContainer(){
// will contain a list of selectables with in specific sized pages
// height is for display, it should use the available space between on the left half of the screen
return Container(
height: 400,
color: Colors.blue,
);
}
Have you tried using Sliver widgets for this?
I haven't done exactly this, but I am pretty sure a combination of SliverList and SliverFillRemaining would work well for this.
You could have a large SliverList to handle the header disappearing, and put all the rest inside a SliverFillRemaining as a child of the large SliverList.
A video about SliverList, SliverGrid and SliverFillRemaining:
https://www.youtube.com/watch?v=k2v3gxtMlDE
I want to display a loading widget while compressing the image selected.
I am using the "image.dart" package to select an image, using ImagePicker.GetImage().
Then I want to display a loading widget while the image is being compressed, and when it's finished display the compressed image.
My code fundamentally works, my loading widget is cool (thanks spinkit), I can select any image, compress it and display the new one, but there is a small freeze (2-3s) while the image is being compressed.
So I'm trying to put a loading widget to not make the user panic and tap 10 000 times to select the image wanted, but I'm not completely comfortable with asynchronous code yet.
Here's my code :
import 'package:image/image.dart' as Img;
#override
Widget build(BuildContext context) {
if (loading == true) {
return LoadingScreen();
} else {
return Scaffold(
backgroundColor: Colors.brown[300],
body: Column(
children: [
SizedBox(
height: 50,
),
RaisedButton(
child: Text('Select an image'),
onPressed: () async {
await getImage();
// You can see here that I'm trying to trigger the loading widget
setState(() {
loading = true;
});
compressImage();
// And I want to disable the loading widget here, after the compression
setState(() {
loading = false;
});
},
),
SizedBox(
height: 10,
),
pickedImage != null ? printSelectedImage() : Center(child: Text('Please select an image')),
],
),
);
}
}
getImage() async {
pickedFile = await picker.getImage(source: ImageSource.gallery);
}
compressImage() async {
Img.Image selectedImage = Img.decodeJpg(File(pickedFile.path).readAsBytesSync());
if (selectedImage.width > selectedImage.height) {
Img.Image compressedImage = Img.copyResize(selectedImage, width: 500);
File(pickedFile.path).writeAsBytesSync(Img.encodePng(compressedImage));
} else {
Img.Image compressedImage = Img.copyResize(selectedImage, height: 500);
File(pickedFile.path).writeAsBytesSync(Img.encodePng(compressedImage));
}
if (pickedFile.path != null) {
setState(() {
pickedImage = pickedFile.path;
});
}
}
But the result is the same, the screen is still stuck in the file selector while compressing, and then directly display the compressed image.
I started learning dart/Flutter 2 weeks ago, so am I missing some fundamental principles of the dart language ? Am I not seeing something obvious ?
Thanks for reading
Making something async doesn't move it into some magical background thread. Dart uses isolates which are basically an execution context in which dart code can run. Flutter has a single isolate which runs your app, if you do too much work in it, your app gets slow or skips frames.
You can create other isolates to do calculations and offload work and communicate between isolates by passing messages with primitive content back and forth. The drawback in Flutter is, that other isolates don't have access to Flutter plugins thus a lot of things don't work there.
There are ways to work around this but they are pretty involved.
The easiest way to start an isolate is the compute(callback, message) function.
Spawn an isolate, run callback on that isolate, passing it message, and
(eventually) return the value returned by callback.
I am not sure if the image/image.dart library uses a plugin or some other features that are not available (dart:ui for example), you can try offloading your image compression into the callback. If it fails with a MissingPluginException or something similar, then it won't work.
Remember, you can only pass primitive messages so you can not path the pickedFile, only the pass as argument.
For your problem however there may be an easier solution. The image picker accepts parameters for max width/height and quality. If you need the image to be encoded as PNG however then you need to create a complex solution yourself.
I am getting image loaded to the CircularProfileAvatar by both means of camera and gallery successfully. But Image rendered on view is not in circular as shown in the screenshot. how should I make it sure that the image rendered to the child of CircularProfileAvatar is circular Image. In the image, you can see the orange portion which should not be visible instead the entire area inside the brown circle should be covered with the image either selected from the gallery or picture from the camera.
I am using building this new app in flutter.
This Dependency is used CircularProfileAvatar
Image imagepic() {
if (_imageFile == null) {
return Image(image: AssetImage('assets/images/logo.png'));
} else {
return Image.file(_imageFile);
}
}
final profilePic = CircularProfileAvatar(
null,
child:
imagepic(), //sets image path, it should be a URL string. default value is empty string, if path is empty it will display only initials
radius: 50,);
Add BoxFit.cover which cover fill the circular area
CircularProfileAvatar(
null,
child: Image(
image: AssetImage('assets/images/logo.png'),
fit: BoxFit.cover,
),
),
https://github.com/fluttercandies/extended_image
https://github.com/fluttercandies/extended_image/tree/master/example
https://github.com/fluttercandies/extended_image/blob/master/example/lib/pages/zoom_image_demo.dart
fluttercandies extended_image. How do I zoom in on an image with double tap of 1 finger instead of needing 2? How do I get a sliding image to navigator pop back when it slides off the page?
Trying to implement a zoom/pan image with double tap by 1 finger instead of the need for 2 to expand zoom an image. Have two issues with this code and was wondering if anyone has any ideas. The class is very simple with just 2 strings: image & title passed into it.
1, I need the image to expand on double tap. I would like the user to have to power to expand the image with one finger and not two. Think I need to put this code near the very end.
The good thing is that once it is expanded the double tap works to reduce the image size. How do I get it to do the opposite when it is at normal size?
2, the sliding of the image off the page results in a black screen. Thankfully, this doesn’t freeze or crash the app but it leaves the user with a blank screen and the need to press the system back button. I would like the slide to result in a navigator pop back to the original screen.
Firstly, here’s a sample code of how I’m passing an image and a title into expandimage.dart.
FlatButton(
child: Image.asset(_kAsset5),
onPressed: () async {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => ExpandImage(
image: _kAsset5,
title: "\'go help\' 1",
)),
);
},
),
Here’s the code that I’m using for this ‘expandimage.dart’ and a lot of it is based on the pan/zoom example from flutter candies / extended image example.
import 'package:flutter/material.dart';
import 'package:extended_image/extended_image.dart';
class ExpandImage extends StatelessWidget {
final String image, title;
ExpandImage({this.image, this.title});
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
backgroundColor: Colors.red[900],
appBar: AppBar(
backgroundColor: Colors.red[900],
leading: IconButton(
icon: Icon(Icons.close),
onPressed: Navigator.of(context).pop,
),
title: Text(
title,
style: TextStyle(
color: Colors.yellow,
inherit: true,
fontWeight: FontWeight.w300,
fontStyle: FontStyle.italic,
letterSpacing: 2.0, //1.2
),
),
centerTitle: true,
),
body: SizedBox.expand(
// child: Hero(
// tag: heroTag,
child: ExtendedImageSlidePage(
slideAxis: SlideAxis.both,
slideType: SlideType.onlyImage,
child: ExtendedImage(
//disable to stop image sliding off page && entering dead end without back button.
//setting to false means it won't slide at all.
enableSlideOutPage: true,
mode: ExtendedImageMode.gesture,
initGestureConfigHandler: (state) => GestureConfig(
minScale: 1.0,
animationMinScale: 0.8,
maxScale: 3.0,
animationMaxScale: 3.5,
speed: 1.0,
inertialSpeed: 100.0,
initialScale: 1.0,
inPageView: false,
),
// onDoubleTap: ? zoom in on image
fit: BoxFit.scaleDown,
image: AssetImage(
image,
),
),
),
),
),
);
}
}
Here is a sample image passed in. the page turns red when sliding the image around and then it goes black as the image slides off the page.
Hope it will help, if have any doubt ask in the comments.
class _DetailState extends State<Detail> with TickerProviderStateMixin{
#override
Widget build(BuildContext context) {
AnimationController _animationController = AnimationController(duration: Duration(milliseconds: 200),vsync: this);
Function() animationListener = () {};
Animation? _animation;
return Scaffold(
body: Container(
height: MediaQuery.of(context).size.height,
child: ExtendedImage.network(
widget.wallpaper.path,
fit: BoxFit.contain,
mode: ExtendedImageMode.gesture,
initGestureConfigHandler: (state) {
return GestureConfig(
minScale: 0.9,
animationMinScale: 0.7,
maxScale: 3.0,
animationMaxScale: 3.5,
speed: 1.0,
inertialSpeed: 100.0,
initialScale: 1.0,
inPageView: false,
initialAlignment: InitialAlignment.center,
);
},
onDoubleTap: (ExtendedImageGestureState state) {
///you can use define pointerDownPosition as you can,
///default value is double tap pointer down postion.
var pointerDownPosition = state.pointerDownPosition;
double begin = state.gestureDetails!.totalScale!;
double end;
_animation?.removeListener(animationListener);
_animationController.stop();
_animationController.reset();
if (begin == 1) {
end = 1.5;
} else {
end = 1;
}
animationListener = () {
//print(_animation.value);
state.handleDoubleTap(
scale: _animation!.value,
doubleTapPosition: pointerDownPosition);
};
_animation = _animationController
.drive(Tween<double>(begin: begin, end: end));
_animation!.addListener(animationListener);
_animationController.forward();
},
),
),
}
}
If it helps, mark it as right.
I love the blurry frost effect using a BackdropFilter (see this).
However, because the BackdropFilter has Opacity and because the widget I'm blurring also has Opacity, the performance is horrendous. This is also because I redraw my widgets a few times a second, but that shouldn't be an issue given Flutter can go 60fps?
I turned on checkerboardOffscreenLayers and see checkerboards for miles. :O
The checkerboards happen due to blurScreen, not due to widgetToBlur but widgetToBlur does slow down performance probably because (in my real code, not this example) it's calling setState() multiple times a second.
Is there a more performant way to make blurs/opacities? The link above says to apply opacity to widgets individually. I can't do that with the blur though (blurScreen below), because the BackdropFilter has to be stacked on top of my widget-that-does-the-redrawing.
I removed the blur effect and my performance is way better (no checkerboards, app doesn't crash).
build() code in question:
final widgetToBlur = Container(
child: Opacity(
opacity: 0.3,
// In my actual code, this is a Stateful widget.
child: Text('Spooky blurry semi-transparent text!'),
),
);
final blurScreen = BackdropFilter(
filter: ImageFilter.blur(sigmaX: 3.0, sigmaY: 3.0),
child: Container(
decoration: BoxDecoration(
color: _backgroundColor.withOpacity(0.3),
),
),
);
return Container(
child: Stack(
children: <Widget>[
widgetToBlur,
blurScreen,
Text('This is in front of the blurred background'),
],
),
);
I ended up drawing the widgetToBlur once, blurred, with opacity, using Paint and Canvas.
This means it only runs the blur and opacity operations once, in initState(), and never has to be re-rendered-with-blur throughout the lifecycle of the widget.
If anyone else ends up stuck with this, you can leave a comment and I can help out more.
I have a similar problem and it also boils down to using canvas and paint.
The only problem now is, if I apply a MaskFilter to the image, not much happens despite the enormously high sigma... Only the edge is a little blurred.
Now the question is why is that so? How did you solved this issue?
canvas.drawImageRect(
image,
Offset(0, 0) & srcSize,
Offset(-delta, 0) & dstSize,
Paint()..maskFilter = MaskFilter.blur(
BlurStyle.normal, 100.0
)
);
For those of you who are interested, I have loaded the image in the init function as follows:
rootBundle.load("assets/gift_1.png").then((bd) {
Uint8List lst = new Uint8List.view(bd.buffer);
Ui.instantiateImageCodec(lst).then((codec) {
codec.getNextFrame().then((frameInfo) {
image = frameInfo.image;
});
});
});
P.s. Unfortunately, I can't write any comments yet; therefore here as a contribution, including solution proposal
you can use this. but I do not know speed.
var pr = ui.PictureRecorder();
var canvas = ui.Canvas(pr);
canvas.drawImage(
img,
ui.Offset(0, 0),
ui.Paint()..maskFilter = ui.MaskFilter.blur(
BlurStyle.normal, 100.0
)
);
var pic = pr.endRecording();
return pic.toImage(img.width, img.height);