How do I get flutter to resize my Image widgets using nearest neighbour interpolation if the size of the widget is not the same as the asset size?
class PlayContainer extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Container(
color: Color.fromARGB(255, 0, 110, 255),
child: SafeArea(
child: Image(
fit: BoxFit.contain,
image: AssetImage("assets/knight.png")
)
)
);
}
}
This resizes the image correctly, but it is blurry due to the bilinear interpolation used to resize it.
Based on the source seems to be rather hard coded?
This is now possible in the master branch thanks to this Pull request:
I've added the possibility to set the filterQuality on Images. This was hardcoded.
The previously hardcoded value is set as default parameter.
Some images look better when scaled with no filter quality (like pixelart). That's why I added the parameter.
Related
to display image according to it's original size i do the following
Image.file(File(fileCreated!.path)),
to display image to fit height and width (full screen) i do the following
Image.file(File(fileCreated!.path),fit: BoxFit.cover,height: double.infinity,width: double.infinity,),
ok it is now in full screen but i noticed there is some missing parts of the image contents is no longer visible on screen like 20 pixel from width and height , i know flutter do it for keeping the image quality the same. but How i ignore that behavior
How could i display image in full screen so the whole image parts is visible on screen ?
i tried with following
height:MediaQuery.of(context).size.height,
width: MediaQuery.of(context).size.width,
whatever i change the height. the width will be auto changing too, even if i did not change the width !!!!
but same result
edit :
full parent
#override
Widget build(BuildContext context) {
return Scaffold(
body: Image.file(File(widget.imageFile,),fit: BoxFit.cover,height: MediaQuery.of(context).size.height,),
);
}
}
You can use MediaQuery, but I will prefer using LayoutBuilder on top widget. Also check the parent widget if it is having padding/margin.
Image.file(
File(fileCreated!.path),
fit: BoxFit.fill,
height:MediaQuery.of(context).size.height,
width: MediaQuery.of(context).size.width,
),
Lets say you have a ListView of variable height:
List items are a Container with a mix of text and images. As such, the list items are of variable height. Sometimes no images. The text renders immediately as expected, but the images may take time to retrieve and render on screen
The images are retrieved from the network using CachedNetworkImage
Images are of variable height
When the Screen is opened the ListView automatically scrolls to item#11 (using ensureVisible technique)
So there are items both above and below your current position
At this point, when one of the network images above your position load up, the entire ListView will be pushed and you will no longer be looking at Item #11, rather somewhere randomly higher up
I considered initiating a new scroll in a callback after each image loads, however, due to network speeds, usually the listview scroll will finish before all the images load. If there are a lot of images, the images could take time to load, so it would be unreasonable to initiate a new scroll each time a new image is loaded, the screen just keeps scrolling forward every few seconds. It becomes dizzying and annoying.
Alternatively, the scrollview could jumpTo a new position as soon as the image loads, but I'm imagining there would be a slight delay between the two events and the user perceive a small "glitch" as the image loads and the listview immediately jumps to offset the image load. Even using a Future.microtask there is a very small perceptible 'glitch' as the image loads and the jumpto fires
It would be most preferable to have the listview expand the content upward somehow, so that the users current scroll position is maintained, as far as they are concerned.
Is it possible to have the ListView keep its position as the images load?
Assuming you have a predefined size for your images, you can wrap the image in a SizedBox(). This way your list will always have the same height and your items won't get pushed around.
EDIT:
Since your images are of variable size, I would probably animate to the desired location on every image load.
CachedNetworkImage has a callback
imageBuilder: (context, imageProvider) {
/// Animate to desired index
return Image(image: imageProvider);
}
Animated container, might help you. It can adjust the height automatically, depending on the height u provide in builder.
Also you can use this answer to determnin image height and width in rnutime.
Images are of variable height
To overcome this, Either we take the image size or aspect ratio of the image while storing the image along with other data.
While retrieving data, along with other text data we will receive the aspect ratio or height for the image.
I would use the same height or ratio and show placeholder image till images are loaded.
CachedNetworkImage(
imageUrl: countryList[index].flagUrl,
height: 60, // Set your height according to aspect ratio or fixed height
width: 60,
fit: BoxFit.cover,
placeholder: (_, __) => Container(
alignment: Alignment.center,
height: 60, // Set your height
width: 60,
color: Colors.red.withAlpha(80),
child: Text(
countryList[index].name[0],
style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
),
),
)
Image must be of specific aspect ratio I believe. You can define height according to aspect ratio.
Try as follows:
ListView.builder(
shrinkWrap: true,
itemCount: images.length,
itemBuilder: (ctx, i) {
return Column(children: [
ButtonItems(i),
const SizedBox(height: 10),
]);
}));
Button Items class
class ButtonItems extends StatefulWidget {
final int i;
ButtonItems(this.i);
#override
_ButtonItems createState() => _ButtonItems();
}
class _ButtonItems extends State<ButtonItems> {
var images = [
"https://opengraph.githubassets.com/2ddb0ff05ef9ccfce35abb56e30d9c5068e01d1d10995484cfd07becee9accf7/dartpad/dartpad.github.io",
null,
"https://opengraph.githubassets.com/2ddb0ff05ef9ccfce35abb56e30d9c5068e01d1d10995484cfd07becee9accf7/dartpad/dartpad.github.io"
];
#override
Widget build(BuildContext context) {
print(images[widget.i]);
return Container(
height: 50,
color: Colors.grey,
child: Row(children: [
AspectRatio(
aspectRatio: 3 / 2,
child: images[widget.i] == null
? Container()
: Image.network(images[widget.i]!, fit: BoxFit.cover),
),
Text("Title " + widget.i.toString()),
]));
}
}
I have a set of images that represent different parts of an animal. I have images for legs, heads, eyes, etc.
So, I need to compose the current animal based on its set of images. The main problem is that I want to resize/translate the images based on the container size and the size of the images themselves in order to always have the full composed animal in the middle of the screen maximizing screen coverage.
I have started with a very naive approximation that could work using a stack, and Positioned widgets and a LayoutBuilder, but I need the size of the images to calculate their position and resizing factor and haven't found anyway to do it:
class AnimalBuilderPage extends StatelessWidget {
const AnimalBuilderPage ({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return Container(child: new LayoutBuilder(builder: (BuildContext context, BoxConstraints constraints) {
double horizontalWidth = constraints.maxWidth/2.0;
double verticalCenter= constraints.maxHeight/2.0;
double bodyOffsetY, bodyOffsetX = "Here I need body image size to know how much I should resyze it and translated";
double headOffsetY, headOffsetX = "Here I need body image size to know how much I should reisze it and translated"
return Stack(
children: [
Positioned(top: bodyOffsetY, left: bodyOffsetX, child: Image.asset('assets/images/body/b1.png',scale: 0.8)),
Positioned(top: headOffsetY, left: headOffsetY, child: Image.asset('assets/images/heads/h1.png', scale:0.7)),
],
);
},));}}
Is there any way to set parent container's height based on height of what is drawn in the child canvas?
I am using a custom painter like this:
double width = MediaQuery.of(context).size.width;
return Container(
color: Colors.yellow,
height: 240,
width: width,
child: CustomPaint(
painter: ShapePainter(),
),
);
Then ShapePainter() draws different shapes (1 shape for each canvas in the list).
But as you can see, some shapes like 2nd rectangle, take twice the space they actually need.
I can calculate height of a shape inside ShapePainter() easily,
but I have no idea how to apply it to its parent's height. (Except calling an insta-setState() from child, but there should be a better way, because this may flicker for one frame)
Thanks for any help!
Flutter has several phases that it goes through when creating a frame, including building, layout, and painting. The size of widgets is determined during the layout phase. So you can't set the height based it what was painted. (Except, as you've said, by using something like setState to generate a new frame.) You'll have to determine the the size you want before any painting has happened. For example, you can give your CustomPainter a getter to provide the shape:
class ShapePainter extends CustomPainter {
ShapePainter({#required this.shape});
final Shape shape;
void paint(Canvas canvas, Size size) {
// the painting
}
Size get size {
// determine size based on shape
}
}
...
Widget build(BuildContext context) {
final shapePainter = ShapePainter();
return Container(
color: Colors.yellow,
height: shapePainter.size.height,
align: Alignment.center,
child: CustomPaint(
painter: shapePainter,
),
);
}
I'm building a card game and using flame to pull the cards from a sprite sheet. The problem is that I set the width and height of the Container that holds the SpriteWidget, but the SpriteWidget expands to either the width or the height of the container, but not both. I want it to expand/stretch to be the same size as the parent container. Unfortunately, the SpriteWidget really has no parameters that could be used to change its size.
I've spent several hours scouring the internet for a solution and tried a number of widgets including FittedBox, Flex, Positioned.fill, etc., but I'm unable to achieve the desired effect. How can I make the SpriteWidget stretch to fill its parent when it has no parameters to do so?
class _PlayerHandPortraitLayout
extends WidgetView<PlayerHand, _PlayerHandController> {
#override
final state;
const _PlayerHandPortraitLayout(this.state) : super(state);
#override
Widget build(BuildContext build) {
return Stack(
children: state.displayHand().asMap().entries.map((cardItem) {
var index = cardItem.key;
var card = cardItem.value;
return Positioned(
left: index * CARD_OVERLAP_OFFSET,
child: Draggable<Container>(
childWhenDragging: Container(),
child: Container(
color: Colors.purple,
width: state.cardWidth,
height: state.cardHeight,
child: SpriteWidget(
sprite: state.spriteImages[card.suite.index][card.value.index],
),
),
feedback: Container(
color: Colors.yellow,
width: state.cardWidth,
height: state.cardHeight,
child: SpriteWidget(
sprite: state.spriteImages[card.suite.index][card.value.index],
),
),
),
);
}).toList(),
);
}
}
actually this will be not possible, SpriteWidget is designed to expand as long as it fits on the smallest dimension available on its parent, you can check on it source code here.
This is done so the Sprite will not get distorted when its parent has a different aspect ratio than the ratio of the Sprite.
If you have an use case where you would want the Sprite to get intentionally distorted, please open an issue on the Flame repository explaining the case, and we can try to take a look on it.