image_scaler

Description:

image scaler

image_scaler #
Light weight flutter library to rescale Images.
Features #
Provides following Algorithms:



Algorithm
Speed
Quality




Nearest Neighbour Interpolation (nni)
Extremely fast
Bad


Improved Nearest Neighbour Interpolation (inni)
Very fast
Average


Megak (megak)
Average
Very good


Lanczos (lanczos)
Slow
Very good



Calculations are carried out in a separate isolate, this will make sure the Main-Thread is not blocked.
ScaleAlgorithms are documented more detailed in the Dartdoc comments.
Getting started #
Add
flutter pub add image_scaler
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Import
import 'package:image_scaler/image_scaler.dart';
import 'package:image_scaler/types.dart';
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Usage #
Flutter Futurebuilder Example
final Future<ui.Image> = scale(
image: widget.round,
newSize: const IntSize(200, 200),
algorithm: ScaleAlgorithm.megak,
areaRadius: 2
);

class MyImage extends StatelessWidget {
final Future<ui.Image> image;

const MyImage(this.image);

@override
Widget build(BuildContext context) {
return FutureBuilder<ui.Image>(
future: image,
builder: (BuildContext context, AsyncSnapshot<ui.Image> snapshot) {
if (snapshot.connectionState == ConnectionState.waiting) {
return const CircularProgressIndicator();
} else if (snapshot.hasError) {
return Text("${snapshot.error}");
} else {
return RawImage(
image: snapshot.data,
fit: BoxFit.cover,
);
}
},
);
}
}
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Flutter Flame prerendered Sprite Example
// PlayerComponent.dart

Future<Image> prerenderSpriteComponent(Sprite sprite, Size size) async {
final spriteComp = SpriteComponent(sprite: sprite);

// Original Image
final oiRecorder = PictureRecorder();
final oiCanvas = Canvas(oiRecorder);
spriteComp.render(oiCanvas);

final oiImage = await oiRecorder.endRecording().toImage(
sprite.srcSize.x.toInt(),
sprite.srcSize.y.toInt(),
);

return await scale(oiImage, IntSize(size.width.toInt(), size.height.toInt()), ScaleAlgorithm.lanczos);
}

ui.Image? playerSpriteRendered;

@override
void onLoad() async {
playerSpriteRendered = await prerenderSpriteComponent(
playerSpriteSheet.getSprite(0, player.color),
Size.fromRadius(player.rad),
);
}

@override
void render(Canvas canvas) {
super.render(canvas);

if (playerSpriteRendered!=null) {
canvas.drawImage(
playerSpriteRendered!,
Offset(-player.rad, -player.rad),
Paint()
);
}
}
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Example #
You will find an example application in the Github Repository.