I found a very interesting picture:

The size of this image is about 8MB although it’s blurring. Then I use below python code to try to resize it using different interpolation strategy:

import cv2

img = cv2.imread("/Users/robin/Downloads/ou1.png")

for inter, name in [(cv2.INTER_AREA, "area"), (cv2.INTER_CUBIC, "cubic"), (cv2.INTER_LINEAR, "linear")]:
    after = cv2.resize(img, (310, 310), inter)
    cv2.imwrite(f"{name}.bmp", after)
“area”“cubic”“linear”

Only cv2.INTER_AREA works well.

Then let me try dart language:

import 'dart:io';
import 'package:image/image.dart' as img;

void main() async {
  // Load the image
  final file = File('/Users/robin/Downloads/ou1.png');
  final bytes = await file.readAsBytes();
  final image = img.decodeImage(bytes);

  if (image == null) {
    print("Failed to load image");
    return;
  }

  // Resize and save images with different methods
  for (var method in ['area', 'cubic', 'linear', 'average']) {
    img.Image resized;
    if (method == 'area' || method == 'linear') {
      // Use `copyResize` for these, `area` will behave similarly to default
      resized = img.copyResize(image, width: 310, height: 310);
    } else if (method == 'cubic') {
      // Simulate cubic interpolation (approximation)
      resized = img.copyResize(image, width: 310, height: 310, interpolation: img.Interpolation.cubic);
    } else if (method == 'average') {
      resized = img.copyResize(image, width: 310, height: 310, interpolation: img.Interpolation.average);
    } else {
      print("Unknown interpolation method: $method");
      continue;
    }

    // Save the resized image
    final output = File('$method.bmp');
    await output.writeAsBytes(img.encodePng(resized));
    print("Saved resized image using $method interpolation as $method.bmp");
  }
}

The result looks also terrible except just one strategy “average”:

“area”“cubic”“linear”“average”

So, better use “Interpolation.average” in dart language.

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