47 lines
1.3 KiB
Dart
47 lines
1.3 KiB
Dart
import 'dart:math' as math;
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import 'dart:typed_data';
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import 'dart:ui' as ui;
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import 'package:flutter/services.dart';
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class Bitmap<T> {
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// This idiosyncratic usage of "bitmap" comes from some other technology.
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// What I'm saying is "don't blame me"
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final math.Rectangle<int> rect;
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final List<T> data;
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Bitmap(this.rect, this.data) {
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assert(this.data.length == this.rect.width * this.rect.height);
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}
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static Future<Bitmap<T>> load<T>(String name, T Function(int) cb) async {
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final assetImageByteData = await rootBundle.load(name);
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final codec =
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await ui.instantiateImageCodec(assetImageByteData.buffer.asUint8List());
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final image = (await codec.getNextFrame()).image;
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final bytedata =
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(await image.toByteData(format: ui.ImageByteFormat.rawStraightRgba))!;
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final sx = image.width;
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final sy = image.height;
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final List<T> data = [];
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for (var i = 0; i < sx * sy; i++) {
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var pixel = bytedata.getUint32(i * 4, Endian.big);
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data.add(cb(pixel));
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}
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return Bitmap(math.Rectangle(0, 0, sx, sy), data);
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}
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T? get(int x, int y) {
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var realX = x - rect.top;
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var realY = y - rect.left;
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if (realX < 0 || realY < 0 || realX > rect.width || realY > rect.height) {
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return null;
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}
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return data[realY * rect.width + realX];
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}
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}
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