59 lines
1.8 KiB
Dart
59 lines
1.8 KiB
Dart
import 'package:flutter/material.dart';
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import './render.dart';
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/// Abstract definition for a [LazyCanvas] background.
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abstract class CanvasBackground {
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/// the fill color of background
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final Color bgColor;
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const CanvasBackground({this.bgColor = Colors.white});
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/// draw the backround on this context. Implement this to have
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/// different kinds of backgrounds
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void paint(Canvas canvas, Offset offset, double scale, Size canvasSize);
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}
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class NoBackground extends CanvasBackground {
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const NoBackground();
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@override
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void paint(Canvas canvas, Offset offset, double scale, Size canvasSize) {}
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}
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class SingleColorBackround extends CanvasBackground {
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const SingleColorBackround(Color backgroundColor) : super(bgColor: backgroundColor);
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@override
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void paint(Canvas canvas, Offset offset, double scale, Size canvasSize) {
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final paint = Paint()
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..color = bgColor
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..style = PaintingStyle.fill;
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canvas.drawRect(Rect.fromLTWH(0, 0, canvasSize.width, canvasSize.height), paint);
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}
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}
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class DotGridBackround extends CanvasBackground {
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final double size;
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final double spacing;
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final Color color;
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const DotGridBackround({this.size = 2.0, this.spacing = 50.0, this.color = Colors.black12}) : super();
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@override
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void paint(Canvas canvas, Offset offset, double scale, Size canvasSize) {
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final paint = Paint()
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..color = color
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..strokeWidth = 1.0 * scale;
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double scaledSpacing = spacing * scale;
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double scaledSize = size * scale;
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double startX = (offset.dx % scaledSpacing) - scaledSpacing;
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double startY = (offset.dy % scaledSpacing) - scaledSpacing;
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for (double x = startX; x < canvasSize.width + scaledSpacing; x += scaledSpacing) {
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for (double y = startY; y < canvasSize.height + scaledSpacing; y += scaledSpacing) {
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canvas.drawCircle(Offset(x, y), scaledSize, paint);
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}
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}
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}
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}
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