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78 行
2.5 KiB

using System.Collections.Generic;
using Unity.UIWidgets.foundation;
using Unity.UIWidgets.ui;
namespace Unity.UIWidgets.widgets {
class _Placeholderpainter : AbstractCustomPainter {
public _Placeholderpainter(
Color color = null,
float strokeWidth = 0f
) {
this.color = color;
this.strokeWidth = strokeWidth;
}
public readonly Color color;
public readonly float strokeWidth;
public override void paint(Canvas canvas, Size size) {
Paint paint = new Paint();
paint.color = color;
paint.style = PaintingStyle.stroke;
paint.strokeWidth = strokeWidth;
Rect rect = Offset.zero & size;
Path path = new Path();
path.addRect(rect);
path.addPolygon(new List<Offset> {rect.topRight, rect.bottomLeft}, false);
path.addPolygon(new List<Offset> {rect.topLeft, rect.bottomRight}, false);
canvas.drawPath(path, paint);
return;
}
public override bool shouldRepaint(CustomPainter oldPainter) {
return ((_Placeholderpainter) oldPainter).color != color ||
((_Placeholderpainter) oldPainter).strokeWidth != strokeWidth;
}
public override bool? hitTest(Offset position) {
return false;
}
}
public class Placeholder : StatelessWidget {
public Placeholder(
Key key = null,
Color color = null,
float strokeWidth = 2.0f,
float fallbackWidth = 400.0f,
float fallbackHeight = 400.0f
) : base(key) {
this.color = color ?? new Color(0xFF455A64);
this.strokeWidth = strokeWidth;
this.fallbackWidth = fallbackWidth;
this.fallbackHeight = fallbackHeight;
}
public readonly Color color;
public readonly float strokeWidth;
public readonly float fallbackWidth;
public readonly float fallbackHeight;
public override Widget build(BuildContext context) {
return new LimitedBox(
maxWidth: fallbackWidth,
maxHeight: fallbackHeight,
child: new CustomPaint(
size: Size.infinite,
foregroundPainter: new _Placeholderpainter(
color: color,
strokeWidth: strokeWidth
)
)
);
}
}
}