paint method

  1. @override
void paint(
  1. Canvas canvas,
  2. Rect rect, {
  3. double? gapStart,
  4. double gapExtent = 0.0,
  5. double gapPercentage = 0.0,
  6. TextDirection? textDirection,
})
override

Draw the custom shape around rect.

The borderSide defines the line's color and weight.

The top side of the border may be interrupted by a single gap if gapExtent is non-null. In that case the gap begins at gapStart - gapPadding (assuming that the textDirection is TextDirection.ltr). The gap's width is (gapPadding + gapExtent + gapPadding) * gapPercentage.

Implementation

@override
void paint(
  Canvas canvas,
  Rect rect, {
  double? gapStart,
  double gapExtent = 0.0,
  double gapPercentage = 0.0,
  TextDirection? textDirection,
}) {
  assert(gapPercentage >= 0.0 && gapPercentage <= 1.0);

  final Paint paint = borderSide.toPaint();
  final Rect deflatedRect = rect.deflate(borderSide.width / 2.0);

  if (gapStart == null || gapExtent <= 0.0 || gapPercentage == 0.0) {
    // Draw the shape without a gap.
    if (shape is OutlinedBorder) {
      final outlinedShape = shape as OutlinedBorder;
      // Create a copy with our border side.
      final OutlinedBorder shapedBorder = outlinedShape.copyWith(side: borderSide);
      shapedBorder.paint(canvas, deflatedRect, textDirection: textDirection);
    } else {
      canvas.drawPath(shape.getOuterPath(deflatedRect, textDirection: textDirection), paint);
    }
  } else {
    final double extent = lerpDouble(0.0, gapExtent + gapPadding * 2.0, gapPercentage)!;
    final double start = switch (textDirection!) {
      TextDirection.rtl => gapStart + gapPadding - extent,
      TextDirection.ltr => gapStart - gapPadding,
    };
    final Path path = _gapBorderPath(
      deflatedRect,
      math.max(0.0, start),
      extent,
      textDirection: textDirection,
    );
    canvas.drawPath(path, paint);
  }
}