paintOverflowIndicator method
To be called when the overflow indicators should be painted.
Typically only called if there is an overflow, and only from within a debug build.
See example code in DebugOverflowIndicatorMixin documentation.
Implementation
void paintOverflowIndicator(
PaintingContext context,
Offset offset,
Rect containerRect,
Rect childRect, {
String overflowHints,
}) {
final RelativeRect overflow = RelativeRect.fromRect(containerRect, childRect);
if (overflow.left <= 0.0 &&
overflow.right <= 0.0 &&
overflow.top <= 0.0 &&
overflow.bottom <= 0.0) {
return;
}
final List<_OverflowRegionData> overflowRegions = _calculateOverflowRegions(overflow, containerRect);
for (_OverflowRegionData region in overflowRegions) {
context.canvas.drawRect(region.rect.shift(offset), _indicatorPaint);
if (_indicatorLabel[region.side.index].text?.text != region.label) {
_indicatorLabel[region.side.index].text = TextSpan(
text: region.label,
style: _indicatorTextStyle,
);
_indicatorLabel[region.side.index].layout();
}
final Offset labelOffset = region.labelOffset + offset;
final Offset centerOffset = Offset(-_indicatorLabel[region.side.index].width / 2.0, 0.0);
final Rect textBackgroundRect = centerOffset & _indicatorLabel[region.side.index].size;
context.canvas.save();
context.canvas.translate(labelOffset.dx, labelOffset.dy);
context.canvas.rotate(region.rotation);
context.canvas.drawRect(textBackgroundRect, _labelBackgroundPaint);
_indicatorLabel[region.side.index].paint(context.canvas, centerOffset);
context.canvas.restore();
}
if (_overflowReportNeeded) {
_overflowReportNeeded = false;
_reportOverflow(overflow, overflowHints);
}
}