public override void paint(PaintingContext context, Offset offset)
{
Canvas canvas = context.canvas;
float currentValue = _state.position.value;
float currentReactionValue = _state._reaction.value;
float visualPosition = 0.0f;
switch (textDirection)
{
case TextDirection.rtl:
visualPosition = 1.0f - currentValue;
break;
case TextDirection.ltr:
visualPosition = currentValue;
break;
}
Paint paint = new Paint()
{
color = Color.lerp(trackColor, activeColor, currentValue)
};
Rect trackRect = Rect.fromLTWH(
offset.dx + (size.width - CupertinoSwitchUtils._kTrackWidth) / 2.0f,
offset.dy + (size.height - CupertinoSwitchUtils._kTrackHeight) / 2.0f,
CupertinoSwitchUtils._kTrackWidth,
CupertinoSwitchUtils._kTrackHeight
);
RRect trackRRect = RRect.fromRectAndRadius(trackRect, Radius.circular(CupertinoSwitchUtils._kTrackRadius));
canvas.drawRRect(trackRRect, paint);
float currentThumbExtension = CupertinoThumbPainter.extension * currentReactionValue;
float thumbLeft = MathUtils.lerpNullableFloat(
trackRect.left + CupertinoSwitchUtils._kTrackInnerStart - CupertinoThumbPainter.radius,
trackRect.left + CupertinoSwitchUtils._kTrackInnerEnd - CupertinoThumbPainter.radius -
currentThumbExtension,
visualPosition
);
float thumbRight = MathUtils.lerpNullableFloat(
trackRect.left + CupertinoSwitchUtils._kTrackInnerStart + CupertinoThumbPainter.radius +
currentThumbExtension,
trackRect.left + CupertinoSwitchUtils._kTrackInnerEnd + CupertinoThumbPainter.radius,
visualPosition
);
float thumbCenterY = offset.dy + size.height / 2.0f;
Rect thumbBounds = Rect.fromLTRB(
thumbLeft,
thumbCenterY - CupertinoThumbPainter.radius,
thumbRight,
thumbCenterY + CupertinoThumbPainter.radius
);
context.pushClipRRect(needsCompositing, Offset.zero, thumbBounds, trackRRect,
(PaintingContext innerContext, Offset offset1) => {
CupertinoThumbPainter.switchThumb().paint(innerContext.canvas, thumbBounds);
});
}
