calculateBoundedFloatingCursorOffset method Null safety
- Offset rawCursorOffset
Returns the position within the text field closest to the raw cursor offset.
Implementation
Offset calculateBoundedFloatingCursorOffset(Offset rawCursorOffset) {
Offset deltaPosition = Offset.zero;
final double topBound = -floatingCursorAddedMargin.top;
final double bottomBound = _textPainter.height - preferredLineHeight + floatingCursorAddedMargin.bottom;
final double leftBound = -floatingCursorAddedMargin.left;
final double rightBound = _textPainter.width + floatingCursorAddedMargin.right;
if (_previousOffset != null) {
deltaPosition = rawCursorOffset - _previousOffset!;
}
// If the raw cursor offset has gone off an edge, we want to reset the relative
// origin of the dragging when the user drags back into the field.
if (_resetOriginOnLeft && deltaPosition.dx > 0) {
_relativeOrigin = Offset(rawCursorOffset.dx - leftBound, _relativeOrigin.dy);
_resetOriginOnLeft = false;
} else if (_resetOriginOnRight && deltaPosition.dx < 0) {
_relativeOrigin = Offset(rawCursorOffset.dx - rightBound, _relativeOrigin.dy);
_resetOriginOnRight = false;
}
if (_resetOriginOnTop && deltaPosition.dy > 0) {
_relativeOrigin = Offset(_relativeOrigin.dx, rawCursorOffset.dy - topBound);
_resetOriginOnTop = false;
} else if (_resetOriginOnBottom && deltaPosition.dy < 0) {
_relativeOrigin = Offset(_relativeOrigin.dx, rawCursorOffset.dy - bottomBound);
_resetOriginOnBottom = false;
}
final double currentX = rawCursorOffset.dx - _relativeOrigin.dx;
final double currentY = rawCursorOffset.dy - _relativeOrigin.dy;
final double adjustedX = math.min(math.max(currentX, leftBound), rightBound);
final double adjustedY = math.min(math.max(currentY, topBound), bottomBound);
final Offset adjustedOffset = Offset(adjustedX, adjustedY);
if (currentX < leftBound && deltaPosition.dx < 0) {
_resetOriginOnLeft = true;
} else if (currentX > rightBound && deltaPosition.dx > 0) {
_resetOriginOnRight = true;
}
if (currentY < topBound && deltaPosition.dy < 0) {
_resetOriginOnTop = true;
} else if (currentY > bottomBound && deltaPosition.dy > 0) {
_resetOriginOnBottom = true;
}
_previousOffset = rawCursorOffset;
return adjustedOffset;
}