setHorizontalMargins method
Sets the horizontal scrolling margin to left and right.
Both values must be between 0 and viewWidth - 1.
Implementation
void setHorizontalMargins(int left, int right) {
final effectiveLeft = left.clamp(0, viewWidth - 1);
final effectiveRight = right.clamp(0, viewWidth - 1);
if (effectiveLeft >= effectiveRight) return;
_marginLeft = effectiveLeft;
_marginRight = effectiveRight;
}