isOffScreen method
Whether or not the shape as any parts that are off screen.
shapeDimension is the width or height of the shape depending on the
ScrollDirection. Width in the case of horizontal (left/right) scrolling
and height in the case of vertical (up/down) scrolling.
screenDimension is the width or height of the screen depending on the
ScrollDirection. Width in the case of horizontal (left/right) scrolling
and height in the case of vertical (up/down) scrolling.
Implementation
bool isOffScreen(double x, double shapeDimension, double screenDimension) {
return x < 0 || x > screenDimension - shapeDimension;
}