How does a vector curve keep its shape when enlarged?

A small vector drawing can become a large sign without simply stretching its old screen pixels. A vector image stores shapes using geometric descriptions, such as endpoints and curve instructions. To display it at a new size, software scales that geometry and draws it again on the output device’s pixel grid.

The illustration uses a quadratic Bézier curve. Its start point A is (0,0), its end point B is (4,0), and its control point H is (2,3). H pulls the curve toward itself but is not generally on the curve. The dashed lines show the control arrangement, not extra edges of the finished drawing.

A parameter from zero to one locates positions along this curve through weighted combinations of A, H and B. Halfway through the parameter range, their weights are one-quarter, one-half and one-quarter, giving the point (2,1.5). Doubling every coordinate makes the endpoints eight units apart and moves that curve point to (4,3). All parts of the geometric shape scale together.

The enlarged result still has to become pixels on a screen. This conversion is rasterization, and finite output resolution still limits visible detail. Enlarging an already rasterized copy does not recover the original vector description. Vector geometry can preserve a smooth path at new sizes; it does not make every photograph resolution-independent or guarantee an unlimited physical display.