The fundamental difference between vector and raster graphics lies in how they represent visual information, and understanding this distinction is essential for anyone working with digital images.

Vector graphics describe images using mathematical geometry. A circle is defined by its center coordinates and radius, a line by its start and end points, and complex shapes by sequences of path commands including straight lines, quadratic and cubic Bezier curves, and elliptical arcs. Because these descriptions are mathematical rather than pixel-based, they can be rendered at any resolution without quality loss. Zooming into a vector circle simply recalculates which pixels to fill at the new scale, producing a perfectly smooth curve regardless of magnification. SVG (Scalable Vector Graphics) is the web standard for vector graphics, using an XML-based format where shapes are described as DOM elements with attributes specifying geometry, fill colors, stroke properties, and transformations.

Raster graphics represent images as rectangular grids of pixels, where each pixel stores a specific color value. The resolution is fixed at creation time, and enlarging a raster image beyond its native resolution produces visible pixelation because no additional detail exists to fill the new pixels. However, raster graphics excel at representing photographs and complex natural imagery where every pixel may have a unique color, something that would require impossibly complex vector descriptions.

The rasterization process converts vector descriptions into pixel grids. For each shape in the SVG, the rasterizer determines which output pixels fall inside the shape and colors them accordingly. The core challenge is handling shape boundaries, where pixels may be partially inside and partially outside a shape. Without anti-aliasing, boundary pixels are either fully filled or not, creating jagged staircase edges called aliasing. Anti-aliasing computes the fraction of each boundary pixel that falls inside the shape and blends the shape color with the background color proportionally. A pixel that is 60% inside a black shape on a white background would be colored 40% gray, creating the perception of a smooth edge. Multi-sample anti-aliasing (MSAA) checks multiple sub-pixel sample points within each pixel, while analytical anti-aliasing computes exact coverage areas using geometric calculations for higher precision.

The scaling factor in SVG-to-raster conversion directly determines output resolution and quality. A 1x scale renders at the SVG's specified viewport dimensions, while 2x doubles both width and height, producing four times as many pixels. This is essential for high-DPI displays like Apple's Retina screens, where a standard-resolution image would appear blurry because each CSS pixel corresponds to 2 or 3 physical display pixels.