The <feComposite> SVG filter primitive performs the combination of two input images pixel-wise in image space using one of the Porter-Duff compositing operations: over, in, atop, out, xor, lighter, or arithmetic.

The isNaN() function determines whether a value is NaN, first converting the value to a number if necessary. Because coercion inside the isNaN() function can be surprising, you may prefer to use Number.isNaN().

The <feTile> SVG filter primitive allows to fill a target rectangle with a repeated, tiled pattern of an input image. The effect is similar to the one of a <pattern>.

The <font-face-uri> SVG element points to a remote definition of the current font.

The <polygon> SVG element defines a closed shape consisting of a set of connected straight line segments. The last point is connected to the first point.

The <feFlood> SVG filter primitive fills the filter subregion with the color and opacity defined by flood-color and flood-opacity.

The <feSpecularLighting> SVG filter primitive lights a source graphic using the alpha channel as a bump map. The resulting image is an RGBA image based on the light color. The lighting calculation follows the standard specular component of the Phong lighting model. The resulting image depends on the light color, light position and surface geometry of the input bump map. The result of the lighting calculation is added. The filter primitive assumes that the viewer is at infinity in the z direction.

The <pattern> SVG element defines a graphics object which can be redrawn at repeated x- and y-coordinate intervals ("tiled") to cover an area.

The const declaration declares block-scoped local variables. The value of a constant can't be changed through reassignment using the assignment operator, but if a constant is an object, its properties can be added, updated, or removed.

The descent attribute defines the maximum unaccented depth of the font.