The requiredFeatures attribute takes a list of feature strings, with the individual strings separated by white space. It determines whether or not all of the named features are supported by the browser; if all of them are supported, the attribute evaluates to true end the element is rendered; otherwise, the attribute evaluates to false and the current element and its children are skipped and thus will not be rendered. This provides a way to design SVG that gracefully falls back when features aren't available.

The maskUnits attribute indicates which coordinate system to use for the geometry properties of the <mask> element.

The vert-origin-x attribute indicates the x-coordinate in the font coordinate system of the origin of a glyph to be used when drawing vertically oriented text.

The viewBox attribute defines the position and dimension, in user space, of an SVG viewport.

The <feColorMatrix> SVG filter element changes colors based on a transformation matrix. Every pixel's color value [R,G,B,A] is matrix multiplied by a 5 by 5 color matrix to create new color [R',G',B',A'].

The <feFuncB> SVG filter primitive defines the transfer function for the blue component of the input graphic of its parent <feComponentTransfer> element.

Now that we covered the basics of the SVG internals, we will take a look at some tools to work with SVG files.

There are several basic shapes used for most SVG drawing. The purpose of these shapes is fairly obvious from their names. Some of the parameters that determine their position and size are given, but an element reference would probably contain more accurate and complete descriptions along with other properties that won't be covered in here. However, since they're used in most SVG documents, it's necessary to give them some sort of introduction.

The <feMergeNode> SVG takes the result of another filter to be processed by its parent <feMerge>.

The <feComponentTransfer> SVG filter primitive performs color-component-wise remapping of data for each pixel. It allows operations like brightness adjustment, contrast adjustment, color balance or thresholding.