The CSS Working Group and the SVG Working Group have published a Working Draft of CSS Masking Module Level 1. CSS Masking provides two means for partially or fully hiding portions of visual elements: masking and clipping. Masking describes how to use another graphical element or image as a luminance or alpha mask. Typically, rendering an element via CSS or SVG can conceptually be described as if the element, including its children, are drawn into a buffer and then that buffer is composited into the element’s parent. Luminance and alpha masks influence the transparency of this buffer before the compositing stage. Clipping describes the visible region of visual elements. The region can be described by using certain SVG graphics elements or basic shapes. Anything outside of this region is not rendered. CSS is a language for describing the rendering of structured documents (such as HTML and XML) on screen, on paper, in speech, etc. Learn more about the Style Activity and the Graphics Activity.