<desc>Defines the alpha channel threshold used to extract the shape using an image. A value of 0.5 means that the shape will enclose all the pixels that are more than 50% opaque.</desc>
<desc>Adds a margin to a 'shape-outside'. This defines a new shape that is the smallest contour that includes all the points that are the 'shape-margin' distance outward in the perpendicular direction from a point on the underlying shape.</desc>
<desc>The creator of SVG content might want to provide a hint to the implementation about what tradeoffs to make as it renders vector graphics elements such as ‘path’ elements and basic shapes such as circles and rectangles.</desc>