This leads to hemorrhages (bleeding) and leakage of fluid from the blocked blood vessels. When a retinal vein is blocked, it cannot drain blood from the retina. This same type of damage can happen anywhere in the body. In a stroke, a small blood clot blocks the flow of blood through one of the arteries in the brain, and the area that is not getting blood becomes damaged. Nerve cells need a constant supply of blood to deliver oxygen and nutrients.
This condition is called retinal vein occlusion (RVO). When the flow of blood from the retina is blocked, it is often because a blot clot is blocking the retinal vein. A blockage in an artery or vein is called an occlusion or stroke. Conditions that affect the retina affect the ability to see.Īrteries carry blood from the heart to other parts of the body, and veins carry the blood back to the heart. It is covered with special nerve cells which convert light into signals that are sent via the optic nerve to the brain, where they are recognized as images. The retina is where the eye focuses the images we see. Calling formats() on an Inline or Block blot will return both the format of the corresponding DOM node represents (if any) and the formats the DOM node's attributes represent (if any).The front of the eye contains a lens that focuses images on the inside of the back of the eye. Like a DOM attribute's relationship to a node, Attributors are meant to belong to Blots. AttributorsĪttributors are the alternative, more lightweight, way to represent formats. The root parent blot of a Parchment document. In these cases Parchment will not manipulate or generally be aware of the element's children, and it will be important to correctly implement the blot's index() and position() functions to correctly work with cursors/selections. Its corresponding DOM node will often be a Void Element, but can be a Normal Element. Embed Blotīasic implementation of a non-text leaf blot, that is formattable. Formatting an inline blot by default either wraps itself with another blot or passes the call to the approprate child. Inline Blotīasic implementation of an inline scoped formattable parent Blot. Formatting a block blot by default will replace the appropriate subsection of the blot. Block Blotīasic implementation of a block scoped formattable parent Blot. Quill also provides many great example implementions in its source code.
Blots must also have a scope, which determine if it is inline or block.Ĭlass Blot LinkBlot. If a Blot is defined with both a tag and class, the class takes precedence, but the tag may be used as a fallback. After implementation, blots need to be registered before usage.Īt the very minimum a Blot must be named with a static blotName and associated with either a tagName or className. In general you will want to extend one of these, instead of building from scratch. Several basic implementations such as Block, Inline, and Embed are provided. Blotsīlots are the basic building blocks of a Parchment document. See Cloning Medium with Parchment for a guide on how Quill uses Parchment its document model. Use the Registry's create() method instead. This may prevent necessary lifecycle functionality of a Blot. Note: You should never instantiate a Blot yourself with new. Attributors can also provide lightweight formatting information. Blots can provide structure, formatting, and/or content. A Parchment tree is made up of Blots, which mirror a DOM node counterpart. It is a parallel tree structure to the DOM tree, and provides functionality useful for content editors, like Quill.
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