![]() ![]() While user agents might choose to also generate pointer events in response to these interfaces, this scenario is not covered in this specification. While this specification defines a unified event model for a variety of pointer inputs, this model does not cover other forms of input such as keyboards or keyboard-like interfaces (for instance, a screen reader or similar assistive technology running on a touchscreen-only device, which allows users sequential navigation through focusable controls and elements). The primary goal is to provide a single set of events and interfaces that allow for easier authoring for cross-device pointer input while still allowing for device-specific handling only when necessary for an augmented experience.Īn additional key goal is to enable multi-threaded user agents to handle direct manipulation actions for panning and zooming (for instance, with a finger or stylus on a touchscreen), without blocking on script execution. For scenarios when device-specific handling is desired, this specification also defines properties for inspecting the device type which produced the event. This model makes it easier to write sites and applications that work well no matter what hardware the user has. A pointer can be any point of contact on the screen made by a mouse cursor, pen, touch (including multi-touch), or other pointing input device. To reduce the cost of coding to multiple input types and also to help with the above described ambiguity with Mouse Events, this specification defines a more abstract form of input, called a pointer. This makes it ambiguous whether a Mouse Event represents an actual mouse device or is being produced from another input type for compatibility, which makes it hard to code to both device types simultaneously. Additionally, for compatibility with existing mouse-based content, most user agents fire Mouse Events for all input types. This often creates a compatibility problem when content is written with only one device type in mind. However, that approach often incurs unnecessary duplication of logic and event handling overhead when adding support for a new input type. Event types have been proposed for handling each of these forms of input individually. ![]() Newer computing devices today, however, incorporate other forms of input, including touchscreens, pen input, etc. Those that handle input in a custom manner typically code to Mouse Events. ![]() Today, most content is used with and/or designed for mouse input. Converting between tiltX / tiltY and altitudeAngle / azimuthAngle
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