A handwriting input method is an important alternative input method for computing devices that are equipped with touch-sensitive surfaces (e.g., touch-sensitive display screens, or touch-pads). Many users, particularly users in some Asian or Arab countries, are accustomed to writing in a cursive style, and may feel comfortable writing in longhand as opposed to typing on a keyboard.
For certain logographic writing systems, such as Hanzi and Kanji (also referred to as Chinese characters), even though alternative syllabic input methods (e.g., Pinyin or Kana) are available to enter characters of the corresponding logographic writing systems, such syllabic input methods are inadequate when the user does not know how to phonetically spell a logographic character, and uses an incorrect phonetic spelling of the logographic character. Therefore, being able to use handwriting input on a computing device becomes crucial for users who are not able to pronounce words well enough or at all for a relevant logographic writing system.
Although handwriting input functionality has gained some popularity in certain regions of the world, improvements are still needed. In particular, human handwriting is highly variable (e.g., in terms of stroke order, size, writing style, etc.), and high-quality handwriting recognition software is complex and requires extensive training. As such, providing efficient, real-time handwriting recognition on a mobile device having limited memory and computing resources has been a challenge.
Furthermore, in today's multi-cultural world, users in many countries are multi-lingual, and may frequently need to write in more than one script (e.g., writing a message in Chinese that mentions a movie title in English). However, manually switching a recognition system to a desired script or language during writing is cumbersome and inefficient. Furthermore, the utility of conventional multi-script handwriting recognition techniques is severely limited because scaling-up the recognition capability of a device to simultaneously handle multiple scripts vastly increases the complexity of the recognition system and the demand on computer resources.
In addition, conventional handwriting techniques rely heavily on language or script-specific particularities to achieve recognition accuracy. Such particularities are not easily portable to other languages or scripts. Thus, adding handwriting input capabilities for new languages or scripts is a daunting task that is not lightly undertaken by suppliers of the software and devices. As a result, users of many languages are deprived of an important alternative input method for their electronic devices.
Conventional user interfaces for providing handwriting input include an area for accepting handwriting input from the user and an area for displaying handwriting recognition results. On portable devices having a small form factor, significant improvement of the user interface is still required to improve the efficiency, accuracy, and user experience in general.