A better calculator: Processing hand-written mathematical expressions to solve problems
Will Thimbleby · 2004
Current methods of calculating and entering mathematical expressions on typical calculators, whether handheld or on screen, are awkward and cum-bersome. Today, computers are capable of almost anything — yet GUI calculators are still imitations the very earliest electronic models! Users are being forced to use calculators a unnatural way dictated by obsolete metaphors. A novel calculator, that provides a natural interface, much like pen and paper is presented. The interface provides a dynamic method of entering conventional written expressions by normal gestures and provides continual feedback showing the calculation and results. Furthermore, the user interface adjusts and copes with partial expressions, morphing the ex-pressions to correct position and syntax. Gestures are also used to edit and manipulate calculations. The user interface is declarative, in that all displays, even with partial user input, are of correct calculations. A usability test was designed and conducted to evaluate the effectiveness