Mercurial > MadButterfly
view orgfiles/index.muse @ 41:400b4b5db0dc
Working on animation
author | Thinker K.F. Li <thinker@branda.to> |
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date | Fri, 08 Aug 2008 21:34:53 +0800 |
parents | 6eecdd331fe7 |
children |
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* MadButterfly #MadButterfly MadButterfly is a [[#SVG][SVG]] browser, HTML browser (ex, Firefox) is a HTML respective one. MadButterfly only understand SVG, controlling from users, and API for applications base on it. It is supposed to be a GUI framework for applications. The host applications can interact with MadButterfly like Javascript applications interacts with DOM objects. MadButterfly is a GUI evnironment based on SVG technologies for desktop and mobile device. It tries to make the work of programmers closed to client-side Javascript ones. MadButterfly is a SVG browser, it can be used to implement file manager, UI of commerical application for business, and even window manager for X Window. We try to implement MadButterfly as a library that can be embedded by host programs. It is alike Firefox been embedded by host programs. * SVG #SVG SVG is "Scalable Vector Graphics". It is a standard of W3C. MadButterfly implements [[http://www.w3.org/TR/SVGMobile12/][SVG Tiny 1.2]], a simplified version of SVG for mobile devices. * Design Most notable of SVG, except sharps, is coordination transforms. To make MadButterfly efficiency, the execution of code should highly leverage time locality and spartial locality. So, we should aggregate computation of a function together. The data of container and contained elements should also be aggregated together. Since the attributes of SVG objects will be chagned frequently, unnecessarily recomputing for coordination transforms should be avoided. A sequential number should be attached to the objects to ditinguish dirty transformation result and recompute it when it is needed. ** Aggregate Computation Every update potentially invokes a function for every graphic elements. To be efficient, calls of a function are collected into a loop to avoid overhead of function calls. It also avoid interleaving of calls of functions to leverage time locality of code cache. ** Aggregate Relative Data Changes of a container usually effect contained elements. So, it had better to put container together with contained elements to increase hit rate of cache. * Transform If a coordination transformation transforms (x, y) to (x', y'), then > x' = xa * x + xb * y + xc > y' = ya * x + yb * y + yc is equal to > | xa xb xc | | x | > | ya yb yc | * | y | > | 0 0 1 | | 1 | A transform function of a element to canvas is production of all transform functions of containers, it is called aggregated transform function. The aggregated transform function of elements are computed with [[http://en.wikipedia.org/wiki/Dynamic_programming][dynamic programming]]. ** Use Absolute Since we need to tranform positions, positions are transform to absolute coordinations if they are specified relative. It is fine when a relative position are rotated or resized. But, it would be wrong when shifting.