Research And Implementation Of Embedded Browser Layout Rendering Engine

With the promotion and popularization of the Internet and embedded applications,embedded browser becomes more important. And accessing the Internet throughbrowsers has become a trend, because embedded browser connecting the network andindividual users.Taking into account the limitation of rescouceses and pursuit of speed,the most important issue of browsers is showing the page quickly and efficiently.The layout/rendering engine, also called browser kernel, is the core part of the webbrowser which is responsible for parsing the page syntax (such as HTML, CSS) andachieve the effect of rendering. Therefore, the layout/rendering engine determines howto display the content and format of information in pages.WebKit, one of the mostpopular browser kernel, is the main research object in this thesis. Firstly, renderingengine of WebKit is introduced; And then a new set of layout/rendering engine isachieved and ported to a variety of mobile terminals successfully based on charactristicsof terminal design.In this thesis, the most popular browser kernel and embedded browser are shown.And then four steps are descripted including Parse HTML and build a DOM tree, Buildrendering tree, Layout the rendering tree, Draw the rendering tree.Parse HTML and build a DOM tree: Parse the HTML resource into a DOM treestructure which uses Body tag as the root element and other label elements asconstituent parts. Then build an orderly interface through DOM.Build rendering tree: According to the DOM tree and CSS properties, build a veryimportant structure: rendering tree. And it will be used as basis of the layout.Layout the rendering tree: According to each CSS’s property and rendering tree tocalculate the size and position of each label elements. This process is in preparation forthe tag drawing.Draw the rendering tree: Draw the label elements on the screen with graphicslibrary interface. As a result, these elements become truly visible interface elements.