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More notes, from the plane.
== Graphics and layout capabilities ==
Graphics and layout changes represent some of the most invasive work proposed for the Gecko 1.9 development cycle. They form the core of the architectural shifts in 1.9, and are considered to be the most difficult and riskiest elements. To that end, this roadmap proposes that they -- especially the cairo-substrate and reflow-branch changes -- be scheduled as early as possible. Both of these work items have meaningful development behind them as of this writing (October 2005), but both will also require significant additional work to reach a level of completeness (including performance) that will allow them to be made default on the trunk.
The changes most graphical in nature (SVG, Canvas, XUL2D) depend on a switch to the cairo graphics library as the fundamental display architecture for Gecko, work on which is already well underway. The aim of these changes, taken together, is to bring modern graphics capabilities to the whole of the web, without requiring proprietary plugins or rendering obsolete the broad and rich set of web authoring techniques developed over the past decade.
The layout changes -- see also the "XUL' and XBL2" section of this roadmap -- center around David Baron's "reflow branch", the aim of which is to eliminate reflow commands and types, and significantly reduce the complexity of the Gecko layout model. This is the first change to global layout architecture in several years, and it is hoped that it will address many problems related to incremental reflow. In addition, it should simplify some problems which are not practically soluble with the current architecture, such as support for inline-table.
=== cairo substrate ===
=== SVG 1.1 ===
=== Canvas ===
== JavaScript 2 ==
The development of the Mozilla suite of applications, from the earliest days of Seamonkey to the current Firefox 1.5 release, has demonstrated the promise of developing significant infrastructure and application logic in JavaScript, rather than the fragile world of Mozilla's minimal C++ dialect. Over the course of that development, though, many limitations in the language and our implementation have come to hinder our development efforts, and the JavaScript 2 work in Gecko 1.9 seeks to address many of them.
Building upon the "Edition 4" proposals before the ECMA-262 technical group responsible for standardizing the ECMAScript dialect of JavaScript, this work will cherry-pick, for early implementation, elements that are key to developing in JavaScript at the scale required for applications like Firefox. (N.B. that this is not a wholesale adoption of the JavaScript 2 proposal written several years ago by Waldemar Horwat, though many elements are retained.)
== Python for XUL ==
The XUL application development community has long clamoured for access to Python's rich set of libraries and its capabilities as an application development language. While Mozilla remains committed to JavaScript as the pre-eminent managed language for our applications, our platform, and the web, we are excited to extend the reach of Gecko and XUL to the Python world.
Mark Hammond's work on PyXPCOM and a language-neutral DOM is well-underway as of October 2005, and we hope that the glue and bindings will be slim enough to be part of a default XULRunner or Firefox distribution when the 1.9 cycle is complete. (N.B. that Mozilla does not intend to distribute a Python runtime with its applications or frameworks, and application developers who wish to take advantage of these capabilities will need to solve that problem on their own. Stub or streaming installer capabilities in Gecko 1.9 or the corresponding Firefox/XULRunner may assist in this.)
== XUL' and XBL2 ==
The XUL and XBL languages have served Mozilla development very well, and are often taken as a model for XML-based UI development in other circles. In some cases, however, our implementations or the (incomplete) specifications are inconsistent, insufficiently robust, or not amenable to some important use cases (including remote XUL applications or rich mixing with other content types such as HTML or SVG). We seek to address these limitations, and generally improve the XUL and XBL development experience, with work in Gecko 1.9.
The XBL work is largely drawn from Ian Hickson's and David Hyatt's work on sXBL and XBL2. Further investigation is required to determine how much of the XBL2 draft will be necessary or implementable in the 1.9 timeframe, but some pieces such as an improved attachment model, clearer lifecycle semantics, and language neutrality are prerequisites for desired application or platform features.
XUL work in Gecko 1.9 will not undertake to create a shining XUL2 jewel, but will instead work to preserve compatibility with "XUL1" where practical, and make clean breaks where unavoidable. Improvements to the XUL box model, based on the specification work done, again, by Hickson and Hyatt should provide a more consistent and flexible layout model for XUL developers, and help to rationalize XUL's interactions with other content types. This box-model work has been proposed for standardization, and Mozilla may participate in that at the W3C, WHATWG, or other appropriate venue.
== Web app deployment and capability improvements ==
The recent resurgence in Web application development as demonstrated the significant power and capability of Web technologies, as well as some key areas of desirable improvement.
Chief among these is a client-local storage capability, which need is not sufficiently addressed by HTTP cookies. Cookies provide limited storage space (on the order of a few kilobytes), require the application developer to manually encode and decode any structure more complex than a simple string, and are transmitted back to the server on each request. In response to these limitations, some application developers are using the Flash plugin simply to gain access to a reliable and capable local store. Ian Hickson and the WHATWG have specified a simple but powerful client-local storage interface that addresses these concerns, and eliminates the dependence on proprietary plugins.
(There is a proposal circulating that Mozilla develop and distribute a small JavaScript library to abstract away different local storage technologies. Released in advance of Gecko 1.9, it would likely use Flash underneath, and perhaps IE's "user-data" capability. An updated version of the library would simply drop in and use the WHATWG client-local storage API if provided by the host browser.)
Another limitation often decried by developers of rich Web applications is the lack of a reasonable offline execution model. Mechanisms to remedy this lack include: facility to pin sets of pages for offline use; a mechanism for detecting that the application is running offline; and events to signal that the user is going offline or returning to online operation. Taken together with the aforementioned client-local storage system, these mechanisms would combine to enable a number of improved and important web experiences.
=== Offline operation ===
