编辑“Gallery:Modules:imagenotes:Design”

==设计==
===概览===
* 保持可扩展性。
*: 希望该模块具有可扩展性，这样没有在此版本中出现的特点可以在将来加入。管理员也可仅启用想要的特点，从而减少页面载入时间，客户端操作时间以及资源占用。

===概念===
; 图片区域：
* 图片区域是图片上具有重要性的特定区域。该图片区域存在于同一张图片的所有版本之中（即源图片的所有派生）。注意派生图片的比例和定向可能与原始图片不同。
* 图片区域是由一个矩形DIV所表示的，也可以是是图片边界内的其他2d形状。
: 应可以将某个矩形DIV选择转为某个合适的2d形状。
* 所有图片区域无论形状都有一个2d划界的框架，这使得冲突检测更便捷。
* ?? 图片区域统筹在2d空间中显示为一个复杂的3维物体。图片区域可在2d空间中定义物体的3d属性，而不仅仅是显示一个2d区域，比如面孔，头部和身体的旋转。?? 这是否可以作为批注/其他关联？
* ?? 图片区域应能提供该区域的可缩放视图，以备页面中再次使用。

; 图片区域集：
* 一个图片区域集（image region set）是一组相关的图片区域。因为3d物体可以在2d空间中以不相交的区域表示出来，所以我们需能够将分离的图片区域链接在一起。（比如，当某人被标记了，而他的胳膊藏在某人背后，这种图片区域组合机制就变得重要了。我们标记整个图片区域集而不是分别标记各独立的2d图片区域）。


; Image region hierarchy... does it make sense to have an image region made up of image region parts, and a part can be a parent to another image region part? Image region always has a root, which is the bounding DIV and then 1 or more children? Does it make sense to do this?


; Annotation:
* An annotation is something that is drawn in the browser (may not be visible due to style, but added into the DOM) and is associated with the image.
* ?? Does an image region need an annotation so that it can be displayed and interacted with? Or should we be able to attach style to an image region itself? If annotation required, need special circumstances to shape the annotation to the image region.
* The annotation, unlike an image region, is not necessarily desired on all sizes of the same image.
* An annotation may have a number of different style attributes depending on the derivative image (and Annotation set) it is being displayed with. Scale and rotation of the annotation may not be as simple as image regions, which are based purely on image co-ordinates.
: e.g. A speech bubble annotation may not want to scale the same amount as the derivative image does.
* An annotation may be, but is not necessarily associated with an image region.
: i.e. Tags and notes are associated with an image region, but a quirky speech bubble isn't.
* An annotation may be shown, hidden, or animated by some event.
* An annotation can be displayed in various positions:
** Absolutely positioned, relative to the image.
** Absolutely positioned, relative to another anotation.
** Absolutely positioned, relative to the cursor.
** In the imagenotes block area?
** In a special annotation region for the annotation type.
** In other special block areas of the correct type?

; ??Annotation parts:
* An annotation may be made up of different parts and shapes and we may not want a database entry for every individual part. This may make the job of referencing different things more difficult however. And parts may want to be attached to different annotation regions. Examples:
** Annotating a tag, we may want to display it at the cursor on mouse over, underneath the image (if a large group of people shown, a table of who's in the picture) and in the imagenotes block. 
** Quirky speech bubble animation contains multiple bubbles, animated together so when one bubble appears the other disappears. They together form a whole annotation, so may not want to be separated.

; Annotation sets:
* We may have lots of data about an image and not want to display all the data at the same time. Also, we may want different behaviours for interacting with the image when it is being viewed.
* An annotation belongs in one or more annotation sets. 
* Annotations may have different properties per annotation set.
* Only one annotation set is viewable at a given time, otherwise different properties of an annotation being displayed may conflict. It should be possible to merge sets into one another, giving the opportunity to resolve conflicts.
* ?? Only one annotation set is rendered at a time (the others are not merely hidden, but don't exist in the DOM)?

; Image region associations:
* There may be reasons for creating associations with an image region that aren't visual markup. Not sure what yet though. :-)

; Theming:
* As with the rest of G2, site owners may want to make imagenotes appear in different ways. Though CSS styles may control a lot, there are instances where non-simple elements are needed. For instance, a selected area may want the inside of the area transparent, whilst not making the border transparent.
; Imagenotes regions:
: There are a number of potentially desirable regions for use with Imagenotes, all with different purposes.
* Imagenotes block. When editing, all of the various image regions/annotations are shown here somehow. This allows you to interact with specific items potentially more easily than when editing over the image.
* Image area. The area within which the image is rendered.
* Sub image area. (Potentially another block?) Somewhere annotations such as who is in the image can be displayed.
* Annotation set selection. When viewing the image, something to choose which annotation set is being displayed (possible hidden when the user can only see one of the available sets).
* By the cursor. This is a special region that moves everywhere the cursor does. Potentially some logic is needed here for keeping this area on screen when the cursor is near the browser/frame border. Also, don't want to call code for moving the region when there is nothing being displayed in it.
* Toolbox. Buttons and/or labels for selection of viewing/editing modes and potentially all their sub toolkits.
* Docking areas (provided by themes or blocks?). Areas where toolboxes can be dragged to and inserted into the flow of the page.
* By an image region. When an image region is first created (or edited) and tags/notes are being applied, a convienient place to get the appropriate options is right next to the image region (or maybe just a modal dialog)

;操作：
:当进行添加/编辑时，以下操作可能是图片区域和批注都需要的。
* 拖动
** 强制的
* 改变比例
** 强制的
** 宽高比
** 最小值和最大值
* Z-ordering（分层）
* 组合/拆分
** 多个组织中的图片区域？
** 为形状设定操作（Union, Intersection, Negation）保留算符？
* 节点移动（当不为一简单矩形时，某形状的各点都可以单独移动）
** 强制的。某形状是否会阻止某节点被移动到特定的位置以维持形状？
* 旋转
* 3d操作

;模式：
:特定模式（及子模式）会在图片交互中被用到。而模式则会决定行为。
* 查看。
* 编辑：
** 编辑图片区域。
** 编辑标记。
** 编辑注释。
** 编辑非图片区域的批注（涂鸦？）
* 用户建议（某不具任何关联的图片区域能够被建议？可能不行）：
** 建议标记。
** 建议注释。
** 建议图画。
* 查看建议？查看形式可能与你编辑建议时的样式不同。 
* 管理（建议回复）。
** 显示谁/什么作出了建议。可以限制对某特定的提出建议者的查看。

===Client side===
====Goals====
* Make all actions responsive
** Keep event handlers simple and quick.
** Be wary of multiple super classes as call times may get out of hand.
** Keep the item being displayed as simple as possible so there is less in the DOM. i.e. don't use templates for editing (with resize handles) when merely displaying.
** ? Destroy classes when changing between modes or not? Memory consumed by keeping, CPU consumed by recreating.
* Minimise resource usage
* Minimise page load time
* Only load required features. Load features as required? (dynamically load JS then eval?)
* Degrade gracefully?

====Notes====
* This all really only works when javascript is enabled. It may be possible to render the markup server side without to atleast some degradeble functionality, but for now this is not being considered (would require the theme to put things in the right place).
* Image notes manager object handles all interactions with any given image (of course, within the scope of the imagenotes module) and is responsible for any page regions associated with the imagenotes (image, block area, toolkit)
* The image notes manager will be instanciated when the imagenotes block is included on photo pages.
* The image notes manager has to be pointed to the image it is managing. Currently a utility function searches out an <img> tag matching the item being displayed (this may not always work), with the image src URL passed in through the imagenotes block smarty template.
* The image notes manager is responsible for putting the image notes into the normal flow of browser focus, so when tabbing through the document editable regions and keyboard input works correctly.
* The image notes manager is responsible for client/server communication, plug in modules will communicate through it (is this bad design?, maybe it's more efficient for plugins to do their own thing to save unnecessary stuff being loaded, but structure the calls through an interface method).
* The image notes manager has a notion of 'mode'. The mode can be changed to allow editing of image regions, creation of annotations, and to generally change the view and behaviour of the imagenotes. An interface class will define the mode and other G2 modules will be able to add modes (collected through factory methods server side).
* The image notes manager will have rubber band functionality (just within the image area?) that is available to modes. Initially intended only for dragging out an image region, it may be useful for selection.
* Mode types, view, edit(/add/delete), suggest.
* Themes can define placement of toolbox, dock areas, annotation areas.
* A class will define an interface for a handler for imagenotes types. It handles a specific imagenote type. (e.g. for image tagging, the handler will look after the tag/image region relationship, even when an annotation doesn't exist)
* A class will define an interface for imagenotes types. An imagenote type is something that may be rendered to the page? and will probably fit into the imagenotes manager mode system. Will have events for it's selection, mouseover, etc.
* Can create annotation areas that fit into page flow and are not absolute(?) Can we determine this with javascript? Does it have to be done per item being displayed? Definitely theme specific. Will it be easily upset by adding other blocks? Sounds too complicated! :-)

===Server side===
====Goals====
* Minimise page load time, whilst being extensible

====Notes====
* Image region at client end should stick to co-ordinates on local image. Server side should convert co-ordinates to full size image co-ordinates for storage and to derivative size co-ordinates for client display.
* Only include javascript in page when necessary. Restrict to needed JS based on user permissions (i.e. edit code is not needed for someone that cannot edit)

===Database structure===
====Goals====
* Minimise page load time
* Design so it's easy and quick to search for interesting things
====Notes====
* Image region needs a unique ID, probably built from a key on the image it's attached to and it's own unique ID for the particular image. Maybe image region ID should have a single unique key to simplify cross referencing from other tables. Image region needs layer information to ensure the desired z-ordering is applied  on rendering.