WAP Pictogram Specification學習筆記

WAP Pictogram Specification學習筆記

1。
Pictograms需要user agent預裝的，它分爲文本和圖片兩種。文本的pictogram一般是unicode 中已經定義的，佔用2－4個字節，不能擴展；圖片的pictogram，則是可以動態添加的。主要分Core和Pictogram Dictionary兩個大的類別。

2。
pict_URI  = abs_URI
abs_URI   = scheme ":" net_path
scheme    = "pict"
net_path  = "//" authority abs_path
abs_path  = "/" path_segments
authority = [ server ]
server    = hostport

hostport      = host [ ":" port ]
host          = hostname | IPv4address
hostname      = *( domainlabel "." ) toplabel [ "." ]
              = alphanum | alphanum *( alphanum | "-" ) alphanum
domainlabel
toplabel      = alpha | alpha *( alphanum | "-" ) alphanum
IPv4address   = 1*digit "." 1*digit "." 1*digit "." 1*digit
port          = *digit
path_segments = class_name "/" pictogram_name
class_name    = segment *( "/" segment )
segment       = *pchar
pictogram_name= *pchar
pchar         = unreserved | escaped |
                ":" | "@" | "&" | "=" | "+" | "$" | ","

3 General Processing Model
1. If "pict" scheme is identified it MUST be treated as a pictogram.
2. If the authority is omitted in the local name, the user agent MUST assume that it is "www.wapforum.org".
3. If the user agent supports graphical image and does not have the image data of the pictogram, it SHOULD download the
   image data from the URL specified in the src attribute if it’s provided.
4. If the user agent does not support graphical image, or unable to download the image by any reason, it MUST render or
   present the alternative text in the alt attribute in the most appropriate way to its capability.