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1 | \section{Cells and Containers}\label{cells} | |
2 | ||
3 | This article describes mechanism used by | |
4 | \helpref{wxHtmlWinParser}{wxhtmlwinparser} and | |
5 | \helpref{wxHtmlWindow}{wxhtmlwindow} to parse and display HTML documents. | |
6 | ||
7 | \wxheading{Cells} | |
8 | ||
9 | You can divide any text (or HTML) into small fragments. Let's call these | |
10 | fragments {\bf cells}. Cell is for example one word, horizontal line, image | |
11 | or any other part of document. Each cell has width and height (except special | |
12 | "magic" cells with zero dimensions - e.g. colour changers or font changers). | |
13 | ||
14 | See \helpref{wxHtmlCell}{wxhtmlcell}. | |
15 | ||
16 | \wxheading{Containers} | |
17 | ||
18 | Container is kind of cell that may contain sub-cells. Its size depends | |
19 | on number and sizes of its sub-cells (and also depends on width of window). | |
20 | ||
21 | See \helpref{wxHtmlContainerCell}{wxhtmlcontainercell}, | |
22 | \helpref{wxHtmlCell::Layout}{wxhtmlcelllayout}. | |
23 | ||
24 | \begin{comment} | |
25 | % Bitmap is corrupt! | |
26 | This image shows you cells and containers: | |
27 | ||
28 | \helponly{\image{}{contbox.bmp}} | |
29 | \end{comment} | |
30 | \wxheading{Using Containers in Tag Handler} | |
31 | ||
32 | \helpref{wxHtmlWinParser}{wxhtmlwinparser} provides a user-friendly way | |
33 | of managing containers. It's based on the idea of opening and closing containers. | |
34 | ||
35 | Use \helpref{OpenContainer}{wxhtmlwinparseropencontainer} to open new | |
36 | a container {\it within an already opened container}. This new container is a | |
37 | {\it sub-container} of the old one. (If you want to create a new container with | |
38 | the same depth level you can call {\tt CloseContainer(); OpenContainer();}.) | |
39 | ||
40 | Use \helpref{CloseContaier}{wxhtmlwinparserclosecontainer} to close the | |
41 | container. This doesn't create a new container with same depth level but | |
42 | it returns "control" to the parent container. | |
43 | ||
44 | \begin{comment} | |
45 | % Bitmap corrupt! | |
46 | See explanation: | |
47 | ||
48 | \helponly{\image{}{cont.bmp}} | |
49 | \end{comment} | |
50 | It's clear there must be same number of calls to | |
51 | OpenContainer as to CloseContainer... | |
52 | ||
53 | \wxheading{Example} | |
54 | ||
55 | This code creates a new paragraph (container at same depth level) | |
56 | with "Hello, world!": | |
57 | ||
58 | \begin{verbatim} | |
59 | m_WParser -> CloseContainer(); | |
60 | c = m_WParser -> OpenContainer(); | |
61 | ||
62 | m_WParser -> AddWord("Hello, "); | |
63 | m_WParser -> AddWord("world!"); | |
64 | ||
65 | m_WParser -> CloseContainer(); | |
66 | m_WParser -> OpenContainer(); | |
67 | \end{verbatim} | |
68 | ||
69 | \begin{comment} | |
70 | % Bitmap corrupt! | |
71 | and here is image of the situation: | |
72 | ||
73 | \helponly{\image{}{hello.bmp}} | |
74 | \end{comment} | |
75 | ||
76 | You can see that there was opened container before running the code. We closed | |
77 | it, created our own container, then closed our container and opened | |
78 | new container. The result was that we had {\it same depth level} after | |
79 | executing. This is general rule that should be followed by tag handlers: | |
80 | leave depth level of containers unmodified (in other words, number of | |
81 | OpenContainer and CloseContainer calls should be same within \helpref{HandleTag}{wxhtmltaghandlerhandletag}'s body). | |
82 |