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<hr><h1>vbi_page Struct Reference<br>
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[<a class="el" href="group__Page.html">Formatted text page</a>]</small>
</h1>Formatted Teletext or Closed Caption page.
<a href="#_details">More...</a>
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<tr><td colspan=2><br><h2>Data Fields</h2></td></tr>
<tr><td nowrap align=right valign=top>vbi_decoder * </td><td valign=bottom><a class="el" href="structvbi__page.html#m0">vbi</a></td></tr>
<tr><td nowrap align=right valign=top><a class="el" href="group__Event.html#a0">vbi_nuid</a> </td><td valign=bottom><a class="el" href="structvbi__page.html#m1">nuid</a></td></tr>
<tr><td nowrap align=right valign=top>int </td><td valign=bottom><a class="el" href="structvbi__page.html#m2">pgno</a></td></tr>
<tr><td nowrap align=right valign=top>int </td><td valign=bottom><a class="el" href="structvbi__page.html#m3">subno</a></td></tr>
<tr><td nowrap align=right valign=top>int </td><td valign=bottom><a class="el" href="structvbi__page.html#m4">rows</a></td></tr>
<tr><td nowrap align=right valign=top>int </td><td valign=bottom><a class="el" href="structvbi__page.html#m5">columns</a></td></tr>
<tr><td nowrap align=right valign=top><a class="el" href="structvbi__char.html">vbi_char</a> </td><td valign=bottom><a class="el" href="structvbi__page.html#m6">text</a> [1056]</td></tr>
<tr><td nowrap>struct {</td></tr>
<tr><td nowrap valign=top>} </td><td valign=bottom><a class="el" href="structvbi__page.html#m10">dirty</a></td></tr>
<tr><td nowrap align=right valign=top><a class="el" href="group__Page.html#a7">vbi_color</a> </td><td valign=bottom><a class="el" href="structvbi__page.html#m11">screen_color</a></td></tr>
<tr><td nowrap align=right valign=top><a class="el" href="group__Page.html#a8">vbi_opacity</a> </td><td valign=bottom><a class="el" href="structvbi__page.html#m12">screen_opacity</a></td></tr>
<tr><td nowrap align=right valign=top><a class="el" href="group__Page.html#a0">vbi_rgba</a> </td><td valign=bottom><a class="el" href="structvbi__page.html#m13">color_map</a> [40]</td></tr>
<tr><td nowrap align=right valign=top>uint8_t * </td><td valign=bottom><a class="el" href="structvbi__page.html#m14">drcs_clut</a></td></tr>
<tr><td nowrap align=right valign=top>uint8_t * </td><td valign=bottom><a class="el" href="structvbi__page.html#m15">drcs</a> [32]</td></tr>
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<hr><a name="_details"></a><h2>Detailed Description</h2>
Formatted Teletext or Closed Caption page.
<p>
Clients can fetch pages from the respective cache using <a class="el" href="group__Cache.html#a4">vbi_fetch_vt_page()</a> or <a class="el" href="group__Cache.html#a3">vbi_fetch_cc_page()</a> for evaluation, display or output. Since the page may reference other objects in cache which are locked by the fetch functions, <a class="el" href="group__Cache.html#a0">vbi_unref_page()</a> must be called when done. Note this structure is large, some 10 KB. <dl compact><dt><b>Examples: </b></dt><dd>
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<a class="el" href="exp-templ_8c-example.html#_a9">exp-templ.c</a>.</dl>
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<hr><h2>Field Documentation</h2>
<a name="m0" doxytag="vbi_page::vbi"></a><p>
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<td class="md" nowrap valign="top"> vbi_decoder* vbi_page::vbi
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Points back to the source context. </td>
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<a name="m1" doxytag="vbi_page::nuid"></a><p>
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<td class="md" nowrap valign="top"> <a class="el" href="group__Event.html#a0">vbi_nuid</a> vbi_page::nuid
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Identifies the network broadcasting this page. </td>
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<a name="m2" doxytag="vbi_page::pgno"></a><p>
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<td class="md" nowrap valign="top"> int vbi_page::pgno
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Page number, see vbi_pgno. </td>
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<a name="m3" doxytag="vbi_page::subno"></a><p>
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<td class="md" nowrap valign="top"> int vbi_page::subno
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Subpage number, see vbi_subno. </td>
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<a name="m4" doxytag="vbi_page::rows"></a><p>
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<td class="md" nowrap valign="top"> int vbi_page::rows
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Number of character rows in the page. </td>
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<td class="md" nowrap valign="top"> int vbi_page::columns
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Number of character columns in the page. </td>
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<a name="m6" doxytag="vbi_page::text"></a><p>
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<td class="md" nowrap valign="top"> <a class="el" href="structvbi__char.html">vbi_char</a> vbi_page::text[1056]
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The page contents, these are <em><a class="el" href="structvbi__page.html#m4">rows</a></em> x <em><a class="el" href="structvbi__page.html#m5">columns</a></em> without padding between the rows. See <a class="el" href="structvbi__char.html">vbi_char</a> for details. </td>
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<a name="m10" doxytag="vbi_page::dirty"></a><p>
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<td class="md" nowrap valign="top"> struct { ... } vbi_page::dirty
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To speed up rendering these variables mark the rows which actually changed since the page has been last fetched from cache. <em>y0</em> ... <em>y1</em> are the first to last row changed, inclusive, in range 0 ... <em><a class="el" href="structvbi__page.html#m4">rows</a></em> - 1. <em>roll</em> indicates the page has been vertically scrolled this number of rows, negative numbers up (towards lower row numbers), positive numbers down. For example -1 means row <em>y0</em> + 1 ... <em>y1</em> moved to <em>y0</em> ... <em>y1</em> - 1, erasing row <em>y1</em> to all spaces.
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Practically this is only used in Closed Caption roll-up mode, otherwise all rows are always marked dirty. Clients are free to ignore this information. </td>
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<a name="m11" doxytag="vbi_page::screen_color"></a><p>
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<td class="md" nowrap valign="top"> <a class="el" href="group__Page.html#a7">vbi_color</a> vbi_page::screen_color
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When a TV displays Teletext or Closed Caption pages, only a section in the center of the screen is actually covered by characters. The remaining space is referred to here as 'border', which can have a color different from the typical black. (In the Teletext specs this is referred to as the screen color, hence the field name.) This is a vbi_color index into the <em><a class="el" href="structvbi__page.html#m13">color_map</a></em>. </td>
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<a name="m12" doxytag="vbi_page::screen_opacity"></a><p>
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<td class="md" nowrap valign="top"> <a class="el" href="group__Page.html#a8">vbi_opacity</a> vbi_page::screen_opacity
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The 'border' can also have a distinguished opacity. Typically this will be VBI_OPAQUE, but pages intended for overlay onto video (Teletext subtitles, newsflash, Caption pages) will have a <em><a class="el" href="structvbi__page.html#m12">screen_opacity</a></em> of VBI_TRANSPARENT_SPACE. See vbi_opacity for details. </td>
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<a name="m13" doxytag="vbi_page::color_map"></a><p>
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<td class="md" nowrap valign="top"> <a class="el" href="group__Page.html#a0">vbi_rgba</a> vbi_page::color_map[40]
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This is the color palette indexed by vbi_color in <a class="el" href="structvbi__char.html">vbi_char</a> and elsewhere, colors defined as vbi_rgba. Note this palette may not correspond to the vbi_color enumeration since Teletext allows editors to redefine the entire palette. Closed Caption and Teletext Level 1.0/1.5 pages use entries 0 ... 7. Teletext Level 2.5/3.5 pages use entries 0 ... 31. Navigation related text (TOP, FLOF) added by libzvbi uses entries 32 ... 39 which are not subject to redefinition. </td>
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<a name="m14" doxytag="vbi_page::drcs_clut"></a><p>
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<td class="md" nowrap valign="top"> uint8_t* vbi_page::drcs_clut
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DRCS (dynamically redefinable characters) can have two, four or sixteen different colors. Without further details, the effective color of each pixel is given by <div class="fragment"><pre> <a class="code" href="structvbi__page.html">vbi_page</a>->color_map[<a class="code" href="structvbi__page.html#m14">drcs_clut</a>[<a class="code" href="structvbi__page.html#m15">drcs</a> pixel color + <a class="code" href="structvbi__char.html">vbi_char</a>->drcs_clut_offs]],
</pre></div> whereby drcs_clut[0] shall be replaced by <a class="el" href="structvbi__char.html">vbi_char</a>->foreground, drcs_clut[1] by <a class="el" href="structvbi__char.html">vbi_char</a>->background. (Renderers are supposed to convert the drcs_clut into a private color map of the desired pixel format.)
<p>
Practically <a class="el" href="structvbi__char.html">vbi_char</a>->drcs_clut_offs encodes the DRCS color depth and selects between the <a class="el" href="structvbi__char.html">vbi_char</a> colors and one of two 4- or 16-entry Color Look-Up Tables. Also the different resolution of DRCS and the bitplane color coding is hidden to speed up rendering. </td>
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<a name="m15" doxytag="vbi_page::drcs"></a><p>
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<td class="md" nowrap valign="top"> uint8_t* vbi_page::drcs[32]
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Pointer to DRCS data. Per definition the maximum number of DRCS usable at the same time, i. e. on one page, is limited to 96. However the number of DRCS defined in a Teletext data stream can be much larger. The 32 pointers here correspond to the 32 DRCS character planes mentioned in the <a class="el" href="structvbi__char.html">vbi_char</a> description. Each of them points to an array of character definitions, a DRCS font. One character occupies 60 bytes or 12 x 10 pixels, stored left to right and top to bottom. The color of each pixel (index into <em><a class="el" href="structvbi__page.html#m14">drcs_clut</a>)</em> is coded in four bits stored in little endian order, first pixel 0x0F, second pixel 0xF0 and so on. For example the first, top/leftmost pixel can be found at <div class="fragment"><pre> <a class="code" href="structvbi__page.html">vbi_page</a>->drcs[(unicode >> 6) & 0x1F][(unicode & 0x3F) * 60]
</pre></div>
<p>
Do not access DRCS data unless referenced by a <a class="el" href="structvbi__char.html">vbi_char</a> in <em><a class="el" href="structvbi__page.html#m6">text</a></em>, a segfault may result. Do not access DRCS data after calling <a class="el" href="group__Cache.html#a0">vbi_unref_page()</a>, it may not be cached anymore. </td>
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