mangavalk/lcdproc
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

document bignum library; fix and shrink bignum library (both S. Herdler)

Browse Source
This commit is contained in:
marschap
2006-04-29 13:47:56 +00:00
parent ecc9320b54
commit aa4b7f922f
2 changed files with 104 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files
docs/lcdproc-dev/make-driver.docbook
+87
View File
@@ -138,6 +138,93 @@ char status = port_in(0x379);
port_deny_multiple(0x378,3);
</screen>
</sect3>
</sect2>
<sect2 id="adv_bignum.h">
<title>adv_bignum.h : Write Big-Numbers</title>
<para><filename>adv_bignum.h</filename> is the headerfile for <filename>lib_bignum.a</filename> (made from <filename>adv_bignum.c</filename>) which contains everything needed to show big-numbers, including the fonts for the different displays. (All files are located in the <filename>server/drivers/</filename> directory.) </para>
<para/>
<para>There are only a few requirements to the calling driver:</para>
<listitem><para>The displays <replaceable>cellwidth</replaceable> has to be 5 and the <replaceable>cellheight</replaceable> 7 or 8.</para></listitem>
<listitem><para>The following functions have to be implemented: <function> chr( )</function>;
<function> set_char( )</function>(only if the display has custom-characters)</para></listitem>
<listitem><para>The custom-characters (if available) have to be at char 0, 1, 2, ..... ,n</para></listitem>
<para/>
<para>The lib determines the correct font, depending on the displaysize and the number of user-character, itself. So it is easy to integrate into the driver.</para>
<sect3 id="adv_bignum.h-usage">
<title>External provided Functions</title>
<funcsynopsis>
<funcprototype>
<funcdef>void <function>lib_adv_bignum</function></funcdef>
<paramdef>Driver *<parameter>drvthis</parameter></paramdef>
<paramdef>int <parameter>x</parameter></paramdef>
<paramdef>int <parameter>num</parameter></paramdef>
<paramdef>int <parameter>height</parameter></paramdef>
<paramdef>int <parameter>do_init</parameter></paramdef>
<paramdef>int <parameter>customchars</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<para>The main thing the driver has to do is to call this function from its the <function>num( )</function> function.</para>
<para>Where <parameter>num</parameter> is the number (legal: 0,...9,:) to be written, <parameter>height</parameter> the displays hight in characters and <parameter>customchars</parameter> the number of available custom-characters.</para>
<para><parameter>x</parameter> is the x position of the top-left corner of the big-number (the big-numbers don't have a y position). The placing of the characters is done by the client, so the driver only has to forward the position to the lib. The bignumlib has no influence on the placing of the characters.</para>
<para>If <parameter>do_init</parameter> is unequal 0 lib_bignum will set the custom-characters of the display for the big-numbers.</para>
<para>The driver has to check if the custom-characters have to be set or if it is already done and tell it to the lib (using the <parameter>do_init</parameter> parameter).
The common way is to use variable called <replaceable>p-&gt;ccmode</replaceable> or similar. In the different drivers there are some differences in the naming and handling of this variable. So the responsibility of checking and setting is left at the driver.</para>
</sect3>
<sect3 id="adv_bignum.h-intern">
<title>Internal Structure and Functions</title>
<para>The only function of <function>lib_adv_bignum( )</function> is to determine the best display-dependent big-number-function for the given display-parameters, and to call it.</para>
<para/>
<para>The display-dependent functions are named <function>adv_bignum_num_N_M( )</function>.
Where <replaceable>N</replaceable> is the display-hight lines and <replaceable>M</replaceable> the number of used user-characters.
The bits of the user-characters are stored in <replaceable>static char bignum</replaceable> (take a look at the source and you will see what I mean). (On a display with a <replaceable>cellheight</replaceable> of 7 the lowest line stored is not shown.) While <replaceable>static char num_map</replaceable> defines the placing in the big number. (A big number is always 3 characters wide and 4 characters high. On a big number for 2 line displays the 2 lower lines are not in use.)</para>
<para>If user-characters have to be set the drivers <function>set_char( )</function> function will be called once for every user-character.</para>
<para>Now <function>adv_bignum_write_num( )</function> is called. This function places the 6 or 12 characters the big-number consists of in the framebuffer using the drivers <function>char( )</function> function.</para>
</sect3>
<sect3 id="adv_bignum.h-example">
<title>Example:</title>
<para>Calling the <function>lib_adv_bignum( )</function> from a drivers_num function. (from <filename>serialVFD.c</filename>):</para>
<screen>
MODULE_EXPORT void
serialVFD_num( Driver * drvthis, int x, int num ){
int do_init=0;
PrivateData *p = drvthis-&gt;private_data;
if (p-&gt;ccmode != CCMODE_BIGNUM){ // Are the custom-characters set up correctly? If not:
do_init=1;// Lib_adv_bignum has to set the custom-characters.
p-&gt;ccmode = CCMODE_BIGNUM; // Switch custom-charactermode to bignum.
}
// Lib_adv_bignum does everything needed to show the big-numbers.
lib_adv_bignum(drvthis, x, num, p-&gt;height, do_init, p-&gt;customchars);
}
</screen>
<para>All that's left to do is to include the header-file</para>
<screen>#include "adv_bignum.h"</screen>
<para>and to add <filename>libbignum.a</filename> to the libs and <filename>adv_bignum.h</filename> sources of your driver.</para>
</sect3>
</sect2>