c - 在c中逐行(从缓冲区)上下滚动

Question

我编写代码从 xmltv 列表中提取数据并将它们显示在 15 行的 osd 页面中。 如何在页面中逐行向上和向下滚动，直到每个 channel 的列表信息结束，然后它们移动到显示另一个 channel 信息的下一页？

channel 1:

|   line1   |                      |   line2   |                |-----------|
|   line2   |                      |   line3   |                |-----------|
|   line3   | scroll down line =>  |   line4   | then clear =>  | lastline  | 
|   line4   |                      |-----------|                |           |
|-----------|                      |   line15  |                |           |
|   line15  |                      |   line16  |                |           |

然后移动到 => channel 2:

|   line1   |                      |   line2   |                |-----------|
|   line2   |                      |   line3   |                |-----------|
|   line3   | scroll down line =>  |   line4   | then clear =>  | lastline  |
|   line4   |                      |-----------|                |           |
|-----------|                      |   line15  |                |           |
|   line15  |                      |   line16  |                |           |

等等

---

代码:

int epg_show_perchannel( tvtime_osd_t* osd, int page, station_mgr_t *stationmgr, xmltv_t *xmltv, int channel )
{
if (!page)
    return 0;
if ( xmltv ){
    const int buf_length = 255;
    const int max_num_lines = 15;
    const int num_stations = station_get_num_stations( stationmgr );
    char *old_channel = strdup( xmltv_get_channel( xmltv ) );
    char buf[buf_length+1];
    int i, cur = 0;
    time_t curtime = time( 0 );
    const char *xmltv_id = 0;

    if (channel > num_stations)  
        channel = 1;
    else if (channel < 1 )
        channel = num_stations;

    if (!(xmltv_id = station_get_xmltv_id( stationmgr, channel-1 ))) 
        xmltv_id = xmltv_lookup_channel( xmltv, station_get_name( stationmgr, channel-1 ));
    xmltv_set_channel( xmltv, xmltv_id);
    xmltv_refresh_withtime( xmltv, curtime );

    /* Header with channel number + name */
    snprintf(buf, buf_length, "%d Next on [%s] %s:", channel, station_get_channel(stationmgr,channel-1), station_get_name( stationmgr, channel-1));
    tvtime_osd_list_set_text( osd, cur++, buf );
    tvtime_osd_list_set_hilight(osd, -1);   

    for( i = 0; i < max_num_lines; i++ ) {
        xmltv_refresh_withtime( xmltv, curtime );

        if (xmltv_get_title( xmltv )) {
            char start_time[50];
            time_t start_timestamp = xmltv_get_start_time( xmltv );
            time_t end_timestamp = xmltv_get_end_time( xmltv );
            strftime( start_time, 50, "%H:%M", localtime( &start_timestamp ) );

            /* starttime of current program + Now showing program */
            snprintf(buf, buf_length, "%s %s", start_time, xmltv_get_title( xmltv ));       
            if (xmltv_get_sub_title( xmltv )){
                strncat(buf," (",buf_length-strlen(buf));  
                strncat(buf,xmltv_get_sub_title( xmltv ),buf_length-strlen(buf));
                strncat(buf,")",buf_length-strlen(buf));  
            }
            tvtime_osd_list_set_multitext( osd, cur++, buf, 1);

            if (!xmltv_get_next_title( xmltv )) {
                char end_time[50];
                /* no next program, print endtime of current programme */       
                strftime( end_time, 50, "%H:%M", localtime( &end_timestamp ) );
                snprintf(buf, buf_length, "%s %s", end_time, "");       
                tvtime_osd_list_set_multitext( osd, cur++, buf, 1);
            }
        curtime = end_timestamp;

        } else {
            /* No XMLTV information for this channel */
            tvtime_osd_list_set_text( osd, cur++, "");
        }

    }
    tvtime_osd_list_set_lines( osd, cur );
    tvtime_osd_show_list( osd, 1, 1 );

    xmltv_set_channel(xmltv, old_channel);
    free(old_channel);
    xmltv_refresh( xmltv );

} else {
    tvtime_osd_list_set_text( osd, 0, "No XMLTV information available" );
    tvtime_osd_list_set_lines( osd, 1 );
    tvtime_osd_show_list( osd, 1, 1 );
}
return channel;
}

代码，当前显示页面只有15行，然后转到下一个 channel 。

我想向下滚动列表直到来自 xmltv channel 列表的信息结束(包含 3-4 天的信息)，然后移动到下一个 channel :

Answer 1

评论中提到的应用程序在 终端 上进行滚动(可能带有终端转义序列)，但您似乎是在使用一些特殊的 API 来显示文本，而这在 cleary 没有的东西上看起来像一个终端，所以我猜这种方法行不通。

你应该重新创建文本，也许你必须删除以前的文本，老实说我不知道​​......检查文档。