shm pixmapとxcbの使い方は？

Question

xcbライブラリで共有メモリピックスマップを使用する方法を学ぼうとしています。あなたの経験があり、サンプルコードや情報を共有したいと思いますか？これは非常に役に立ちます。

おかげ

Answer 1

いくつかの研究の後、私はXCBで共有メモリピックスマップを使用する方法を見つけました。ここで

は私testcodeです：

#include <stdlib.h> 
#include <stdio.h> 

#include <sys/ipc.h> 
#include <sys/shm.h> 

#include <xcb/xcb.h> 
#include <xcb/shm.h> 
#include <xcb/xcb_image.h> 


#define WID 512 
#define HEI 512 



int main(){ 
    xcb_connection_t*  connection; 
    xcb_window_t   window; 
    xcb_screen_t*   screen; 
    xcb_gcontext_t   gcontext; 
    xcb_generic_event_t* event; 

    uint32_t value_mask; 
    uint32_t value_list[2]; 

    //connect to the X server and get screen 

    connection = xcb_connect(NULL, NULL); 
    screen = xcb_setup_roots_iterator(xcb_get_setup(connection)).data; 

    //create a window 

    value_mask = XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK; 
    value_list[0] = screen->black_pixel; 
    value_list[1] = XCB_EVENT_MASK_EXPOSURE; 

    window = xcb_generate_id(connection); 

    xcb_create_window(
     connection,    
     screen->root_depth, 
     window,  
     screen->root,  
     0, 0,   
     WID, HEI,  
     0,    
     XCB_WINDOW_CLASS_INPUT_OUTPUT, 
     screen->root_visual,  
     value_mask, value_list 
    ); 

    //create a graphic context 

    value_mask = XCB_GC_FOREGROUND | XCB_GC_GRAPHICS_EXPOSURES; 
    value_list[0] = screen->black_pixel; 
    value_list[1] = 0; 

    gcontext = xcb_generate_id(connection); 
    xcb_create_gc(connection, gcontext, window, value_mask, value_list); 

    //map the window onto the screen 

    xcb_map_window(connection, window); 
    xcb_flush(connection); 


    //Shm test 
    xcb_shm_query_version_reply_t* reply; 
    xcb_shm_segment_info_t   info; 

    reply = xcb_shm_query_version_reply(
     connection, 
     xcb_shm_query_version(connection), 
     NULL 
    ); 

    if(!reply || !reply->shared_pixmaps){ 
     printf("Shm error...\n"); 
     exit(0); 
    } 

    info.shmid = shmget(IPC_PRIVATE, WID*HEI*4, IPC_CREAT | 0777); 
    info.shmaddr = shmat(info.shmid, 0, 0); 

    info.shmseg = xcb_generate_id(connection); 
    xcb_shm_attach(connection, info.shmseg, info.shmid, 0); 
    shmctl(info.shmid, IPC_RMID, 0); 

    uint32_t* data = info.shmaddr; 

    xcb_pixmap_t pix = xcb_generate_id(connection); 
    xcb_shm_create_pixmap(
     connection, 
     pix, 
     window, 
     WID, HEI, 
     screen->root_depth, 
     info.shmseg, 
     0 
    ); 

    int i = 0; 
    while(1){ 
     usleep(10000); 

     data[i] = 0xFFFFFF; 
     i++; 

     xcb_copy_area(
      connection, 
      pix, 
      window, 
      gcontext, 
      0, 0, 0, 0, 
      WID, HEI 
     ); 

     xcb_flush(connection); 
    } 

    xcb_shm_detach(connection, info.shmseg); 
    shmdt(info.shmaddr); 

    xcb_free_pixmap(connection, pix); 

    xcb_destroy_window(connection, window); 
    xcb_disconnect(connection); 

    return 0; 
}