void guac_vnc_update()

in src/protocols/vnc/display.c [46:139]

• 58 lines of code
• 7 McCabe index (conditional complexity)

void guac_vnc_update(rfbClient* client, int x, int y, int w, int h) {

    guac_client* gc = rfbClientGetClientData(client, GUAC_VNC_CLIENT_KEY);
    guac_vnc_client* vnc_client = (guac_vnc_client*) gc->data;

    int dx, dy;

    /* Cairo image buffer */
    int stride;
    unsigned char* buffer;
    unsigned char* buffer_row_current;
    cairo_surface_t* surface;

    /* VNC framebuffer */
    unsigned int bpp;
    unsigned int fb_stride;
    unsigned char* fb_row_current;

    /* Ignore extra update if already handled by copyrect */
    if (vnc_client->copy_rect_used) {
        vnc_client->copy_rect_used = 0;
        return;
    }

    /* Init Cairo buffer */
    stride = cairo_format_stride_for_width(CAIRO_FORMAT_RGB24, w);
    buffer = malloc(h*stride);
    buffer_row_current = buffer;

    bpp = client->format.bitsPerPixel/8;
    fb_stride = bpp * client->width;
    fb_row_current = client->frameBuffer + (y * fb_stride) + (x * bpp);

    /* Copy image data from VNC client to PNG */
    for (dy = y; dy<y+h; dy++) {

        unsigned int*  buffer_current;
        unsigned char* fb_current;
        
        /* Get current buffer row, advance to next */
        buffer_current      = (unsigned int*) buffer_row_current;
        buffer_row_current += stride;

        /* Get current framebuffer row, advance to next */
        fb_current      = fb_row_current;
        fb_row_current += fb_stride;

        for (dx = x; dx<x+w; dx++) {

            unsigned char red, green, blue;
            unsigned int v;

            switch (bpp) {
                case 4:
                    v = *((uint32_t*)  fb_current);
                    break;

                case 2:
                    v = *((uint16_t*) fb_current);
                    break;

                default:
                    v = *((uint8_t*)  fb_current);
            }

            /* Translate value to RGB */
            red   = (v >> client->format.redShift)   * 0x100 / (client->format.redMax  + 1);
            green = (v >> client->format.greenShift) * 0x100 / (client->format.greenMax+ 1);
            blue  = (v >> client->format.blueShift)  * 0x100 / (client->format.blueMax + 1);

            /* Output RGB */
            if (vnc_client->settings->swap_red_blue)
                *(buffer_current++) = (blue << 16) | (green << 8) | red;
            else
                *(buffer_current++) = (red  << 16) | (green << 8) | blue;

            fb_current += bpp;

        }
    }

    /* Create surface from decoded buffer */
    surface = cairo_image_surface_create_for_data(buffer, CAIRO_FORMAT_RGB24,
            w, h, stride);

    /* Draw directly to default layer */
    guac_common_surface_draw(vnc_client->display->default_surface,
            x, y, surface);

    /* Free surface */
    cairo_surface_destroy(surface);
    free(buffer);

}