xcb illustrate pseudo transparency (copy of root window pixmap to a children window background)

xcb

Solution

As nobody helps me, I find the solution alone:

I just have to copy part of the root pixmap in my window:

xcb_copy_area_checked(backbone.connection,
          rootpix,
          my_window,
          graphic_context,
          x, y,
          0, 0,
          width, height)

It works even if I am not sure it's the best way to do it.

Problem

I want to illustrate the pseudo transparency of windows with xcb (copy part of root windows pixmap on a window background) For that, I use: the root pixmap is set with feh then I launch my programm which do (just part of code): ->initialize connection : ``` xcb_connect() ``` ->create the window: ``` xcb_create_window() xcb_create_pixmap( connection,screen->root_depth, pixmap, screen->root, width, height) xcb_create_gc( connection, graphic_context, pixmap, XCB_GC_FOREGROUND | XCB_GC_BACKGROUND, gc_values_mask) xcb_map_window ``` ->grab xcb event: ``` xcb_wait_for_event ``` ->answer to map_request_event ( when it's the request of our window) or property_notify (when changed property is the root pixmap via feh): get the root pixmap: ``` xcb_get_property / xcb_get_property_reply / xcb_get_property_value ==> this works ``` copy part of the root pixmap to window pixmap: ``` xcb_copy_area_checked(backbone.connection, rootpix, pixmap, graphic_context, x, y, 0, 0, width, height) ``` I use xcb_request_check but it seems that I have no error with this last request. Then I draw elements in my window with cairo. The problem is that I just see a white window with the element draw by cairo. Even without the cairo elements, I can't display the copied pixmap of my window. Have you got any idea to help me? Thanks

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