screen: store RandR information

Signed-off-by: Julien Danjou <julien@danjou.info>

screen.c

@@ -23,6 +23,7 @@
 
 #include <xcb/xcb.h>
 #include <xcb/xinerama.h>
+#include <xcb/randr.h>
 
 #include "screen.h"
 #include "ewmh.h"
@@ -33,6 +34,16 @@
 #include "luaa.h"
 #include "common/xutil.h"
 
+struct screen_output_t
+{
+    /** The XRandR names of the output */
+    char *name;
+    /** The size in millimeters */
+    uint32_t mm_width, mm_height;
+};
+
+ARRAY_FUNCS(screen_output_t, screen_output, DO_NOTHING)
+
 static inline area_t
 screen_xsitoarea(xcb_xinerama_screen_info_t si)
 {
@@ -65,6 +76,79 @@ screen_default_visual(xcb_screen_t *s)
  */
 void
 screen_scan(void)
+{
+    /* Check for extension before checking for XRandR */
+    if(xcb_get_extension_data(globalconf.connection, &xcb_randr_id)->present)
+    {
+        xcb_randr_query_version_reply_t *version_reply =
+            xcb_randr_query_version_reply(globalconf.connection,
+                                          xcb_randr_query_version(globalconf.connection, 1, 1), 0);
+        if(version_reply)
+        {
+            /* A quick XRandR recall:
+             * You have CRTC that manages a part of a SCREEN.
+             * Each CRTC can draw stuff on one or more OUTPUT. */
+            xcb_screen_t *screen = xutil_screen_get(globalconf.connection, globalconf.default_screen);
+
+            xcb_randr_get_screen_resources_cookie_t screen_res_c = xcb_randr_get_screen_resources(globalconf.connection, screen->root);
+            xcb_randr_get_screen_resources_reply_t *screen_res_r = xcb_randr_get_screen_resources_reply(globalconf.connection, screen_res_c, NULL);
+
+            /* We go through CRTC, and build a screen for each one. */
+            xcb_randr_crtc_t *randr_crtcs = xcb_randr_get_screen_resources_crtcs(screen_res_r);
+
+            for(int i = 0; i < screen_res_r->num_crtcs; i++)
+            {
+                /* Get info on the output crtc */
+                xcb_randr_get_crtc_info_cookie_t crtc_info_c = xcb_randr_get_crtc_info(globalconf.connection, randr_crtcs[i], XCB_CURRENT_TIME);
+                xcb_randr_get_crtc_info_reply_t *crtc_info_r = xcb_randr_get_crtc_info_reply(globalconf.connection, crtc_info_c, NULL);
+
+                /* If CRTC has no OUTPUT, ignore it */
+                if(!xcb_randr_get_crtc_info_outputs_length(crtc_info_r))
+                    continue;
+
+                /* Prepare the new screen */
+                screen_t new_screen;
+                p_clear(&new_screen, 1);
+                new_screen.geometry.x = crtc_info_r->x;
+                new_screen.geometry.y = crtc_info_r->y;
+                new_screen.geometry.width= crtc_info_r->width;
+                new_screen.geometry.height= crtc_info_r->height;
+
+                xcb_randr_output_t *randr_outputs = xcb_randr_get_crtc_info_outputs(crtc_info_r);
+
+                for(int j = 0; j < xcb_randr_get_crtc_info_outputs_length(crtc_info_r); j++)
+                {
+                    xcb_randr_get_output_info_cookie_t output_info_c = xcb_randr_get_output_info(globalconf.connection, randr_outputs[j], XCB_CURRENT_TIME);
+                    xcb_randr_get_output_info_reply_t *output_info_r = xcb_randr_get_output_info_reply(globalconf.connection, output_info_c, NULL);
+
+                    int len = xcb_randr_get_output_info_name_length(output_info_r);
+                    /* name is not NULL terminated */
+                    char *name = memcpy(p_new(char *, len + 1), xcb_randr_get_output_info_name(output_info_r), len);
+                    name[len] = '\0';
+
+                    screen_output_array_append(&new_screen.outputs,
+                                               (screen_output_t) { .name = name,
+                                                                   .mm_width = output_info_r->mm_width,
+                                                                   .mm_height = output_info_r->mm_height });
+
+                    p_delete(&output_info_r);
+                }
+
+                screen_array_append(&globalconf.screens, new_screen);
+
+                p_delete(&crtc_info_r);
+            }
+
+            p_delete(&screen_res_r);
+
+            /* If RandR provides more than 2 active CRTC, Xinerama is enabled */
+            if(globalconf.screens.len > 1)
+                globalconf.xinerama_is_active = true;
+
+            globalconf.screens.tab[0].visual = screen_default_visual(xutil_screen_get(globalconf.connection, globalconf.default_screen));
+        }
+    }
+    else
     {
         /* Check for extension before checking for Xinerama */
         if(xcb_get_extension_data(globalconf.connection, &xcb_xinerama_id)->present)
@@ -135,6 +219,7 @@ screen_scan(void)
                 s.visual = screen_default_visual(xcb_screen);
                 screen_array_append(&globalconf.screens, s);
             }
+    }
 
     globalconf.screen_focus = globalconf.screens.tab;
 }

screen.h

@@ -25,6 +25,9 @@
 #include "globalconf.h"
 #include "draw.h"
 
+typedef struct screen_output_t screen_output_t;
+ARRAY_TYPE(screen_output_t, screen_output)
+
 struct a_screen
 {
     /** Screen geometry */
@@ -50,6 +53,8 @@ struct a_screen
     signal_array_t signals;
     /** True if the banning on this screen needs to be updated */
     bool need_lazy_banning;
+    /** The screen outputs informations */
+    screen_output_array_t outputs;
 };
 ARRAY_FUNCS(screen_t, screen, DO_NOTHING)