first step of the big refactoring ("tree" branch).

From here on, we can track changes. It made no sense to put the
development up to this point into git.

src/render.c

@@ -0,0 +1,137 @@
+/*
+ * vim:ts=4:sw=4:expandtab
+ */
+
+#include "all.h"
+
+/*
+ * "Renders" the given container (and its children), meaning that all rects are
+ * updated correctly. Note that this function does not call any xcb_*
+ * functions, so the changes are completely done in memory only (and
+ * side-effect free). As soon as you call x_push_changes(), the changes will be
+ * updated in X11.
+ *
+ */
+void render_con(Con *con) {
+    printf("currently rendering node %p / %s / layout %d\n",
+            con, con->name, con->layout);
+    int children = 0;
+    Con *child;
+    TAILQ_FOREACH(child, &(con->nodes_head), nodes)
+        children++;
+    printf("children: %d, orientation = %d\n", children, con->orientation);
+
+    /* Copy container rect, subtract container border */
+    /* This is the actually usable space inside this container for clients */
+    Rect rect = con->rect;
+    rect.x += 2;
+    rect.y += 2;
+    rect.width -= 2 * 2;
+    rect.height -= 2 * 2;
+
+    int x = rect.x;
+    int y = rect.y;
+
+    int i = 0;
+
+    printf("mapped = true\n");
+    con->mapped = true;
+
+    /* Check for fullscreen nodes */
+    Con *fullscreen = con_get_fullscreen_con(con);
+    if (fullscreen) {
+        LOG("got fs node: %p\n", fullscreen);
+        fullscreen->rect = rect;
+        render_con(fullscreen);
+        return;
+    }
+
+
+    TAILQ_FOREACH(child, &(con->nodes_head), nodes) {
+
+        /* default layout */
+        if (con->layout == L_DEFAULT) {
+            double percentage = 1.0 / children;
+            if (child->percent > 0.0)
+                percentage = child->percent;
+            printf("child %p / %s requests percentage %f\n",
+                    child, child->name, percentage);
+
+            if (con->orientation == HORIZ) {
+                child->rect.x = x;
+                child->rect.y = y;
+                child->rect.width = percentage * rect.width;
+                child->rect.height = rect.height;
+                x += child->rect.width;
+            } else {
+                child->rect.x = x;
+                child->rect.y = y;
+                child->rect.width = rect.width;
+                child->rect.height = percentage * rect.height;
+                y += child->rect.height;
+            }
+
+            /* first we have the decoration, if this is a leaf node */
+            if (con_is_leaf(child)) {
+                printf("that child is a leaf node, subtracting deco\n");
+                /* TODO: make a function for relative coords? */
+                child->deco_rect.x = child->rect.x - con->rect.x;
+                child->deco_rect.y = child->rect.y - con->rect.y;
+
+                child->rect.y += 17;
+                child->rect.height -= 17;
+
+                child->deco_rect.width = child->rect.width;
+                child->deco_rect.height = 17;
+            }
+        }
+
+        if (con->layout == L_STACKED) {
+            printf("stacked con\n");
+            child->rect.x = x;
+            child->rect.y = y;
+            child->rect.width = rect.width;
+            child->rect.height = rect.height;
+
+            child->rect.y += (17 * children);
+            child->rect.height -= (17 * children);
+
+            child->deco_rect.x = x - con->rect.x;
+            child->deco_rect.y = y - con->rect.y + (i * 17);
+            child->deco_rect.width = child->rect.width;
+            child->deco_rect.height = 17;
+        }
+
+        printf("child at (%d, %d) with (%d x %d)\n",
+                child->rect.x, child->rect.y, child->rect.width, child->rect.height);
+        printf("x now %d, y now %d\n", x, y);
+        if (child->window) {
+            /* depending on the border style, the rect of the child window
+             * needs to be smaller */
+            Rect *inset = &(child->window_rect);
+            *inset = (Rect){0, 0, child->rect.width, child->rect.height};
+            /* TODO: different border styles */
+            inset->x += 2;
+            inset->width -= 2 * 2;
+            inset->height -= 2;
+        }
+        x_raise_con(child);
+        render_con(child);
+        i++;
+    }
+
+    /* in a stacking container, we ensure the focused client is raised */
+    if (con->layout == L_STACKED) {
+        Con *foc = TAILQ_FIRST(&(con->focus_head));
+        x_raise_con(foc);
+    }
+
+    TAILQ_FOREACH(child, &(con->floating_head), floating_windows) {
+        LOG("render floating:\n");
+        LOG("floating child at (%d,%d) with %d x %d\n", child->rect.x, child->rect.y, child->rect.width, child->rect.height);
+        x_raise_con(child);
+        render_con(child);
+    }
+
+    printf("-- level up\n");
+}