add ui element helper macros

src/ui.h

@@ -5,6 +5,20 @@
 
 #define MAX_UI_ELEMENTS 2048
 
+#define _elm(index) (&cx->frame_elements.data[index])
+
+#define _first(index) (_elm(index)->first)
+#define _last(index) (_elm(index)->last)
+#define _next(index) (_elm(index)->next)
+#define _prev(index) (_elm(index)->prev)
+#define _parent(index) (_elm(index)->parent)
+
+#define _first_ref(index) (_elm(_first(index)))
+#define _last_ref(index) (_elm(_last(index)))
+#define _next_ref(index) (_elm(_next(index)))
+#define _prev_ref(index) (_elm(_prev(index)))
+#define _parent_ref(index) (_elm(_parent(index)))
+
 #include <stddef.h>
 #include <stdint.h>
 #include <stdbool.h>
@@ -99,16 +113,6 @@ ui_context init_ui_context() {
     };
 }
 
-static ui_element_frame_data *_ui_element_last(ui_context *cx, size_t parent_index) {
-    size_t last_index = cx->frame_elements.data[parent_index].last;
-
-    if (last_index) {
-        return &cx->frame_elements.data[last_index];
-    }
-
-    return NULL;
-}
-
 size_t ui_element(ui_context *cx, string label) {
     ui_element_frame_data frame_data = (ui_element_frame_data) {
         .index = cx->frame_elements.size,
@@ -140,12 +144,19 @@ size_t ui_element(ui_context *cx, string label) {
     pushArray(ui_element_frame_data, &cx->frame_elements, frame_data);
 
     if (frame_data.prev) {
-        cx->frame_elements.data[frame_data.prev].next = frame_data.index;
+        _prev_ref(frame_data.index)->next = frame_data.index;
     }
-    if (cx->frame_elements.data[cx->current_parent].first == 0) {
-        cx->frame_elements.data[cx->current_parent].first = frame_data.index;
+    if (_elm(cx->current_parent)->first == 0) {
+        _elm(cx->current_parent)->first = frame_data.index;
     }
-    cx->frame_elements.data[cx->current_parent].last = frame_data.index;
+    _elm(cx->current_parent)->last = frame_data.index;
+}
+
+void ui_compute_layout(ui_context *cx, uint32_t canvas_size[2], size_t element_index) {
+    ui_axis axis = UI_AXIS_HORIZONTAL;
+
+    // FIXME: change me to use -1 for no reference to element
+    // TODO: actually compute layout
 }
 
 #endif