added support for combo from an array of struct

demo/common/overview.c

@@ -18,7 +18,7 @@ overview(struct nk_context *ctx)
 
 #ifdef INCLUDE_STYLE
     /* styles */
-    static const char* themes[] = {"Black", "White", "Red", "Blue", "Dark", "Dracula", 
+    static const char* themes[] = {"Black", "White", "Red", "Blue", "Dark", "Dracula",
       "Catppucin Latte", "Catppucin Frappe", "Catppucin Macchiato", "Catppucin Mocha"};
     static int current_theme = 0;
 #endif
@@ -584,6 +584,50 @@ overview(struct nk_context *ctx)
                         nk_combo_end(ctx);
                     }
                 }
+                {
+                    /* Combobox from array of struct */
+                    static int sel=0;
+                    struct student {
+                        int id;
+                        char* name;
+                        int age;
+                        char* major;
+                    };
+
+                    static struct student students[3] = {
+                        {
+                            .id = 1,
+                            .name = "Mike",
+                            .age = 20,
+                            .major = "CS"
+                        },
+                        {
+                            .id = 2,
+                            .name = "Jim",
+                            .age = 19,
+                            .major = "Maths"
+                        },
+                        {
+                            .id = 3,
+                            .name = "Julia",
+                            .age = 20,
+                            .major = "Biology"
+                        }
+                    };
+                    sel = nk_combo_from_struct_array(ctx, &students, 3,
+                                sizeof(struct student),
+                                offsetof(struct student, name),
+                                sel, 15, nk_vec2(200,200));
+                    if(sel>0){
+                        nk_layout_row_static(ctx, 30,300, 2);
+                        nk_labelf(ctx, NK_TEXT_LEFT, "id:%d | name:%s | age:%d | major:%s",
+                                   students[sel].id,
+                                   students[sel].name,
+                                   students[sel].age,
+                                   students[sel].major
+                                  );
+                    }
+                }
 
                 nk_tree_pop(ctx);
             }

nuklear.h

@@ -3765,7 +3765,8 @@ NK_API int nk_combo(struct nk_context*, const char *const *items, int count, int
 NK_API int nk_combo_separator(struct nk_context*, const char *items_separated_by_separator, int separator, int selected, int count, int item_height, struct nk_vec2 size);
 NK_API int nk_combo_string(struct nk_context*, const char *items_separated_by_zeros, int selected, int count, int item_height, struct nk_vec2 size);
 NK_API int nk_combo_callback(struct nk_context*, void(*item_getter)(void*, int, const char**), void *userdata, int selected, int count, int item_height, struct nk_vec2 size);
-NK_API void nk_combobox(struct nk_context*, const char *const *items, int count, int *selected, int item_height, struct nk_vec2 size);
+NK_API int nk_combo_from_struct_array(struct nk_context *ctx, const void *items, int count, int item_sz, int stride, int selected, int item_height, struct nk_vec2 size);
+NK_API void nk_combobox(struct nk_context*, const char **items, int count, int *selected, int item_height, struct nk_vec2 size);
 NK_API void nk_combobox_string(struct nk_context*, const char *items_separated_by_zeros, int *selected, int count, int item_height, struct nk_vec2 size);
 NK_API void nk_combobox_separator(struct nk_context*, const char *items_separated_by_separator, int separator, int *selected, int count, int item_height, struct nk_vec2 size);
 NK_API void nk_combobox_callback(struct nk_context*, void(*item_getter)(void*, int, const char**), void*, int *selected, int count, int item_height, struct nk_vec2 size);
@@ -30504,6 +30505,41 @@ nk_combo_callback(struct nk_context *ctx, void(*item_getter)(void*, int, const c
         nk_combo_end(ctx);
     } return selected;
 }
+
+
+NK_API int nk_combo_from_struct_array(struct nk_context *ctx, const void *items, int count, int item_sz, int stride, int selected, int item_height, struct nk_vec2 size)
+{
+    int i = 0;
+    int max_height;
+    struct nk_vec2 item_spacing;
+    struct nk_vec2 window_padding;
+    char* sel;
+    char* name;
+    NK_ASSERT(ctx);
+    NK_ASSERT(items);
+    NK_ASSERT(ctx->current);
+    if (!ctx || !items ||!count)
+        return selected;
+
+    item_spacing = ctx->style.window.spacing;
+    window_padding = nk_panel_get_padding(&ctx->style, ctx->current->layout->type);
+    max_height = count * item_height + count * (int)item_spacing.y;
+    max_height += (int)item_spacing.y * 2 + (int)window_padding.y * 2;
+    size.y = NK_MIN(size.y, (float)max_height);
+    sel = *(char**)((char*)items + (item_sz*selected) + stride);
+    if (nk_combo_begin_label(ctx, sel, size)) {
+        nk_layout_row_dynamic(ctx, (float)item_height, 1);
+        for (i = 0; i < count; ++i) {
+            name = *(char**)((char*)items + stride);
+            if (nk_combo_item_label(ctx, name, NK_TEXT_LEFT))
+                selected = i;
+            items = (char*)items + item_sz;
+        }
+        nk_combo_end(ctx);
+    }
+    return selected;
+}
+
 NK_API void
 nk_combobox(struct nk_context *ctx, const char *const *items, int count,
     int *selected, int item_height, struct nk_vec2 size)

src/nuklear.h

@@ -3543,7 +3543,28 @@ NK_API int nk_combo(struct nk_context*, const char *const *items, int count, int
 NK_API int nk_combo_separator(struct nk_context*, const char *items_separated_by_separator, int separator, int selected, int count, int item_height, struct nk_vec2 size);
 NK_API int nk_combo_string(struct nk_context*, const char *items_separated_by_zeros, int selected, int count, int item_height, struct nk_vec2 size);
 NK_API int nk_combo_callback(struct nk_context*, void(*item_getter)(void*, int, const char**), void *userdata, int selected, int count, int item_height, struct nk_vec2 size);
-NK_API void nk_combobox(struct nk_context*, const char *const *items, int count, int *selected, int item_height, struct nk_vec2 size);
+/*
+ * \brief create a combobox from an array of strct containing a `char*` member that we use as a name
+ *  this avoids the need to have two arrays (one being for the array of structs, and one for the names)
+ *
+ * \details
+ * ```c
+ *  int nk_combo_from_struct_array(struct nk_context *ctx, const void *items, int count, int item_sz, int stride, int selected, int item_height, struct nk_vec2 size);
+ *  ```
+ *
+ *  \param[in] ctx             | Must point to an previously initialized `nk_context` struct after calling a layouting function
+ *  \param[in] items           | `void` pointer to a list of structures
+ *  \param[in] count           | Number of elements in the array of structs
+ *  \param[in] items_sz        | Size of an individual structure.
+ *  \param[in] stride          | Stride to a char* member inside the structure
+ *  \param[in] selected        | the index of the current selected item
+ *  \param[in] item_height     | Height of the element
+ *  \param[in] size            | Size of the element listing, must point to a `nk_vec2` structure
+ *
+ *  \returns the index of the newly selected item.
+ */
+NK_API int nk_combo_from_struct_array(struct nk_context *ctx, const void *items, int count, int item_sz, int stride, int selected, int item_height, struct nk_vec2 size);
+NK_API void nk_combobox(struct nk_context*, const char **items, int count, int *selected, int item_height, struct nk_vec2 size);
 NK_API void nk_combobox_string(struct nk_context*, const char *items_separated_by_zeros, int *selected, int count, int item_height, struct nk_vec2 size);
 NK_API void nk_combobox_separator(struct nk_context*, const char *items_separated_by_separator, int separator, int *selected, int count, int item_height, struct nk_vec2 size);
 NK_API void nk_combobox_callback(struct nk_context*, void(*item_getter)(void*, int, const char**), void*, int *selected, int count, int item_height, struct nk_vec2 size);

src/nuklear_combo.c

@@ -819,6 +819,43 @@ nk_combo_callback(struct nk_context *ctx, void(*item_getter)(void*, int, const c
         nk_combo_end(ctx);
     } return selected;
 }
+
+
+NK_API int nk_combo_from_struct_array(struct nk_context *ctx, const void *items, int count, int item_sz, int stride, int selected, int item_height, struct nk_vec2 size)
+{
+    int i = 0;
+    int max_height;
+    struct nk_vec2 item_spacing;
+    struct nk_vec2 window_padding;
+    char* sel;
+    char* name;
+    NK_ASSERT(ctx);
+    NK_ASSERT(items);
+    NK_ASSERT(ctx->current);
+    if (!ctx || !items ||!count)
+        return selected;
+
+    item_spacing = ctx->style.window.spacing;
+    window_padding = nk_panel_get_padding(&ctx->style, ctx->current->layout->type);
+    max_height = count * item_height + count * (int)item_spacing.y;
+    max_height += (int)item_spacing.y * 2 + (int)window_padding.y * 2;
+    size.y = NK_MIN(size.y, (float)max_height);
+    sel = *(char**)((char*)items + (item_sz*selected) + stride);
+    if (nk_combo_begin_label(ctx, sel, size)) {
+        nk_layout_row_dynamic(ctx, (float)item_height, 1);
+        for (i = 0; i < count; ++i) {
+            name = *(char**)((char*)items + stride);
+            if(!name)
+                name = "";
+            if (nk_combo_item_label(ctx, name, NK_TEXT_LEFT))
+                selected = i;
+            items = (char*)items + item_sz;
+        }
+        nk_combo_end(ctx);
+    }
+    return selected;
+}
+
 NK_API void
 nk_combobox(struct nk_context *ctx, const char *const *items, int count,
     int *selected, int item_height, struct nk_vec2 size)