added last_frame in nano seconds

updated example

3 files changed, 12 insertions, 3 deletions

diff --git a/src/main.c b/src/main.c
index b77e944..77c5f49 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,3 +1,4 @@
+#include <stdint.h>
 #include <stdio.h>
 #include <unistd.h>
 
@@ -11,6 +12,9 @@ void on_button_click(const MOUSE_ACTION *mouse_action) {
 
 WIDGET *ui_build(TUI *tui) {
   if (is_clicked) {
+    char frame[20+3+1];
+    const uint64_t fps = 1000000000/tui->last_frame;
+    sprintf(frame, "%ldfps", fps);
     return tui_make_box(
         -1, -1,
         tui_make_column(tui_make_widget_array(
@@ -20,7 +24,7 @@ WIDGET *ui_build(TUI *tui) {
                 tui_make_box(
                     20, 3,
                     tui_make_column(tui_make_widget_array(
-                        tui_make_text("This is the second page", COLOR_BLUE),
+                        tui_make_text(frame, COLOR_BLUE),
                         tui_make_button(tui_make_text("       Back", COLOR_RED),
                                         on_button_click))),
                     COLOR_WHITE))))),
diff --git a/src/ui/tui.c b/src/ui/tui.c
index 16cef30..5f6acaa 100644
--- a/src/ui/tui.c
+++ b/src/ui/tui.c
@@ -1,6 +1,7 @@
 #include "tui.h"
 
 #include <stdarg.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -513,10 +514,11 @@ bool widget_eqauls(const WIDGET *restrict left, const WIDGET *restrict right) {
 
 const int NANO_TO_SECOND = 1000000000;
 
-void nano_sleep(long int nano_seconds) {
+int64_t nano_sleep(long int nano_seconds) {
   struct timespec remaining,
       request = {nano_seconds / NANO_TO_SECOND, nano_seconds % NANO_TO_SECOND};
   nanosleep(&request, &remaining);
+  return remaining.tv_sec * NANO_TO_SECOND + remaining.tv_nsec;
 }
 
 long int nano_time() {
@@ -528,6 +530,7 @@ long int nano_time() {
 void tui_main_loop(TUI *tui, WIDGET_BUILDER widget_builder, int fps) {
   const long int frame_nano =
       (fps == FRAME_UNLIMITED) ? 0 : NANO_TO_SECOND / fps;
+  int64_t last_remaining = 0;
   while (1) {
     const long int start = nano_time();
     tui_save_cursor();
@@ -546,8 +549,9 @@ void tui_main_loop(TUI *tui, WIDGET_BUILDER widget_builder, int fps) {
     tui_restore_cursor();
     if (fps != FRAME_UNLIMITED) {
       const long int diff = nano_time() - start;
-      nano_sleep(frame_nano - diff);
+      last_remaining = nano_sleep(frame_nano - diff + last_remaining);
     }
+    tui->last_frame = nano_time() - start;
     if (kbhit()) {
       if (handle_input(tui)) {
         return;
diff --git a/src/ui/tui.h b/src/ui/tui.h
index 436e132..baf0c3a 100644
--- a/src/ui/tui.h
+++ b/src/ui/tui.h
@@ -62,6 +62,7 @@ typedef struct TUI {
   int init_cursor_x, init_cursor_y;
   TERMINAL_CELL *cells;
   size_t cells_length;
+  uint64_t last_frame; // in nanoseconds
 } TUI;
 
 typedef enum WIDGET_TYPE {