Added test code to see how drawing lines would work.

src/cpu_display.c

@@ -1,4 +1,6 @@
 #include "../include/cpu_display.h"
+#include <SDL2/SDL_render.h>
+#include <stdio.h>
 
 void renderStatsBox(SDL_Renderer* renderer, TTF_Font* font, char* msg) {
     SDL_Rect dest, text_rect;
@@ -33,6 +35,36 @@ void renderBorderAndHeader(SDL_Renderer* renderer, TTF_Font* font) {
 
     SDL_Rect cell = {.x = 0, .y = 0};
 
-    cell.w = viewPort.w / CPU_STATS_DISPLAY_WIDTH;
-    cell.h = viewPort.h / CPU_STATS_DISPLAY_HEIGHT;
+    cell.w = viewPort.w / CPU_STATS_DISPLAY_COLUMN_COUNT;
+    cell.h = viewPort.h / CPU_STATS_DISPLAY_ROW_COUNT;
+    
+    unsigned int bg = 0x00000000;
+    //Set line color
+    SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
+
+    SDL_RenderDrawLine(renderer, cell.w / 2, cell.h / 2, cell.w / 2, cell.h * (CPU_STATS_DISPLAY_ROW_COUNT - 1) + cell.h / 2);
+
+    for (int i = 1; i < CPU_STATS_DISPLAY_ROW_COUNT - 1; i++) {
+        for(int j = 1; j < CPU_STATS_DISPLAY_COLUMN_COUNT - 1; j++) {
+            char red, green, blue;
+            red = bg >> 16 & 0xFF;
+            green = bg >> 8 & 0xFF;
+            blue = bg & 0xFF;
+
+            SDL_SetRenderDrawColor(renderer, red, green, blue, 255);
+
+            cell.x = cell.w * j;
+            cell.y = cell.h * i;
+
+            SDL_RenderFillRect(renderer, &cell);
+
+            SDL_SetRenderDrawColor(renderer, 255, 0, 0, 255);
+
+            SDL_RenderDrawLine(renderer, cell.x, cell.y + cell.h / 2, cell.x + cell.w, cell.y + cell.h / 2);
+
+            bg ^= 0xFFFFFFFF;
+        }
+
+        bg ^= 0xFFFFFFFF;
+    }
 }

src/main.c

@@ -124,7 +124,7 @@ void prepareScene(void)
   
   SDL_RenderSetViewport(app.renderer, &rect);
 
-  renderStatsBox(app.renderer, app.font, "Hello, World!");
+  renderBorderAndHeader(app.renderer, app.font);
 }
 
 void presentScene(void)