made turn_left working (sorta)

I need to make it infinite, the it will be perfect

res/script.js

@@ -1,16 +1,38 @@
+const WIDTH = 1000;
+const ASPECT_RATIO = 1/2;
+
+//CANVAS SHIT
+let ctx;
+let canvas;
+let img; //THE PANORAMA IMAGE
+
+//CURRENT IMAGE STATE
+let x1 = WIDTH / 2;
+let x2;
+
 function load_panorama()
 {
-    let ctx = document.getElementById('panorama').getContext('2d');
+    canvas = document.getElementById('panorama');
-    let img = new Image();
+    ctx = canvas.getContext('2d');
-    const width = 5000;
+    img = new Image(); //IMAGE
 
-    ctx.canvas.width = width;
+    ctx.canvas.height = WIDTH / 2;
-    ctx.canvas.height = width / 2;
+    ctx.canvas.width = WIDTH / 2;
 
     img.onload = function()
     {
-        ctx.drawImage(img, 0, 0, img.width, img.height, 0, 0, width, width / 2);
+        x2 = img.width;
+        ctx.drawImage(img, x1, 0, x2, img.height, 0, 0, WIDTH, WIDTH * ASPECT_RATIO); //DRAW A HALF OF img
     };
 
     img.src = './res/img/test.jpg';
 }
+
+function turn_left() //TODO: MOVE THE RIGHT PART TO LEFT
+{
+    //MOVE AN 8th TO LEFT
+    x1 -= WIDTH / 8;
+    x2 -= WIDTH / 8;
+
+    ctx.drawImage(img, x1, 0, img.width - WIDTH / 8, img.height, 0, 0, WIDTH, WIDTH * ASPECT_RATIO); //DRAW
+}