calculate cropping boxes for the image

src/pages/profile_page.html

@@ -103,6 +103,7 @@
             class="noselect"
             draggable="false"
         />
+        <div id="image_dark_overlay" draggable="false"></div>
     </div>
     <div id="grab-area" draggable="false">
         <div id="box-scale-holder">
@@ -127,7 +128,9 @@
                 class="resize_anchor"
             ></div>
         </div>
-        <div id="resize_photo_box" draggable="false"></div>
+        <div id="resize_photo_box" draggable="false">
+            <div id="circle-display"></div>
+        </div>
     </div>
     <button id="confirm_change" draggable="false">Confirm Change</button>
 </div>
@@ -261,6 +264,12 @@
         new_profile_image.style.setProperty("--x-size", image_width + "px");
         new_profile_image.style.setProperty("--y-size", image_height + "px");
 
+        image_dark_overlay.style.setProperty("--x-size", image_width + "px");
+        image_dark_overlay.style.setProperty("--y-size", image_height + "px");
+
+        image_dark_overlay.style.setProperty("--x-offset", "0px");
+        image_dark_overlay.style.setProperty("--y-offset", "0px");
+
         resize_photo_box.style.setProperty("--size", "350px");
     });
 

static/javascript/resize_photo_dialouge.js

@@ -1,4 +1,5 @@
 const resize_photo_box = document.getElementById("resize_photo_box");
+const image_dark_overlay = document.getElementById("image_dark_overlay");
 
 // Drag handling
 var startXOffset = 0,
@@ -22,14 +23,42 @@ function calculateOffsets() {
   return { x: xOffset + left + right, y: yOffset + top + bottom };
 }
 
+function calculateBoxBoundsOnImage() {
+  offsets = calculateOffsets();
+
+  const x_overspill = image_width - 360;
+  const left_overspill = x_overspill / 2 - offsets.x;
+  // const right_overspill = x_overspill / 2 - offsets.y;
+
+  const y_overspill = image_height - 360;
+  const top_overspill = y_overspill / 2 - offsets.y;
+
+  return {
+    left: left_overspill + 5,
+    right: left_overspill + 5 + 350,
+    top: top_overspill + 5,
+    bottom: top_overspill + 350 + 5,
+  };
+}
+
 var mouseClicked = false;
 resize_photo_box.addEventListener("mousemove", () => {
   if (!mouseClicked) return;
 
   offsets = calculateOffsets();
 
-  y_top = new_profile_image.style.setProperty("--x-offset", offsets.x + "px");
+  new_profile_image.style.setProperty("--x-offset", offsets.x + "px");
   new_profile_image.style.setProperty("--y-offset", offsets.y + "px");
+
+  image_dark_overlay.style.setProperty("--x-offset", offsets.x + "px");
+  image_dark_overlay.style.setProperty("--y-offset", offsets.y + "px");
+
+  bounds = calculateBoxBoundsOnImage();
+  image_dark_overlay.style.setProperty("--left-edge", bounds.left + "px");
+  image_dark_overlay.style.setProperty("--right-edge", bounds.right + "px");
+
+  image_dark_overlay.style.setProperty("--top-edge", bounds.top + "px");
+  image_dark_overlay.style.setProperty("--bottom-edge", bounds.bottom + "px");
 });
 
 resize_photo_box.addEventListener("mousedown", () => {

static/profile_page.css

@@ -156,6 +156,7 @@
 
 #image_container {
     position: absolute;
+    display: inline-block;
 }
 
 #darken_part {
@@ -252,3 +253,42 @@
     width: 360px;
     height: 360px;
 }
+
+#circle-display {
+    width: 100%;
+    height: 100%;
+    background: radial-gradient(
+        circle closest-side,
+        transparent 99%,
+        rgba(0, 0, 0, 0.5) 100%
+    );
+    display: none;
+}
+
+#image_dark_overlay {
+    background-color: rgba(0, 0, 0, 0.5);
+    pointer-events: none;
+
+    z-index: 2;
+
+    transform: translateX(calc(-50% + var(--x-offset) + 5px))
+        translateY(calc(-50% + var(--y-offset) + 5px));
+    position: absolute;
+    left: calc(350px / 2);
+    top: calc(350px / 2);
+    width: var(--x-size);
+    height: var(--y-size);
+
+    clip-path: polygon(
+        0% 0%,
+        0% 100%,
+        var(--left-edge) 100%,
+        var(--left-edge) var(--top-edge),
+        var(--right-edge) var(--top-edge),
+        var(--right-edge) var(--bottom-edge),
+        var(--left-edge) var(--bottom-edge),
+        var(--left-edge) 100%,
+        100% 100%,
+        100% 0%
+    );
+}