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node_modules/potpack/index.js

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+/**
+ * @typedef {Object} PotpackBox
+ * @property {number} w Box width.
+ * @property {number} h Box height.
+ * @property {number} [x] X coordinate in the resulting container.
+ * @property {number} [y] Y coordinate in the resulting container.
+ */
+
+/**
+ * @typedef {Object} PotpackStats
+ * @property {number} w Width of the resulting container.
+ * @property {number} h Height of the resulting container.
+ * @property {number} fill The space utilization value (0 to 1). Higher is better.
+ */
+
+/**
+ * Packs 2D rectangles into a near-square container.
+ *
+ * Mutates the {@link boxes} array: it's sorted (by height/width),
+ * and box objects are augmented with `x`, `y` coordinates.
+ *
+ * @param {PotpackBox[]} boxes
+ * @return {PotpackStats}
+ */
+export default function potpack(boxes) {
+
+    // calculate total box area and maximum box width
+    let area = 0;
+    let maxWidth = 0;
+
+    for (const box of boxes) {
+        area += box.w * box.h;
+        maxWidth = Math.max(maxWidth, box.w);
+    }
+
+    // sort the boxes for insertion by height, descending
+    boxes.sort((a, b) => b.h - a.h);
+
+    // aim for a squarish resulting container,
+    // slightly adjusted for sub-100% space utilization
+    const startWidth = Math.max(Math.ceil(Math.sqrt(area / 0.95)), maxWidth);
+
+    // start with a single empty space, unbounded at the bottom
+    const spaces = [{x: 0, y: 0, w: startWidth, h: Infinity}];
+
+    let width = 0;
+    let height = 0;
+
+    for (const box of boxes) {
+        // look through spaces backwards so that we check smaller spaces first
+        for (let i = spaces.length - 1; i >= 0; i--) {
+            const space = spaces[i];
+
+            // look for empty spaces that can accommodate the current box
+            if (box.w > space.w || box.h > space.h) continue;
+
+            // found the space; add the box to its top-left corner
+            // |-------|-------|
+            // |  box  |       |
+            // |_______|       |
+            // |         space |
+            // |_______________|
+            box.x = space.x;
+            box.y = space.y;
+
+            height = Math.max(height, box.y + box.h);
+            width = Math.max(width, box.x + box.w);
+
+            if (box.w === space.w && box.h === space.h) {
+                // space matches the box exactly; remove it
+                const last = spaces.pop();
+                if (last && i < spaces.length) spaces[i] = last;
+
+            } else if (box.h === space.h) {
+                // space matches the box height; update it accordingly
+                // |-------|---------------|
+                // |  box  | updated space |
+                // |_______|_______________|
+                space.x += box.w;
+                space.w -= box.w;
+
+            } else if (box.w === space.w) {
+                // space matches the box width; update it accordingly
+                // |---------------|
+                // |      box      |
+                // |_______________|
+                // | updated space |
+                // |_______________|
+                space.y += box.h;
+                space.h -= box.h;
+
+            } else {
+                // otherwise the box splits the space into two spaces
+                // |-------|-----------|
+                // |  box  | new space |
+                // |_______|___________|
+                // | updated space     |
+                // |___________________|
+                spaces.push({
+                    x: space.x + box.w,
+                    y: space.y,
+                    w: space.w - box.w,
+                    h: box.h
+                });
+                space.y += box.h;
+                space.h -= box.h;
+            }
+            break;
+        }
+    }
+
+    return {
+        w: width, // container width
+        h: height, // container height
+        fill: (area / (width * height)) || 0 // space utilization
+    };
+}