remove gaps from between tiles

fixes #42

extension.js

@@ -127,14 +127,17 @@ function moveApp(app, loc) {
     _log(`moveApp) isNotUltrawide: ${isNotUltrawide}`);
 
     var colCount = config.cols === 2 || (config.ultrawideOnly && isNotUltrawide) ? 2 : config.cols;
+    space.parts = splitScreenWidth(space.width, colCount);
+    _log(`space: ${JSON.stringify(space)}`);
     if (loc.col >= colCount)
         loc.col = 1;
-    var colWidth = Math.floor(space.width / colCount);
+
+    var colWidth = space.parts[loc.col].partialWidth;
     var rowHeight = Math.floor(space.height / 2);
 
-    let x = loc.col * colWidth + space.x;
+    let x = space.parts[loc.col].partialOffset + space.x;
     let y = loc.row * rowHeight + space.y;
-    let w = loc.width * colWidth;
+    let w = colWidth;
     let h = loc.height * rowHeight;
 
     if (!config.useMaximize) {
@@ -1115,6 +1118,23 @@ function getCurrentMonitor() {
     return monitorProvider.get_current_monitor();
 }
 
+/**
+ * @param {number} screenWidth - screen width
+ * @param {number} colCount - number of cols to split into
+ */
+function splitScreenWidth(screenWidth, colCount) {
+    var partSize = Math.floor(screenWidth / colCount);
+    var leftover = screenWidth % colCount;
+
+    var parts = new Array(colCount).fill(partSize).map(function (size, index) {
+        return {
+            partialWidth: size + (index < leftover ? 1 : 0),
+            partialOffset: index * partSize + Math.min(index, leftover)
+        };
+    });
+    return parts;
+}
+
 /**
  *
  */