add action columns-width-equalize (resolves #22)

src/Actions.ts

@@ -176,6 +176,12 @@ namespace Actions {
                 });
             },
 
+            columnsWidthEqualize: () => {
+                world.do((clientManager, desktopManager) => {
+                    desktopManager.getCurrentDesktop().equalizeVisibleColumnsWidths();
+                });
+            },
+
             gridScrollLeft: () => {
                 gridScroll(world, -config.manualScrollStep);
             },

src/keyBindings/definition.ts

@@ -125,6 +125,12 @@ const keyBindings: KeyBinding[] = [
         "defaultKeySequence": "Meta+Ctrl+-",
         "action": "columnWidthDecrease",
     },
+    {
+        "name": "columns-width-equalize",
+        "description": "Equalize widths of visible columns",
+        "defaultKeySequence": "Meta+Ctrl+X",
+        "action": "columnsWidthEqualize",
+    },
     {
         "name": "grid-scroll-focused",
         "description": "Center focused window",

src/layout/Desktop.ts

@@ -145,6 +145,20 @@ class Desktop {
         this.setScroll(this.scrollX, false);
     }
 
+    public equalizeVisibleColumnsWidths() {
+        const scrollPos = this.getCurrentScrollPos();
+        const visibleColumns = Array.from(this.grid.getVisibleColumns(scrollPos, true));
+
+        let remainingWidth = this.tilingArea.width - (visibleColumns.length-1) * this.grid.config.gapsInnerHorizontal;
+        let remainingColumns = visibleColumns.length;
+        for (const column of visibleColumns) {
+            const columnWidth = Math.round(remainingWidth / remainingColumns);
+            column.setWidth(columnWidth, true);
+            remainingWidth -= columnWidth;
+            remainingColumns--;
+        }
+    }
+
     public arrange() {
         // TODO (optimization): only arrange visible windows
         this.updateArea();

src/layout/Grid.ts

@@ -113,6 +113,14 @@ class Grid {
         return last;
     }
 
+    public *getVisibleColumns(scrollPos: Desktop.ScrollPos, fullyVisible: boolean) {
+        for (const column of this.columns.iterator()) {
+            if (column.isVisible(scrollPos, fullyVisible)) {
+                yield column;
+            }
+        }
+    }
+
     public getVisibleColumnsWidth(scrollPos: Desktop.ScrollPos, fullyVisible: boolean) {
         let width = 0;
         let nVisible = 0;