cut down on the number of loops through the directory listing

main.go

@@ -93,24 +93,26 @@ func newBrowse(file string) {
 		log.Printf("could not open dir: %v", err)
 		return
 	}
-	directoryState.images = []string{}
-	for _, v := range dirfiles {
-		if filetypes.IsImage(v) {
-			directoryState.images = append(directoryState.images, v.Name())
-		}
-	}
-	slices.SortFunc(directoryState.images, func(a, b string) int {
-		if natural.Less(a, b) {
+	// natsort the directory listing first...
+	slices.SortFunc(dirfiles, func(a, b os.DirEntry) int {
+		if natural.Less(a.Name(), b.Name()) {
 			return -1
 		}
 		return 1
 	})
+	// ...that way we only have to do this loop once.
 	clearFileList()
-	for i, v := range directoryState.images {
-		insertIntoFileList(directoryState.images[i])
-		if v == filepath.Base(file) {
-			directoryState.i = i
-			moveSelectionInFileList(i)
+	directoryState.images = []string{}
+	i := 0
+	for _, v := range dirfiles {
+		if filetypes.IsImage(v) {
+			directoryState.images = append(directoryState.images, v.Name())
+			insertIntoFileList(directoryState.images[i])
+			if v.Name() == filepath.Base(file) {
+				directoryState.i = i
+				moveSelectionInFileList(i)
+			}
+			i++
 		}
 	}
 	updateImage(file)
@@ -225,19 +227,18 @@ func constructFileList() {
 		fileList = nil
 		fileListBindVar.Set("0")
 	}))
+	clearFileList()
+	for i := range directoryState.images {
+		insertIntoFileList(directoryState.images[i])
+		if directoryState.i == i {
+			moveSelectionInFileList(i)
+		}
+	}
 }
 
 func showFileList() {
 	if fileList == nil {
 		constructFileList()
-		// repopulate
-		lb.Delete("0", "end")
-		for i := range directoryState.images {
-			lb.Insert("end", directoryState.images[i])
-			if directoryState.i == i {
-				lb.SelectionSet(i)
-			}
-		}
 	}
 	tk.WmDeiconify(fileList.Window)
 	fileListBindVar.Set("1")