Add date format specifiers "j" for day-of-year and "w" for week-of-year

closes #49
closes #50

PasteIntoFile/Main.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Globalization;
 using System.IO;
 using System.Text.RegularExpressions;
 using System.Threading.Tasks;
@@ -540,6 +541,14 @@ public string Format(string format, object arg, IFormatProvider formatProvider)
                 }
                 throw new FormatException("Invalid format string '" + format + "'. Expected a positive integer specifying maximum length.");
             }
+            // DateTime
+            if (arg is DateTime dt && !string.IsNullOrEmpty(format)) {
+                // `j` for day of year
+                format = Regex.Replace(format, @"j+", m => dt.DayOfYear.ToString(new string('0', m.Value.Length)));
+                // `w` for week of year
+                var week = CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(dt, CultureInfo.CurrentCulture.DateTimeFormat.CalendarWeekRule, CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek);
+                format = Regex.Replace(format, @"w+", m => week.ToString(new string('0', m.Value.Length)));
+            }
             // default formatting
             return string.Format("{0:" + format + "}", arg);
         }

PasteIntoFile/TemplateEdit.cs

@@ -28,8 +28,9 @@ public TemplateEdit() {
                 Settings.Default.filenameTemplate,
                 "{0:yyyy-MM-dd HH-mm-ss}",
                 "{0:yyyyMMdd_HHmmss}",
-                "{0:yyyy-MM-dd}_{1:000}",
+                "{0:yyyy-jjj}_{1:000}",
                 "PasteIntoFile_{1:000}_{0:fffffff}",
+                "{0:yyyy-ww}/{0:ddd HHᵸmm´ss´´}",
                 "{2:10}",
             });
             textTemplate.Text = Settings.Default.filenameTemplate;

README.md

@@ -120,12 +120,11 @@ For non-text files, the file path is copied as text in addition to the image con
 <a id="template-format"></a>
 ### Filename template format
 The filename and/or subfolder template string may contain the following placeholders:
-- `{0}`: The current date and time.
-    The format can be specified, e.g. `{0:yyyy-MM-dd HH-mm-ss}`, see [format specifiers](https://docs.microsoft.com/en-us/dotnet/standard/base-types/custom-date-and-time-format-strings) for details.
-- `{1}`: A counter for batch mode.
-    The format can be specified, e.g. `{1:000}` for zero padding, see [format specifiers](https://learn.microsoft.com/en-us/dotnet/standard/base-types/custom-numeric-format-strings) for details.
-- `{2}`: The clipboard text.
-    The format can be specified, e.g. `{2:15}` to limit it to 15 characters.
+- `{0}`: The current date and time, e.g. `{0:yyyy-MM-dd HH-mm-ss}`.
+    In addition to the [standard format specifiers](https://docs.microsoft.com/en-us/dotnet/standard/base-types/custom-date-and-time-format-strings),
+    `j` for day-of-year and `w` for week-of-year are supported.
+- `{1}`: The save counter for batch mode. E.g. `{1:000}` for 3-digit zero padding. See [format specifiers](https://learn.microsoft.com/en-us/dotnet/standard/base-types/custom-numeric-format-strings) for details.
+- `{2}`: The clipboard text. E.g. `{2:15}` to limit it to 15 characters.
 
 ### Command Line