From 3bd5e94c34f4668fb1cd42946974970d67dfb61d Mon Sep 17 00:00:00 2001
From: Ed Rogers <edwin.rogers@gmail.com>
Date: Sat, 7 Jan 2023 22:55:29 -0600
Subject: [PATCH 1/3] Make default filename for screenshots use ISO8601
 datetime format

---
 CHANGELOG.md       |  1 +
 src/textual/app.py | 15 +++++++++------
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6eed955935..c8eb04ce67 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - `MouseScrollUp` and `MouseScrollDown` now inherit from `MouseEvent` and have attached modifier keys. https://github.com/Textualize/textual/pull/1458
 - Fail-fast and print pretty tracebacks for Widget compose errors https://github.com/Textualize/textual/pull/1505
+- The default filename for screenshots uses ISO8601 datetime format, with colons and spaces replaced with underscores https://github.com/Textualize/textual/pull/1518
 
 ### Fixed
 
diff --git a/src/textual/app.py b/src/textual/app.py
index b207bbd025..ea1e43b3c1 100644
--- a/src/textual/app.py
+++ b/src/textual/app.py
@@ -644,7 +644,7 @@ def save_screenshot(
         self,
         filename: str | None = None,
         path: str = "./",
-        time_format: str = "%Y%m%d %H%M%S %f",
+        time_format: str | None = None,
     ) -> str:
         """Save an SVG screenshot of the current screen.
 
@@ -652,16 +652,19 @@ def save_screenshot(
             filename (str | None, optional): Filename of SVG screenshot, or None to auto-generate
                 a filename with the date and time. Defaults to None.
             path (str, optional): Path to directory for output. Defaults to current working directory.
-            time_format (str, optional): Time format to use if filename is None. Defaults to "%Y-%m-%d %X %f".
+            time_format (str | None, optional): Date and time format to use if filename is None.
+                Defaults to ISO 8601 format. Colons are replaced with underscores.
 
         Returns:
             str: Filename of screenshot.
         """
         if filename is None:
-            svg_filename = (
-                f"{self.title.lower()} {datetime.now().strftime(time_format)}.svg"
-            )
-            for reserved in '<>:"/\\|?*':
+            if time_format is None:
+                dt = datetime.now().isoformat()
+            else:
+                dt = datetime.now().strftime(time_format)
+            svg_filename = f"{self.title.lower()} {dt}.svg"
+            for reserved in ' <>:"/\\|?*':
                 svg_filename = svg_filename.replace(reserved, "_")
         else:
             svg_filename = filename

From 61da0c5c70f518646900569a75f720af2bc6ac25 Mon Sep 17 00:00:00 2001
From: Ed Rogers <edwin.rogers@gmail.com>
Date: Wed, 18 Jan 2023 18:56:40 -0600
Subject: [PATCH 2/3] Add full stop to reserved character list

---
 CHANGELOG.md       | 2 +-
 src/textual/app.py | 7 ++++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c8eb04ce67..31d343be69 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,7 +17,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - `MouseScrollUp` and `MouseScrollDown` now inherit from `MouseEvent` and have attached modifier keys. https://github.com/Textualize/textual/pull/1458
 - Fail-fast and print pretty tracebacks for Widget compose errors https://github.com/Textualize/textual/pull/1505
-- The default filename for screenshots uses ISO8601 datetime format, with colons and spaces replaced with underscores https://github.com/Textualize/textual/pull/1518
+- The default filename for screenshots uses a datetime format similar to ISO8601, but with reserved characters replaced by underscores https://github.com/Textualize/textual/pull/1518
 
 ### Fixed
 
diff --git a/src/textual/app.py b/src/textual/app.py
index ea1e43b3c1..8da8846f6e 100644
--- a/src/textual/app.py
+++ b/src/textual/app.py
@@ -663,9 +663,10 @@ def save_screenshot(
                 dt = datetime.now().isoformat()
             else:
                 dt = datetime.now().strftime(time_format)
-            svg_filename = f"{self.title.lower()} {dt}.svg"
-            for reserved in ' <>:"/\\|?*':
-                svg_filename = svg_filename.replace(reserved, "_")
+            svg_filename_stem = f"{self.title.lower()} {dt}"
+            for reserved in ' <>:"/\\|?*.':
+                svg_filename_stem = svg_filename_stem.replace(reserved, "_")
+                svg_filename = svg_filename_stem + ".svg"
         else:
             svg_filename = filename
         svg_path = os.path.expanduser(os.path.join(path, svg_filename))

From 1c3329ad47df93c44f19c0435f8ecb360c4f6b09 Mon Sep 17 00:00:00 2001
From: Ed Rogers <edwin.rogers@gmail.com>
Date: Wed, 18 Jan 2023 19:07:21 -0600
Subject: [PATCH 3/3] Update doc-string

---
 src/textual/app.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/textual/app.py b/src/textual/app.py
index 8da8846f6e..0cd23f40fb 100644
--- a/src/textual/app.py
+++ b/src/textual/app.py
@@ -653,7 +653,7 @@ def save_screenshot(
                 a filename with the date and time. Defaults to None.
             path (str, optional): Path to directory for output. Defaults to current working directory.
             time_format (str | None, optional): Date and time format to use if filename is None.
-                Defaults to ISO 8601 format. Colons are replaced with underscores.
+                Defaults to a format like ISO 8601 with some reserved characters replaced with underscores.
 
         Returns:
             str: Filename of screenshot.