From: Serhiy Storchaka <storchaka@gmail.com>
Date: Mon, 22 Jun 2026 15:19:56 +0000 (+0300)
Subject: gh-151888: Add tkinter PhotoImage.redither method (GH-151889)
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b86c305c746f6d5be52227c946b77a009bad8928;p=thirdparty%2FPython%2Fcpython.git

gh-151888: Add tkinter PhotoImage.redither method (GH-151889)

Wrap the photo image "redither" Tk command (since Tk 8.5) as the method
PhotoImage.redither(), which recalculates the dithered image in each
window where it is displayed (useful when the image data was supplied in
pieces), completing the wrapping of the photo image subcommands.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
---

diff --git a/Doc/library/tkinter.rst b/Doc/library/tkinter.rst
index 95b4a088ef91..db6834fbea53 100644
--- a/Doc/library/tkinter.rst
+++ b/Doc/library/tkinter.rst
@@ -6076,6 +6076,14 @@ Image classes
       it is displayed as transparent and the background of whatever window it
       is displayed in shows through.
 
+   .. method:: redither()
+
+      Recalculate the dithered image in each window where it is displayed.
+      This is useful when the image data was supplied in pieces, in which case
+      the dithered image may not be exactly correct.
+
+      .. versionadded:: next
+
    .. method:: cget(option)
 
       Return the current value of the configuration option *option*.
diff --git a/Doc/whatsnew/3.16.rst b/Doc/whatsnew/3.16.rst
index 1dc6a62cc16d..eb13c67ac6a5 100644
--- a/Doc/whatsnew/3.16.rst
+++ b/Doc/whatsnew/3.16.rst
@@ -194,6 +194,11 @@ tkinter
   badge) and :meth:`~tkinter.Wm.wm_stackorder` (toplevel stacking order).
   (Contributed by Serhiy Storchaka in :gh:`151874`.)
 
+* Added the :meth:`~tkinter.PhotoImage.redither` method which recalculates the
+  dithered image when its data was supplied in pieces.
+  (Contributed by Serhiy Storchaka in :gh:`151888`.)
+
+
 xml
 ---
 
diff --git a/Lib/test/test_tkinter/test_images.py b/Lib/test/test_tkinter/test_images.py
index f9b314da9e8a..099996feb565 100644
--- a/Lib/test/test_tkinter/test_images.py
+++ b/Lib/test/test_tkinter/test_images.py
@@ -311,6 +311,12 @@ class PhotoImageTest(BaseImageTest, AbstractTkTest, unittest.TestCase):
         self.assertEqual(image.height(), 16)
         self.assertEqual(image.get(4, 6), self.colorlist(0, 0, 0))
 
+    def test_redither(self):
+        image = self.create()
+        pixel = image.get(4, 6)
+        image.redither()  # Recalculates the dithering; the data is unchanged.
+        self.assertEqual(image.get(4, 6), pixel)
+
     def test_copy(self):
         image = self.create()
         image2 = image.copy()
diff --git a/Lib/tkinter/__init__.py b/Lib/tkinter/__init__.py
index 7fcc7d764da3..bf1a0290088f 100644
--- a/Lib/tkinter/__init__.py
+++ b/Lib/tkinter/__init__.py
@@ -4571,6 +4571,13 @@ class PhotoImage(Image):
         """Display a transparent image."""
         self.tk.call(self.name, 'blank')
 
+    def redither(self):
+        """Recalculate the dithered image in each window where it is displayed.
+
+        Useful when the image data was supplied in pieces, in which case the
+        dithered image may not be exactly correct."""
+        self.tk.call(self.name, 'redither')
+
     def cget(self, option):
         """Return the value of OPTION."""
         return self.tk.call(self.name, 'cget', '-' + option)
diff --git a/Misc/NEWS.d/next/Library/2026-06-22-01-57-55.gh-issue-151888.hO7mxi.rst b/Misc/NEWS.d/next/Library/2026-06-22-01-57-55.gh-issue-151888.hO7mxi.rst
new file mode 100644
index 000000000000..8a2d5ed765d2
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-06-22-01-57-55.gh-issue-151888.hO7mxi.rst
@@ -0,0 +1,2 @@
+Add the :meth:`!tkinter.PhotoImage.redither` method, wrapping the photo image
+``redither`` Tk command.