From 6de70d82522a8b884b1b271686707697ce193238 Mon Sep 17 00:00:00 2001
From: Ivor Wanders <ivor@iwanders.net>
Date: Sat, 9 Aug 2025 11:13:20 -0400
Subject: [PATCH] X11: Prevent BadWindow when creating small windows

The glfwCreateWindow function ensures that the width and height are
at least greater or equal than zero, but on X11 it is invalid to
create a window with dimensions that equal zero, see [1].

This change ensures that the dimensions passed to XCreateWindow are
at least 1 by 1.

This issue was detected in [2], where a call to glfwCreateWindow
was done to request a 1x1 window, with a _glfw.x11.contentScaleX of
less than 1.0 (0.958333) this results in a request for a 0x0 window
which then causes an BadWindow error from X11.

[1]: https://gitlab.freedesktop.org/xorg/lib/libx11/-/blob/e003f52661679e95b51ff24e317af6178fe2a73c/specs/libX11/CH03.xml#L1333-1337
[2]: https://github.com/WerWolv/ImHex/pull/2390
---
 CONTRIBUTORS.md  | 1 +
 README.md        | 2 ++
 src/x11_window.c | 4 ++++
 3 files changed, 7 insertions(+)

diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
index cfb4f42ca..e3956e61d 100644
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -282,6 +282,7 @@ video tutorials.
  - Corentin Wallez
  - Torsten Walluhn
  - Patrick Walton
+ - Ivor Wanders
  - Jim Wang
  - Xo Wang
  - Andre Weissflog
diff --git a/README.md b/README.md
index 1c7ced36e..5e882e277 100644
--- a/README.md
+++ b/README.md
@@ -149,6 +149,8 @@ information on what to include when reporting a bug.
  - [Null] Added EGL context creation on Mesa via `EGL_MESA_platform_surfaceless`
  - [EGL] Allowed native access on Wayland with `GLFW_CONTEXT_CREATION_API` set to
    `GLFW_NATIVE_CONTEXT_API` (#2518)
+ - [X11] Bugfix: Prevent BadWindow when creating small windows with a content scale
+   less than 1 (#2754)
 
 
 ## Contact
diff --git a/src/x11_window.c b/src/x11_window.c
index 986bfb93b..65d7eb2cb 100644
--- a/src/x11_window.c
+++ b/src/x11_window.c
@@ -576,6 +576,10 @@ static GLFWbool createNativeWindow(_GLFWwindow* window,
         height *= _glfw.x11.contentScaleY;
     }
 
+    // The dimensions must be nonzero, or a BadValue error results.
+    width = _glfw_max(1, width);
+    height = _glfw_max(1, height);
+
     int xpos = 0, ypos = 0;
 
     if (wndconfig->xpos != GLFW_ANY_POSITION && wndconfig->ypos != GLFW_ANY_POSITION)