From 22e121f4e47542a41c6301ee2438b075f689942d Mon Sep 17 00:00:00 2001
From: pedrosland <pedrosland@gmail.com>
Date: Sat, 11 Jul 2026 15:19:12 +0100
Subject: [PATCH] Fix unreadable overlay elements in 3D view on XWayland/Intel
 (#11557)

Fix unreadable overlay elements in 3D view on XWayland/Intel - closes #10287
---
 src/slic3r/GUI/ImGuiWrapper.cpp | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/slic3r/GUI/ImGuiWrapper.cpp b/src/slic3r/GUI/ImGuiWrapper.cpp
index d4d08aa84f..c7609be5ef 100644
--- a/src/slic3r/GUI/ImGuiWrapper.cpp
+++ b/src/slic3r/GUI/ImGuiWrapper.cpp
@@ -2781,6 +2781,11 @@ void ImGuiWrapper::init_font(bool compress)
     builder.BuildRanges(&ranges); // Build the final result (ordered ranges with all the unique characters submitted)
 
     io.Fonts->Flags |= ImFontAtlasFlags_NoPowerOfTwoHeight;
+    // TexDesiredWidth will be increased adaptively below if the built height
+    // exceeds GL_MAX_TEXTURE_SIZE. Leave it at 0 so ImGui picks the minimum
+    // width for small glyph sets and we only widen when actually necessary.
+    io.Fonts->TexDesiredWidth = 0;
+
     ImFontConfig cfg = ImFontConfig();
     cfg.OversampleH = cfg.OversampleV = 1;
     //FIXME replace with io.Fonts->AddFontFromMemoryTTF(buf_decompressed_data, (int)buf_decompressed_size, m_font_size, nullptr, ranges.Data);
@@ -2852,7 +2857,23 @@ void ImGuiWrapper::init_font(bool compress)
         io.Fonts->AddCustomRectFontGlyph(default_font, icon.first, icon_sz * 4, icon_sz * 4, 3.0 * font_scale + icon_sz * 4);
     }
 
-    // Build texture atlas
+    // Build texture atlas, widening it if the height would exceed GL_MAX_TEXTURE_SIZE.
+    // Increasing the width allows the packing algorithm to grow more horizontally which reduces the height.
+    io.Fonts->Build();
+    GLint gl_max_tex_size = 0;
+    glsafe(::glGetIntegerv(GL_MAX_TEXTURE_SIZE, &gl_max_tex_size));
+    constexpr int max_retries = 6;
+    for (int attempt = 0; attempt < max_retries && io.Fonts->TexHeight > gl_max_tex_size; ++attempt) {
+        io.Fonts->TexDesiredWidth = (io.Fonts->TexDesiredWidth > 0 ? io.Fonts->TexDesiredWidth : io.Fonts->TexWidth) * 2;
+        io.Fonts->Build();
+    }
+    if (io.Fonts->TexHeight > gl_max_tex_size) {
+        // Shouldn't really happen
+        BOOST_LOG_TRIVIAL(error) << "Font atlas height " << io.Fonts->TexHeight
+            << " still exceeds GL_MAX_TEXTURE_SIZE (" << gl_max_tex_size << ")"
+            << " after " << max_retries << " attempts; rendering may be incomplete";
+    }
+
     unsigned char* pixels;
     int width, height;
     io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);   // Load as RGBA 32-bits (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory.