From 743dc1026ddd7d92e6527b87470eafc742aedcca Mon Sep 17 00:00:00 2001
From: Hakan Seven <hakanseven8125@gmail.com>
Date: Fri, 17 Jul 2026 02:58:59 +0300
Subject: [PATCH] fix(linetype): route placeholder-complex linetypes to the
 dash path
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A linetype element can carry a `complex` record with no renderable content
(shape #0, null style handle, zero scale) — some DWGs store plain dash
elements that way (e.g. ISO03W100 "ISO dash space"). document_complex_lt
treated any `complex.is_some()` as complex and sent the entity down the CPU
apply_along path, which skips the GPU dash shader and its A-type endpoint
alignment. Gate on *renderable* content (non-empty text, or a shape with a
real shape-file handle) so these fall through to resolve_pattern and dash on
the GPU with proper A-type alignment.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 src/io/linetypes.rs | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/io/linetypes.rs b/src/io/linetypes.rs
index b5f004f62..51fe535a8 100644
--- a/src/io/linetypes.rs
+++ b/src/io/linetypes.rs
@@ -153,7 +153,20 @@ pub fn document_complex_lt(document: &CadDocument, name: &str) -> Option<Complex
         .line_types
         .iter()
         .find(|l| l.name.eq_ignore_ascii_case(name))?;
-    if !lt.elements.iter().any(|e| e.complex.is_some()) {
+    // Treat the linetype as complex only when an element carries *renderable*
+    // embedded content — a non-empty text string, or a shape backed by a shape
+    // file. Some DWGs store dash elements with a placeholder `complex` (shape
+    // #0, null style handle, zero scale) that draws nothing; routing those
+    // through the CPU complex-linetype path needlessly skips the normal dash
+    // shader — and with it the "A"-type endpoint alignment. Fall through to the
+    // ordinary `resolve_pattern` path for them.
+    let has_real_complex = lt.elements.iter().any(|e| {
+        e.complex.as_ref().is_some_and(|cx| match &cx.content {
+            LineTypeComplexContent::Text { text } => !text.trim().is_empty(),
+            LineTypeComplexContent::Shape { .. } => !cx.style_handle.is_null(),
+        })
+    });
+    if !has_real_complex {
         return None;
     }
     document_lt_segments(document, name)