From a2bee8b49e66aaa7298201660fb4875faa34e1da Mon Sep 17 00:00:00 2001
From: Marco Arnulfo <103679419+marcoarnulfo@users.noreply.github.com>
Date: Mon, 19 Oct 2026 08:30:56 +0200
Subject: [PATCH] LTSCALE typed at the command line asks for the scale factor
 (fixes #1194) (#1199)

---
 crates/engine/src/cmd/props.rs | 37 ++++++++++++++++++++++++++++++++--
 crates/engine/src/tests.rs     | 19 +++++++++++++++++
 2 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/crates/engine/src/cmd/props.rs b/crates/engine/src/cmd/props.rs
index 6e68a9d8..454756ff 100644
--- a/crates/engine/src/cmd/props.rs
+++ b/crates/engine/src/cmd/props.rs
@@ -11,7 +11,7 @@ use cadcraft_geom::Vec3;
 use serde_json::{Value, json};
 
 use super::*;
-use crate::{Result, Session};
+use crate::{Accept, Input, Interactive, Prompt, Result, Session, Step};
 
 pub fn specs() -> Vec<CommandSpec> {
     vec![
@@ -30,7 +30,7 @@ pub fn specs() -> Vec<CommandSpec> {
             .noundo(),
         CommandSpec::new("-linetype", "Linetype", run_linetype).params("{current?, load?, file? | text?, reload?} (as LINETYPE)").interactive(|_| Ok(Box::new(linfile::DashLinetype::new()))),
         CommandSpec::new("lweight", "Lineweight...", run_lweight).menu(&["Format", "Lineweight..."]).alias(&["lw", "lineweight"]).params("{lineweight: mm | ByLayer}"),
-        CommandSpec::new("ltscale", "Linetype Scale", run_ltscale).alias(&["lts"]).params("{scale}"),
+        CommandSpec::new("ltscale", "Linetype Scale", run_ltscale).alias(&["lts"]).params("{scale}").interactive(|_| Ok(Box::new(LtscaleM))),
         CommandSpec::new("units", "Units...", run_units).menu(&["Format", "Units..."]).alias(&["un"]).params("{lunits?: 1..5, luprec?: 0..8, aunits?: 0..4, auprec?: 0..8, insunits?}"),
         CommandSpec::new("limits", "Drawing Limits", run_limits).menu(&["Format", "Drawing Limits"]).params("{min: [x,y], max: [x,y]}"),
         CommandSpec::new("style", "Text Style...", run_style)
@@ -471,6 +471,39 @@ fn run_ltscale(s: &mut Session, p: &Value) -> Result<Value> {
     Ok(json!({ "message": "Regenerating model." }))
 }
 
+/// Typed LTSCALE: "Enter new linetype scale factor <1.0000>:".
+struct LtscaleM;
+
+impl Interactive for LtscaleM {
+    fn name(&self) -> &'static str {
+        "LTSCALE"
+    }
+    fn prompt(&self, s: &Session) -> Prompt {
+        let cur = s.doc().map(|d| d.header.f64("LTSCALE", 1.0)).unwrap_or(1.0);
+        Prompt::new("Enter new linetype scale factor", Accept::NUMBER).default(format!("{cur:.4}"))
+    }
+    fn input(&mut self, s: &mut Session, i: Input) -> Result<Step> {
+        let text = match i {
+            Input::Enter | Input::Cancel => return Ok(Step::Done),
+            Input::Text(t) => t,
+            _ => return Ok(Step::Continue),
+        };
+        let scale = text.trim().parse::<f64>().ok().filter(|v| v.is_finite() && *v > 0.0);
+        match scale.map(|v| run_ltscale(s, &json!({ "scale": v }))) {
+            Some(Ok(r)) => {
+                if let Some(m) = r.get("message").and_then(Value::as_str) {
+                    s.echo(m.to_string());
+                }
+                Ok(Step::Done)
+            }
+            _ => {
+                s.echo("Requires a positive number.");
+                Ok(Step::Continue)
+            }
+        }
+    }
+}
+
 fn run_units(s: &mut Session, p: &Value) -> Result<Value> {
     let d = s.doc_mut()?;
     for (k, lo, hi) in [("lunits", 1, 5), ("luprec", 0, 8), ("aunits", 0, 4), ("auprec", 0, 8), ("insunits", 0, 24)] {
diff --git a/crates/engine/src/tests.rs b/crates/engine/src/tests.rs
index 93eba770..f205c2ea 100644
--- a/crates/engine/src/tests.rs
+++ b/crates/engine/src/tests.rs
@@ -1274,6 +1274,25 @@ fn bare_variable_name_runs_setvar() {
     assert!(s.cmdline("-pickadd").is_err());
 }
 
+#[test]
+fn typed_ltscale_asks_for_the_scale() {
+    let mut s = Session::new();
+    s.execute("setvar", &json!({"name": "LTSCALE", "value": 2.5})).unwrap();
+    s.cmdline("ltscale").unwrap();
+    assert!(s.prompt_text().contains("Enter new linetype scale factor <2.5000>"), "{}", s.prompt_text());
+    // A scale that is not positive is refused and asked again.
+    s.cmdline("0").unwrap();
+    assert!(s.current_prompt().is_some(), "asked again");
+    s.cmdline("0.1").unwrap();
+    assert!(s.current_prompt().is_none());
+    assert_eq!(s.doc().unwrap().header.f64("LTSCALE", 0.0), 0.1);
+    // Enter keeps the current scale.
+    s.cmdline("lts").unwrap();
+    s.cmdline("").unwrap();
+    assert!(s.current_prompt().is_none());
+    assert_eq!(s.doc().unwrap().header.f64("LTSCALE", 0.0), 0.1);
+}
+
 fn setvar_prompt_open(s: &Session) -> bool {
     s.running.as_ref().is_some_and(|r| r.id == "setvar")
 }