feat: correct viewport scale calculation with correct dimension and text scaling

examples/inspect_anno.rs

@@ -0,0 +1,233 @@
+// Inspect DIMSCALE, dimstyles, text heights, and xdata to diagnose
+// annotation-scale bugs in paper-space viewports.
+//
+// cargo run --release --example inspect_anno -- <file>
+
+use acadrust::entities::{Dimension, EntityType};
+use acadrust::io::dwg::DwgReader;
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let path = std::env::args().nth(1).expect("usage: inspect_anno <file>");
+    let doc = DwgReader::from_file(&path)?.read()?;
+    println!("file: {}\n", path);
+
+    println!("─── header ──────────────────────────────");
+    println!("  DIMSCALE (dim_scale)      = {}", doc.header.dim_scale);
+    println!("  DIMTXT   (dim_text_height)= {}", doc.header.dim_text_height);
+    println!("  DIMASZ   (dim_arrow_size) = {}", doc.header.dim_arrow_size);
+    println!("  TEXTSIZE (text_height)    = {}", doc.header.text_height);
+    println!("  LTSCALE                   = {}", doc.header.linetype_scale);
+    println!("  PSLTSCALE (psls)          = {}", doc.header.paper_space_linetype_scaling);
+    println!("  CELTSCALE                 = {}", doc.header.current_entity_linetype_scale);
+    println!("  viewport_scale_factor     = {}", doc.header.viewport_scale_factor);
+    println!();
+    println!("─── linetypes (first 10) ────────────────");
+    let mut shown = 0;
+    for lt in doc.line_types.iter() {
+        if shown >= 10 { break; }
+        println!(
+            "  {:<24} pattern_len={:.4}  elements={}",
+            lt.name, lt.pattern_length, lt.elements.len()
+        );
+        shown += 1;
+    }
+    println!();
+
+    println!("─── dim_styles ──────────────────────────");
+    println!(
+        "  {:<24} {:>10} {:>10} {:>10} {:>10}",
+        "name", "dimscale", "dimtxt", "dimasz", "dimexe"
+    );
+    for s in doc.dim_styles.iter() {
+        println!(
+            "  {:<24} {:>10.4} {:>10.4} {:>10.4} {:>10.4}",
+            s.name, s.dimscale, s.dimtxt, s.dimasz, s.dimexe
+        );
+    }
+    println!();
+
+    println!("─── text_styles ─────────────────────────");
+    for s in doc.text_styles.iter() {
+        println!(
+            "  {:<24}  height={:.4}  last_height={:.4}  font={:?}",
+            s.name, s.height, s.last_height, s.font_file
+        );
+    }
+    println!();
+
+    let mut n_text = 0u32;
+    let mut n_text_with_xdata = 0u32;
+    let mut n_text_with_acanno = 0u32;
+    let mut n_mtext = 0u32;
+    let mut n_mtext_with_xdata = 0u32;
+    let mut n_mtext_with_acanno = 0u32;
+    let mut n_dim = 0u32;
+    let mut n_dim_with_xdata = 0u32;
+    let mut n_dim_with_acanno = 0u32;
+    let mut xd_app_counts: std::collections::BTreeMap<String, u32> = Default::default();
+
+    let mut sample_text_h: Vec<f64> = vec![];
+    let mut sample_mtext_h: Vec<f64> = vec![];
+    let mut sample_dim_style: std::collections::BTreeMap<String, u32> = Default::default();
+    // For MTEXT: bucket by owner block name (paper vs model) and height range.
+    let mut mtext_by_owner: std::collections::BTreeMap<String, Vec<f64>> = Default::default();
+
+    let acanno_keys = ["AcAnnoPO", "AcAnnotativeData", "AcAnnoScaleObj", "AcDbXrecObject"];
+
+    for e in doc.entities() {
+        match e {
+            EntityType::Text(t) => {
+                n_text += 1;
+                let xd = &t.common.extended_data;
+                let has_xd = !xd.records().is_empty();
+                if has_xd {
+                    n_text_with_xdata += 1;
+                    for r in xd.records() {
+                        *xd_app_counts.entry(r.application_name.clone()).or_default() += 1;
+                    }
+                }
+                if acanno_keys.iter().any(|k| xd.get_record(k).is_some()) {
+                    n_text_with_acanno += 1;
+                }
+                if sample_text_h.len() < 10 {
+                    sample_text_h.push(t.height);
+                }
+            }
+            EntityType::MText(t) => {
+                n_mtext += 1;
+                let xd = &t.common.extended_data;
+                let has_xd = !xd.records().is_empty();
+                if has_xd {
+                    n_mtext_with_xdata += 1;
+                    for r in xd.records() {
+                        *xd_app_counts.entry(r.application_name.clone()).or_default() += 1;
+                    }
+                }
+                if acanno_keys.iter().any(|k| xd.get_record(k).is_some()) {
+                    n_mtext_with_acanno += 1;
+                }
+                if sample_mtext_h.len() < 10 {
+                    sample_mtext_h.push(t.height);
+                }
+                // Look up the owning block-record by handle and label as
+                // "*Model_Space" / "*Paper_Space*" / "<other>".
+                let owner_h = t.common.owner_handle;
+                let owner_label = doc
+                    .block_records
+                    .iter()
+                    .find_map(|br: &acadrust::BlockRecord| {
+                        if br.handle == owner_h {
+                            Some(br.name.clone())
+                        } else {
+                            None
+                        }
+                    })
+                    .unwrap_or_else(|| format!("h{}", owner_h.value()));
+                mtext_by_owner
+                    .entry(owner_label)
+                    .or_default()
+                    .push(t.height);
+            }
+            EntityType::Dimension(d) => {
+                n_dim += 1;
+                let base = match d {
+                    Dimension::Aligned(d) => &d.base,
+                    Dimension::Linear(d) => &d.base,
+                    Dimension::Radius(d) => &d.base,
+                    Dimension::Diameter(d) => &d.base,
+                    Dimension::Angular2Ln(d) => &d.base,
+                    Dimension::Angular3Pt(d) => &d.base,
+                    Dimension::Ordinate(d) => &d.base,
+                };
+                let xd = &base.common.extended_data;
+                let has_xd = !xd.records().is_empty();
+                if has_xd {
+                    n_dim_with_xdata += 1;
+                    for r in xd.records() {
+                        *xd_app_counts.entry(r.application_name.clone()).or_default() += 1;
+                    }
+                }
+                if acanno_keys.iter().any(|k| xd.get_record(k).is_some()) {
+                    n_dim_with_acanno += 1;
+                }
+                *sample_dim_style.entry(base.style_name.clone()).or_default() += 1;
+            }
+            _ => {}
+        }
+    }
+
+    println!("─── annotation entity counts ────────────");
+    println!(
+        "  TEXT      total={:<5} xdata={:<5} AcAnno={}",
+        n_text, n_text_with_xdata, n_text_with_acanno
+    );
+    println!(
+        "  MTEXT     total={:<5} xdata={:<5} AcAnno={}",
+        n_mtext, n_mtext_with_xdata, n_mtext_with_acanno
+    );
+    println!(
+        "  DIMENSION total={:<5} xdata={:<5} AcAnno={}",
+        n_dim, n_dim_with_xdata, n_dim_with_acanno
+    );
+    println!();
+
+    println!("─── xdata application names seen ────────");
+    for (k, v) in &xd_app_counts {
+        println!("  {:>5}  {}", v, k);
+    }
+    println!();
+
+    if !sample_text_h.is_empty() {
+        println!("─── first 10 TEXT heights ───────────────");
+        for h in &sample_text_h {
+            println!("  {:.4}", h);
+        }
+        println!();
+    }
+    if !sample_mtext_h.is_empty() {
+        println!("─── first 10 MTEXT heights ──────────────");
+        for h in &sample_mtext_h {
+            println!("  {:.4}", h);
+        }
+        println!();
+    }
+    if !mtext_by_owner.is_empty() {
+        println!("─── MTEXT by owner ──────────────────────");
+        for (owner, heights) in &mtext_by_owner {
+            let mut h = heights.clone();
+            h.sort_by(|a, b| a.partial_cmp(b).unwrap());
+            let min = h.first().copied().unwrap_or(0.0);
+            let max = h.last().copied().unwrap_or(0.0);
+            let median = h[h.len() / 2];
+            let n_below_10 = h.iter().filter(|&&x| x < 10.0).count();
+            let n_above_100 = h.iter().filter(|&&x| x > 100.0).count();
+            println!(
+                "  {:<20} n={:<4} min={:.2} med={:.2} max={:.2}  <10:{}  >100:{}",
+                owner,
+                h.len(),
+                min,
+                median,
+                max,
+                n_below_10,
+                n_above_100
+            );
+        }
+        println!();
+    }
+
+    if !sample_dim_style.is_empty() {
+        println!("─── dimension styles used (count) ───────");
+        for (k, v) in &sample_dim_style {
+            let used_style = doc.dim_styles.iter().find(|s| s.name == *k);
+            let ds = used_style.map(|s| s.dimscale).unwrap_or(f64::NAN);
+            let dt = used_style.map(|s| s.dimtxt).unwrap_or(f64::NAN);
+            let da = used_style.map(|s| s.dimasz).unwrap_or(f64::NAN);
+            println!(
+                "  {:>5}× style=\"{}\"  dimscale={:.4} dimtxt={:.4} dimasz={:.4}",
+                v, k, ds, dt, da
+            );
+        }
+    }
+
+    Ok(())
+}

src/app/commands.rs

@@ -2493,7 +2493,11 @@ impl H7CAD {
                                         vp.center.clone(),
                                         vp.width,
                                         vp.height,
-                                        vp.custom_scale,
+                                        crate::scene::vp_effective_scale(
+                                            vp.custom_scale,
+                                            vp.view_height,
+                                            vp.height,
+                                        ),
                                         vp.status.is_on,
                                         vp.status.locked,
                                     ))

src/entities/viewport.rs

@@ -105,7 +105,12 @@ fn grips(vp: &Viewport) -> Vec<GripDef> {
 
 fn properties(vp: &Viewport) -> PropSection {
     let scale_opts: Vec<String> = STANDARD_SCALES.iter().map(|(s, _)| s.to_string()).collect();
-    let current_scale_label = scale_label(vp.custom_scale);
+    let effective_scale = crate::scene::vp_effective_scale(
+        vp.custom_scale,
+        vp.view_height,
+        vp.height,
+    );
+    let current_scale_label = scale_label(effective_scale);
 
     let view_opts: Vec<String> = STD_VIEWS.iter().map(|s| s.to_string()).collect();
     let current_view = viewport_view_label(vp);
@@ -124,8 +129,8 @@ fn properties(vp: &Viewport) -> PropSection {
             edit("Center Z", "center_z", vp.center.z),
             edit("Width", "vp_w", vp.width),
             edit("Height", "vp_h", vp.height),
-            // Numeric scale entry.
-            edit("Scale (num)", "vscale", vp.custom_scale),
+            // Numeric scale entry (derived from view_height; writes both).
+            edit("Scale (num)", "vscale", effective_scale),
             // Standard scale picker.
             Property {
                 label: "Scale".into(),

src/scene/mod.rs

@@ -70,6 +70,24 @@ use std::sync::Arc;
 /// GPU Pipeline to skip re-uploading geometry when switching tabs.
 static GEOMETRY_EPOCH: AtomicU64 = AtomicU64::new(1);
 
+/// Resolve a viewport's paper-to-model scale ratio from its two
+/// DXF-derived sources.
+///
+/// `view_height` (model-space view extent) is the canonical source — it
+/// is what AutoCAD actually uses to draw, and what we keep in sync on
+/// every write. `custom_scale` is consulted only when `view_height` is
+/// missing or zero (some third-party exporters omit it).
+#[inline]
+pub fn vp_effective_scale(custom_scale: f64, view_height: f64, vp_height: f64) -> f64 {
+    if view_height.abs() > 1e-9 {
+        return vp_height / view_height;
+    }
+    if custom_scale.abs() > 1e-9 {
+        return custom_scale;
+    }
+    1.0
+}
+
 /// Pre-built entity caches returned by [`build_derived_caches`].
 /// Produced in the file-load background task so the UI thread only assigns.
 #[derive(Debug, Clone)]
@@ -839,14 +857,11 @@ impl Scene {
         self.document.entities().find_map(|e| {
             if let EntityType::Viewport(vp) = e {
                 if Self::is_content_viewport(vp) && vp.common.owner_handle == layout_block {
-                    let scale = if vp.custom_scale.abs() > 1e-9 {
-                        vp.custom_scale
-                    } else if vp.view_height.abs() > 1e-9 {
-                        vp.height / vp.view_height
-                    } else {
-                        1.0
-                    };
-                    return Some(scale);
+                    return Some(vp_effective_scale(
+                        vp.custom_scale,
+                        vp.view_height,
+                        vp.height,
+                    ));
                 }
             }
             None
@@ -1821,12 +1836,18 @@ impl Scene {
                 effective_view_center = (self.world_offset[0], self.world_offset[1]);
             }
 
-            let scale = if effective_view_height.abs() > 1e-9 {
+            // When the saved view did not overlap the model cluster we just
+            // forced `effective_view_height` to a fit value above — that
+            // override must win regardless of the configured priority,
+            // otherwise broken files render blank under custom_scale-first.
+            let scale = if !saved_overlaps {
                 vp.height as f32 / effective_view_height
-            } else if vp.custom_scale.abs() > 1e-9 {
-                vp.custom_scale as f32
             } else {
-                1.0
+                vp_effective_scale(
+                    vp.custom_scale,
+                    effective_view_height as f64,
+                    vp.height,
+                ) as f32
             };
 
             let pcx = vp.center.x as f32;
@@ -1994,13 +2015,8 @@ impl Scene {
             Some(acadrust::EntityType::Viewport(vp)) => vp,
             _ => return paper_pt,
         };
-        let scale = if vp.custom_scale.abs() > 1e-9 {
-            vp.custom_scale as f32
-        } else if vp.view_height.abs() > 1e-9 {
-            (vp.height / vp.view_height) as f32
-        } else {
-            1.0
-        };
+        let scale =
+            vp_effective_scale(vp.custom_scale, vp.view_height, vp.height) as f32;
         if scale.abs() < 1e-9 {
             return paper_pt;
         }
@@ -2083,13 +2099,8 @@ impl Scene {
 
             if let Some(cp) = cursor_paper {
                 // Compute the model-space point under the cursor before zoom.
-                let scale_before = if vp.custom_scale.abs() > 1e-9 {
-                    vp.custom_scale as f32
-                } else if vp.view_height.abs() > 1e-9 {
-                    (vp.height / vp.view_height) as f32
-                } else {
-                    1.0
-                };
+                let scale_before =
+                    vp_effective_scale(vp.custom_scale, vp.view_height, vp.height) as f32;
                 let cx = vp.center.x as f32;
                 let cy = vp.center.y as f32;
                 let tx = vp.view_target.x as f32;
@@ -4327,13 +4338,8 @@ impl Scene {
         let (frozen, vp_anno_scale) = match self.document.get_entity(vp_handle) {
             Some(EntityType::Viewport(vp)) => {
                 let f: HSet<Handle> = vp.frozen_layers.iter().cloned().collect();
-                let vp_scale = if vp.custom_scale.abs() > 1e-9 {
-                    vp.custom_scale
-                } else if vp.view_height.abs() > 1e-9 {
-                    vp.height / vp.view_height
-                } else {
-                    1.0
-                };
+                let vp_scale =
+                    vp_effective_scale(vp.custom_scale, vp.view_height, vp.height);
                 let anno = if vp_scale > 1e-9 {
                     (1.0 / vp_scale) as f32
                 } else {

src/scene/tessellate.rs

@@ -120,17 +120,20 @@ pub fn tessellate(
     let name = handle.value().to_string();
 
     // Determine effective annotation scale for this entity.
-    // AutoCAD marks annotative objects with "AcAnnoPO" xdata (R2007+).
-    // If no xdata at all: old file without annotation system → treat as annotative.
-    // If xdata present but no "AcAnnoPO": R2007+ file, entity is non-annotative → no scaling.
+    //
+    // AutoCAD's R2007+ "annotative" system marks objects via extension-
+    // dictionary records or "AcAnnoPO" / "AcAnnotativeData" xdata. Only
+    // entities so marked should be auto-scaled by the viewport's
+    // paper-scale; everything else is treated as manually pre-scaled
+    // (old DXF/DWG convention with $DIMSCALE and oversized text).
+    //
+    // Default: NOT annotative (anno_scale = 1.0). Opt-in via explicit
+    // xdata marker. Files that mark every entity annotative are rare; the
+    // pre-R2007 manual-scale convention is far more common in field data.
     let anno_scale = {
         let xdata = &entity.common().extended_data;
-        let is_annotative = if xdata.is_empty() {
-            // Old DXF / no annotation metadata — treat as annotative.
-            true
-        } else {
-            xdata.get_record("AcAnnoPO").is_some()
-        };
+        let is_annotative = xdata.get_record("AcAnnoPO").is_some()
+            || xdata.get_record("AcAnnotativeData").is_some();
         if is_annotative {
             anno_scale
         } else {
@@ -465,22 +468,33 @@ pub fn tessellate_dimension(
     };
     let name = handle.value().to_string();
     let style_name = &dim.base().style_name;
-    let (arrow_size, dimexo, dimexe) = document
-        .dim_styles
-        .iter()
-        .find(|s| {
-            s.name.eq_ignore_ascii_case(style_name)
-                || (style_name.trim().is_empty() && s.name.eq_ignore_ascii_case("Standard"))
+    let style = document.dim_styles.iter().find(|s| {
+        s.name.eq_ignore_ascii_case(style_name)
+            || (style_name.trim().is_empty() && s.name.eq_ignore_ascii_case("Standard"))
+    });
+
+    // DIMSCALE rule:
+    //   dimstyle.dimscale > 0  →  that's the *final* multiplier; ignore anno_scale.
+    //   dimstyle.dimscale == 0 →  annotative: use anno_scale (= 1/vp_scale in viewports).
+    let dim_scale = style
+        .map(|s| {
+            if s.dimscale > 1e-6 {
+                s.dimscale
+            } else {
+                anno_scale as f64
+            }
         })
+        .unwrap_or(1.0);
+    let (arrow_size, dimexo, dimexe, dim_txt) = style
         .map(|s| {
-            let scale = (if s.dimscale > 1e-6 { s.dimscale } else { 1.0 }) * anno_scale as f64;
             (
-                ((s.dimasz * scale) as f32).max(0.001),
-                (s.dimexo * scale) as f32,
-                (s.dimexe * scale) as f32,
+                ((s.dimasz * dim_scale) as f32).max(0.001),
+                (s.dimexo * dim_scale) as f32,
+                (s.dimexe * dim_scale) as f32,
+                s.dimtxt * dim_scale,
             )
         })
-        .unwrap_or((0.12, 0.0, 0.0));
+        .unwrap_or((0.12, 0.0, 0.0, 2.5));
     let points = dimension_geometry(dim, arrow_size, dimexo, dimexe, world_offset);
     let key_vertices = points
         .iter()
@@ -508,7 +522,7 @@ pub fn tessellate_dimension(
         fill_tris: vec![],
     }];
 
-    if let Some(text) = dimension_text_entity(dim) {
+    if let Some(text) = dimension_text_entity(dim, dim_txt) {
         let mut wire = tessellate(
             document,
             handle,
@@ -519,7 +533,9 @@ pub fn tessellate_dimension(
             [0.0; 8],
             line_weight_px,
             world_offset,
-            anno_scale,
+            // dim text already baked dim_scale into its height — don't
+            // let the inner tessellate re-apply anno_scale.
+            1.0,
         );
         wire.name = name;
         wires.push(wire);
@@ -1688,7 +1704,7 @@ fn dimension_snap_pts(dim: &Dimension, world_offset: [f64; 3]) -> Vec<(Vec3, Sna
     }
 }
 
-fn dimension_text_entity(dim: &Dimension) -> Option<Text> {
+fn dimension_text_entity(dim: &Dimension, text_height: f64) -> Option<Text> {
     let value = dimension_text_value(dim)?;
     // Use f64 position directly to avoid f32 round-trip precision loss at large
     // coordinates (e.g. Turkish UTM ~4,000,000 m). tessellate() will apply
@@ -1701,7 +1717,7 @@ fn dimension_text_entity(dim: &Dimension) -> Option<Text> {
         dimension_text_natural_rotation(dim)
     };
     let mut text = Text::with_value(value, pos_f64)
-        .with_height(dimension_text_height(dim))
+        .with_height(text_height)
         .with_rotation(rotation);
     text.style = base.style_name.clone();
     text.common = base.common.clone();
@@ -1767,15 +1783,6 @@ fn dimension_text_position(dim: &Dimension, world_offset: [f64; 3]) -> Vec3 {
     }
 }
 
-fn dimension_text_height(dim: &Dimension) -> f64 {
-    let scale = (dim.measurement().abs() * 0.12).clamp(0.25, 2.0);
-    if scale.is_finite() {
-        scale
-    } else {
-        0.25
-    }
-}
-
 fn vec3_local(v: Vector3, off: [f64; 3]) -> Vec3 {
     Vec3::new(
         (v.x - off[0]) as f32,

src/ui/scale_popup.rs

@@ -27,7 +27,7 @@ const COMMON_SCALES: &[(&str, f32, f64)] = &[
 ///
 /// - `is_model`: true = model space (dispatches SetAnnotationScale), false = paper space (SetViewportScale).
 /// - `current_anno_scale`: current annotation_scale from Scene (used to highlight active row in model space).
-/// - `viewport_scale`: current vp.custom_scale (used to highlight in paper space).
+/// - `viewport_scale`: current effective vp scale, view_height-first (used to highlight in paper space).
 pub fn scale_popup_overlay(
     is_model: bool,
     current_anno_scale: f32,