fix(render): preserve transparency inheritance

Resolve ByBlock alpha independently from color and keep explicit opaque values from falling back to layer transparency.

Pin the matching cadcodec API across desktop, plugin, and web targets.

Refs HakanSeven12/cadcodec#2

src/scene/cache/block_cache.rs

@@ -88,6 +88,7 @@ pub struct LocalWire {
     /// `points.is_empty() && !fill_tris.is_empty()`.
     pub is_fill_only: bool,
     pub color_is_byblock: bool,
+    pub transparency_is_byblock: bool,
     pub lt_is_byblock: bool,
     pub lw_is_byblock: bool,
     /// Set when this child sits on layer "0" and the matching property is
@@ -710,7 +711,8 @@ fn tessellate_sub_local(
         .unwrap_or(true);
     let color_l0 =
         !has_book_color && on_l0 && sub.common().color == AcadColor::ByLayer;
-    let transparency_l0 = on_l0 && sub.common().transparency.alpha() == 0;
+    let transparency_is_byblock = sub.common().transparency.is_by_block();
+    let transparency_l0 = on_l0 && sub.common().transparency.is_by_layer();
     let lt_l0 = on_l0 && {
         let lt = &sub.common().linetype;
         lt.is_empty() || lt.eq_ignore_ascii_case("bylayer")
@@ -846,10 +848,11 @@ fn tessellate_sub_local(
             hide_unselected: frame_mode == Some(0),
             is_fill_only,
             color_is_byblock: color_is_byblock && wire_on_base_color,
+            transparency_is_byblock,
             lt_is_byblock,
             lw_is_byblock,
             color_l0: color_l0 && wire_on_base_color,
-            transparency_l0: transparency_l0 && wire_on_base_color,
+            transparency_l0,
             lt_l0,
             lw_l0,
             aabb_local,
@@ -1990,24 +1993,28 @@ fn expand_defn(
 /// layer-0 rule → insert-layer colour, else the cached colour; finally xref
 /// fade. Shared by the stroke, fill, and greeked-text emit paths.
 fn resolve_wire_color(lw: &LocalWire, ctx: &ExpandCtx) -> [f32; 4] {
-    let c = if ctx.selected {
+    let mut color = if ctx.selected {
         WireModel::SELECTED
     } else if lw.color_is_byblock {
         ctx.ins_color
     } else if lw.color_l0 {
-        let alpha = if lw.transparency_l0 {
+        ctx.l0.color
+    } else {
+        lw.color
+    };
+    if !ctx.selected {
+        color[3] = if lw.transparency_is_byblock {
+            ctx.ins_color[3]
+        } else if lw.transparency_l0 {
             ctx.l0.color[3]
         } else {
             lw.color[3]
         };
-        [ctx.l0.color[0], ctx.l0.color[1], ctx.l0.color[2], alpha]
-    } else {
-        lw.color
-    };
+    }
     if ctx.is_xref && !ctx.selected {
-        fade_toward_bg(c, ctx.bg_color)
+        fade_toward_bg(color, ctx.bg_color)
     } else {
-        c
+        color
     }
 }
 
@@ -2592,7 +2599,7 @@ fn emit_wire(
             pos: [hx, hy, hz],
             pos_low: [lx, ly, lz],
             uv: tv.uv,
-            color: [rgb[0], rgb[1], rgb[2], tv.color[3]],
+            color: [rgb[0], rgb[1], rgb[2], final_color[3]],
             draw_depth: tv.draw_depth,
         });
     }

src/scene/cache/properties.rs

@@ -1,4 +1,4 @@
-use acadrust::{EntityType, Handle};
+use acadrust::{EntityType, Handle, Transparency};
 use crate::t;
 
 use crate::scene::model::object::{PropSection, PropValue, Property};
@@ -10,15 +10,12 @@ pub fn general_section(entity: &EntityType) -> PropSection {
     } else {
         common.linetype.clone()
     };
-    // Alpha 0 is ByLayer, Alpha 1 is ByBlock; show them by name and fall back
-    // to a rounded percentage for explicit values.
-    let transp_display = match common.transparency.alpha() {
-        0 => "ByLayer".to_string(),
-        1 => "ByBlock".to_string(),
-        alpha => format!(
-            "{}",
-            (alpha as f64 / 255.0 * 100.0).round() as u32
-        ),
+    let transp_display = match common.transparency {
+        Transparency::ByLayer => "ByLayer".to_string(),
+        Transparency::ByBlock => "ByBlock".to_string(),
+        Transparency::Explicit(alpha) => {
+            ((alpha as f64 / 255.0 * 100.0).round() as u32).to_string()
+        }
     };
 
     // Hyperlink is stored in XDATA under the "PE_URL" application.