fix: fix issue #7 (#8)

Author: mlightcad

bindings/javascript/package.json

@@ -3,7 +3,7 @@
   "description": "A DWG/DXF JavaScript parser based on libredwg",
   "license": "GPL-2.0-only",
   "private": false,
-  "version": "0.6.7",
+  "version": "0.6.9",
   "author": "MLight Lee <mlight.lee@outlook.com>",
   "type": "module",
   "repository": {

bindings/javascript/src/converter/converter.ts

@@ -655,12 +655,15 @@ export class LibreDwgConverter {
     const method = color.method
     let colorIndex = 256
     let rgbColor = 0xffffff
-    // It looks like that libredwg always returns 256 for property 'index' in Dwg_Color
-    if (method === 0xc3 || ((color.rgb >>> 24) & 0xff) === 0xc3) {
-      colorIndex = color.rgb & 0x000000ff
-    } else if (method == 0xc2 || ((color.rgb >>> 24) & 0xff) === 0xc2) {
-      rgbColor = color.rgb & 0x00ffffff
-    }
+    // NOTE: Some older DWG formats use method=0x0 and provide the ACI index via color.index.
+    if (method === 0xc3 || ((color.rgb >>> 24) & 0xff) === 0xc3) {
+      colorIndex = color.rgb & 0x000000ff
+    } else if (method == 0xc2 || ((color.rgb >>> 24) & 0xff) === 0xc2) {
+      rgbColor = color.rgb & 0x00ffffff
+    } else if (color.index >= 1 && color.index <= 255) {
+      // Older DWG format: ACI index is directly available in color.index.
+      colorIndex = color.index
+    }
 
     return {
       ...commonAttrs,

bindings/javascript/src/svg/svgConverter.ts

@@ -692,7 +692,7 @@ export class SvgConverter {
       color.color = entity.color
     }
 
-    // If it is white color, convert it to black because the background of svg is white
+    // ACI 7 is one background-dependent color
     if (color.colorIndex == 7) {
       color.colorIndex = 256
     }