add trace bitmap

README.md

@@ -82,6 +82,17 @@ Traces a given canvas.
   - canvas: canvas containing the image
   - options: trace options
 
+**POTRACE.bitmap**
+
+Traces a given bitmap.
+
+  ```javascript
+  [...Path] = POTRACE.traceBitmap(bitmap: POTRACE.Bitmap, [ options: Object ])
+  ```
+    - bitmap: bitmap containing image info (1 and 0 values)
+    - options: trace options
+
+
 **POTRACE.getSVG**
 
 Converts trace result to svg.

src/index.js

@@ -3,6 +3,7 @@ import bitmapToPathList from './bitmapToPathList.js';
 import processPath from './processPath.js';
 import getSVG from './getSVG.js';
 import getPaths from './getPaths.js';
+import Bitmap from './Bitmap.js';
 
 const OPTIONS = {
   turnpolicy: 'right',
@@ -29,12 +30,17 @@ export function traceImage(image, options) {
   return traceCanvas(canvas, options);
 }
 
-export function traceCanvas(canvas, options = OPTIONS) {
+export function traceCanvas(canvas, options) {
   const bitmap = createBitmap(canvas);
+
+  return traceBitmap(bitmap, options);
+}
+
+export function traceBitmap(bitmap, options = OPTIONS) {
   const pathList = bitmapToPathList(bitmap, options);
   processPath(pathList, options);
 
   return pathList;
 }
 
-export { getSVG, getPaths };
+export { getSVG, getPaths, Bitmap };