diff --git a/lib/zin/wg/think3c/js/v1.js b/lib/zin/wg/think3c/js/v1.js
index 05adfd9458..2b4c865fb2 100644
--- a/lib/zin/wg/think3c/js/v1.js
+++ b/lib/zin/wg/think3c/js/v1.js
@@ -189,10 +189,20 @@ function colorRegions(binaryImageData)
             const pixels = ctx.getImageData(0, 0, canvas.width, canvas.height).data;
             let regions  = findRegions(pixels, canvas.width, canvas.height);
 
+            ctx.globalCompositeOperation = 'source-over';
+
             /* 过滤掉小区域。 */
             /* Filter out small regions. */
             const minArea = 90;
             regions       = regions.filter(r => r.area >= minArea);
+
+            regions.forEach((region, colorIndex) => {
+                /* 保存当前状态。 */
+                /* Save current state. */
+                ctx.save();
+
+                ctx.fillStyle = colors[colorIndex % colors.length];
+            });
             resolve(canvas.toDataURL());
         };
     });