diff --git a/inc/thorvg.h b/inc/thorvg.h
index 6a137b79..f51b2c81 100644
--- a/inc/thorvg.h
+++ b/inc/thorvg.h
@@ -1724,6 +1724,7 @@ public:
      * @param[in] h The height (in pixels) of the raster image.
      *
      * @warning This API is experimental and not officially supported. It may be modified or removed in future versions.
+     * @warning Drawing on the main surface is currently not permitted. If the identifier (@p id) is set to @c 0, the operation will be aborted.
      *
      * @note Currently, this only allows the GL_RGBA8 color space format.
      * @note Experimental API
diff --git a/src/renderer/gl_engine/tvgGlRenderer.cpp b/src/renderer/gl_engine/tvgGlRenderer.cpp
index 3d7ffdb8..f83ec846 100644
--- a/src/renderer/gl_engine/tvgGlRenderer.cpp
+++ b/src/renderer/gl_engine/tvgGlRenderer.cpp
@@ -57,7 +57,7 @@ bool GlRenderer::clear()
 
 bool GlRenderer::target(int32_t id, uint32_t w, uint32_t h)
 {
-    assert(w > 0 && h > 0);
+    if (id == GL_INVALID_VALUE || w == 0 || h == 0) return false;
 
     surface.stride = w;
     surface.w = w;
@@ -70,6 +70,11 @@ bool GlRenderer::target(int32_t id, uint32_t w, uint32_t h)
 
     mTargetFboId = static_cast<GLint>(id);
 
+    //TODO: It's not allow to draw onto the main surface. Need to confirm the policy.
+    if (mTargetFboId == 0) {
+        GL_CHECK(glGetIntegerv(GL_FRAMEBUFFER_BINDING, &mTargetFboId));
+    }
+
     mRootTarget = make_unique<GlRenderTarget>(surface.w, surface.h);
     mRootTarget->init(mTargetFboId);