diff --git a/src/egegapi.cpp b/src/egegapi.cpp
index d64b65a..fb87892 100644
--- a/src/egegapi.cpp
+++ b/src/egegapi.cpp
@@ -2391,7 +2391,7 @@ void ege_path_widen(ege_path* path, float lineWidth, const ege_transform_matrix*
 
             if (matrix != NULL) {
                 Gdiplus::Matrix mat;
-                matrixConvert(matrix, mat);
+                matrixConvert(*matrix, mat);
                 graphicsPath->Widen(&pen, &mat, flatness);
             } else {
                 graphicsPath->Widen(&pen, NULL, flatness);
@@ -2413,7 +2413,7 @@ void ege_path_flatten(ege_path* path, const ege_transform_matrix* matrix, float
         if (graphicsPath != NULL) {
             if (matrix != NULL) {
                 Gdiplus::Matrix mat;
-                matrixConvert(matrix, mat);
+                matrixConvert(*matrix, mat);
                 graphicsPath->Flatten(&mat, flatness);
             } else {
                 graphicsPath->Flatten(NULL, flatness);
@@ -2439,7 +2439,7 @@ void ege_path_warp(ege_path* path, const ege_point* points, int count, const ege
 
             if (matrix != NULL) {
                 Gdiplus::Matrix mat;
-                matrixConvert(matrix, mat);
+                matrixConvert(*matrix, mat);
                 graphicsPath->Warp(p, count, r, &mat, Gdiplus::WarpModePerspective, flatness);
             } else {
                 graphicsPath->Warp(p, count, r, NULL, Gdiplus::WarpModePerspective, flatness);
@@ -2460,7 +2460,7 @@ void ege_path_outline(ege_path* path, const ege_transform_matrix* matrix, float
         if (graphicsPath != NULL) {
             if (matrix != NULL) {
                 Gdiplus::Matrix mat;
-                matrixConvert(matrix, mat);
+                matrixConvert(*matrix, mat);
                 graphicsPath->Outline(&mat, flatness);
             } else {
                 graphicsPath->Outline(NULL, flatness);
@@ -2552,7 +2552,7 @@ ege_rect ege_path_getbounds(const ege_path* path, const ege_transform_matrix* ma
         if (graphicsPath != NULL) {
             if (matrix != NULL) {
                 Gdiplus::Matrix mat;
-                matrixConvert(matrix, mat);
+                matrixConvert(*matrix, mat);
                 graphicsPath->GetBounds((Gdiplus::RectF*)&bounds, &mat);
             } else {
                 graphicsPath->GetBounds((Gdiplus::RectF*)&bounds, NULL);
@@ -2572,7 +2572,7 @@ ege_rect ege_path_getbounds(const ege_path* path, const ege_transform_matrix* ma
             PIMAGE img = CONVERT_IMAGE_CONST((PIMAGE)pimg);
             if (matrix != NULL) {
                 Gdiplus::Matrix mat;
-                matrixConvert(matrix, mat);
+                matrixConvert(*matrix, mat);
                 graphicsPath->GetBounds((Gdiplus::RectF*)&bounds, &mat, img->getPen());
             } else {
                 graphicsPath->GetBounds((Gdiplus::RectF*)&bounds, NULL, img->getPen());
@@ -2633,7 +2633,7 @@ void ege_path_transform(ege_path* path, const ege_transform_matrix *matrix)
         Gdiplus::GraphicsPath* graphicsPath = (Gdiplus::GraphicsPath*)path->data();
         if (graphicsPath != NULL) {
             Gdiplus::Matrix mat;
-            matrixConvert(matrix, mat);
+            matrixConvert(*matrix, mat);
             graphicsPath->Transform(&mat);
         }
     }
@@ -2890,7 +2890,7 @@ void EGEAPI ege_set_transform(const ege_transform_matrix* matrix, PIMAGE pimg)
     if (img && matrix) {
         Gdiplus::Graphics* graphics = img->getGraphics();
         Gdiplus::Matrix mat;
-        matrixConvert(matrix, mat);
+        matrixConvert(*matrix, mat);
         graphics->SetTransform(&mat);
     }
     CONVERT_IMAGE_END;
diff --git a/src/gdi_conv.cpp b/src/gdi_conv.cpp
index 7754c1b..e18a9f8 100644
--- a/src/gdi_conv.cpp
+++ b/src/gdi_conv.cpp
@@ -8,15 +8,10 @@ namespace ege
  * 将 ege_transform_matrix 类型转换为 Gdiplus::Matrix 类型
  * @param[in]  from  输入的矩阵
  * @param[out] to    保存转换结果
- * @note 如果 from 参数为 NULL，输出结果为单位矩阵。
  */
-void matrixConvert(const ege_transform_matrix* from, Gdiplus::Matrix& to)
+void matrixConvert(const ege_transform_matrix& from, Gdiplus::Matrix& to)
 {
-    if (from) {
-        to.SetElements(from->m11, from->m12, from->m21, from->m22, from->m31, from->m32);
-    } else {
-        to.Reset();
-    }
+    to.SetElements(from.m11, from.m12, from.m21, from.m22, from.m31, from.m32);
 }
 
 }
diff --git a/src/gdi_conv.h b/src/gdi_conv.h
index 182d3eb..c57cb68 100644
--- a/src/gdi_conv.h
+++ b/src/gdi_conv.h
@@ -5,5 +5,5 @@
 namespace ege
 {
     /* 矩阵类型转换 */
-    void matrixConvert(const ege_transform_matrix* from, Gdiplus::Matrix& to);
+    void matrixConvert(const ege_transform_matrix& from, Gdiplus::Matrix& to);
 }