diff --git a/include/common.h b/include/common.h
index 3b71cc15..89f3c398 100644
--- a/include/common.h
+++ b/include/common.h
@@ -2055,6 +2055,13 @@ int init_minigui_printf (int (*output_char) (int ch),
     #define TCS_CLRLINE(fp)
 #endif
 
+#define _WRN_PRINTF(fmt, ...)                   \
+    do {                                        \
+        TCS_PURPLE (stderr);                    \
+        fprintf (stderr, fmt, ##__VA_ARGS__);   \
+        TCS_NONE (stderr);                      \
+    } while (0)
+
 #define _ERR_PRINTF(fmt, ...)                   \
     do {                                        \
         TCS_RED (stderr);                       \
diff --git a/include/gdi.h b/include/gdi.h
index 0f21b782..d1680b2b 100644
--- a/include/gdi.h
+++ b/include/gdi.h
@@ -12516,7 +12516,7 @@ MG_EXPORT TEXTRUNSINFO* GUIAPI CreateTextRunsInfo(Uchar32* ucs, int nr_ucs,
 
 /**
  * Set font of part characters. Please call this function before
- * calling ShapeTextRunsBaisc or ShapeTextRunsComplex.
+ * calling InitBasicShapingEngine or InitComplexShapingEngine.
  */
 MG_EXPORT BOOL GUIAPI SetPartFontInTextRuns(TEXTRUNSINFO* run_info,
     int start_index, int length, const char* logfont_name);
@@ -12554,7 +12554,7 @@ MG_EXPORT BOOL GUIAPI ResetDirectionInTextRuns(TEXTRUNSINFO* run_info,
 MG_EXPORT BOOL GUIAPI DestroyTextRunsInfo(TEXTRUNSINFO* run_info);
 
 /**
- * \fn BOOL GUIAPI ShapeTextRunsBaisc()
+ * \fn BOOL GUIAPI InitBasicShapingEngine()
  * \brief Analyse and generate a shaped glyph string of a Unicode string
  *      under specific language and writing system.
  *
@@ -12605,7 +12605,7 @@ MG_EXPORT BOOL GUIAPI InitBasicShapingEngine(TEXTRUNSINFO* run_info);
 #ifdef _MGCOMPLEX_SCRIPTS
 
 /**
- * \fn int GUIAPI ShapeTextRunsComplex()
+ * \fn int GUIAPI InitComplexShapingEngine()
  * \brief Analyse and generate a shaped glyph string of a Unicode string
  *      under specific language and writing system. This is the complex
  *      implementation based on HarfBuzz, which is LGPL'd shaping engine.
@@ -12677,25 +12677,30 @@ MG_EXPORT BOOL GUIAPI InitComplexShapingEngine(TEXTRUNSINFO* run_info);
 typedef struct _LAYOUTINFO LAYOUTINFO;
 typedef struct _LAYOUTLINE LAYOUTLINE;
 
+/**
+ * Create layout information structure for laying out a paragraph.
+ */
 MG_EXPORT LAYOUTINFO* GUIAPI CreateLayoutInfo(
         const TEXTRUNSINFO* run_info, Uint32 render_flags,
         const BreakOppo* break_oppos, BOOL persist_lines,
         int letter_spacing, int word_spacing, int tab_size);
 
+/**
+ * Destroy the specified layout information structure.
+ */
 MG_EXPORT BOOL GUIAPI DestroyLayoutInfo(LAYOUTINFO* layout_info);
 
 typedef void (*CB_GLYPH_LAID_OUT) (GHANDLE ctxt,
         LOGFONT* lf, RGBCOLOR color, Glyph32 gv, const GLYPHPOS* pos);
 
-MG_EXPORT int GUIAPI LayoutNextLine(LAYOUTINFO* layout_info,
+/**
+ * Layout the next line of a paragraph according to the layout information.
+ */
+MG_EXPORT LAYOUTLINE* GUIAPI LayoutNextLine(LAYOUTINFO* layout_info,
+        LAYOUTLINE* prev_Line,
         int* x, int* y, int max_extent, SIZE* line_size,
         CB_GLYPH_LAID_OUT cb_laid_out, GHANDLE ctxt);
 
-MG_EXPORT int GUIAPI GetShapedGlyphsFittingLine(const TEXTRUNSINFO* run_info,
-        const BreakOppo* break_oppos,
-        int uc_start_index, int x, int y, Uint32 render_flags,
-        int letter_spacing, int word_spacing, int tab_size, int max_extent,
-        SIZE* line_size, GLYPHPOS** glyph_pos, int* nr_glyphs);
 /**
  * \fn int GUIAPI GetGlyphsExtentInfo()
  *
diff --git a/src/newgdi/Makefile.am b/src/newgdi/Makefile.am
index c50494bc..63130143 100644
--- a/src/newgdi/Makefile.am
+++ b/src/newgdi/Makefile.am
@@ -19,7 +19,7 @@ SRC_FILES = gdi.c attr.c clip.c map.c coor.c rect.c  \
             glyph-unicode.c \
             textrunsinfo.c \
             shape-glyphs-basic.c shape-glyphs-complex.c \
-            layout-shaped-glyphs.c
+            layoutinfo.c
 endif
 
 HDR_FILES = drawtext.h mi.h midc.h mistruct.h miwideline.h \
diff --git a/src/newgdi/layout-shaped-glyphs.c b/src/newgdi/layoutinfo.c
similarity index 97%
rename from src/newgdi/layout-shaped-glyphs.c
rename to src/newgdi/layoutinfo.c
index 1a6ac883..251005ba 100644
--- a/src/newgdi/layout-shaped-glyphs.c
+++ b/src/newgdi/layoutinfo.c
@@ -33,7 +33,7 @@
  */
 
 /*
-** layout-shaped-glyphs.c: The implementation of APIs related shaped-glyphs
+** layoutinfo.c: The implementation of APIs related LAYOUTINFO
 **
 ** Create by WEI Yongming at 2019/03/14
 */
@@ -51,6 +51,7 @@
 #include "window.h"
 #include "devfont.h"
 #include "unicode-ops.h"
+#include "layoutinfo.h"
 
 #if 0
 int GUIAPI DrawShapedGlyphString(HDC hdc,
diff --git a/src/newgdi/layoutinfo.h b/src/newgdi/layoutinfo.h
index 7137f37b..9648e283 100644
--- a/src/newgdi/layoutinfo.h
+++ b/src/newgdi/layoutinfo.h
@@ -42,12 +42,12 @@
     #define _MG_NEWGDI_LAYOUTINFO_H
 
 #include "list.h"
-#include "textruninfo.h"
+#include "textrunsinfo.h"
 
 typedef struct _GLYPHRUN        GLYPHRUN;
-typedef struct _GLYPHINFO       GLYPHINFO;
+typedef struct _SHAPEDGLYPH     SHAPEDGLYPH;
 
-struct _GLYPHINFO {
+struct _SHAPEDGLYPH {
     Glyph32 gv;
     int     x_off;
     int     y_off;
@@ -57,12 +57,12 @@ struct _GLYPHINFO {
 };
 
 struct _GLYPHSTRING {
-    GLYPHINFO*  glyphs;
+    SHAPEDGLYPH*  glyphs;
     int*        log_clusters;
 
     int         nr_glyphs;
     int         reserved;
-} GLYPHSTRING;
+};
 
 struct _GLYPHRUN {
     struct list_head    list;
@@ -72,7 +72,7 @@ struct _GLYPHRUN {
 
 struct _LAYOUTLINE {
     struct list_head    list;
-    GLYPHLAYOUTINFO*    layout_info;
+    LAYOUTINFO*         layout_info;
     int*                log_widths; // the widths of the logical chars
 
     struct list_head    run_head;   // the list head for glyph runs
@@ -98,7 +98,7 @@ struct _GLYPHLAYOUTINFO {
     struct list_head    line_head;  // the list head of lines
 
     LAYOUTLINE          *curr_line; // current line
-    int                 idx_next_char;
+    int                 left_ucs;   // the number of chars not laied out.
 };
 
 #ifdef __cplusplus
diff --git a/src/newgdi/shape-glyphs-basic.c b/src/newgdi/shape-glyphs-basic.c
index b13604cf..fdbd0b20 100644
--- a/src/newgdi/shape-glyphs-basic.c
+++ b/src/newgdi/shape-glyphs-basic.c
@@ -33,7 +33,7 @@
  */
 
 /*
-** shaped-glyph.c: The implementation of APIs related shaped-glyphs
+** shaped-glyph-basic.c: The implementation of basic shaping engine.
 **
 ** Reference:
 **
@@ -79,7 +79,7 @@ static void bidi_reverse_shaped_glyphs (void* context, int len, int pos)
 #   define LOCAL_ARRAY_SIZE 128
 #endif
 
-BOOL GUIAPI ShapeTextRunsBasic(TEXTRUNSINFO* run_info, Uint32 rf)
+BOOL GUIAPI InitBasicShapingEngine(TEXTRUNSINFO* run_info)
 {
 #if 0
     int ret_value = 0;
diff --git a/src/newgdi/shape-glyphs-complex.c b/src/newgdi/shape-glyphs-complex.c
index c52e4a61..b5b63cb0 100644
--- a/src/newgdi/shape-glyphs-complex.c
+++ b/src/newgdi/shape-glyphs-complex.c
@@ -57,10 +57,10 @@
 #include "unicode-ops.h"
 #include "textrunsinfo.h"
 
-BOOL GUIAPI ShapeTextRunsComplex(TEXTRUNSINFO* run_info, Uint32 rf)
+BOOL GUIAPI InitComplexShapingEngine(TEXTRUNSINFO* run_info)
 {
     return FALSE;
 }
 
-#endif /*  _MGCHARSET_UNICODE */
+#endif /* defined(_MGCHARSET_UNICODE) && defined(_MGCOMPLEX_SCRIPTS) */
 
diff --git a/src/newgdi/textrunsinfo.c b/src/newgdi/textrunsinfo.c
index 08e9e0ca..59eb08f0 100644
--- a/src/newgdi/textrunsinfo.c
+++ b/src/newgdi/textrunsinfo.c
@@ -195,7 +195,7 @@ static LOGFONT* create_logfont_for_run(const TEXTRUNSINFO* runinfo,
         fontname[orient_pos] = FONT_ORIENT_SIDEWAYS_LEFT;
         break;
     default:
-        _DBG_PRINTF("%s: bad orientation param: %d\n",
+        _WRN_PRINTF("%s: bad orientation param: %d\n",
             __FUNCTION__, run->ort);
         return NULL;
     }
@@ -236,7 +236,7 @@ static void release_logfont_for_run(const TEXTRUNSINFO* runinfo,
         fontname[orient_pos] = FONT_ORIENT_SIDEWAYS_LEFT;
         break;
     default:
-        _DBG_PRINTF("%s: bad orientation param: %d\n",
+        _WRN_PRINTF("%s: bad orientation param: %d\n",
             __FUNCTION__, run->ort);
         return;
     }
@@ -467,7 +467,8 @@ TEXTRUNSINFO* GUIAPI CreateTextRunsInfo(Uchar32* ucs, int nr_ucs,
         els = (BidiLevel*)malloc (nr_ucs * sizeof(BidiLevel));
 
     if (!els) {
-        _DBG_PRINTF("%s: failed to allocate space for embedding levels.\n");
+        _ERR_PRINTF("%s: failed to allocate space for embedding levels.\n",
+            __FUNCTION__);
         goto out;
     }
 
@@ -477,7 +478,8 @@ TEXTRUNSINFO* GUIAPI CreateTextRunsInfo(Uchar32* ucs, int nr_ucs,
     // Calculate the breaking opportunities
     if (UStrGetBreaks(script_type, ctr, wbr, lbp,
             ucs, nr_ucs, &bos) == 0) {
-        _DBG_PRINTF("%s: failed to get breaking opportunities.\n");
+        _ERR_PRINTF("%s: failed to get breaking opportunities.\n",
+            __FUNCTION__);
         goto out;
     }
     */
@@ -532,7 +534,7 @@ TEXTRUNSINFO* GUIAPI CreateTextRunsInfo(Uchar32* ucs, int nr_ucs,
 #endif
 
     if (!create_glyph_runs(runinfo, els)) {
-        _DBG_PRINTF("%s: failed to call create_glyph_runs.\n",
+        _ERR_PRINTF("%s: failed to call create_glyph_runs.\n",
             __FUNCTION__);
         goto out;
     }
@@ -557,10 +559,6 @@ BOOL GUIAPI SetPartFontInTextRuns(TEXTRUNSINFO* runinfo,
     if (runinfo == NULL)
         return FALSE;
 
-    // can not change font after shaped the glyphs
-    if (runinfo->sei.inst != NULL)
-        return FALSE;
-
     // can not change font for empty runs
     if (list_empty(&runinfo->run_head))
         return FALSE;
@@ -657,11 +655,6 @@ BOOL GUIAPI ResetDirectionInTextRuns(TEXTRUNSINFO* runinfo,
         set_run_dir(runinfo, run, run_dir, glyph_orient);
     }
 
-    if (runinfo->sei.inst) {
-        runinfo->sei.free(runinfo->sei.inst);
-        runinfo->sei.inst = NULL;
-    }
-
     return TRUE;
 }
 
@@ -690,7 +683,8 @@ BOOL GUIAPI ResetBreaksInTextRuns(TEXTRUNSINFO* runinfo,
     // Re-calculate the breaking opportunities
     if (UStrGetBreaks(runinfo->run_head.st, ctr, wbr, lbp,
             runinfo->ucs, runinfo->run_head.nr_ucs, &runinfo->bos) == 0) {
-        _DBG_PRINTF("%s: failed to get breaking opportunities.\n");
+        _ERR_PRINTF("%s: failed to get breaking opportunities.\n",
+            __FUNCTION__);
         return FALSE;
     }