freetype: force font y alignment for gridmode

Line height is always set to max of the rendered glyphs height.
This causes 'dancing' lines because row height it never the
same, amplified by number of preceding empty rows.

modules/text_renderer/freetype.c

@@ -996,7 +996,7 @@ static int Render( filter_t *p_filter, subpicture_region_t *p_region_out,
 
     rv = LayoutText( p_filter,
                      &p_lines, &bbox, &i_max_face_height,
-                     psz_text, pp_styles, pi_k_durations, i_text_length );
+                     psz_text, pp_styles, pi_k_durations, i_text_length, p_region_in->b_gridmode );
 
     p_region_out->i_x = p_region_in->i_x;
     p_region_out->i_y = p_region_in->i_y;

modules/text_renderer/text_layout.c

@@ -868,7 +868,7 @@ static int LoadGlyphs( filter_t *p_filter, paragraph_t *p_paragraph,
 static int LayoutLine( filter_t *p_filter,
                        paragraph_t *p_paragraph,
                        int i_start_offset, int i_end_offset,
-                       line_desc_t **pp_line )
+                       line_desc_t **pp_line, bool b_grid )
 {
     if( p_paragraph->i_size <= 0 || p_paragraph->i_runs_count <= 0
      || i_start_offset >= i_end_offset
@@ -898,6 +898,7 @@ static int LayoutLine( filter_t *p_filter,
     int i_line_index = 0;
 
     int i_font_width = 0;
+    int i_font_max_advance_y = 0;
     int i_ul_offset = 0;
     int i_ul_thickness = 0;
 
@@ -1057,10 +1058,22 @@ static int LayoutLine( filter_t *p_filter,
 
         pen.x += p_bitmaps->i_x_advance;
         pen.y += p_bitmaps->i_y_advance;
+
+        /* Get max advance for grid mode */
+        if( b_grid && i_font_max_advance_y == 0 )
+        {
+            i_font_max_advance_y = abs( FT_FLOOR( FT_MulFix( p_face->max_advance_height,
+                                      p_face->size->metrics.y_scale ) ) );
+        }
     }
 
     p_line->i_width = __MAX( 0, p_line->bbox.xMax - p_line->bbox.xMin );
+
+    if( b_grid )
+        p_line->i_height = i_font_max_advance_y;
+    else
         p_line->i_height = __MAX( 0, p_line->bbox.yMax - p_line->bbox.yMin );
+
     p_line->i_character_count = i_line_index;
 
     if( i_ul_thickness > 0 )
@@ -1081,7 +1094,8 @@ static int LayoutLine( filter_t *p_filter,
 }
 
 static int LayoutParagraph( filter_t *p_filter, paragraph_t *p_paragraph,
-                            int i_max_pixel_width, line_desc_t **pp_lines )
+                            int i_max_pixel_width, line_desc_t **pp_lines,
+                            bool b_grid )
 {
     if( p_paragraph->i_size <= 0 || p_paragraph->i_runs_count <= 0 )
     {
@@ -1118,7 +1132,7 @@ static int LayoutParagraph( filter_t *p_filter, paragraph_t *p_paragraph,
         {
             if( i_line_start < i )
                 if( LayoutLine( p_filter, p_paragraph,
-                                i_line_start, i, pp_line ) )
+                                i_line_start, i, pp_line, b_grid ) )
                     goto error;
 
             break;
@@ -1176,7 +1190,7 @@ static int LayoutParagraph( filter_t *p_filter, paragraph_t *p_paragraph,
                 i_end_offset = i;
 
             if( LayoutLine( p_filter, p_paragraph, i_line_start,
-                            i_end_offset, pp_line ) )
+                            i_end_offset, pp_line, b_grid ) )
                 goto error;
 
             pp_line = &( *pp_line )->p_next;
@@ -1207,7 +1221,7 @@ int LayoutText( filter_t *p_filter, line_desc_t **pp_lines,
                 FT_BBox *p_bbox, int *pi_max_face_height,
 
                 const uni_char_t *psz_text, const text_style_t **pp_styles,
-                uint32_t *pi_k_dates, int i_len )
+                uint32_t *pi_k_dates, int i_len, bool b_grid )
 {
     line_desc_t *p_first_line = 0;
     line_desc_t **pp_line = &p_first_line;
@@ -1273,7 +1287,7 @@ int LayoutText( filter_t *p_filter, line_desc_t **pp_lines,
             int i_max_width = ( int ) p_filter->fmt_out.video.i_visible_width
                               - 2 * p_filter->p_sys->p_style->i_font_size;
             if( LayoutParagraph( p_filter, p_paragraph,
-                                 i_max_width, pp_line ) )
+                                 i_max_width, pp_line, b_grid ) )
                 goto error;
 
             FreeParagraph( p_paragraph );

modules/text_renderer/text_layout.h

@@ -56,4 +56,4 @@ line_desc_t *NewLine( int i_count );
 int LayoutText(filter_t *p_filter, line_desc_t **pp_lines,
                 FT_BBox *p_bbox, int *pi_max_face_height,
                 const uni_char_t *psz_text, const text_style_t **pp_styles,
-                uint32_t *pi_k_dates, int i_len );
+                uint32_t *pi_k_dates, int i_len, bool );