improve ascent/descent for type 3 fonts

src/HTMLRenderer/font.cc

@@ -58,6 +58,7 @@ string HTMLRenderer::dump_embedded_font (GfxFont * font, FontInfo & info)
     string filepath;
 
     long long fn_id = info.id;
+    info.font_size_scale = 1.0;
 
     try
     {
@@ -195,13 +196,17 @@ string HTMLRenderer::dump_type3_font (GfxFont * font, FontInfo & info)
     auto * cur_font = font_engine.getFont(font, cur_doc, true, xref);
     auto used_map = preprocessor.get_code_map(hash_ref(font->getID()));
 
+    //calculate transformed metrics
     double * font_bbox = font->getFontBBox();
     // TODO: font matrix may not exists
     double * font_matrix = font->getFontMatrix();
-
-    //calculate transformations
     double transformed_bbox[4];
     memcpy(transformed_bbox, font_bbox, 4 * sizeof(double));
+    // add the origin to the bbox
+    if(transformed_bbox[0] > 0) transformed_bbox[0] = 0;
+    if(transformed_bbox[1] > 0) transformed_bbox[1] = 0;
+    if(transformed_bbox[2] < 0) transformed_bbox[2] = 0;
+    if(transformed_bbox[3] < 0) transformed_bbox[3] = 0;
     tm_transform_bbox(font_matrix, transformed_bbox);
     double transformed_bbox_width = transformed_bbox[2] - transformed_bbox[0];
     double transformed_bbox_height = transformed_bbox[3] - transformed_bbox[1];
@@ -212,10 +217,10 @@ string HTMLRenderer::dump_type3_font (GfxFont * font, FontInfo & info)
     std::cerr << std::endl;
     // we want the glyphs is rendered in a box of size around 100 x 100
     // for rectangles, the longer edge should be 100
-    info.type3_font_size_scale = std::max(transformed_bbox_width, transformed_bbox_height);
+    info.font_size_scale = std::max(transformed_bbox_width, transformed_bbox_height);
 
     const double GLYPH_DUMP_SIZE = 100.0;
-    double scale = GLYPH_DUMP_SIZE / info.type3_font_size_scale;
+    double scale = GLYPH_DUMP_SIZE / info.font_size_scale;
 
     // determine the position of the origin of the glyph
     double ox, oy;
@@ -224,9 +229,11 @@ string HTMLRenderer::dump_type3_font (GfxFont * font, FontInfo & info)
     ox -= transformed_bbox[0];
     oy -= transformed_bbox[1];
 
-    
+    // we choose ttf as it does not use char names
-    // dump each glyph into svg and combine them
+    // or actually we don't use char names for ttf (see embed_font)
     ffw_new_font();
+    ffw_set_metric(transformed_bbox[3] / transformed_bbox_height, transformed_bbox[1] / transformed_bbox_height);
+    // dump each glyph into svg and combine them
     for(int code = 0; code < 256; ++code)
     {
         if(!used_map[code]) continue;
@@ -331,8 +338,6 @@ string HTMLRenderer::dump_type3_font (GfxFont * font, FontInfo & info)
         ffw_import_svg_glyph(code, glyph_filename.c_str());
     }
 
-    // we choose ttf as it does not use char names
-    // or actually we don't use char names for ttf (see embed_font)
     string font_filename = (char*)str_fmt("%s/f%llx.ttf", param.tmp_dir.c_str(), fn_id);
     tmp_files.add(font_filename);
     ffw_save(font_filename.c_str());
@@ -400,7 +405,8 @@ void HTMLRenderer::embed_font(const string & filepath, GfxFont * font, FontInfo
 
     if(get_metric_only)
     {
-        ffw_metric(&info.ascent, &info.descent);
+        ffw_fix_metric();
+        ffw_get_metric(&info.ascent, &info.descent);
         ffw_close();
         return;
     }
@@ -647,8 +653,7 @@ void HTMLRenderer::embed_font(const string & filepath, GfxFont * font, FontInfo
                     cur_width = font_cid->getWidth(buf, 2) ;
                 }
 
-                if(info.is_type3)
+                cur_width /= info.font_size_scale;
-                    cur_width /= info.type3_font_size_scale;
 
                 if(u == ' ')
                 {
@@ -693,8 +698,7 @@ void HTMLRenderer::embed_font(const string & filepath, GfxFont * font, FontInfo
                 char buf[2] = {0, ' '};
                 info.space_width = font_cid->getWidth(buf, 2);
             }
-            if(info.is_type3)
+            info.space_width /= info.font_size_scale;
-                info.space_width /= info.type3_font_size_scale;
 
             /* See comments above */
             if(equal(info.space_width,0))
@@ -777,7 +781,8 @@ void HTMLRenderer::embed_font(const string & filepath, GfxFont * font, FontInfo
         tmp_files.add(fn);
 
     ffw_load_font(cur_tmp_fn.c_str());
-    ffw_metric(&info.ascent, &info.descent);
+    ffw_fix_metric();
+    ffw_get_metric(&info.ascent, &info.descent);
     if(param.override_fstype)
         ffw_override_fstype();
     ffw_save(fn.c_str());

src/HTMLRenderer/state.cc

@@ -274,11 +274,6 @@ void HTMLRenderer::check_state_change(GfxState * state)
 
         double new_draw_font_size = cur_font_size;
 
-        if(cur_text_state.font_info->is_type3 && param.process_type3)
-        {
-            new_draw_font_size *= cur_text_state.font_info->type3_font_size_scale;
-        }
-
         if(is_positive(new_draw_text_scale))
         {
             // scale both font size and matrix 

src/HTMLState.h

@@ -26,9 +26,11 @@ struct FontInfo
      * we have to scale the font to about 1,
      * then apply the scaling when using the font
      *
-     * The scaling factor is stored as type3_font_size_scale
+     * The scaling factor is stored as font_size_scale
+     *
+     * The value is 1 for other fonts
      */
-    double type3_font_size_scale;
+    double font_size_scale;
 };
 
 struct HTMLTextState

src/HTMLTextLine.cc

@@ -60,7 +60,10 @@ void HTMLTextLine::append_state(const HTMLTextState & text_state)
         states.back().hash_umask = 0;
     }
 
-    (HTMLTextState&)(states.back()) = text_state;
+    HTMLTextState & last_state = states.back();
+    last_state = text_state;
+    //apply font scale
+    last_state.font_size *= last_state.font_info->font_size_scale;
 }
 
 void HTMLTextLine::dump_text(ostream & out)
@@ -251,7 +254,8 @@ void HTMLTextLine::prepare(void)
     // note that vertical_align cannot be calculated here
     for(auto iter = states.begin(); iter != states.end(); ++iter)
     {
-        iter->ids[State::FONT_ID] = iter->font_info->id;
+        auto font_info = iter->font_info;
+        iter->ids[State::FONT_ID] = font_info->id;
         iter->ids[State::FONT_SIZE_ID]      = all_manager.font_size.install(iter->font_size);
         iter->ids[State::FILL_COLOR_ID]     = all_manager.fill_color.install(iter->fill_color);
         iter->ids[State::STROKE_COLOR_ID]   = all_manager.stroke_color.install(iter->stroke_color);
@@ -260,10 +264,10 @@ void HTMLTextLine::prepare(void)
         iter->hash();
 
         accum_vertical_align += iter->vertical_align;
-        double cur_ascent = accum_vertical_align + iter->font_info->ascent * iter->font_size;
+        double cur_ascent = accum_vertical_align + font_info->ascent * iter->font_size;
         if(cur_ascent > ascent)
             ascent = cur_ascent;
-        double cur_descent = accum_vertical_align + iter->font_info->descent * iter->font_size;
+        double cur_descent = accum_vertical_align + font_info->descent * iter->font_size;
         if(cur_descent < descent)
             descent = cur_descent;
     }

src/util/ffw.c

@@ -302,29 +302,22 @@ int ffw_get_em_size(void)
     return cur_fv->sf->ascent + cur_fv->sf->descent;
 }
 
-void ffw_metric(double * ascent, double * descent)
+void ffw_fix_metric()
+{
+    double ascent, descent;
+    ffw_get_metric(&ascent, &descent);
+    //debug
+    printf("fix metrix: %lf %lf\n", ascent, descent);
+    ffw_set_metric(ascent, descent);
+}
+
+void ffw_get_metric(double * ascent, double * descent)
 {
     SplineFont * sf = cur_fv->sf;
-    struct pfminfo * info = &sf->pfminfo;
-
-    SFDefaultOS2Info(info, sf, sf->fontname);
-    info->pfmset = 1;
-    sf->changed = 1;
 
     DBounds bb;
     SplineFontFindBounds(sf, &bb);
 
-    /*
-    printf("bb %lf %lf\n", bb.maxy, bb.miny);
-    printf("_ %d %d\n", sf->ascent, sf->descent);
-    printf("win %d %d\n", info->os2_winascent, info->os2_windescent);
-    printf("%d %d\n", info->winascent_add, info->windescent_add);
-    printf("typo %d %d\n", info->os2_typoascent, info->os2_typodescent);
-    printf("%d %d\n", info->typoascent_add, info->typodescent_add);
-    printf("hhead %d %d\n", info->hhead_ascent, info->hhead_descent);
-    printf("%d %d\n", info->hheadascent_add, info->hheaddescent_add);
-    */
-
     int em = sf->ascent + sf->descent;
 
     if (em > 0)
@@ -336,10 +329,21 @@ void ffw_metric(double * ascent, double * descent)
     {
         *ascent = *descent = 0;
     }
+}
+
+void ffw_set_metric(double ascent, double descent)
+{
+    SplineFont * sf = cur_fv->sf;
+    struct pfminfo * info = &sf->pfminfo;
+
+    SFDefaultOS2Info(info, sf, sf->fontname);
+    info->pfmset = 1;
+    sf->changed = 1;
+
+    int em = sf->ascent + sf->descent;
+    int a = floor(ascent * em + 0.5);
+    int d = floor(descent * em + 0.5);
 
-    int a = floor(bb.maxy + 0.5);
-    int d = floor(bb.miny + 0.5);
-    
     if(a < 0) a = 0;
     if(d > 0) d = 0;
 
@@ -354,7 +358,6 @@ void ffw_metric(double * ascent, double * descent)
      * But have to unify them, for different browsers on different platforms
      * Things may become easier when there are CSS rules for baseline-based positioning.
      */
-
     info->os2_winascent = a;
     info->os2_typoascent = a;
     info->hhead_ascent = a;
@@ -430,13 +433,23 @@ void ffw_import_svg_glyph(int code, const char * filename)
     if(enc == -1)
         return;
 
-    SFMakeChar(cur_fv->sf, cur_fv->map, enc);
+    SplineChar * sc = SFMakeChar(cur_fv->sf, cur_fv->map, enc);
 
     memset(cur_fv->selected, 0, cur_fv->map->enccount);
     cur_fv->selected[enc] = 1;
     int ok = FVImportImages(cur_fv, (char*)filename, fv_svg, 0, -1);
     if(!ok)
         err("Import SVG glyph failed");
+
+    // correct the origin
+    {
+        real transform[6]; 
+        transform[0] = 1.0;
+        transform[3] = 1.0;
+        transform[1] = transform[2] = transform[4];
+        transform[5] = cur_fv->sf->descent;
+        FVTrans(cur_fv, sc, transform, NULL, fvt_alllayers | fvt_dontmovewidth);
+    }
 }
 
 void ffw_auto_hint(void)

src/util/ffw.h

@@ -48,8 +48,14 @@ void ffw_add_empty_char(int32_t unicode, int width);
 ////////////////////////
 // metrics
 int ffw_get_em_size(void);
-// fix metrics and get them
+// manipulate ascent and descent
-void ffw_metric(double * ascent, double * descent);
+// asscent is between 0 and 1
+// descent is between -1 and 0
+void ffw_fix_metric();
+// get ascent/descent based on the shape
+void ffw_get_metric(double * ascent, double * descent);
+// set corresponding fields
+void ffw_set_metric(double ascent, double descent);
 
 void ffw_set_widths(int * width_list, int mapping_len, 
         int stretch_narrow, int squeeze_wide);