]> granicus.if.org Git - libass/blobdiff - libass/ass_font.c
Message callback funtionality
[libass] / libass / ass_font.c
index f70b7c59e3bc9d03db8bcdc9124f4116c5ad3ce4..34ae292c466ceac7a4bfb36b9cc563d61765764d 100644 (file)
@@ -1,5 +1,3 @@
-// -*- c-basic-offset: 8; indent-tabs-mode: t -*-
-// vim:ts=8:sw=8:noet:ai:
 /*
  * Copyright (C) 2006 Evgeniy Stepanov <eugeni.stepanov@gmail.com>
  *
 #include "ass_cache.h"
 #include "ass_fontconfig.h"
 #include "ass_utils.h"
-#include "mputils.h"
 
 /**
  * Select Microfost Unicode CharMap, if the font has one.
  * Otherwise, let FreeType decide.
  */
-static void charmap_magic(FT_Face face)
+static void charmap_magic(ass_library_t *library, FT_Face face)
 {
-       int i;
-       for (i = 0; i < face->num_charmaps; ++i) {
-               FT_CharMap cmap = face->charmaps[i];
-               unsigned pid = cmap->platform_id;
-               unsigned eid = cmap->encoding_id;
-               if (pid == 3 /*microsoft*/ && (eid == 1 /*unicode bmp*/ || eid == 10 /*full unicode*/)) {
-                       FT_Set_Charmap(face, cmap);
-                       return;
-               }
-       }
-
-       if (!face->charmap) {
-               if (face->num_charmaps == 0) {
-                       mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_NoCharmaps);
-                       return;
-               }
-               mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_NoCharmapAutodetected);
-               FT_Set_Charmap(face, face->charmaps[0]);
-               return;
-       }
+    int i;
+    for (i = 0; i < face->num_charmaps; ++i) {
+        FT_CharMap cmap = face->charmaps[i];
+        unsigned pid = cmap->platform_id;
+        unsigned eid = cmap->encoding_id;
+        if (pid == 3 /*microsoft */ 
+            && (eid == 1 /*unicode bmp */ 
+                || eid == 10 /*full unicode */ )) {
+            FT_Set_Charmap(face, cmap);
+            return;
+        }
+    }
+
+    if (!face->charmap) {
+        if (face->num_charmaps == 0) {
+            ass_msg(library, MSGL_WARN, "Font face with no charmaps");
+            return;
+        }
+        ass_msg(library, MSGL_WARN,
+                "No charmap autodetected, trying the first one");
+        FT_Set_Charmap(face, face->charmaps[0]);
+        return;
+    }
 }
 
-static void update_transform(ass_font_tfont)
+static void update_transform(ass_font_t *font)
 {
-       int i;
-       FT_Matrix m;
-       m.xx = double_to_d16(font->scale_x);
-       m.yy = double_to_d16(font->scale_y);
-       m.xy = m.yx = 0;
-       for (i = 0; i < font->n_faces; ++i)
-               FT_Set_Transform(font->faces[i], &m, &font->v);
+    int i;
+    FT_Matrix m;
+    m.xx = double_to_d16(font->scale_x);
+    m.yy = double_to_d16(font->scale_y);
+    m.xy = m.yx = 0;
+    for (i = 0; i < font->n_faces; ++i)
+        FT_Set_Transform(font->faces[i], &m, &font->v);
 }
 
 /**
  * \brief find a memory font by name
  */
-static int find_font(ass_library_t* library, char* name)
+static int find_font(ass_library_t *library, char *name)
 {
-       int i;
-       for (i = 0; i < library->num_fontdata; ++i)
-               if (strcasecmp(name, library->fontdata[i].name) == 0)
-                       return i;
-       return -1;
+    int i;
+    for (i = 0; i < library->num_fontdata; ++i)
+        if (strcasecmp(name, library->fontdata[i].name) == 0)
+            return i;
+    return -1;
 }
 
 static void face_set_size(FT_Face face, double size);
 
 static void buggy_font_workaround(FT_Face face)
 {
-       // Some fonts have zero Ascender/Descender fields in 'hhea' table.
-       // In this case, get the information from 'os2' table or, as
-       // a last resort, from face.bbox.
-       if (face->ascender + face->descender == 0 || face->height == 0) {
-               TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
-               if (os2) {
-                       face->ascender = os2->sTypoAscender;
-                       face->descender = os2->sTypoDescender;
-                       face->height = face->ascender - face->descender;
-               } else {
-                       face->ascender = face->bbox.yMax;
-                       face->descender = face->bbox.yMin;
-                       face->height = face->ascender - face->descender;
-               }
-       }
+    // Some fonts have zero Ascender/Descender fields in 'hhea' table.
+    // In this case, get the information from 'os2' table or, as
+    // a last resort, from face.bbox.
+    if (face->ascender + face->descender == 0 || face->height == 0) {
+        TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
+        if (os2) {
+            face->ascender = os2->sTypoAscender;
+            face->descender = os2->sTypoDescender;
+            face->height = face->ascender - face->descender;
+        } else {
+            face->ascender = face->bbox.yMax;
+            face->descender = face->bbox.yMin;
+            face->height = face->ascender - face->descender;
+        }
+    }
 }
 
 /**
  * \brief Select a face with the given charcode and add it to ass_font_t
  * \return index of the new face in font->faces, -1 if failed
  */
-static int add_face(void* fc_priv, ass_font_t* font, uint32_t ch)
+static int add_face(void *fc_priv, ass_font_t *font, uint32_t ch)
 {
-       char* path;
-       int index;
-       FT_Face face;
-       int error;
-       int mem_idx;
-       
-       if (font->n_faces == ASS_FONT_MAX_FACES)
-               return -1;
-       
-       path = fontconfig_select(fc_priv, font->desc.family, font->desc.bold,
-                                             font->desc.italic, &index, ch);
-
-       mem_idx = find_font(font->library, path);
-       if (mem_idx >= 0) {
-               error = FT_New_Memory_Face(font->ftlibrary, (unsigned char*)font->library->fontdata[mem_idx].data,
-                                          font->library->fontdata[mem_idx].size, 0, &face);
-               if (error) {
-                       mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_ErrorOpeningMemoryFont, path);
-                       return -1;
-               }
-       } else {
-               error = FT_New_Face(font->ftlibrary, path, index, &face);
-               if (error) {
-                       mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_ErrorOpeningFont, path, index);
-                       return -1;
-               }
-       }
-       charmap_magic(face);
-       buggy_font_workaround(face);
-       
-       font->faces[font->n_faces++] = face;
-       update_transform(font);
-       face_set_size(face, font->size);
-       return font->n_faces - 1;
+    char *path;
+    int index;
+    FT_Face face;
+    int error;
+    int mem_idx;
+
+    if (font->n_faces == ASS_FONT_MAX_FACES)
+        return -1;
+
+    path =
+        fontconfig_select(font->library, fc_priv, font->desc.family,
+                          font->desc.treat_family_as_pattern,
+                          font->desc.bold, font->desc.italic, &index, ch);
+    if (!path)
+        return -1;
+
+    mem_idx = find_font(font->library, path);
+    if (mem_idx >= 0) {
+        error =
+            FT_New_Memory_Face(font->ftlibrary,
+                               (unsigned char *) font->library->
+                               fontdata[mem_idx].data,
+                               font->library->fontdata[mem_idx].size, 0,
+                               &face);
+        if (error) {
+            ass_msg(font->library, MSGL_WARN,
+                    "Error opening memory font: '%s'", path);
+            free(path);
+            return -1;
+        }
+    } else {
+        error = FT_New_Face(font->ftlibrary, path, index, &face);
+        if (error) {
+            ass_msg(font->library, MSGL_WARN,
+                    "Error opening font: '%s', %d", path, index);
+            free(path);
+            return -1;
+        }
+    }
+    charmap_magic(font->library, face);
+    buggy_font_workaround(face);
+
+    font->faces[font->n_faces++] = face;
+    update_transform(font);
+    face_set_size(face, font->size);
+    free(path);
+    return font->n_faces - 1;
 }
 
 /**
  * \brief Create a new ass_font_t according to "desc" argument
  */
-ass_font_t* ass_font_new(ass_library_t* library, FT_Library ftlibrary, void* fc_priv, ass_font_desc_t* desc)
+ass_font_t *ass_font_new(void *font_cache, ass_library_t *library,
+                         FT_Library ftlibrary, void *fc_priv,
+                         ass_font_desc_t *desc)
 {
-       int error;
-       ass_font_t* fontp;
-       ass_font_t font;
-
-       fontp = ass_font_cache_find(desc);
-       if (fontp)
-               return fontp;
-       
-       font.library = library;
-       font.ftlibrary = ftlibrary;
-       font.n_faces = 0;
-       font.desc.family = strdup(desc->family);
-       font.desc.bold = desc->bold;
-       font.desc.italic = desc->italic;
-
-       font.scale_x = font.scale_y = 1.;
-       font.v.x = font.v.y = 0;
-       font.size = 0.;
-
-       error = add_face(fc_priv, &font, 0);
-       if (error == -1) {
-               free(font.desc.family);
-               return 0;
-       } else
-               return ass_font_cache_add(&font);
+    int error;
+    ass_font_t *fontp;
+    ass_font_t font;
+
+    fontp = ass_font_cache_find((hashmap_t *) font_cache, desc);
+    if (fontp)
+        return fontp;
+
+    font.library = library;
+    font.ftlibrary = ftlibrary;
+    font.n_faces = 0;
+    font.desc.family = strdup(desc->family);
+    font.desc.treat_family_as_pattern = desc->treat_family_as_pattern;
+    font.desc.bold = desc->bold;
+    font.desc.italic = desc->italic;
+
+    font.scale_x = font.scale_y = 1.;
+    font.v.x = font.v.y = 0;
+    font.size = 0.;
+
+    error = add_face(fc_priv, &font, 0);
+    if (error == -1) {
+        free(font.desc.family);
+        return 0;
+    } else
+        return ass_font_cache_add((hashmap_t *) font_cache, &font);
 }
 
 /**
  * \brief Set font transformation matrix and shift vector
  **/
-void ass_font_set_transform(ass_font_t* font, double scale_x, double scale_y, FT_Vector* v)
+void ass_font_set_transform(ass_font_t *font, double scale_x,
+                            double scale_y, FT_Vector *v)
 {
-       font->scale_x = scale_x;
-       font->scale_y = scale_y;
-       font->v.x = v->x;
-       font->v.y = v->y;
-       update_transform(font);
+    font->scale_x = scale_x;
+    font->scale_y = scale_y;
+    font->v.x = v->x;
+    font->v.y = v->y;
+    update_transform(font);
 }
 
 static void face_set_size(FT_Face face, double size)
 {
 #if (FREETYPE_MAJOR > 2) || ((FREETYPE_MAJOR == 2) && (FREETYPE_MINOR > 1))
-       TT_HoriHeader *hori = FT_Get_Sfnt_Table(face, ft_sfnt_hhea);
-       TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
-       double mscale = 1.;
-       FT_Size_RequestRec rq;
-       FT_Size_Metrics *m = &face->size->metrics;
-       // VSFilter uses metrics from TrueType OS/2 table
-       // The idea was borrowed from asa (http://asa.diac24.net)
-       if (hori && os2) {
-               int hori_height = hori->Ascender - hori->Descender;
-               int os2_height = os2->usWinAscent + os2->usWinDescent;
-               if (hori_height && os2_height)
-                       mscale = (double)hori_height / os2_height;
-       }
-       memset(&rq, 0, sizeof(rq));
-       rq.type = FT_SIZE_REQUEST_TYPE_REAL_DIM;
-       rq.width = 0;
-       rq.height = double_to_d6(size * mscale);
-       rq.horiResolution = rq.vertResolution = 0;
-       FT_Request_Size(face, &rq);
-       m->ascender /= mscale;
-       m->descender /= mscale;
-       m->height /= mscale;
+    TT_HoriHeader *hori = FT_Get_Sfnt_Table(face, ft_sfnt_hhea);
+    TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
+    double mscale = 1.;
+    FT_Size_RequestRec rq;
+    FT_Size_Metrics *m = &face->size->metrics;
+    // VSFilter uses metrics from TrueType OS/2 table
+    // The idea was borrowed from asa (http://asa.diac24.net)
+    if (hori && os2) {
+        int hori_height = hori->Ascender - hori->Descender;
+        int os2_height = os2->usWinAscent + os2->usWinDescent;
+        if (hori_height && os2_height)
+            mscale = (double) hori_height / os2_height;
+    }
+    memset(&rq, 0, sizeof(rq));
+    rq.type = FT_SIZE_REQUEST_TYPE_REAL_DIM;
+    rq.width = 0;
+    rq.height = double_to_d6(size * mscale);
+    rq.horiResolution = rq.vertResolution = 0;
+    FT_Request_Size(face, &rq);
+    m->ascender /= mscale;
+    m->descender /= mscale;
+    m->height /= mscale;
 #else
-       FT_Set_Char_Size(face, 0, double_to_d6(size), 0, 0);
+    FT_Set_Char_Size(face, 0, double_to_d6(size), 0, 0);
 #endif
 }
 
 /**
  * \brief Set font size
  **/
-void ass_font_set_size(ass_font_tfont, double size)
+void ass_font_set_size(ass_font_t *font, double size)
 {
-       int i;
-       if (font->size != size) {
-               font->size = size;
-               for (i = 0; i < font->n_faces; ++i)
-                       face_set_size(font->faces[i], size);
-       }
+    int i;
+    if (font->size != size) {
+        font->size = size;
+        for (i = 0; i < font->n_faces; ++i)
+            face_set_size(font->faces[i], size);
+    }
 }
 
 /**
@@ -244,125 +261,226 @@ void ass_font_set_size(ass_font_t* font, double size)
  * \param ch character code
  * The values are extracted from the font face that provides glyphs for the given character
  **/
-void ass_font_get_asc_desc(ass_font_t* font, uint32_t ch, int* asc, int* desc)
+void ass_font_get_asc_desc(ass_font_t *font, uint32_t ch, int *asc,
+                           int *desc)
 {
-       int i;
-       for (i = 0; i < font->n_faces; ++i) {
-               FT_Face face = font->faces[i];
-               if (FT_Get_Char_Index(face, ch)) {
-                       *asc = face->size->metrics.ascender;
-                       *desc = - face->size->metrics.descender;
-                       return;
-               }
-       }
-       
-       *asc = *desc = 0;
+    int i;
+    for (i = 0; i < font->n_faces; ++i) {
+        FT_Face face = font->faces[i];
+        if (FT_Get_Char_Index(face, ch)) {
+            *asc = face->size->metrics.ascender;
+            *desc = -face->size->metrics.descender;
+            return;
+        }
+    }
+
+    *asc = *desc = 0;
+}
+
+/*
+ * Strike a glyph with a horizontal line; it's possible to underline it
+ * and/or strike through it.  For the line's position and size, truetype
+ * tables are consulted.  Obviously this relies on the data in the tables
+ * being accurate.
+ *
+ */
+static int ass_strike_outline_glyph(FT_Face face, ass_font_t *font,
+                                    FT_Glyph glyph, int under, int through)
+{
+    TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
+    TT_Postscript *ps = FT_Get_Sfnt_Table(face, ft_sfnt_post);
+    FT_Outline *ol = &((FT_OutlineGlyph) glyph)->outline;
+    int bear, advance, y_scale, i;
+
+    // Grow outline
+    i = (under ? 4 : 0) + (through ? 4 : 0);
+    ol->points = realloc(ol->points, sizeof(FT_Vector) *
+                         (ol->n_points + i));
+    ol->tags = realloc(ol->tags, ol->n_points + i);
+    i = !!under + !!through;
+    ol->contours = realloc(ol->contours, sizeof(short) *
+                           (ol->n_contours + i));
+
+    // If the bearing is negative, the glyph starts left of the current
+    // pen position
+    bear = FFMIN(face->glyph->metrics.horiBearingX, 0);
+    // We're adding half a pixel to avoid small gaps
+    advance = d16_to_d6(glyph->advance.x) + 32;
+    y_scale = face->size->metrics.y_scale;
+
+    // Add points to the outline
+    if (under) {
+        int pos, size;
+        pos = FT_MulFix(ps->underlinePosition, y_scale * font->scale_y);
+        size = FT_MulFix(ps->underlineThickness,
+                         y_scale * font->scale_y / 2);
+
+        if (pos > 0 || size <= 0)
+            return 0;
+
+        FT_Vector points[4] = {
+            {.x = bear,      .y = pos + size},
+            {.x = advance,   .y = pos + size},
+            {.x = advance,   .y = pos - size},
+            {.x = bear,      .y = pos - size},
+        };
+
+        for (i = 0; i < 4; i++) {
+            ol->points[ol->n_points] = points[i];
+            ol->tags[ol->n_points++] = 1;
+        }
+        ol->contours[ol->n_contours++] = ol->n_points - 1;
+    }
+
+    if (through) {
+        int pos, size;
+        pos = FT_MulFix(os2->yStrikeoutPosition, y_scale * font->scale_y);
+        size = FT_MulFix(os2->yStrikeoutSize, y_scale * font->scale_y / 2);
+
+        if (pos < 0 || size <= 0)
+            return 0;
+
+        FT_Vector points[4] = {
+            {.x = bear,      .y = pos + size},
+            {.x = advance,   .y = pos + size},
+            {.x = advance,   .y = pos - size},
+            {.x = bear,      .y = pos - size},
+        };
+
+        for (i = 0; i < 4; i++) {
+            ol->points[ol->n_points] = points[i];
+            ol->tags[ol->n_points++] = 1;
+        }
+
+        ol->contours[ol->n_contours++] = ol->n_points - 1;
+    }
+
+    return 1;
 }
 
 /**
  * \brief Get a glyph
  * \param ch character code
  **/
-FT_Glyph ass_font_get_glyph(void* fontconfig_priv, ass_font_t* font, uint32_t ch, ass_hinting_t hinting)
+FT_Glyph ass_font_get_glyph(void *fontconfig_priv, ass_font_t *font,
+                            uint32_t ch, ass_hinting_t hinting, int deco)
 {
-       int error;
-       int index = 0;
-       int i;
-       FT_Glyph glyph;
-       FT_Face face = 0;
-       int flags = 0;
-
-       if (ch < 0x20)
-               return 0;
-       if (font->n_faces == 0)
-               return 0;
-
-       for (i = 0; i < font->n_faces; ++i) {
-               face = font->faces[i];
-               index = FT_Get_Char_Index(face, ch);
-               if (index)
-                       break;
-       }
-
-#ifdef HAVE_FONTCONFIG
-       if (index == 0) {
-               int face_idx;
-               mp_msg(MSGT_ASS, MSGL_INFO, MSGTR_LIBASS_GlyphNotFoundReselectingFont,
-                      ch, font->desc.family, font->desc.bold, font->desc.italic);
-               face_idx = add_face(fontconfig_priv, font, ch);
-               if (face_idx >= 0) {
-                       face = font->faces[face_idx];
-                       index = FT_Get_Char_Index(face, ch);
-                       if (index == 0) {
-                               mp_msg(MSGT_ASS, MSGL_ERR, MSGTR_LIBASS_GlyphNotFound,
-                                      ch, font->desc.family, font->desc.bold, font->desc.italic);
-                       }
-               }
-       }
+    int error;
+    int index = 0;
+    int i;
+    FT_Glyph glyph;
+    FT_Face face = 0;
+    int flags = 0;
+
+    if (ch < 0x20)
+        return 0;
+    if (font->n_faces == 0)
+        return 0;
+
+    for (i = 0; i < font->n_faces; ++i) {
+        face = font->faces[i];
+        index = FT_Get_Char_Index(face, ch);
+        if (index)
+            break;
+    }
+
+#ifdef CONFIG_FONTCONFIG
+    if (index == 0) {
+        int face_idx;
+        ass_msg(font->library, MSGL_INFO,
+                "Glyph 0x%X not found, selecting one more "
+                "font for (%s, %d, %d)", ch, font->desc.family,
+                font->desc.bold, font->desc.italic);
+        face_idx = add_face(fontconfig_priv, font, ch);
+        if (face_idx >= 0) {
+            face = font->faces[face_idx];
+            index = FT_Get_Char_Index(face, ch);
+            if (index == 0) {
+                ass_msg(font->library, MSGL_ERR,
+                        "Glyph 0x%X not found in font for (%s, %d, %d)",
+                        ch, font->desc.family, font->desc.bold,
+                        font->desc.italic);
+            }
+        }
+    }
 #endif
 
-       switch (hinting) {
-       case ASS_HINTING_NONE: flags = FT_LOAD_NO_HINTING; break;
-       case ASS_HINTING_LIGHT: flags = FT_LOAD_FORCE_AUTOHINT | FT_LOAD_TARGET_LIGHT; break;
-       case ASS_HINTING_NORMAL: flags = FT_LOAD_FORCE_AUTOHINT; break;
-       case ASS_HINTING_NATIVE: flags = 0; break;
-       }
-       
-       error = FT_Load_Glyph(face, index, FT_LOAD_NO_BITMAP | flags);
-       if (error) {
-               mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_ErrorLoadingGlyph);
-               return 0;
-       }
-       
+    switch (hinting) {
+    case ASS_HINTING_NONE:
+        flags = FT_LOAD_NO_HINTING;
+        break;
+    case ASS_HINTING_LIGHT:
+        flags = FT_LOAD_FORCE_AUTOHINT | FT_LOAD_TARGET_LIGHT;
+        break;
+    case ASS_HINTING_NORMAL:
+        flags = FT_LOAD_FORCE_AUTOHINT;
+        break;
+    case ASS_HINTING_NATIVE:
+        flags = 0;
+        break;
+    }
+
+    error = FT_Load_Glyph(face, index, FT_LOAD_NO_BITMAP | flags);
+    if (error) {
+        ass_msg(font->library, MSGL_WARN, "Error loading glyph, index %d",
+                index);
+        return 0;
+    }
 #if (FREETYPE_MAJOR > 2) || \
     ((FREETYPE_MAJOR == 2) && (FREETYPE_MINOR >= 2)) || \
     ((FREETYPE_MAJOR == 2) && (FREETYPE_MINOR == 1) && (FREETYPE_PATCH >= 10))
 // FreeType >= 2.1.10 required
-       if (!(face->style_flags & FT_STYLE_FLAG_ITALIC) && 
-                       (font->desc.italic > 55)) {
-               FT_GlyphSlot_Oblique(face->glyph);
-       }
+    if (!(face->style_flags & FT_STYLE_FLAG_ITALIC) &&
+        (font->desc.italic > 55)) {
+        FT_GlyphSlot_Oblique(face->glyph);
+    }
 #endif
-       error = FT_Get_Glyph(face->glyph, &glyph);
-       if (error) {
-               mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_ErrorLoadingGlyph);
-               return 0;
-       }
-       
-       return glyph;
+    error = FT_Get_Glyph(face->glyph, &glyph);
+    if (error) {
+        ass_msg(font->library, MSGL_WARN, "Error loading glyph, index %d",
+                index);
+        return 0;
+    }
+
+    ass_strike_outline_glyph(face, font, glyph, deco & DECO_UNDERLINE,
+                             deco & DECO_STRIKETHROUGH);
+
+    return glyph;
 }
 
 /**
  * \brief Get kerning for the pair of glyphs.
  **/
-FT_Vector ass_font_get_kerning(ass_font_tfont, uint32_t c1, uint32_t c2)
+FT_Vector ass_font_get_kerning(ass_font_t *font, uint32_t c1, uint32_t c2)
 {
-       FT_Vector v = {0, 0};
-       int i;
-
-       for (i = 0; i < font->n_faces; ++i) {
-               FT_Face face = font->faces[i];
-               int i1 = FT_Get_Char_Index(face, c1);
-               int i2 = FT_Get_Char_Index(face, c2);
-               if (i1 && i2) {
-                       if (FT_HAS_KERNING(face))
-                               FT_Get_Kerning(face, i1, i2, FT_KERNING_DEFAULT, &v);
-                       return v;
-               }
-               if (i1 || i2) // these glyphs are from different font faces, no kerning information
-                       return v;
-       }
-       return v;
+    FT_Vector v = { 0, 0 };
+    int i;
+
+    for (i = 0; i < font->n_faces; ++i) {
+        FT_Face face = font->faces[i];
+        int i1 = FT_Get_Char_Index(face, c1);
+        int i2 = FT_Get_Char_Index(face, c2);
+        if (i1 && i2) {
+            if (FT_HAS_KERNING(face))
+                FT_Get_Kerning(face, i1, i2, FT_KERNING_DEFAULT, &v);
+            return v;
+        }
+        if (i1 || i2)           // these glyphs are from different font faces, no kerning information
+            return v;
+    }
+    return v;
 }
 
 /**
  * \brief Deallocate ass_font_t
  **/
-void ass_font_free(ass_font_tfont)
+void ass_font_free(ass_font_t *font)
 {
-       int i;
-       for (i = 0; i < font->n_faces; ++i)
-               if (font->faces[i]) FT_Done_Face(font->faces[i]);
-       if (font->desc.family) free(font->desc.family);
-       free(font);
+    int i;
+    for (i = 0; i < font->n_faces; ++i)
+        if (font->faces[i])
+            FT_Done_Face(font->faces[i]);
+    if (font->desc.family)
+        free(font->desc.family);
+    free(font);
 }