Add CFF CID Fallback

Switching to CID font embedding requires a fallback font for
the case where CFF CID or TrueType CID subsetting fails.

The new function _cairo_type2_charstrings_init() added to
cairo-type1-fallback.c creates Type2 charstrings from glyph
paths. _cairo_cff_fallback_init() in cairo-cff-subset.c
wraps these charstrings in a CFF CID font.

1 files changed, 152 insertions, 59 deletions

diff --git a/src/cairo-type1-fallback.c b/src/cairo-type1-fallback.c
index dcf55f440..3a0bd1249 100644
--- a/src/cairo-type1-fallback.c
+++ b/src/cairo-type1-fallback.c
@@ -39,6 +39,11 @@
 #include "cairo-path-fixed-private.h"
 #include "cairo-output-stream-private.h"
 
+typedef enum {
+    CAIRO_CHARSTRING_TYPE1,
+    CAIRO_CHARSTRING_TYPE2,
+} cairo_charstring_type_t;
+
 typedef struct _cairo_type1_font {
     int *widths;
 
@@ -90,7 +95,7 @@ cairo_type1_font_create (cairo_scaled_font_subset_t  *scaled_font_subset,
 
     font_face = cairo_scaled_font_get_font_face (scaled_font_subset->scaled_font);
 
-    cairo_matrix_init_scale (&font_matrix, 1000, 1000);
+    cairo_matrix_init_scale (&font_matrix, 1000, -1000);
     cairo_matrix_init_identity (&ctm);
 
     _cairo_font_options_init_default (&font_options);
@@ -156,7 +161,9 @@ charstring_encode_command (cairo_array_t *data, int command)
  * bytes that will be used is 5.
  */
 static void
-charstring_encode_integer (cairo_array_t *data, int i)
+charstring_encode_integer (cairo_array_t *data,
+                           int i,
+                           cairo_charstring_type_t type)
 {
     cairo_status_t status;
     int orig_size;
@@ -174,11 +181,19 @@ charstring_encode_integer (cairo_array_t *data, int i)
         *p++ = (i >> 8)+ 251;
         *p++ = i & 0xff;
     } else {
-        *p++ = 0xff;
-        *p++ = i >> 24;
-        *p++ = (i >> 16) & 0xff;
-        *p++ = (i >> 8)  & 0xff;
-        *p++ = i & 0xff;
+        if (type == CAIRO_CHARSTRING_TYPE1) {
+            *p++ = 0xff;
+            *p++ = i >> 24;
+            *p++ = (i >> 16) & 0xff;
+            *p++ = (i >> 8)  & 0xff;
+            *p++ = i & 0xff;
+        } else {
+            *p++ = 0xff;
+            *p++ = (i >> 8)  & 0xff;
+            *p++ = i & 0xff;
+            *p++ = 0;
+            *p++ = 0;
+        }
     }
 
     /* Ensure the array doesn't grow, which allows this function to
@@ -193,6 +208,7 @@ charstring_encode_integer (cairo_array_t *data, int i)
 typedef struct _ps_path_info {
     cairo_array_t *data;
     int current_x, current_y;
+    cairo_charstring_type_t type;
 } t1_path_info_t;
 
 static cairo_status_t
@@ -209,8 +225,8 @@ _charstring_move_to (void          *closure,
 
     dx = _cairo_fixed_integer_part (point->x) - path_info->current_x;
     dy = _cairo_fixed_integer_part (point->y) - path_info->current_y;
-    charstring_encode_integer (path_info->data, dx);
-    charstring_encode_integer (path_info->data, dy);
+    charstring_encode_integer (path_info->data, dx, path_info->type);
+    charstring_encode_integer (path_info->data, dy, path_info->type);
     path_info->current_x += dx;
     path_info->current_y += dy;
 
@@ -233,8 +249,8 @@ _charstring_line_to (void          *closure,
 
     dx = _cairo_fixed_integer_part (point->x) - path_info->current_x;
     dy = _cairo_fixed_integer_part (point->y) - path_info->current_y;
-    charstring_encode_integer (path_info->data, dx);
-    charstring_encode_integer (path_info->data, dy);
+    charstring_encode_integer (path_info->data, dx, path_info->type);
+    charstring_encode_integer (path_info->data, dy, path_info->type);
     path_info->current_x += dx;
     path_info->current_y += dy;
 
@@ -263,12 +279,12 @@ _charstring_curve_to (void	    *closure,
     dy2 = _cairo_fixed_integer_part (point2->y) - path_info->current_y - dy1;
     dx3 = _cairo_fixed_integer_part (point3->x) - path_info->current_x - dx1 - dx2;
     dy3 = _cairo_fixed_integer_part (point3->y) - path_info->current_y - dy1 - dy2;
-    charstring_encode_integer (path_info->data, dx1);
-    charstring_encode_integer (path_info->data, dy1);
-    charstring_encode_integer (path_info->data, dx2);
-    charstring_encode_integer (path_info->data, dy2);
-    charstring_encode_integer (path_info->data, dx3);
-    charstring_encode_integer (path_info->data, dy3);
+    charstring_encode_integer (path_info->data, dx1, path_info->type);
+    charstring_encode_integer (path_info->data, dy1, path_info->type);
+    charstring_encode_integer (path_info->data, dx2, path_info->type);
+    charstring_encode_integer (path_info->data, dy2, path_info->type);
+    charstring_encode_integer (path_info->data, dx3, path_info->type);
+    charstring_encode_integer (path_info->data, dy3, path_info->type);
     path_info->current_x += dx1 + dx2 + dx3;
     path_info->current_y += dy1 + dy2 + dy3;
     charstring_encode_command (path_info->data, CHARSTRING_rcurveto);
@@ -282,6 +298,9 @@ _charstring_close_path (void *closure)
     cairo_status_t status;
     t1_path_info_t *path_info = (t1_path_info_t *) closure;
 
+    if (path_info->type == CAIRO_CHARSTRING_TYPE2)
+        return CAIRO_STATUS_SUCCESS;
+
     status = _cairo_array_grow_by (path_info->data, 2);
     if (status)
 	return status;
@@ -309,7 +328,7 @@ charstring_encrypt (cairo_array_t *data)
 }
 
 static cairo_int_status_t
-create_notdef_charstring (cairo_array_t *data)
+create_notdef_charstring (cairo_array_t *data, cairo_charstring_type_t type)
 {
     cairo_status_t status;
 
@@ -320,13 +339,15 @@ create_notdef_charstring (cairo_array_t *data)
     if (status)
         return status;
 
-    charstring_encode_integer (data, 0);
-    charstring_encode_integer (data, 0);
+    if (type == CAIRO_CHARSTRING_TYPE1) {
+        charstring_encode_integer (data, 0, type);
+        charstring_encode_integer (data, 0, type);
 
-    /* The width and height is arbitrary. */
-    charstring_encode_integer (data, 500);
-    charstring_encode_integer (data, 500);
-    charstring_encode_command (data, CHARSTRING_sbw);
+        /* The width and height is arbitrary. */
+        charstring_encode_integer (data, 500, type);
+        charstring_encode_integer (data, 500, type);
+        charstring_encode_command (data, CHARSTRING_sbw);
+    }
 
     charstring_encode_command (data, CHARSTRING_endchar);
 
@@ -334,10 +355,11 @@ create_notdef_charstring (cairo_array_t *data)
 }
 
 static cairo_int_status_t
-cairo_type1_font_create_charstring (cairo_type1_font_t *font,
-                                    int                 subset_index,
-                                    int                 glyph_index,
-                                    cairo_array_t      *data)
+cairo_type1_font_create_charstring (cairo_type1_font_t      *font,
+                                    int                      subset_index,
+                                    int                      glyph_index,
+                                    cairo_charstring_type_t  type,
+                                    cairo_array_t           *data)
 {
     cairo_int_status_t status;
     cairo_scaled_glyph_t *scaled_glyph;
@@ -369,21 +391,29 @@ cairo_type1_font_create_charstring (cairo_type1_font_t *font,
         if (metrics->y_bearing + metrics->height > font->y_max)
             font->y_max = metrics->y_bearing + metrics->height;
     }
-    font->widths[subset_index] = metrics->width;
+    font->widths[subset_index] = metrics->x_advance;
 
     status = _cairo_array_grow_by (data, 30);
     if (status)
         return status;
 
-    charstring_encode_integer (data, (int) scaled_glyph->metrics.x_bearing);
-    charstring_encode_integer (data, (int) scaled_glyph->metrics.y_bearing);
-    charstring_encode_integer (data, (int) scaled_glyph->metrics.width);
-    charstring_encode_integer (data, (int) scaled_glyph->metrics.height);
-    charstring_encode_command (data, CHARSTRING_sbw);
+    if (type == CAIRO_CHARSTRING_TYPE1) {
+        charstring_encode_integer (data, (int) scaled_glyph->metrics.x_bearing, type);
+        charstring_encode_integer (data, (int) scaled_glyph->metrics.y_bearing, type);
+        charstring_encode_integer (data, (int) scaled_glyph->metrics.width, type);
+        charstring_encode_integer (data, (int) scaled_glyph->metrics.height, type);
+        charstring_encode_command (data, CHARSTRING_sbw);
 
+        path_info.current_x = (int) scaled_glyph->metrics.x_bearing;
+        path_info.current_y = (int) scaled_glyph->metrics.y_bearing;
+    } else {
+        charstring_encode_integer (data, (int) scaled_glyph->metrics.width, type);
+
+        path_info.current_x = 0;
+        path_info.current_y = 0;
+    }
     path_info.data = data;
-    path_info.current_x = (int) scaled_glyph->metrics.x_bearing;
-    path_info.current_y = (int) scaled_glyph->metrics.y_bearing;
+    path_info.type = type;
     status = _cairo_path_fixed_interpret (scaled_glyph->path,
                                           CAIRO_DIRECTION_FORWARD,
                                           _charstring_move_to,
@@ -429,6 +459,7 @@ cairo_type1_font_write_charstrings (cairo_type1_font_t    *font,
             goto fail;
         status = cairo_type1_font_create_charstring (font, i,
 						     font->scaled_font_subset->glyphs[i],
+                                                     CAIRO_CHARSTRING_TYPE1,
 						     &data);
         if (status)
             goto fail;
@@ -448,7 +479,7 @@ cairo_type1_font_write_charstrings (cairo_type1_font_t    *font,
     status = _cairo_array_append_multiple (&data, zeros, 4);
     if (status)
         goto fail;
-    status = create_notdef_charstring (&data);
+    status = create_notdef_charstring (&data, CAIRO_CHARSTRING_TYPE1);
     if (status)
         goto fail;
     charstring_encrypt (&data);
@@ -464,35 +495,22 @@ fail:
     return status;
 }
 
-static cairo_status_t
+static void
 cairo_type1_font_write_header (cairo_type1_font_t *font,
                                const char         *name)
 {
-    cairo_matrix_t matrix;
-    cairo_status_t status;
     unsigned int i;
     const char spaces[50] = "                                                  ";
 
-    matrix = font->type1_scaled_font->scale;
-    matrix.xy = -matrix.xy;
-    matrix.yy = -matrix.yy;
-    status = cairo_matrix_invert (&matrix);
-    if (status)
-	return status;
-
     _cairo_output_stream_printf (font->output,
                                  "%%!FontType1-1.1 %s 1.0\n"
                                  "11 dict begin\n"
                                  "/FontName /%s def\n"
                                  "/PaintType 0 def\n"
                                  "/FontType 1 def\n"
-                                 "/FontMatrix [%f %f %f %f 0 0] readonly def\n",
-                                 name,
+                                  "/FontMatrix [0.001 0 0 0.001 0 0] readonly def\n",
                                  name,
-                                 matrix.xx,
-				 matrix.yx,
-				 matrix.xy,
-				 matrix.yy);
+                                 name);
 
     /* We don't know the bbox values until after the charstrings have
      * been generated.  Reserve some space and fill in the bbox
@@ -515,8 +533,6 @@ cairo_type1_font_write_header (cairo_type1_font_t *font,
                                  "readonly def\n"
                                  "currentdict end\n"
                                  "currentfile eexec\n");
-
-    return CAIRO_STATUS_SUCCESS;
 }
 
 static cairo_status_t
@@ -640,10 +656,7 @@ cairo_type1_font_write (cairo_type1_font_t *font,
 {
     cairo_int_status_t status;
 
-    status = cairo_type1_font_write_header (font, name);
-    if (status)
-	return status;
-
+    cairo_type1_font_write_header (font, name);
     font->header_size = _cairo_output_stream_get_position (font->output);
 
     status = cairo_type1_font_write_private_dict (font, name);
@@ -798,3 +811,83 @@ _cairo_type1_fallback_fini (cairo_type1_subset_t *subset)
     free (subset->widths);
     free (subset->data);
 }
+
+cairo_status_t
+_cairo_type2_charstrings_init (cairo_type2_charstrings_t *type2_subset,
+                               cairo_scaled_font_subset_t *scaled_font_subset)
+{
+    cairo_type1_font_t *font;
+    cairo_status_t status;
+    unsigned int i;
+    cairo_array_t charstring;
+
+    status = cairo_type1_font_create (scaled_font_subset, &font, FALSE);
+    if (status)
+	return status;
+
+    _cairo_array_init (&type2_subset->charstrings, sizeof (cairo_array_t));
+
+    type2_subset->widths = calloc (sizeof (int), font->scaled_font_subset->num_glyphs);
+    if (type2_subset->widths == NULL) {
+        status = CAIRO_STATUS_NO_MEMORY;
+        goto fail1;
+    }
+
+    for (i = 0; i < font->scaled_font_subset->num_glyphs; i++) {
+        _cairo_array_init (&charstring, sizeof (unsigned char));
+        status = _cairo_array_grow_by (&charstring, 32);
+        if (status)
+            goto fail2;
+
+        if (i == 0) {
+            status = create_notdef_charstring (&charstring, CAIRO_CHARSTRING_TYPE2);
+        } else {
+            status = cairo_type1_font_create_charstring (font, i,
+                                                         font->scaled_font_subset->glyphs[i],
+                                                         CAIRO_CHARSTRING_TYPE2,
+                                                         &charstring);
+        }
+        if (status)
+            goto fail2;
+
+        status = _cairo_array_append (&type2_subset->charstrings, &charstring);
+        if (status)
+            goto fail2;
+    }
+
+    for (i = 0; i < font->scaled_font_subset->num_glyphs; i++)
+	type2_subset->widths[i] = font->widths[i];
+
+    type2_subset->x_min   = (int) font->x_min;
+    type2_subset->y_min   = (int) font->y_min;
+    type2_subset->x_max   = (int) font->x_max;
+    type2_subset->y_max   = (int) font->y_max;
+    type2_subset->ascent  = (int) font->y_max;
+    type2_subset->descent = (int) font->y_min;
+
+    cairo_type1_font_destroy (font);
+    return CAIRO_STATUS_SUCCESS;
+
+fail2:
+    _cairo_array_fini (&charstring);
+    _cairo_type2_charstrings_fini (type2_subset);
+fail1:
+    cairo_type1_font_destroy (font);
+    return status;
+}
+
+void
+_cairo_type2_charstrings_fini (cairo_type2_charstrings_t *type2_subset)
+{
+    unsigned int i, num_charstrings;
+    cairo_array_t *charstring;
+
+    num_charstrings = _cairo_array_num_elements (&type2_subset->charstrings);
+    for (i = 0; i < num_charstrings; i++) {
+        charstring = _cairo_array_index (&type2_subset->charstrings, i);
+        _cairo_array_fini (charstring);
+    }
+    _cairo_array_fini (&type2_subset->charstrings);
+
+    free (type2_subset->widths);
+}