Implement PDF Type 3 font subsetting of user fonts

show_glyphs inside a Type 3 font currently results in a fallback
image. Some refactoring is required before font subsets can be created
while emitting all the font subsets.

1 files changed, 465 insertions, 0 deletions

diff --git a/src/cairo-type3-glyph-surface.c b/src/cairo-type3-glyph-surface.c
new file mode 100644
index 000000000..ded725c6b
--- /dev/null
+++ b/src/cairo-type3-glyph-surface.c
@@ -0,0 +1,465 @@
+/* -*- Mode: c; c-basic-offset: 4; indent-tabs-mode: t; tab-width: 8; -*- */
+/* cairo - a vector graphics library with display and print output
+ *
+ * Copyright © 2008 Adrian Johnson
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it either under the terms of the GNU Lesser General Public
+ * License version 2.1 as published by the Free Software Foundation
+ * (the "LGPL") or, at your option, under the terms of the Mozilla
+ * Public License Version 1.1 (the "MPL"). If you do not alter this
+ * notice, a recipient may use your version of this file under either
+ * the MPL or the LGPL.
+ *
+ * You should have received a copy of the LGPL along with this library
+ * in the file COPYING-LGPL-2.1; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * You should have received a copy of the MPL along with this library
+ * in the file COPYING-MPL-1.1
+ *
+ * The contents of this file are subject to the Mozilla Public License
+ * Version 1.1 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
+ * OF ANY KIND, either express or implied. See the LGPL or the MPL for
+ * the specific language governing rights and limitations.
+ *
+ * The Original Code is the cairo graphics library.
+ *
+ * The Initial Developer of the Original Code is Adrian Johnson.
+ *
+ * Contributor(s):
+ *	Adrian Johnson <ajohnson@redneon.com>
+ */
+
+#include "cairoint.h"
+#include "cairo-type3-glyph-surface-private.h"
+#include "cairo-output-stream-private.h"
+#include "cairo-meta-surface-private.h"
+
+static const cairo_surface_backend_t cairo_type3_glyph_surface_backend;
+
+cairo_surface_t *
+_cairo_type3_glyph_surface_create (cairo_scaled_font_t	 *scaled_font,
+				   cairo_output_stream_t *stream)
+{
+    cairo_type3_glyph_surface_t *surface;
+    cairo_matrix_t invert_y_axis;
+
+    surface = malloc (sizeof (cairo_type3_glyph_surface_t));
+    if (surface == NULL)
+	return _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_NO_MEMORY));
+
+    _cairo_surface_init (&surface->base, &cairo_type3_glyph_surface_backend,
+			 CAIRO_CONTENT_COLOR_ALPHA);
+
+    surface->scaled_font = scaled_font;
+    surface->stream = stream;
+
+    /* Setup the transform from the user-font device space to Type 3
+     * font space. The Type 3 font space is defined by the FontMatrix
+     * entry in the Type 3 dictionary. In the PDF backend this is an
+     * identity matrix. */
+    surface->cairo_to_pdf = scaled_font->scale_inverse;
+    cairo_matrix_init_scale (&invert_y_axis, 1, -1);
+    cairo_matrix_multiply (&surface->cairo_to_pdf, &surface->cairo_to_pdf, &invert_y_axis);
+
+    _cairo_pdf_operators_init (&surface->pdf_operators,
+			       surface->stream,
+			       &surface->cairo_to_pdf,
+			       NULL);
+
+    return &surface->base;
+}
+
+static cairo_status_t
+_cairo_type3_glyph_surface_emit_image (cairo_type3_glyph_surface_t *surface,
+				       cairo_image_surface_t       *image,
+				       cairo_matrix_t              *image_matrix)
+{
+    cairo_status_t status;
+    cairo_image_surface_t *image_mask;
+    unsigned char *byte, output_byte;
+    int row, col, num_cols;
+
+    /* The only image type supported by Type 3 fonts are 1-bit image
+     * masks */
+    if (image->format == CAIRO_FORMAT_A1) {
+	image_mask = image;
+    } else {
+	image_mask = _cairo_image_surface_clone (image, CAIRO_FORMAT_A1);
+	status = cairo_surface_status (&image->base);
+	if (status)
+	    return status;
+    }
+
+    _cairo_output_stream_printf (surface->stream,
+				 "q %f %f %f %f %f %f cm\n",
+				 image_matrix->xx,
+				 image_matrix->xy,
+				 image_matrix->yx,
+				 image_matrix->yy,
+				 image_matrix->x0,
+				 image_matrix->y0);
+
+    _cairo_output_stream_printf (surface->stream,
+				 "BI\n"
+				 "/IM true\n"
+				 "/W %d\n"
+				 "/H %d\n"
+				 "/BPC 1\n"
+				 "/D [1 0]\n",
+				 image_mask->width,
+				 image_mask->height);
+
+    _cairo_output_stream_printf (surface->stream,
+				 "ID ");
+
+    num_cols = (image_mask->width + 7) / 8;
+    for (row = 0; row < image_mask->height; row++) {
+	byte = image_mask->data + row * image_mask->stride;
+	for (col = 0; col < num_cols; col++) {
+	    output_byte = CAIRO_BITSWAP8_IF_LITTLE_ENDIAN (*byte);
+	    _cairo_output_stream_write (surface->stream, &output_byte, 1);
+	    byte++;
+	}
+    }
+    _cairo_output_stream_printf (surface->stream,
+				 "\nEI Q\n");
+
+    if (image_mask != image)
+	cairo_surface_destroy (&image_mask->base);
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+static cairo_status_t
+_cairo_type3_glyph_surface_emit_image_pattern (cairo_type3_glyph_surface_t *surface,
+					       cairo_image_surface_t       *image,
+					       cairo_matrix_t              *pattern_matrix)
+{
+    cairo_matrix_t mat, upside_down;
+    cairo_status_t status;
+
+    if (image->width == 0 || image->height == 0)
+	return CAIRO_STATUS_SUCCESS;
+
+    mat = *pattern_matrix;
+
+    /* Get the pattern space to user space matrix  */
+    status = cairo_matrix_invert (&mat);
+
+    /* cairo_pattern_set_matrix ensures the matrix is invertible */
+    assert (status == CAIRO_STATUS_SUCCESS);
+
+    /* Make this a pattern space to Type 3 font space matrix */
+    cairo_matrix_multiply (&mat, &mat, &surface->cairo_to_pdf);
+
+    /* PDF images are in a 1 unit by 1 unit image space. Turn the 1 by
+     * 1 image upside down to convert to flip the Y-axis going from
+     * cairo to PDF. Then scale the image up to the required size. */
+    cairo_matrix_scale (&mat, image->width, image->height);
+    cairo_matrix_init (&upside_down, 1, 0, 0, -1, 0, 1);
+    cairo_matrix_multiply (&mat, &upside_down, &mat);
+
+    return _cairo_type3_glyph_surface_emit_image (surface, image, &mat);
+}
+
+static cairo_status_t
+_cairo_type3_glyph_surface_finish (void *abstract_surface)
+{
+    cairo_type3_glyph_surface_t *surface = abstract_surface;
+
+    return _cairo_pdf_operators_fini (&surface->pdf_operators);
+}
+
+static cairo_int_status_t
+_cairo_type3_glyph_surface_intersect_clip_path (void		   *abstract_surface,
+						cairo_path_fixed_t *path,
+						cairo_fill_rule_t   fill_rule,
+						double		    tolerance,
+						cairo_antialias_t   antialias)
+{
+    cairo_type3_glyph_surface_t *surface = abstract_surface;
+
+    if (path == NULL) {
+	_cairo_output_stream_printf (surface->stream, "Q q\n");
+	return CAIRO_STATUS_SUCCESS;
+    }
+
+    return _cairo_pdf_operators_clip (&surface->pdf_operators,
+				      path,
+				      fill_rule);
+}
+
+static cairo_int_status_t
+_cairo_type3_glyph_surface_paint (void			*abstract_surface,
+				  cairo_operator_t	 op,
+				  cairo_pattern_t	*source)
+{
+    cairo_type3_glyph_surface_t *surface = abstract_surface;
+    cairo_surface_pattern_t *pattern;
+    cairo_image_surface_t *image;
+    void *image_extra;
+    cairo_status_t status;
+
+    if (source->type != CAIRO_PATTERN_TYPE_SURFACE)
+	return CAIRO_INT_STATUS_IMAGE_FALLBACK;
+
+    pattern = (cairo_surface_pattern_t *) source;
+    status = _cairo_surface_acquire_source_image (pattern->surface, &image, &image_extra);
+    if (status)
+	goto fail;
+
+    status = _cairo_type3_glyph_surface_emit_image_pattern (surface,
+							    image,
+							    &pattern->base.matrix);
+
+fail:
+    _cairo_surface_release_source_image (pattern->surface, image, image_extra);
+
+    return status;
+}
+
+static cairo_int_status_t
+_cairo_type3_glyph_surface_mask (void			*abstract_surface,
+				 cairo_operator_t	 op,
+				 cairo_pattern_t	*source,
+				 cairo_pattern_t	*mask)
+{
+    return _cairo_type3_glyph_surface_paint (abstract_surface, op, mask);
+}
+
+static cairo_int_status_t
+_cairo_type3_glyph_surface_stroke (void			*abstract_surface,
+				   cairo_operator_t	 op,
+				   cairo_pattern_t	*source,
+				   cairo_path_fixed_t	*path,
+				   cairo_stroke_style_t	*style,
+				   cairo_matrix_t	*ctm,
+				   cairo_matrix_t	*ctm_inverse,
+				   double		 tolerance,
+				   cairo_antialias_t	 antialias)
+{
+    cairo_type3_glyph_surface_t *surface = abstract_surface;
+
+    return _cairo_pdf_operators_stroke (&surface->pdf_operators,
+					path,
+					style,
+					ctm,
+					ctm_inverse);
+}
+
+static cairo_int_status_t
+_cairo_type3_glyph_surface_fill (void			*abstract_surface,
+				 cairo_operator_t	 op,
+				 cairo_pattern_t	*source,
+				 cairo_path_fixed_t	*path,
+				 cairo_fill_rule_t	 fill_rule,
+				 double			 tolerance,
+				 cairo_antialias_t	 antialias)
+{
+    cairo_type3_glyph_surface_t *surface = abstract_surface;
+    cairo_int_status_t status;
+
+    status = _cairo_pdf_operators_fill (&surface->pdf_operators,
+					path,
+					fill_rule);
+
+    return status;
+}
+
+static cairo_int_status_t
+_cairo_type3_glyph_surface_show_glyphs (void		     *abstract_surface,
+					cairo_operator_t      op,
+					cairo_pattern_t	     *source,
+					cairo_glyph_t        *glyphs,
+					int		      num_glyphs,
+					cairo_scaled_font_t  *scaled_font,
+					int		     *remaining_glyphs)
+{
+    /* XXX: Some refactoring is required before we can add font
+     * subsets in the middle of emitting all the subsets. */
+
+    return CAIRO_INT_STATUS_IMAGE_FALLBACK;
+}
+
+static const cairo_surface_backend_t cairo_type3_glyph_surface_backend = {
+    CAIRO_INTERNAL_SURFACE_TYPE_TYPE3_GLYPH,
+    NULL, /* _cairo_type3_glyph_surface_create_similar */
+    _cairo_type3_glyph_surface_finish,
+    NULL, /* acquire_source_image */
+    NULL, /* release_source_image */
+    NULL, /* acquire_dest_image */
+    NULL, /* release_dest_image */
+    NULL, /* clone_similar */
+    NULL, /* composite */
+    NULL, /* fill_rectangles */
+    NULL, /* composite_trapezoids */
+    NULL, /* cairo_type3_glyph_surface_copy_page */
+    NULL, /* _cairo_type3_glyph_surface_show_page */
+    NULL, /* set_clip_region */
+    _cairo_type3_glyph_surface_intersect_clip_path,
+    NULL, /* _cairo_type3_glyph_surface_get_extents */
+    NULL, /* old_show_glyphs */
+    NULL, /* _cairo_type3_glyph_surface_get_font_options */
+    NULL, /* flush */
+    NULL, /* mark_dirty_rectangle */
+    NULL, /* scaled_font_fini */
+    NULL, /* scaled_glyph_fini */
+    _cairo_type3_glyph_surface_paint,
+    _cairo_type3_glyph_surface_mask,
+    _cairo_type3_glyph_surface_stroke,
+    _cairo_type3_glyph_surface_fill,
+    _cairo_type3_glyph_surface_show_glyphs,
+    NULL, /* snapshot */
+};
+
+static void
+_cairo_type3_glyph_surface_set_stream (cairo_type3_glyph_surface_t *surface,
+				       cairo_output_stream_t       *stream)
+{
+    surface->stream = stream;
+    _cairo_pdf_operators_set_stream (&surface->pdf_operators, stream);
+}
+
+static cairo_status_t
+_cairo_type3_glyph_surface_emit_fallback_image (cairo_type3_glyph_surface_t *surface,
+						unsigned long		     glyph_index)
+{
+    cairo_scaled_glyph_t *scaled_glyph;
+    cairo_status_t status;
+    cairo_image_surface_t *image;
+    cairo_matrix_t mat;
+    double width, height, x, y;
+
+    status = _cairo_scaled_glyph_lookup (surface->scaled_font,
+					 glyph_index,
+					 CAIRO_SCALED_GLYPH_INFO_METRICS |
+					 CAIRO_SCALED_GLYPH_INFO_SURFACE,
+					 &scaled_glyph);
+    if (status)
+	return status;
+
+    image = scaled_glyph->surface;
+    if (image->width == 0 || image->height == 0)
+	return CAIRO_STATUS_SUCCESS;
+
+    x = _cairo_fixed_to_double (scaled_glyph->bbox.p1.x);
+    y = _cairo_fixed_to_double (scaled_glyph->bbox.p2.y);
+    width = _cairo_fixed_to_double (scaled_glyph->bbox.p2.x) -
+	_cairo_fixed_to_double (scaled_glyph->bbox.p1.x);
+    height = _cairo_fixed_to_double (scaled_glyph->bbox.p2.y) -
+	_cairo_fixed_to_double (scaled_glyph->bbox.p1.y);
+    mat.xx = width;
+    mat.xy = 0;
+    mat.yx = 0;
+    mat.yy = height;
+    mat.x0 = x;
+    mat.y0 = y;
+    cairo_matrix_multiply (&mat, &mat, &surface->scaled_font->scale_inverse);
+    mat.y0 *= -1;
+
+    return _cairo_type3_glyph_surface_emit_image (surface, image, &mat);
+}
+
+cairo_status_t
+_cairo_type3_glyph_surface_emit_notdef_glyph (void		    *abstract_surface,
+					      cairo_output_stream_t *stream,
+					      cairo_box_t           *bbox,
+					      double                *width)
+{
+    bbox->p1.x = 0;
+    bbox->p1.y = 0;
+    bbox->p2.x = 0;
+    bbox->p2.y = 0;
+    *width = 0.0;
+    _cairo_output_stream_printf (stream, "0 0 0 0 0 0 d1\n");
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+cairo_status_t
+_cairo_type3_glyph_surface_emit_glyph (void		     *abstract_surface,
+				       cairo_output_stream_t *stream,
+				       unsigned long	      glyph_index,
+				       cairo_box_t           *bbox,
+				       double                *width)
+{
+    cairo_type3_glyph_surface_t *surface = abstract_surface;
+    cairo_scaled_glyph_t *scaled_glyph;
+    cairo_status_t status, status2;
+    double x_advance, y_advance;
+    cairo_output_stream_t *mem_stream;
+    cairo_matrix_t font_matrix_inverse;
+
+    _cairo_type3_glyph_surface_set_stream (surface, stream);
+    status = _cairo_scaled_glyph_lookup (surface->scaled_font,
+					 glyph_index,
+					 CAIRO_SCALED_GLYPH_INFO_METRICS |
+					 CAIRO_SCALED_GLYPH_INFO_META_SURFACE,
+					 &scaled_glyph);
+    if (status && status != CAIRO_INT_STATUS_UNSUPPORTED)
+	return status;
+
+    if (status == CAIRO_INT_STATUS_UNSUPPORTED) {
+	status = _cairo_scaled_glyph_lookup (surface->scaled_font,
+					     glyph_index,
+					     CAIRO_SCALED_GLYPH_INFO_METRICS,
+					     &scaled_glyph);
+	if (status)
+	    return status;
+
+	status = CAIRO_INT_STATUS_IMAGE_FALLBACK;
+    }
+
+    x_advance = scaled_glyph->metrics.x_advance;
+    y_advance = scaled_glyph->metrics.y_advance;
+    font_matrix_inverse = surface->scaled_font->font_matrix;
+    status2 = cairo_matrix_invert (&font_matrix_inverse);
+
+    /* The invertability of font_matrix is tested in
+     * pdf_operators_show_glyphs before any glyphs are mappped to the
+     * subset. */
+    assert (status2 == CAIRO_STATUS_SUCCESS);
+
+    cairo_matrix_transform_distance (&font_matrix_inverse, &x_advance, &y_advance);
+    *width = x_advance;
+
+    *bbox = scaled_glyph->bbox;
+    _cairo_matrix_transform_bounding_box_fixed (&surface->scaled_font->scale_inverse,
+						bbox, NULL);
+
+    _cairo_output_stream_printf (surface->stream,
+				 "%f 0 %f %f %f %f d1\n",
+                                 x_advance,
+				 _cairo_fixed_to_double (bbox->p1.x),
+				 - _cairo_fixed_to_double (bbox->p2.y),
+				 _cairo_fixed_to_double (bbox->p2.x),
+				 - _cairo_fixed_to_double (bbox->p1.y));
+
+    if (status == CAIRO_STATUS_SUCCESS) {
+	mem_stream = _cairo_memory_stream_create ();
+	_cairo_type3_glyph_surface_set_stream (surface, mem_stream);
+
+	_cairo_output_stream_printf (surface->stream, "q\n");
+	status = _cairo_meta_surface_replay (scaled_glyph->meta_surface,
+					 &surface->base);
+	_cairo_output_stream_printf (surface->stream, "Q\n");
+
+	_cairo_type3_glyph_surface_set_stream (surface, stream);
+	if (status == CAIRO_STATUS_SUCCESS)
+	    _cairo_memory_stream_copy (mem_stream, stream);
+
+	status2 = _cairo_output_stream_destroy (mem_stream);
+	if (status2)
+	    return status2;
+    }
+
+    if (status == CAIRO_INT_STATUS_IMAGE_FALLBACK)
+	status = _cairo_type3_glyph_surface_emit_fallback_image (surface, glyph_index);
+
+    return status;
+}