[cairo-commit] src/cairo-pdf-surface.c src/cairo-ps-surface.c src/cairo-scaled-font.c src/cairo-scaled-font-private.h

[Behdad Esfahbod]

 src/cairo-pdf-surface.c         |    5 +----
 src/cairo-ps-surface.c          |    5 +----
 src/cairo-scaled-font-private.h |    1 +
 src/cairo-scaled-font.c         |   19 ++++++++-----------
 4 files changed, 11 insertions(+), 19 deletions(-)

New commits:
commit efd3a965244305a069ec231b7ec28cff8d6c67c8
Author: Behdad Esfahbod <behdad at behdad.org>
Date:   Thu Jan 24 23:35:06 2008 -0500

    [cairo-scaled-font] Don't err on font size 0, really
    
    First, seems like we were rejecting degenerate font matrix right away
    at the constructor.  Don't do that.
    
    Next, PS/PDF were inverting the font scale matrix, assuming that it's
    invertible.  We now keep the inverse too, so they can use it.  For the
    case of a size 0 font, both the scale matrix and its invert are set to
    0,0,0,0.  That's safe, even if slightly inconsistent.

diff --git a/src/cairo-pdf-surface.c b/src/cairo-pdf-surface.c
index 075fb05..77fd95b 100644
--- a/src/cairo-pdf-surface.c
+++ b/src/cairo-pdf-surface.c
@@ -3575,10 +3575,7 @@ _cairo_pdf_surface_emit_type3_font_subset (cairo_pdf_surface_t		*surface,
     }
 
     _cairo_pdf_surface_update_object (surface, subset_resource);
-    matrix = font_subset->scaled_font->scale;
-    status = cairo_matrix_invert (&matrix);
-    /* _cairo_scaled_font_init ensures the matrix is invertible */
-    assert (status == CAIRO_STATUS_SUCCESS);
+    matrix = font_subset->scaled_font->scale_inverse;
     _cairo_output_stream_printf (surface->output,
 				 "%d 0 obj\r\n"
 				 "<< /Type /Font\r\n"
diff --git a/src/cairo-ps-surface.c b/src/cairo-ps-surface.c
index 87efa40..5d6b3e6 100644
--- a/src/cairo-ps-surface.c
+++ b/src/cairo-ps-surface.c
@@ -754,10 +754,7 @@ _cairo_ps_surface_emit_type3_font_subset (cairo_ps_surface_t		*surface,
 				 "%% _cairo_ps_surface_emit_type3_font_subset\n");
 #endif
 
-    matrix = font_subset->scaled_font->scale;
-    status = cairo_matrix_invert (&matrix);
-    /* _cairo_scaled_font_init ensures the matrix is invertible */
-    assert (status == CAIRO_STATUS_SUCCESS);
+    matrix = font_subset->scaled_font->scale_inverse;
     _cairo_output_stream_printf (surface->final_stream,
 				 "8 dict begin\n"
 				 "/FontType 3 def\n"
diff --git a/src/cairo-scaled-font-private.h b/src/cairo-scaled-font-private.h
index f16487c..87a4616 100644
--- a/src/cairo-scaled-font-private.h
+++ b/src/cairo-scaled-font-private.h
@@ -91,6 +91,7 @@ struct _cairo_scaled_font {
 
     /* "live" scaled_font members */
     cairo_matrix_t scale;	  /* font space => device space */
+    cairo_matrix_t scale_inverse; /* device space => font space */
     cairo_font_extents_t extents; /* user space */
 
     /* The mutex protects modification to all subsequent fields. */
diff --git a/src/cairo-scaled-font.c b/src/cairo-scaled-font.c
index 45b6e44..eba474c 100644
--- a/src/cairo-scaled-font.c
+++ b/src/cairo-scaled-font.c
@@ -191,6 +191,7 @@ const cairo_scaled_font_t _cairo_scaled_font_nil = {
       CAIRO_HINT_STYLE_DEFAULT,
       CAIRO_HINT_METRICS_DEFAULT} ,
     { 1., 0., 0., 1., 0, 0},	/* scale */
+    { 1., 0., 0., 1., 0, 0},	/* scale_inverse */
     { 0., 0., 0., 0., 0. },	/* extents */
     CAIRO_MUTEX_NIL_INITIALIZER,/* mutex */
     NULL,			/* glyphs */
@@ -463,7 +464,6 @@ _cairo_scaled_font_init (cairo_scaled_font_t               *scaled_font,
 			 const cairo_font_options_t	   *options,
 			 const cairo_scaled_font_backend_t *backend)
 {
-    cairo_matrix_t inverse;
     cairo_status_t status;
 
     if (options != NULL) {
@@ -472,8 +472,6 @@ _cairo_scaled_font_init (cairo_scaled_font_t               *scaled_font,
 	    return status;
     }
 
-    /* Initialize scaled_font->scale early for easier bail out on an
-     * invalid matrix. */
     _cairo_scaled_font_init_key (scaled_font, font_face,
 				 font_matrix, ctm, options);
 
@@ -481,20 +479,22 @@ _cairo_scaled_font_init (cairo_scaled_font_t               *scaled_font,
 			   &scaled_font->font_matrix,
 			   &scaled_font->ctm);
 
-    inverse = scaled_font->scale;
-    status = cairo_matrix_invert (&inverse);
+    scaled_font->scale_inverse = scaled_font->scale;
+    status = cairo_matrix_invert (&scaled_font->scale_inverse);
     /* If the font scale matrix rank 0, just using an all-zero inverse matrix
      * makes everything work correctly.  This make font size 0 work without
      * producing an error.
      *
      * FIXME:  If the scale is rank 1, we still go into error mode.  But then
      * again, that's what we doo everywhere in cairo.
+     *
+     * Also, the check for == 0. below may bee too harsh...
      */
     if (status &&
 	scaled_font->scale.xx == 0. && scaled_font->scale.xy == 0. &&
 	scaled_font->scale.yx == 0. && scaled_font->scale.yy == 0.)
       {
-        cairo_matrix_init (&inverse,
+        cairo_matrix_init (&scaled_font->scale_inverse,
 			   0, 0, 0, 0,
 			   -scaled_font->scale.x0,
 			   -scaled_font->scale.y0);
@@ -629,11 +629,8 @@ cairo_scaled_font_create (cairo_font_face_t          *font_face,
 	return (cairo_scaled_font_t *)&_cairo_scaled_font_nil;
     }
 
-    if (! _cairo_matrix_is_invertible (font_matrix))
-	return (cairo_scaled_font_t *)&_cairo_scaled_font_nil;
-
-    if (! _cairo_matrix_is_invertible (ctm))
-	return (cairo_scaled_font_t *)&_cairo_scaled_font_nil;
+    /* Note that degenerate ctm or font_matrix *are* allowed.
+     * We want to support a font size of 0. */
 
     font_map = _cairo_scaled_font_map_lock ();
     if (font_map == NULL)