Implement cairo_backend_t

Allow a backend to completely reimplement the Cairo API as it wants. The
goal is to pass operations to the native backends such as Quartz,
Direct2D, Qt, Skia, OpenVG with no overhead. And to permit complete
logging contexts, and whatever else the imagination holds. Perhaps to
experiment with double-paths?

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 70 insertions, 72 deletions

diff --git a/src/cairo-gstate.c b/src/cairo-gstate.c
index d9672c22c..7aea6c1d7 100644
--- a/src/cairo-gstate.c
+++ b/src/cairo-gstate.c
@@ -91,6 +91,7 @@ _cairo_gstate_init (cairo_gstate_t  *gstate,
     gstate->next = NULL;
 
     gstate->op = CAIRO_GSTATE_OPERATOR_DEFAULT;
+    gstate->opacity = 1.;
 
     gstate->tolerance = CAIRO_GSTATE_TOLERANCE_DEFAULT;
     gstate->antialias = CAIRO_ANTIALIAS_DEFAULT;
@@ -147,6 +148,7 @@ _cairo_gstate_init_copy (cairo_gstate_t *gstate, cairo_gstate_t *other)
     VG (VALGRIND_MAKE_MEM_UNDEFINED (gstate, sizeof (cairo_gstate_t)));
 
     gstate->op = other->op;
+    gstate->opacity = other->opacity;
 
     gstate->tolerance = other->tolerance;
     gstate->antialias = other->antialias;
@@ -429,6 +431,20 @@ _cairo_gstate_get_operator (cairo_gstate_t *gstate)
 }
 
 cairo_status_t
+_cairo_gstate_set_opacity (cairo_gstate_t *gstate, double op)
+{
+    gstate->opacity = op;
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+double
+_cairo_gstate_get_opacity (cairo_gstate_t *gstate)
+{
+    return gstate->opacity;
+}
+
+cairo_status_t
 _cairo_gstate_set_tolerance (cairo_gstate_t *gstate, double tolerance)
 {
     gstate->tolerance = tolerance;
@@ -1066,6 +1082,8 @@ _cairo_gstate_mask (cairo_gstate_t  *gstate,
     if (_clipped (gstate))
 	return CAIRO_STATUS_SUCCESS;
 
+    assert (gstate->opacity == 1.0);
+
     if (_cairo_pattern_is_opaque (mask, NULL))
 	return _cairo_gstate_paint (gstate);
 
@@ -1143,6 +1161,8 @@ _cairo_gstate_stroke (cairo_gstate_t *gstate, cairo_path_fixed_t *path)
     if (_clipped (gstate))
 	return CAIRO_STATUS_SUCCESS;
 
+    assert (gstate->opacity == 1.0);
+
     memcpy (&style, &gstate->stroke_style, sizeof (gstate->stroke_style));
     if (_cairo_stroke_style_dash_can_approximate (&gstate->stroke_style, &gstate->ctm, gstate->tolerance)) {
         style.dash = dash;
@@ -1243,6 +1263,8 @@ _cairo_gstate_fill (cairo_gstate_t *gstate, cairo_path_fixed_t *path)
     if (_clipped (gstate))
 	return CAIRO_STATUS_SUCCESS;
 
+    assert (gstate->opacity == 1.0);
+
     if (_cairo_path_fixed_fill_is_empty (path)) {
 	if (_cairo_operator_bounded_by_mask (gstate->op))
 	    return CAIRO_STATUS_SUCCESS;
@@ -1580,22 +1602,14 @@ _cairo_gstate_unset_scaled_font (cairo_gstate_t *gstate)
 }
 
 cairo_status_t
-_cairo_gstate_select_font_face (cairo_gstate_t       *gstate,
-				const char           *family,
-				cairo_font_slant_t    slant,
-				cairo_font_weight_t   weight)
+_cairo_gstate_set_font_size (cairo_gstate_t *gstate,
+			     double          size)
 {
-    cairo_font_face_t *font_face;
-    cairo_status_t status;
-
-    font_face = cairo_toy_font_face_create (family, slant, weight);
-    if (font_face->status)
-	return font_face->status;
+    _cairo_gstate_unset_scaled_font (gstate);
 
-    status = _cairo_gstate_set_font_face (gstate, font_face);
-    cairo_font_face_destroy (font_face);
+    cairo_matrix_init_scale (&gstate->font_matrix, size, size);
 
-    return status;
+    return CAIRO_STATUS_SUCCESS;
 }
 
 cairo_status_t
@@ -1810,31 +1824,6 @@ _cairo_gstate_get_font_extents (cairo_gstate_t *gstate,
 }
 
 cairo_status_t
-_cairo_gstate_text_to_glyphs (cairo_gstate_t	         *gstate,
-			      double		          x,
-			      double		          y,
-			      const char	         *utf8,
-			      int		          utf8_len,
-			      cairo_glyph_t	        **glyphs,
-			      int		         *num_glyphs,
-			      cairo_text_cluster_t      **clusters,
-			      int		         *num_clusters,
-			      cairo_text_cluster_flags_t *cluster_flags)
-{
-    cairo_status_t status;
-
-    status = _cairo_gstate_ensure_scaled_font (gstate);
-    if (unlikely (status))
-	return status;
-
-    return cairo_scaled_font_text_to_glyphs (gstate->scaled_font, x, y,
-					     utf8, utf8_len,
-					     glyphs, num_glyphs,
-					     clusters, num_clusters,
-					     cluster_flags);
-}
-
-cairo_status_t
 _cairo_gstate_set_font_face (cairo_gstate_t    *gstate,
 			     cairo_font_face_t *font_face)
 {
@@ -1873,20 +1862,16 @@ _cairo_gstate_glyph_extents (cairo_gstate_t *gstate,
 
 cairo_status_t
 _cairo_gstate_show_text_glyphs (cairo_gstate_t		   *gstate,
-				const char		   *utf8,
-				int			    utf8_len,
 				const cairo_glyph_t	   *glyphs,
 				int			    num_glyphs,
-				const cairo_text_cluster_t *clusters,
-				int			    num_clusters,
-				cairo_text_cluster_flags_t  cluster_flags)
+				cairo_glyph_text_info_t    *info)
 {
     cairo_pattern_union_t source_pattern;
     const cairo_pattern_t *pattern;
     cairo_glyph_t stack_transformed_glyphs[CAIRO_STACK_ARRAY_LENGTH (cairo_glyph_t)];
     cairo_glyph_t *transformed_glyphs;
     cairo_text_cluster_t stack_transformed_clusters[CAIRO_STACK_ARRAY_LENGTH (cairo_text_cluster_t)];
-    cairo_text_cluster_t *transformed_clusters;
+    cairo_text_cluster_t *transformed_clusters = NULL;
     cairo_operator_t op;
     cairo_status_t status;
     cairo_clip_t clip;
@@ -1906,8 +1891,6 @@ _cairo_gstate_show_text_glyphs (cairo_gstate_t		   *gstate,
 	return status;
 
     transformed_glyphs = stack_transformed_glyphs;
-    transformed_clusters = stack_transformed_clusters;
-
     if (num_glyphs > ARRAY_LENGTH (stack_transformed_glyphs)) {
 	transformed_glyphs = cairo_glyph_allocate (num_glyphs);
 	if (unlikely (transformed_glyphs == NULL)) {
@@ -1916,26 +1899,32 @@ _cairo_gstate_show_text_glyphs (cairo_gstate_t		   *gstate,
 	}
     }
 
-    /* Just in case */
-    if (!clusters)
-	num_clusters = 0;
-
-    if (num_clusters > ARRAY_LENGTH (stack_transformed_clusters)) {
-	transformed_clusters = cairo_text_cluster_allocate (num_clusters);
-	if (unlikely (transformed_clusters == NULL)) {
-	    status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
-	    goto CLEANUP_GLYPHS;
+    if (info != NULL) {
+	transformed_clusters = stack_transformed_clusters;
+	if (info->num_clusters > ARRAY_LENGTH (stack_transformed_clusters)) {
+	    transformed_clusters = cairo_text_cluster_allocate (info->num_clusters);
+	    if (unlikely (transformed_clusters == NULL)) {
+		status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
+		goto CLEANUP_GLYPHS;
+	    }
 	}
-    }
 
-    status = _cairo_gstate_transform_glyphs_to_backend (gstate,
-							glyphs, num_glyphs,
-							clusters,
-							num_clusters,
-							cluster_flags,
-							transformed_glyphs,
-							&num_glyphs,
-							transformed_clusters);
+	status = _cairo_gstate_transform_glyphs_to_backend (gstate,
+							    glyphs, num_glyphs,
+							    info->clusters,
+							    info->num_clusters,
+							    info->cluster_flags,
+							    transformed_glyphs,
+							    &num_glyphs,
+							    transformed_clusters);
+    } else {
+	status = _cairo_gstate_transform_glyphs_to_backend (gstate,
+							    glyphs, num_glyphs,
+							    NULL, 0, 0,
+							    transformed_glyphs,
+							    &num_glyphs,
+							    NULL);
+    }
 
     if (status || num_glyphs == 0)
 	goto CLEANUP_GLYPHS;
@@ -1961,13 +1950,22 @@ _cairo_gstate_show_text_glyphs (cairo_gstate_t		   *gstate,
     if (cairo_surface_has_show_text_glyphs (gstate->target) ||
 	_cairo_scaled_font_get_max_scale (gstate->scaled_font) <= 10240)
     {
-	status = _cairo_surface_show_text_glyphs (gstate->target, op, pattern,
-						  utf8, utf8_len,
-						  transformed_glyphs, num_glyphs,
-						  transformed_clusters, num_clusters,
-						  cluster_flags,
-						  gstate->scaled_font,
-						  _gstate_get_clip (gstate, &clip));
+	if (info != NULL) {
+	    status = _cairo_surface_show_text_glyphs (gstate->target, op, pattern,
+						      info->utf8, info->utf8_len,
+						      transformed_glyphs, num_glyphs,
+						      transformed_clusters, info->num_clusters,
+						      info->cluster_flags,
+						      gstate->scaled_font,
+						      _gstate_get_clip (gstate, &clip));
+	} else {
+	    status = _cairo_surface_show_text_glyphs (gstate->target, op, pattern,
+						      NULL, 0,
+						      transformed_glyphs, num_glyphs,
+						      NULL, 0, 0,
+						      gstate->scaled_font,
+						      _gstate_get_clip (gstate, &clip));
+	}
     }
     else
     {
@@ -2028,7 +2026,7 @@ _cairo_gstate_glyph_path (cairo_gstate_t      *gstate,
 							glyphs, num_glyphs,
 							NULL, 0, 0,
 							transformed_glyphs,
-							NULL, NULL);
+							&num_glyphs, NULL);
     if (unlikely (status))
 	goto CLEANUP_GLYPHS;