Support component-alpha.

Within our code base we carried a few hacks to utilize the component
alpha capabilities of pixman, whilst not supporting the concept for our
own masks. Thus we were setting it upon the pixman_image_t that we
passed around through code that was blissfully unaware and indeed the
component-alpha property was forgotten (e.g. upgrading glyph masks).

The real issue is that without explicit support that a pattern carries
subpixel masking information, that information is lost when using that
pattern with composite. Again we can look at the example of compositing
a sub-pixel glyph mask onto a remote xlib surface for further failure.

14 files changed, 234 insertions, 134 deletions

diff --git a/src/cairo-ft-font.c b/src/cairo-ft-font.c
index 036bfa06f..05f65628b 100644
--- a/src/cairo-ft-font.c
+++ b/src/cairo-ft-font.c
@@ -802,7 +802,6 @@ _get_bitmap_surface (FT_Bitmap		     *bitmap,
     int width, height, stride;
     unsigned char *data;
     int format = CAIRO_FORMAT_A8;
-    cairo_bool_t subpixel = FALSE;
 
     width = bitmap->width;
     height = bitmap->rows;
@@ -970,7 +969,6 @@ _get_bitmap_surface (FT_Bitmap		     *bitmap,
 	    data = data_rgba;
 	    stride = stride_rgba;
 	    format = CAIRO_FORMAT_ARGB32;
-	    subpixel = TRUE;
 	    break;
 	}
 	}
@@ -993,9 +991,6 @@ _get_bitmap_surface (FT_Bitmap		     *bitmap,
 	return (*surface)->base.status;
     }
 
-    if (subpixel)
-	pixman_image_set_component_alpha ((*surface)->pixman_image, TRUE);
-
     _cairo_image_surface_assume_ownership_of_data ((*surface));
 
     _cairo_debug_check_image_surface_is_defined (&(*surface)->base);
diff --git a/src/cairo-gl-glyphs.c b/src/cairo-gl-glyphs.c
index ff599d881..4370fdbaf 100644
--- a/src/cairo-gl-glyphs.c
+++ b/src/cairo-gl-glyphs.c
@@ -341,6 +341,7 @@ _render_glyphs (cairo_gl_surface_t	*dst,
 		int			 num_glyphs,
 		const cairo_rectangle_int_t *glyph_extents,
 		cairo_scaled_font_t	*scaled_font,
+		cairo_bool_t		*has_component_alpha,
 		cairo_region_t		*clip_region,
 		int			*remaining_glyphs)
 {
@@ -353,6 +354,8 @@ _render_glyphs (cairo_gl_surface_t	*dst,
     int i = 0;
     GLuint vbo = 0;
 
+    *has_component_alpha = FALSE;
+
     status = _cairo_gl_operand_init (&composite_setup.src, source, dst,
 				     glyph_extents->x, glyph_extents->y,
 				     dst_x, dst_y,
@@ -376,6 +379,7 @@ _render_glyphs (cairo_gl_surface_t	*dst,
     glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR);
     glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA);
 
+    /* XXX component alpha */
     glTexEnvi (GL_TEXTURE_ENV, GL_SRC1_RGB, GL_TEXTURE1);
     glTexEnvi (GL_TEXTURE_ENV, GL_SRC1_ALPHA, GL_TEXTURE1);
     glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND1_RGB, GL_SRC_ALPHA);
@@ -466,6 +470,10 @@ _render_glyphs (cairo_gl_surface_t	*dst,
 	    glBindTexture (GL_TEXTURE_2D, cache->tex);
 
 	    last_format = scaled_glyph->surface->format;
+	    if (last_format == CAIRO_FORMAT_ARGB32)
+		*has_component_alpha = TRUE;
+
+	    /* XXX component alpha */
 	}
 
 	if (scaled_glyph->surface_private == NULL) {
@@ -545,10 +553,11 @@ _cairo_gl_surface_show_glyphs_via_mask (cairo_gl_surface_t	*dst,
     cairo_surface_t *mask;
     cairo_status_t status;
     cairo_solid_pattern_t solid;
+    cairo_bool_t has_component_alpha;
     int i;
 
     mask = cairo_gl_surface_create (dst->ctx,
-	                            CAIRO_CONTENT_ALPHA,
+	                            CAIRO_CONTENT_COLOR_ALPHA,
 				    glyph_extents->width,
 				    glyph_extents->height);
     if (unlikely (mask->status))
@@ -559,15 +568,17 @@ _cairo_gl_surface_show_glyphs_via_mask (cairo_gl_surface_t	*dst,
 	glyphs[i].y -= glyph_extents->y;
     }
 
-    _cairo_pattern_init_solid (&solid, CAIRO_COLOR_WHITE, CAIRO_CONTENT_ALPHA);
+    _cairo_pattern_init_solid (&solid, CAIRO_COLOR_WHITE, CAIRO_CONTENT_COLOR_ALPHA);
     status = _render_glyphs ((cairo_gl_surface_t *) mask, 0, 0,
-	                     CAIRO_OPERATOR_ADD, &solid.base,
+	                     CAIRO_OPERATOR_SOURCE, &solid.base,
 	                     glyphs, num_glyphs, glyph_extents,
-			     scaled_font, NULL, remaining_glyphs);
+			     scaled_font, &has_component_alpha,
+			     NULL, remaining_glyphs);
     if (likely (status == CAIRO_STATUS_SUCCESS)) {
 	cairo_surface_pattern_t mask_pattern;
 
 	_cairo_pattern_init_for_surface (&mask_pattern, mask);
+	mask_pattern.base.has_component_alpha = has_component_alpha;
 	cairo_matrix_init_translate (&mask_pattern.base.matrix,
 		                     -glyph_extents->x, -glyph_extents->y);
 	status = _cairo_surface_mask (&dst->base, op,
@@ -601,6 +612,7 @@ _cairo_gl_surface_show_glyphs (void			*abstract_dst,
     cairo_region_t *clip_region = NULL;
     cairo_solid_pattern_t solid_pattern;
     cairo_bool_t overlap, use_mask = FALSE;
+    cairo_bool_t has_component_alpha;
     cairo_status_t status;
 
     if (! GLEW_ARB_vertex_buffer_object)
@@ -712,7 +724,8 @@ _cairo_gl_surface_show_glyphs (void			*abstract_dst,
     return _render_glyphs (dst, extents.x, extents.y,
 	                   op, source,
 			   glyphs, num_glyphs, &extents,
-			   scaled_font, clip_region, remaining_glyphs);
+			   scaled_font, &has_component_alpha,
+			   clip_region, remaining_glyphs);
 
 EMPTY:
     *remaining_glyphs = 0;
diff --git a/src/cairo-gl-surface.c b/src/cairo-gl-surface.c
index 29bf950da..07b6d4d38 100644
--- a/src/cairo-gl-surface.c
+++ b/src/cairo-gl-surface.c
@@ -1004,6 +1004,7 @@ _cairo_gl_pattern_surface_texture_setup (cairo_gl_composite_operand_t *operand,
     operand->operand.texture.tex = gl_surface->tex;
     operand->operand.texture.surface = NULL;
     attributes->matrix = src->base.matrix;
+    attributes->has_component_alpha = src->base.has_component_alpha;
     attributes->extend = src->base.extend;
     attributes->filter = src->base.filter;
     /* Demote the filter if we're doing a 1:1 mapping of pixels. */
@@ -1257,7 +1258,7 @@ _cairo_gl_set_src_operand (cairo_gl_context_t *ctx,
     switch (setup->src.type) {
     case OPERAND_CONSTANT:
 	_cairo_gl_set_tex_combine_constant_color (ctx, 0,
-	    setup->src.operand.constant.color);
+						  setup->src.operand.constant.color);
 	break;
     case OPERAND_TEXTURE:
 	_cairo_gl_set_texture_surface (0, setup->src.operand.texture.tex,
@@ -1317,6 +1318,13 @@ _cairo_gl_surface_composite (cairo_operator_t		  op,
     if (! _cairo_gl_operator_is_supported (op))
 	return CAIRO_INT_STATUS_UNSUPPORTED;
 
+    /* XXX: There is no sane way of expressing ComponentAlpha using
+     * fixed-function combiners and every possible operator. Look at the
+     * EXA drivers for the more appropriate fallback conditions.
+     */
+    if (mask && mask->has_component_alpha)
+	return CAIRO_INT_STATUS_UNSUPPORTED;
+
     memset (&setup, 0, sizeof (setup));
 
     status = _cairo_gl_operand_init (&setup.src, src, dst,
@@ -1327,9 +1335,6 @@ _cairo_gl_surface_composite (cairo_operator_t		  op,
 	return status;
     src_attributes = &setup.src.operand.texture.attributes;
 
-    if (mask != NULL && _cairo_pattern_is_opaque (mask))
-	mask = NULL;
-
     if (mask != NULL) {
 	status = _cairo_gl_operand_init (&setup.mask, mask, dst,
 					 mask_x, mask_y,
@@ -1352,13 +1357,13 @@ _cairo_gl_surface_composite (cairo_operator_t		  op,
 	switch (setup.mask.type) {
 	case OPERAND_CONSTANT:
 	    _cairo_gl_set_tex_combine_constant_color (ctx, 1,
-		setup.mask.operand.constant.color);
+						      setup.mask.operand.constant.color);
 	    break;
+
 	case OPERAND_TEXTURE:
 	    _cairo_gl_set_texture_surface (1, setup.mask.operand.texture.tex,
 					   mask_attributes);
 
-	    /* IN: dst.argb = src.argb * mask.aaaa */
 	    glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE);
 	    glTexEnvi (GL_TEXTURE_ENV, GL_COMBINE_RGB, GL_MODULATE);
 	    glTexEnvi (GL_TEXTURE_ENV, GL_COMBINE_ALPHA, GL_MODULATE);
@@ -1368,6 +1373,7 @@ _cairo_gl_surface_composite (cairo_operator_t		  op,
 	    glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR);
 	    glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA);
 
+	    /* IN: dst.argb = src.argb * mask.aaaa */
 	    glTexEnvi (GL_TEXTURE_ENV, GL_SRC1_RGB, GL_TEXTURE1);
 	    glTexEnvi (GL_TEXTURE_ENV, GL_SRC1_ALPHA, GL_TEXTURE1);
 	    glTexEnvi (GL_TEXTURE_ENV, GL_OPERAND1_RGB, GL_SRC_ALPHA);
diff --git a/src/cairo-gstate.c b/src/cairo-gstate.c
index 7ee88d6df..86e20bc90 100644
--- a/src/cairo-gstate.c
+++ b/src/cairo-gstate.c
@@ -1002,17 +1002,22 @@ _cairo_gstate_mask (cairo_gstate_t  *gstate,
     _cairo_gstate_copy_transformed_source (gstate, &source_pattern.base);
     _cairo_gstate_copy_transformed_mask (gstate, &mask_pattern.base, mask);
 
-    /* XXX: This optimization assumes that there is no color
-     * information in mask, so this will need to change if we
-     * support RENDER-style 4-channel masks.
-     */
     if (source_pattern.type == CAIRO_PATTERN_TYPE_SOLID &&
 	mask_pattern.type == CAIRO_PATTERN_TYPE_SOLID)
     {
 	cairo_color_t combined;
 
-	combined = source_pattern.solid.color;
-	_cairo_color_multiply_alpha (&combined, mask_pattern.solid.color.alpha);
+	if (mask_pattern.base.has_component_alpha) {
+#define M(R, A, B, c) R.c = A.c * B.c
+	    M(combined, source_pattern.solid.color, mask_pattern.solid.color, red);
+	    M(combined, source_pattern.solid.color, mask_pattern.solid.color, green);
+	    M(combined, source_pattern.solid.color, mask_pattern.solid.color, blue);
+	    M(combined, source_pattern.solid.color, mask_pattern.solid.color, alpha);
+#undef M
+	} else {
+	    combined = source_pattern.solid.color;
+	    _cairo_color_multiply_alpha (&combined, mask_pattern.solid.color.alpha);
+	}
 
 	_cairo_pattern_init_solid (&source_pattern.solid, &combined,
 				   source_pattern.solid.content |
diff --git a/src/cairo-image-surface.c b/src/cairo-image-surface.c
index d4b607e1e..b0a26bf9d 100644
--- a/src/cairo-image-surface.c
+++ b/src/cairo-image-surface.c
@@ -931,36 +931,63 @@ _cairo_image_surface_set_filter (cairo_image_surface_t *surface,
 }
 
 static cairo_status_t
-_cairo_image_surface_set_attributes (cairo_image_surface_t      *surface,
-				     cairo_surface_attributes_t *attributes,
-				     double xc, double yc)
+_cairo_image_surface_set_extend (cairo_image_surface_t *surface,
+				 cairo_extend_t extend)
 {
-    cairo_int_status_t status;
-
-    status = _cairo_image_surface_set_matrix (surface, &attributes->matrix,
-					      xc, yc);
-    if (unlikely (status))
-	return status;
+    pixman_repeat_t pixman_repeat;
 
-    switch (attributes->extend) {
+    switch (extend) {
     case CAIRO_EXTEND_NONE:
-        pixman_image_set_repeat (surface->pixman_image, PIXMAN_REPEAT_NONE);
+	pixman_repeat = PIXMAN_REPEAT_NONE;
 	break;
     case CAIRO_EXTEND_REPEAT:
-        pixman_image_set_repeat (surface->pixman_image, PIXMAN_REPEAT_NORMAL);
+	pixman_repeat = PIXMAN_REPEAT_NORMAL;
 	break;
     case CAIRO_EXTEND_REFLECT:
-        pixman_image_set_repeat (surface->pixman_image, PIXMAN_REPEAT_REFLECT);
+	pixman_repeat = PIXMAN_REPEAT_REFLECT;
 	break;
     case CAIRO_EXTEND_PAD:
-        pixman_image_set_repeat (surface->pixman_image, PIXMAN_REPEAT_PAD);
+	pixman_repeat = PIXMAN_REPEAT_PAD;
 	break;
     }
 
+    pixman_image_set_repeat (surface->pixman_image, pixman_repeat);
+    return CAIRO_STATUS_SUCCESS;
+}
+
+static cairo_status_t
+_cairo_image_surface_set_component_alpha (cairo_image_surface_t *surface,
+					  cairo_bool_t ca)
+{
+    pixman_image_set_component_alpha (surface->pixman_image, ca);
+    return CAIRO_STATUS_SUCCESS;
+}
+
+static cairo_status_t
+_cairo_image_surface_set_attributes (cairo_image_surface_t      *surface,
+				     cairo_surface_attributes_t *attributes,
+				     double xc, double yc)
+{
+    cairo_int_status_t status;
+
+    status = _cairo_image_surface_set_matrix (surface, &attributes->matrix,
+					      xc, yc);
+    if (unlikely (status))
+	return status;
+
     status = _cairo_image_surface_set_filter (surface, attributes->filter);
     if (unlikely (status))
 	return status;
 
+    status = _cairo_image_surface_set_extend (surface, attributes->extend);
+    if (unlikely (status))
+	return status;
+
+    status = _cairo_image_surface_set_component_alpha (surface,
+						       attributes->has_component_alpha);
+    if (unlikely (status))
+	return status;
+
     return CAIRO_STATUS_SUCCESS;
 }
 
diff --git a/src/cairo-pattern.c b/src/cairo-pattern.c
index d72867a0b..a566183c2 100644
--- a/src/cairo-pattern.c
+++ b/src/cairo-pattern.c
@@ -129,6 +129,8 @@ _cairo_pattern_init (cairo_pattern_t *pattern, cairo_pattern_type_t type)
 
     pattern->filter    = CAIRO_FILTER_DEFAULT;
 
+    pattern->has_component_alpha = FALSE;
+
     cairo_matrix_init_identity (&pattern->matrix);
 }
 
@@ -1522,6 +1524,7 @@ _cairo_pattern_acquire_surface_for_gradient (const cairo_gradient_pattern_t *pat
 	attr->matrix = matrix;
 	attr->extend = pattern->base.extend;
 	attr->filter = CAIRO_FILTER_NEAREST;
+	attr->has_component_alpha = pattern->base.has_component_alpha;
 
 	*out = &image->base;
 
@@ -1615,6 +1618,7 @@ _cairo_pattern_acquire_surface_for_gradient (const cairo_gradient_pattern_t *pat
     cairo_matrix_init_identity (&attr->matrix);
     attr->extend = repeat ? CAIRO_EXTEND_REPEAT : CAIRO_EXTEND_NONE;
     attr->filter = CAIRO_FILTER_NEAREST;
+    attr->has_component_alpha = pattern->base.has_component_alpha;
 
     return status;
 }
@@ -1759,6 +1763,7 @@ NOCACHE:
     cairo_matrix_init_identity (&attribs->matrix);
     attribs->extend = CAIRO_EXTEND_REPEAT;
     attribs->filter = CAIRO_FILTER_NEAREST;
+    attribs->has_component_alpha = pattern->base.has_component_alpha;
 
     status = CAIRO_STATUS_SUCCESS;
 
@@ -1845,6 +1850,9 @@ _cairo_pattern_is_opaque (const cairo_pattern_t *abstract_pattern)
 {
     const cairo_pattern_union_t *pattern;
 
+    if (abstract_pattern->has_component_alpha)
+	return FALSE;
+
     pattern = (cairo_pattern_union_t *) abstract_pattern;
     switch (pattern->base.type) {
     case CAIRO_PATTERN_TYPE_SOLID:
@@ -1953,6 +1961,7 @@ _cairo_pattern_acquire_surface_for_surface (const cairo_surface_pattern_t   *pat
     attr->matrix = pattern->base.matrix;
     attr->extend = pattern->base.extend;
     attr->filter = _cairo_pattern_analyze_filter (&pattern->base, &pad);
+    attr->has_component_alpha = pattern->base.has_component_alpha;
 
     attr->x_offset = attr->y_offset = tx = ty = 0;
     if (_cairo_matrix_is_integer_translation (&attr->matrix, &tx, &ty)) {
@@ -2370,11 +2379,10 @@ _cairo_pattern_acquire_surfaces (const cairo_pattern_t	    *src,
     /* If src and mask are both solid, then the mask alpha can be
      * combined into src and mask can be ignored. */
 
-    /* XXX: This optimization assumes that there is no color
-     * information in mask, so this will need to change when we
-     * support RENDER-style 4-channel masks. */
     if (src->type == CAIRO_PATTERN_TYPE_SOLID &&
-	mask && mask->type == CAIRO_PATTERN_TYPE_SOLID)
+	mask &&
+	! mask->has_component_alpha &&
+	mask->type == CAIRO_PATTERN_TYPE_SOLID)
     {
 	cairo_color_t combined;
 	cairo_solid_pattern_t *src_solid = (cairo_solid_pattern_t *) src;
@@ -2651,6 +2659,9 @@ _cairo_pattern_hash (const cairo_pattern_t *pattern)
 				  &pattern->filter, sizeof (pattern->filter));
 	hash = _cairo_hash_bytes (hash,
 				  &pattern->extend, sizeof (pattern->extend));
+	hash = _cairo_hash_bytes (hash,
+				  &pattern->has_component_alpha,
+				  sizeof (pattern->has_component_alpha));
     }
 
     switch (pattern->type) {
@@ -2808,6 +2819,9 @@ _cairo_pattern_equal (const cairo_pattern_t *a, const cairo_pattern_t *b)
     if (a->type != b->type)
 	return FALSE;
 
+    if (a->has_component_alpha != b->has_component_alpha)
+	return FALSE;
+
     if (a->type != CAIRO_PATTERN_TYPE_SOLID) {
 	if (memcmp (&a->matrix, &b->matrix, sizeof (cairo_matrix_t)))
 	    return FALSE;
diff --git a/src/cairo-pdf-surface.c b/src/cairo-pdf-surface.c
index 896980a89..60ebfe5e7 100644
--- a/src/cairo-pdf-surface.c
+++ b/src/cairo-pdf-surface.c
@@ -5433,9 +5433,13 @@ _cairo_pdf_surface_mask	(void			*abstract_surface,
 	if (_cairo_status_is_error (source_status))
 	    return source_status;
 
-	mask_status = _cairo_pdf_surface_analyze_operation (surface, op, mask);
-	if (_cairo_status_is_error (mask_status))
-	    return mask_status;
+	if (mask->has_component_alpha) {
+	    mask_status = CAIRO_INT_STATUS_UNSUPPORTED;
+	} else {
+	    mask_status = _cairo_pdf_surface_analyze_operation (surface, op, mask);
+	    if (_cairo_status_is_error (mask_status))
+		return mask_status;
+	}
 
 	return _cairo_analysis_surface_merge_status (source_status,
 						     mask_status);
diff --git a/src/cairo-scaled-font.c b/src/cairo-scaled-font.c
index 199ad39e5..179844fc3 100644
--- a/src/cairo-scaled-font.c
+++ b/src/cairo-scaled-font.c
@@ -2169,8 +2169,10 @@ _cairo_scaled_font_show_glyphs (cairo_scaled_font_t	*scaled_font,
 	    }
 
 	    _cairo_pattern_init_for_surface (&mask_pattern, mask);
-
-	    status = _cairo_surface_composite (CAIRO_OPERATOR_ADD,
+	    /* Note that we only upgrade masks, i.e. A1 -> A8 -> ARGB32, so there is
+	     * never any component alpha here.
+	     */
+	    status = _cairo_surface_composite (CAIRO_OPERATOR_SOURCE,
 					       &white_pattern.base,
 					       &mask_pattern.base,
 					       new_mask,
@@ -2203,6 +2205,8 @@ _cairo_scaled_font_show_glyphs (cairo_scaled_font_t	*scaled_font,
 
 	    _cairo_pattern_init_for_surface (&glyph_pattern,
 					     &glyph_surface->base);
+	    if (mask_format == CAIRO_FORMAT_ARGB32)
+		glyph_pattern.base.has_component_alpha = TRUE;
 
 	    status = _cairo_surface_composite (CAIRO_OPERATOR_ADD,
 					       &white_pattern.base,
@@ -2222,11 +2226,9 @@ _cairo_scaled_font_show_glyphs (cairo_scaled_font_t	*scaled_font,
 	}
     }
 
-    if (mask_format == CAIRO_FORMAT_ARGB32) {
-	pixman_image_set_component_alpha (((cairo_image_surface_t*) mask)->
-					  pixman_image, TRUE);
-    }
     _cairo_pattern_init_for_surface (&mask_pattern, mask);
+    if (mask_format == CAIRO_FORMAT_ARGB32)
+	mask_pattern.base.has_component_alpha = TRUE;
 
     status = _cairo_surface_composite (op, pattern, &mask_pattern.base,
 				       surface,
diff --git a/src/cairo-svg-surface.c b/src/cairo-svg-surface.c
index 26ae3d9d8..6277af180 100644
--- a/src/cairo-svg-surface.c
+++ b/src/cairo-svg-surface.c
@@ -2262,9 +2262,13 @@ _cairo_svg_surface_mask (void		    *abstract_surface,
 	if (_cairo_status_is_error (source_status))
 	    return source_status;
 
-	mask_status = _cairo_svg_surface_analyze_operation (surface, op, mask);
-	if (_cairo_status_is_error (mask_status))
-	    return mask_status;
+	if (mask->has_component_alpha) {
+	    mask_status = CAIRO_INT_STATUS_UNSUPPORTED;
+	} else {
+	    mask_status = _cairo_svg_surface_analyze_operation (surface, op, mask);
+	    if (_cairo_status_is_error (mask_status))
+		return mask_status;
+	}
 
 	return _cairo_analysis_surface_merge_status (source_status,
 						     mask_status);
diff --git a/src/cairo-types-private.h b/src/cairo-types-private.h
index 82754cff2..16b27c254 100644
--- a/src/cairo-types-private.h
+++ b/src/cairo-types-private.h
@@ -340,4 +340,75 @@ struct _cairo_mime_data {
     void *closure;
 };
 
+struct _cairo_pattern {
+    cairo_pattern_type_t	type;
+    cairo_reference_count_t	ref_count;
+    cairo_status_t		status;
+    cairo_user_data_array_t	user_data;
+
+    cairo_matrix_t		matrix;
+    cairo_filter_t		filter;
+    cairo_extend_t		extend;
+
+    cairo_bool_t		has_component_alpha;
+};
+
+struct _cairo_solid_pattern {
+    cairo_pattern_t base;
+    cairo_color_t color;
+    cairo_content_t content;
+};
+
+typedef struct _cairo_surface_pattern {
+    cairo_pattern_t base;
+
+    cairo_surface_t *surface;
+} cairo_surface_pattern_t;
+
+typedef struct _cairo_gradient_stop {
+    double offset;
+    cairo_color_t color;
+} cairo_gradient_stop_t;
+
+typedef struct _cairo_gradient_pattern {
+    cairo_pattern_t base;
+
+    unsigned int	    n_stops;
+    unsigned int	    stops_size;
+    cairo_gradient_stop_t  *stops;
+    cairo_gradient_stop_t   stops_embedded[2];
+} cairo_gradient_pattern_t;
+
+typedef struct _cairo_linear_pattern {
+    cairo_gradient_pattern_t base;
+
+    cairo_point_t p1;
+    cairo_point_t p2;
+} cairo_linear_pattern_t;
+
+typedef struct _cairo_radial_pattern {
+    cairo_gradient_pattern_t base;
+
+    cairo_point_t c1;
+    cairo_fixed_t r1;
+    cairo_point_t c2;
+    cairo_fixed_t r2;
+} cairo_radial_pattern_t;
+
+typedef union {
+    cairo_gradient_pattern_t base;
+
+    cairo_linear_pattern_t linear;
+    cairo_radial_pattern_t radial;
+} cairo_gradient_pattern_union_t;
+
+typedef union {
+    cairo_pattern_type_t	    type;
+    cairo_pattern_t		    base;
+
+    cairo_solid_pattern_t	    solid;
+    cairo_surface_pattern_t	    surface;
+    cairo_gradient_pattern_union_t  gradient;
+} cairo_pattern_union_t;
+
 #endif /* CAIRO_TYPES_PRIVATE_H */
diff --git a/src/cairo-win32-font.c b/src/cairo-win32-font.c
index 216c75134..7a86cc8c7 100644
--- a/src/cairo-win32-font.c
+++ b/src/cairo-win32-font.c
@@ -1437,10 +1437,6 @@ _cairo_win32_scaled_font_show_glyphs (void			*abstract_font,
 		_invert_argb32_mask (tmp_surface);
 
 	    mask_surface = &tmp_surface->base;
-
-	    /* XXX: Hacky, should expose this in cairo_image_surface */
-	    pixman_image_set_component_alpha (((cairo_image_surface_t *)tmp_surface->image)->pixman_image, TRUE);
-
 	} else {
 	    mask_surface = _compute_a8_mask (tmp_surface);
 	    cairo_surface_destroy (&tmp_surface->base);
@@ -1454,6 +1450,10 @@ _cairo_win32_scaled_font_show_glyphs (void			*abstract_font,
 	 * destination
 	 */
 	_cairo_pattern_init_for_surface (&mask, mask_surface);
+	cairo_surface_destroy (mask_surface);
+
+	if (scaled_font->quality == CLEARTYPE_QUALITY)
+	    mask.base.has_component_alpha = TRUE;
 
 	status = _cairo_surface_composite (op, pattern,
 					   &mask.base,
@@ -1466,8 +1466,6 @@ _cairo_win32_scaled_font_show_glyphs (void			*abstract_font,
 
 	_cairo_pattern_fini (&mask.base);
 
-	cairo_surface_destroy (mask_surface);
-
 	return status;
     }
 }
diff --git a/src/cairo-xlib-surface-private.h b/src/cairo-xlib-surface-private.h
index 92107e7f9..b30848d57 100644
--- a/src/cairo-xlib-surface-private.h
+++ b/src/cairo-xlib-surface-private.h
@@ -95,6 +95,7 @@ struct _cairo_xlib_surface {
     XRenderPictFormat *xrender_format;
     cairo_filter_t filter;
     cairo_extend_t extend;
+    cairo_bool_t has_component_alpha;
     XTransform xtransform;
 
     uint32_t a_mask;
diff --git a/src/cairo-xlib-surface.c b/src/cairo-xlib-surface.c
index 994a4f9d7..8965373e3 100644
--- a/src/cairo-xlib-surface.c
+++ b/src/cairo-xlib-surface.c
@@ -1539,11 +1539,11 @@ _cairo_xlib_surface_set_filter (cairo_xlib_surface_t *surface,
 }
 
 static cairo_status_t
-_cairo_xlib_surface_set_repeat (cairo_xlib_surface_t *surface,
-				cairo_extend_t extend)
+_cairo_xlib_surface_set_repeat (cairo_xlib_surface_t	*surface,
+				cairo_extend_t		 extend,
+				unsigned long		*mask,
+				XRenderPictureAttributes *pa)
 {
-    XRenderPictureAttributes pa;
-    unsigned long	     mask;
     int repeat;
 
     if (surface->extend == extend)
@@ -1573,12 +1573,26 @@ _cairo_xlib_surface_set_repeat (cairo_xlib_surface_t *surface,
 	return CAIRO_INT_STATUS_UNSUPPORTED;
     }
 
-    mask = CPRepeat;
-    pa.repeat = repeat;
+    *mask |= CPRepeat;
+    pa->repeat = repeat;
 
-    XRenderChangePicture (surface->dpy, surface->src_picture, mask, &pa);
     surface->extend = extend;
+    return CAIRO_STATUS_SUCCESS;
+}
+
+static cairo_status_t
+_cairo_xlib_surface_set_component_alpha (cairo_xlib_surface_t *surface,
+					 cairo_bool_t		ca,
+					 unsigned long		*mask,
+					 XRenderPictureAttributes *pa)
+{
+    if (surface->has_component_alpha == ca)
+	return CAIRO_STATUS_SUCCESS;
 
+    *mask |= CPComponentAlpha;
+    pa->component_alpha = ca;
+
+    surface->has_component_alpha = ca;
     return CAIRO_STATUS_SUCCESS;
 }
 
@@ -1589,6 +1603,8 @@ _cairo_xlib_surface_set_attributes (cairo_xlib_surface_t	    *surface,
 				    double			     yc)
 {
     cairo_int_status_t status;
+    XRenderPictureAttributes pa;
+    unsigned long mask = 0;
 
     _cairo_xlib_surface_ensure_src_picture (surface);
 
@@ -1597,7 +1613,14 @@ _cairo_xlib_surface_set_attributes (cairo_xlib_surface_t	    *surface,
     if (unlikely (status))
 	return status;
 
-    status = _cairo_xlib_surface_set_repeat (surface, attributes->extend);
+    status = _cairo_xlib_surface_set_repeat (surface, attributes->extend,
+					     &mask, &pa);
+    if (unlikely (status))
+	return status;
+
+    status = _cairo_xlib_surface_set_component_alpha (surface,
+						      attributes->has_component_alpha,
+						      &mask, &pa);
     if (unlikely (status))
 	return status;
 
@@ -1605,6 +1628,9 @@ _cairo_xlib_surface_set_attributes (cairo_xlib_surface_t	    *surface,
     if (unlikely (status))
 	return status;
 
+    if (mask)
+	XRenderChangePicture (surface->dpy, surface->src_picture, mask, &pa);
+
     return CAIRO_STATUS_SUCCESS;
 }
 
@@ -2946,6 +2972,7 @@ found:
     surface->depth = depth;
     surface->filter = CAIRO_FILTER_NEAREST;
     surface->extend = CAIRO_EXTEND_NONE;
+    surface->has_component_alpha = FALSE;
     surface->xtransform = identity;
 
     surface->clip_region = NULL;
diff --git a/src/cairoint.h b/src/cairoint.h
index fc1046e34..c309f3dbc 100644
--- a/src/cairoint.h
+++ b/src/cairoint.h
@@ -871,81 +871,14 @@ extern const cairo_private cairo_surface_backend_t _cairo_image_surface_backend;
 #define CAIRO_EXTEND_GRADIENT_DEFAULT CAIRO_EXTEND_PAD
 #define CAIRO_FILTER_DEFAULT CAIRO_FILTER_GOOD
 
-struct _cairo_pattern {
-    cairo_pattern_type_t	type;
-    cairo_reference_count_t	ref_count;
-    cairo_status_t		status;
-    cairo_user_data_array_t	user_data;
-
-    cairo_matrix_t		matrix;
-    cairo_filter_t		filter;
-    cairo_extend_t		extend;
-};
-
-struct _cairo_solid_pattern {
-    cairo_pattern_t base;
-    cairo_color_t color;
-    cairo_content_t content;
-};
-
 extern const cairo_private cairo_solid_pattern_t _cairo_pattern_black;
 
-typedef struct _cairo_surface_pattern {
-    cairo_pattern_t base;
-
-    cairo_surface_t *surface;
-} cairo_surface_pattern_t;
-
-typedef struct _cairo_gradient_stop {
-    double offset;
-    cairo_color_t color;
-} cairo_gradient_stop_t;
-
-typedef struct _cairo_gradient_pattern {
-    cairo_pattern_t base;
-
-    unsigned int	    n_stops;
-    unsigned int	    stops_size;
-    cairo_gradient_stop_t  *stops;
-    cairo_gradient_stop_t   stops_embedded[2];
-} cairo_gradient_pattern_t;
-
-typedef struct _cairo_linear_pattern {
-    cairo_gradient_pattern_t base;
-
-    cairo_point_t p1;
-    cairo_point_t p2;
-} cairo_linear_pattern_t;
-
-typedef struct _cairo_radial_pattern {
-    cairo_gradient_pattern_t base;
-
-    cairo_point_t c1;
-    cairo_fixed_t r1;
-    cairo_point_t c2;
-    cairo_fixed_t r2;
-} cairo_radial_pattern_t;
-
-typedef union {
-    cairo_gradient_pattern_t base;
-
-    cairo_linear_pattern_t linear;
-    cairo_radial_pattern_t radial;
-} cairo_gradient_pattern_union_t;
-
-typedef union {
-    cairo_pattern_type_t	    type;
-    cairo_pattern_t		    base;
-
-    cairo_solid_pattern_t	    solid;
-    cairo_surface_pattern_t	    surface;
-    cairo_gradient_pattern_union_t  gradient;
-} cairo_pattern_union_t;
 
 typedef struct _cairo_surface_attributes {
     cairo_matrix_t matrix;
     cairo_extend_t extend;
     cairo_filter_t filter;
+    cairo_bool_t has_component_alpha;
     int		   x_offset;
     int		   y_offset;
     void	   *extra;