Split _cairo_operator_bounded into two separate functions _cairo_operator_bounded_by_mask and _cairo_operator_bound_by_source to distinguish between how operators use source and mask operands.

4 files changed, 57 insertions, 18 deletions

diff --git a/src/cairo-gstate.c b/src/cairo-gstate.c
index e28b7be0e..40403657c 100644
--- a/src/cairo-gstate.c
+++ b/src/cairo-gstate.c
@@ -750,20 +750,20 @@ _cairo_gstate_paint (cairo_gstate_t *gstate)
 }
 
 /**
- * _cairo_operator_bounded:
+ * _cairo_operator_bounded_by_mask:
  * @operator: a #cairo_operator_t
  * 
- * A bounded operator is one where a source or mask pixel
+ * A bounded operator is one where mask pixel
  * of zero results in no effect on the destination image.
  *
  * Unbounded operators often require special handling; if you, for
  * example, draw trapezoids with an unbounded operator, the effect
  * extends past the bounding box of the trapezoids.
  *
- * Return value: %TRUE if the operator is bounded
+ * Return value: %TRUE if the operator is bounded by the mask operand
  **/
 cairo_bool_t
-_cairo_operator_bounded (cairo_operator_t operator)
+_cairo_operator_bounded_by_mask (cairo_operator_t operator)
 {
     switch (operator) {
     case CAIRO_OPERATOR_CLEAR:
@@ -788,6 +788,46 @@ _cairo_operator_bounded (cairo_operator_t operator)
     return FALSE;
 }
 
+/**
+ * _cairo_operator_bounded_by_source:
+ * @operator: a #cairo_operator_t
+ * 
+ * A bounded operator is one where source pixels of zero
+ * (in all four components, r, g, b and a) effect no change
+ * in the resulting destination image.
+ *
+ * Unbounded operators often require special handling; if you, for
+ * example, copy a surface with the SOURCE operator, the effect
+ * extends past the bounding box of the source surface.
+ *
+ * Return value: %TRUE if the operator is bounded by the source operand
+ **/
+cairo_bool_t
+_cairo_operator_bounded_by_source (cairo_operator_t operator)
+{
+    switch (operator) {
+    case CAIRO_OPERATOR_OVER:
+    case CAIRO_OPERATOR_ATOP:
+    case CAIRO_OPERATOR_DEST:
+    case CAIRO_OPERATOR_DEST_OVER:
+    case CAIRO_OPERATOR_DEST_OUT:
+    case CAIRO_OPERATOR_XOR:
+    case CAIRO_OPERATOR_ADD:
+    case CAIRO_OPERATOR_SATURATE:
+	return TRUE;
+    case CAIRO_OPERATOR_CLEAR:
+    case CAIRO_OPERATOR_SOURCE:
+    case CAIRO_OPERATOR_OUT:
+    case CAIRO_OPERATOR_IN:
+    case CAIRO_OPERATOR_DEST_IN:
+    case CAIRO_OPERATOR_DEST_ATOP:
+	return FALSE;
+    }
+    
+    ASSERT_NOT_REACHED;
+    return FALSE;
+}
+
 static cairo_status_t
 _create_composite_mask_pattern (cairo_surface_pattern_t *mask_pattern,
 				cairo_clip_t            *clip,
@@ -1057,7 +1097,7 @@ _cairo_gstate_clip_and_composite (cairo_clip_t            *clip,
 							      src,
 							      draw_func, draw_closure,
 							      dst, extents);
-	else if (_cairo_operator_bounded (operator))
+	else if (_cairo_operator_bounded_by_mask (operator))
 	    status = _cairo_gstate_clip_and_composite_with_mask (clip, operator,
 								 src,
 								 draw_func, draw_closure,
@@ -1338,7 +1378,7 @@ _cairo_surface_clip_and_composite_trapezoids (cairo_pattern_t *src,
     if (status)
 	return status;
 
-    if (_cairo_operator_bounded (operator))
+    if (_cairo_operator_bounded_by_mask (operator))
     {
 	if (trap_region) {
 	    status = _cairo_clip_intersect_to_region (clip, trap_region);
@@ -1411,7 +1451,7 @@ _cairo_surface_clip_and_composite_trapezoids (cairo_pattern_t *src,
 	    goto out;
 	}
 
-	if ((_cairo_operator_bounded (operator) && operator != CAIRO_OPERATOR_SOURCE) ||
+	if ((_cairo_operator_bounded_by_mask (operator) && operator != CAIRO_OPERATOR_SOURCE) ||
 	    !clip->surface)
 	{
 	    /* For a simple rectangle, we can just use composite(), for more
@@ -2011,7 +2051,7 @@ _cairo_gstate_show_glyphs (cairo_gstate_t *gstate,
 				       &transformed_glyphs[i].y);
     }
 
-    if (_cairo_operator_bounded (gstate->operator))
+    if (_cairo_operator_bounded_by_mask (gstate->operator))
 	status = _cairo_scaled_font_glyph_device_extents (gstate->scaled_font,
 							  transformed_glyphs, 
 							  num_glyphs, 
diff --git a/src/cairo-image-surface.c b/src/cairo-image-surface.c
index 20d14c170..c05dfeb60 100644
--- a/src/cairo-image-surface.c
+++ b/src/cairo-image-surface.c
@@ -620,9 +620,7 @@ _cairo_image_surface_composite (cairo_operator_t	operator,
 			  width, height);
     }
     
-    if (!_cairo_operator_bounded (operator) ||
-	operator == CAIRO_OPERATOR_SOURCE ||
-	operator == CAIRO_OPERATOR_CLEAR)
+    if (!_cairo_operator_bounded_by_source (operator))
 	status = _cairo_surface_composite_fixup_unbounded (&dst->base,
 							   &src_attr, src->width, src->height,
 							   mask ? &mask_attr : NULL,
@@ -785,7 +783,7 @@ _cairo_image_surface_composite_trapezoids (cairo_operator_t	operator,
 		      dst_x, dst_y,
 		      width, height);
 
-    if (!_cairo_operator_bounded (operator))
+    if (!_cairo_operator_bounded_by_mask (operator))
 	status = _cairo_surface_composite_shape_fixup_unbounded (&dst->base,
 								 &attributes, src->width, src->height,
 								 width, height,
diff --git a/src/cairo-xlib-surface.c b/src/cairo-xlib-surface.c
index 3c6caf645..47ef825e1 100644
--- a/src/cairo-xlib-surface.c
+++ b/src/cairo-xlib-surface.c
@@ -1302,9 +1302,7 @@ _cairo_xlib_surface_composite (cairo_operator_t		operator,
 	ASSERT_NOT_REACHED;
     }
 
-    if (!_cairo_operator_bounded (operator) ||
-	operator == CAIRO_OPERATOR_SOURCE ||
-	operator == CAIRO_OPERATOR_CLEAR)
+    if (!_cairo_operator_bounded_by_source (operator))
       status = _cairo_surface_composite_fixup_unbounded (&dst->base,
 							 &src_attr, src->width, src->height,
 							 mask ? &mask_attr : NULL,
@@ -1511,7 +1509,7 @@ _cairo_xlib_surface_composite_trapezoids (cairo_operator_t	operator,
     if (status)
 	goto FAIL;
 
-    if (!_cairo_operator_bounded (operator)) {
+    if (!_cairo_operator_bounded_by_mask (operator)) {
 	/* XRenderCompositeTrapezoids() creates a mask only large enough for the
 	 * trapezoids themselves, but if the operator is unbounded, then we need
 	 * to actually composite all the way out to the bounds, so we create
@@ -2478,7 +2476,7 @@ _cairo_xlib_surface_show_glyphs (cairo_scaled_font_t    *scaled_font,
 						    source_y + attributes.y_offset - dest_y, 
 						    glyphs, num_glyphs);
 
-    if (status == CAIRO_STATUS_SUCCESS && !_cairo_operator_bounded (operator)) {
+    if (status == CAIRO_STATUS_SUCCESS && !_cairo_operator_bounded_by_mask (operator)) {
 	cairo_rectangle_t   extents;
 	status = _cairo_scaled_font_glyph_device_extents (scaled_font,
 							  glyphs,
diff --git a/src/cairoint.h b/src/cairoint.h
index a6b7f88b5..91e7ce661 100644
--- a/src/cairoint.h
+++ b/src/cairoint.h
@@ -1243,7 +1243,10 @@ _cairo_gstate_clip_and_composite (cairo_clip_t            *clip,
 				  const cairo_rectangle_t *extents);
 
 cairo_private cairo_bool_t
-_cairo_operator_bounded (cairo_operator_t operator);
+_cairo_operator_bounded_by_mask (cairo_operator_t operator);
+
+cairo_private cairo_bool_t
+_cairo_operator_bounded_by_source (cairo_operator_t operator);
 
 /* cairo_color.c */
 cairo_private const cairo_color_t *