static cairo_status_t
_cairo_default_context_paint_with_alpha (void *abstract_cr,
        double alpha)
{
    cairo_default_context_t *cr = abstract_cr;
    cairo_solid_pattern_t pattern;
    cairo_status_t status;
    cairo_color_t color;

    if (CAIRO_ALPHA_IS_OPAQUE (alpha))
        return _cairo_gstate_paint (cr->gstate);

    if (CAIRO_ALPHA_IS_ZERO (alpha) &&
            _cairo_operator_bounded_by_mask (cr->gstate->op)) {
        return CAIRO_STATUS_SUCCESS;
    }

    _cairo_color_init_rgba (&color, 0., 0., 0., alpha);
    _cairo_pattern_init_solid (&pattern, &color);

    status = _cairo_gstate_mask (cr->gstate, &pattern.base);
    _cairo_pattern_fini (&pattern.base);

    return status;
}
static cairo_status_t
_cairo_skia_context_paint_with_alpha (void *abstract_cr,
				      double alpha)
{
    cairo_skia_context_t *cr = (cairo_skia_context_t *) abstract_cr;
    cairo_status_t status;

    if (CAIRO_ALPHA_IS_OPAQUE (alpha))
	return _cairo_skia_context_paint (cr);

    cr->paint->setAlpha(SkScalarRound(255*alpha));
    status = _cairo_skia_context_paint (cr);
    cr->paint->setAlpha(255);

    return status;
}
static cairo_int_status_t
composite_aligned_boxes (const cairo_spans_compositor_t		*compositor,
			 const cairo_composite_rectangles_t	*extents,
			 cairo_boxes_t				*boxes)
{
    cairo_surface_t *dst = extents->surface;
    cairo_operator_t op = extents->op;
    const cairo_pattern_t *source = &extents->source_pattern.base;
    cairo_int_status_t status;
    cairo_bool_t need_clip_mask = extents->clip->path != NULL;
    cairo_bool_t op_is_source;
    cairo_bool_t no_mask;
    cairo_bool_t inplace;

    if (need_clip_mask && ! extents->is_bounded)
	return CAIRO_INT_STATUS_UNSUPPORTED;

    op_is_source = op_reduces_to_source (extents);
    no_mask = extents->mask_pattern.base.type == CAIRO_PATTERN_TYPE_SOLID &&
	CAIRO_ALPHA_IS_OPAQUE (extents->mask_pattern.solid.color.alpha);
    inplace = ! need_clip_mask && op_is_source && no_mask;

    if (op == CAIRO_OPERATOR_SOURCE && (need_clip_mask || ! no_mask)) {
	/* SOURCE with a mask is actually a LERP in cairo semantics */
	if ((compositor->flags & CAIRO_SPANS_COMPOSITOR_HAS_LERP) == 0)
	    return CAIRO_INT_STATUS_UNSUPPORTED;
    }

    /* Are we just copying a recording surface? */
    if (inplace &&
	recording_pattern_contains_sample (&extents->source_pattern.base,
					   &extents->source_sample_area))
    {
	cairo_clip_t *recording_clip;
	const cairo_pattern_t *source = &extents->source_pattern.base;

	/* XXX could also do tiling repeat modes... */

	/* first clear the area about to be overwritten */
	if (! dst->is_clear)
	    status = compositor->fill_boxes (dst,
					     CAIRO_OPERATOR_CLEAR,
					     CAIRO_COLOR_TRANSPARENT,
					     boxes);

	recording_clip = _cairo_clip_from_boxes (boxes);
	status = _cairo_recording_surface_replay_with_clip (unwrap_surface (source),
							    &source->matrix,
							    dst, recording_clip);
	_cairo_clip_destroy (recording_clip);

	return status;
    }

    if (! need_clip_mask && no_mask && source->type == CAIRO_PATTERN_TYPE_SOLID) {
	const cairo_color_t *color;

	color = &((cairo_solid_pattern_t *) source)->color;
	if (op_is_source)
	    op = CAIRO_OPERATOR_SOURCE;
	status = compositor->fill_boxes (dst, op, color, boxes);
#if 0
    } else if (inplace && source->type == CAIRO_PATTERN_TYPE_SURFACE) {
	status = upload_inplace (compositor, extents, boxes);
#endif
    } else {
	cairo_surface_t *src;
	cairo_surface_t *mask = NULL;
	int src_x, src_y;
	int mask_x = 0, mask_y = 0;

	/* All typical cases will have been resolved before now... */
	if (need_clip_mask) {
	    mask = get_clip_surface (compositor, dst, extents->clip,
				     &extents->bounded);
	    if (unlikely (mask->status))
		return mask->status;

	    mask_x = -extents->bounded.x;
	    mask_y = -extents->bounded.y;
	}

	/* XXX but this is still ugly */
	if (! no_mask) {
	    src = compositor->pattern_to_surface (dst,
						  &extents->mask_pattern.base,
						  TRUE,
						  &extents->bounded,
						  &extents->mask_sample_area,
						  &src_x, &src_y);
	    if (unlikely (src->status)) {
		cairo_surface_destroy (mask);
		return src->status;
	    }

	    if (mask != NULL) {
		status = compositor->composite_boxes (mask, CAIRO_OPERATOR_IN,
						      src, NULL,
						      src_x, src_y,
						      0, 0,
						      mask_x, mask_y,
						      boxes, &extents->bounded);

		cairo_surface_destroy (src);
	    } else {
		mask = src;
		mask_x = src_x;
		mask_y = src_y;
	    }
	}

	src = compositor->pattern_to_surface (dst, source, FALSE,
					      &extents->bounded,
					      &extents->source_sample_area,
					      &src_x, &src_y);
	if (likely (src->status == CAIRO_STATUS_SUCCESS)) {
	    status = compositor->composite_boxes (dst, op, src, mask,
						  src_x, src_y,
						  mask_x, mask_y,
						  0, 0,
						  boxes, &extents->bounded);
	    cairo_surface_destroy (src);
	} else
	    status = src->status;

	cairo_surface_destroy (mask);
    }

    if (status == CAIRO_INT_STATUS_SUCCESS && ! extents->is_bounded)
	status = fixup_unbounded_boxes (compositor, extents, boxes);

    return status;
}