The Tor Browser: gfx/cairo/quartz-minimize-gradient-repeat.patch@97036ab72558 (annotated)

gfx/cairo/quartz-minimize-gradient-repeat.patch@97036ab72558 (annotated)

gfx/cairo/quartz-minimize-gradient-repeat.patch

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 # HG changeset patch
 # User Robert O'Callahan <robert@ocallahan.org>
 # Date 1249558989 -43200
 # Node ID 0bac4c903d2bb1d5c0d5426209001fc2a77cc105
 # Parent  963b9451ad305924738d05d997a640698cd3af91
 Bug 508730. Don't repeat a Quartz gradient more times than necessary, to avoid Quartz quality problems when there are lots of repeated color stops. r=jmuizelaar
 diff --git a/gfx/cairo/cairo/src/cairo-quartz-surface.c b/gfx/cairo/cairo/src/cairo-quartz-surface.c
 --- a/gfx/cairo/cairo/src/cairo-quartz-surface.c
 +++ b/gfx/cairo/cairo/src/cairo-quartz-surface.c
@@ -710,82 +710,100 @@ CreateGradientFunction (const cairo_grad
      return CGFunctionCreate (pat,
 ,
  			     input_value_range,
 ,
  			     gradient_output_value_ranges,
  			     &gradient_callbacks);
  }
 +static void
 +UpdateLinearParametersToIncludePoint(double *min_t, double *max_t, CGPoint *start,
 +                                     double dx, double dy,
 +                                     double x, double y)
 +{
 +    /* Compute a parameter t such that a line perpendicular to the (dx,dy)
 +       vector, passing through (start->x + dx*t, start->y + dy*t), also
 +       passes through (x,y).
 +
 +       Let px = x - start->x, py = y - start->y.
 +       t is given by
 +         (px - dx*t)*dx + (py - dy*t)*dy = 0
 +
 +       Solving for t we get
 +         numerator = dx*px + dy*py
 +         denominator = dx^2 + dy^2
 +         t = numerator/denominator
 +
 +       In CreateRepeatingLinearGradientFunction we know the length of (dx,dy)
 +       is not zero. (This is checked in _cairo_quartz_setup_linear_source.)
 +    */
 +    double px = x - start->x;
 +    double py = y - start->y;
 +    double numerator = dx*px + dy*py;
 +    double denominator = dx*dx + dy*dy;
 +    double t = numerator/denominator;
 +
 +    if (*min_t > t) {
 +        *min_t = t;
 +    }
 +    if (*max_t < t) {
 +        *max_t = t;
 +    }
 +}
 +
  static CGFunctionRef
  CreateRepeatingLinearGradientFunction (cairo_quartz_surface_t *surface,
  				       const cairo_gradient_pattern_t *gpat,
  				       CGPoint *start, CGPoint *end,
 -				       CGAffineTransform matrix)
 +				       cairo_rectangle_int_t *extents)
  {
      cairo_pattern_t *pat;
      float input_value_range[2];
 +    double t_min = 0.;
 +    double t_max = 0.;
 +    double dx = end->x - start->x;
 +    double dy = end->y - start->y;
 +    double bounds_x1, bounds_x2, bounds_y1, bounds_y2;
 -    CGPoint mstart, mend;
 +    if (!extents) {
 +        extents = &surface->extents;
 +    }
 +    bounds_x1 = extents->x;
 +    bounds_y1 = extents->y;
 +    bounds_x2 = extents->x + extents->width;
 +    bounds_y2 = extents->y + extents->height;
 +    _cairo_matrix_transform_bounding_box (&gpat->base.matrix,
 +                                          &bounds_x1, &bounds_y1,
 +                                          &bounds_x2, &bounds_y2,
 +                                          NULL);
 -    double dx, dy;
 -    int x_rep_start = 0, x_rep_end = 0;
 -    int y_rep_start = 0, y_rep_end = 0;
 +    UpdateLinearParametersToIncludePoint(&t_min, &t_max, start, dx, dy,
 +                                         bounds_x1, bounds_y1);
 +    UpdateLinearParametersToIncludePoint(&t_min, &t_max, start, dx, dy,
 +                                         bounds_x2, bounds_y1);
 +    UpdateLinearParametersToIncludePoint(&t_min, &t_max, start, dx, dy,
 +                                         bounds_x2, bounds_y2);
 +    UpdateLinearParametersToIncludePoint(&t_min, &t_max, start, dx, dy,
 +                                         bounds_x1, bounds_y2);
 -    int rep_start, rep_end;
 -
 -    // figure out how many times we'd need to repeat the gradient pattern
 -    // to cover the whole (transformed) surface area
 -    mstart = CGPointApplyAffineTransform (*start, matrix);
 -    mend = CGPointApplyAffineTransform (*end, matrix);
 -
 -    dx = fabs (mend.x - mstart.x);
 -    dy = fabs (mend.y - mstart.y);
 -
 -    if (dx > 1e-6) {
 -	x_rep_start = (int) ceil(MIN(mstart.x, mend.x) / dx);
 -	x_rep_end = (int) ceil((surface->extents.width - MAX(mstart.x, mend.x)) / dx);
 -
 -	if (mend.x < mstart.x) {
 -	    int swap = x_rep_end;
 -	    x_rep_end = x_rep_start;
 -	    x_rep_start = swap;
 -	}
 -    }
 -
 -    if (dy > 1e-6) {
 -	y_rep_start = (int) ceil(MIN(mstart.y, mend.y) / dy);
 -	y_rep_end = (int) ceil((surface->extents.width - MAX(mstart.y, mend.y)) / dy);
 -
 -	if (mend.y < mstart.y) {
 -	    int swap = y_rep_end;
 -	    y_rep_end = y_rep_start;
 -	    y_rep_start = swap;
 -	}
 -    }
 -
 -    rep_start = MAX(x_rep_start, y_rep_start);
 -    rep_end = MAX(x_rep_end, y_rep_end);
 -
 -    // extend the line between start and end by rep_start times from the start
 -    // and rep_end times from the end
 -
 -    dx = end->x - start->x;
 -    dy = end->y - start->y;
 -
 -    start->x = start->x - dx * rep_start;
 -    start->y = start->y - dy * rep_start;
 -
 -    end->x = end->x + dx * rep_end;
 -    end->y = end->y + dy * rep_end;
 +    /* Move t_min and t_max to the nearest usable integer to try to avoid
 +       subtle variations due to numerical instability, especially accidentally
 +       cutting off a pixel. Extending the gradient repetitions is always safe. */
 +    t_min = floor (t_min);
 +    t_max = ceil (t_max);
 +    end->x = start->x + dx*t_max;
 +    end->y = start->y + dy*t_max;
 +    start->x = start->x + dx*t_min;
 +    start->y = start->y + dy*t_min;
      // set the input range for the function -- the function knows how to
      // map values outside of 0.0 .. 1.0 to that range for REPEAT/REFLECT.
 -    input_value_range[0] = 0.0 - 1.0 * rep_start;
 -    input_value_range[1] = 1.0 + 1.0 * rep_end;
 +    input_value_range[0] = t_min;
 +    input_value_range[1] = t_max;
      if (_cairo_pattern_create_copy (&pat, &gpat->base))
  	/* quartz doesn't deal very well with malloc failing, so there's
  	 * not much point in us trying either */
  	return NULL;
      return CGFunctionCreate (pat,
 ,
@@ -840,35 +858,43 @@ UpdateRadialParameterToIncludePoint(doub
      }
  }
  /* This must only be called when one of the circles properly contains the other */
  static CGFunctionRef
  CreateRepeatingRadialGradientFunction (cairo_quartz_surface_t *surface,
                                         const cairo_gradient_pattern_t *gpat,
                                         CGPoint *start, double *start_radius,
 -                                       CGPoint *end, double *end_radius)
 +                                       CGPoint *end, double *end_radius,
 +                                       cairo_rectangle_int_t *extents)
  {
 -    CGRect clip = CGContextGetClipBoundingBox (surface->cgContext);
 -    CGAffineTransform transform;
      cairo_pattern_t *pat;
      float input_value_range[2];
      CGPoint *inner;
      double *inner_radius;
      CGPoint *outer;
      double *outer_radius;
      /* minimum and maximum t-parameter values that will make our gradient
         cover the clipBox */
      double t_min, t_max, t_temp;
      /* outer minus inner */
      double dr, dx, dy;
 +    double bounds_x1, bounds_x2, bounds_y1, bounds_y2;
 -    _cairo_quartz_cairo_matrix_to_quartz (&gpat->base.matrix, &transform);
 -    /* clip is in cairo device coordinates; get it into cairo user space */
 -    clip = CGRectApplyAffineTransform (clip, transform);
 +    if (!extents) {
 +        extents = &surface->extents;
 +    }
 +    bounds_x1 = extents->x;
 +    bounds_y1 = extents->y;
 +    bounds_x2 = extents->x + extents->width;
 +    bounds_y2 = extents->y + extents->height;
 +    _cairo_matrix_transform_bounding_box (&gpat->base.matrix,
 +                                          &bounds_x1, &bounds_y1,
 +                                          &bounds_x2, &bounds_y2,
 +                                          NULL);
      if (*start_radius < *end_radius) {
          /* end circle contains start circle */
          inner = start;
          outer = end;
          inner_radius = start_radius;
          outer_radius = end_radius;
      } else {
@@ -878,36 +904,37 @@ CreateRepeatingRadialGradientFunction (c
          inner_radius = end_radius;
          outer_radius = start_radius;
      }
      dr = *outer_radius - *inner_radius;
      dx = outer->x - inner->x;
      dy = outer->y - inner->y;
 +    /* We can't round or fudge t_min here, it has to be as accurate as possible. */
      t_min = -(*inner_radius/dr);
      inner->x += t_min*dx;
      inner->y += t_min*dy;
      *inner_radius = 0.;
      t_temp = 0.;
      UpdateRadialParameterToIncludePoint(&t_temp, inner, dr, dx, dy,
 -                                        clip.origin.x, clip.origin.y);
 +                                        bounds_x1, bounds_y1);
      UpdateRadialParameterToIncludePoint(&t_temp, inner, dr, dx, dy,
 -                                        clip.origin.x + clip.size.width, clip.origin.y);
 +                                        bounds_x2, bounds_y1);
      UpdateRadialParameterToIncludePoint(&t_temp, inner, dr, dx, dy,
 -                                        clip.origin.x + clip.size.width, clip.origin.y + clip.size.height);
 +                                        bounds_x2, bounds_y2);
      UpdateRadialParameterToIncludePoint(&t_temp, inner, dr, dx, dy,
 -                                        clip.origin.x, clip.origin.y + clip.size.height);
 +                                        bounds_x1, bounds_y2);
      /* UpdateRadialParameterToIncludePoint assumes t=0 means radius 0.
         But for the parameter values we use with Quartz, t_min means radius 0.
 -       Also, add a small fudge factor to avoid rounding issues. Since the
 -       circles are alway expanding and containing the earlier circles, this is
 -       OK. */
 -    t_temp += 1e-6;
 +       Since the circles are alway expanding and contain the earlier circles,
 +       it's safe to extend t_max/t_temp as much as we want, so round t_temp up
 +       to the nearest integer. This may help us give stable results. */
 +    t_temp = ceil (t_temp);
      t_max = t_min + t_temp;
      outer->x = inner->x + t_temp*dx;
      outer->y = inner->y + t_temp*dy;
      *outer_radius = t_temp*dr;
      /* set the input range for the function -- the function knows how to
         map values outside of 0.0 .. 1.0 to that range for REPEAT/REFLECT. */
      if (*start_radius < *end_radius) {
@@ -1218,33 +1245,57 @@ _cairo_quartz_setup_fallback_source (cai
      surface->sourceImageRect = CGRectMake (0.0, 0.0, w, h);
      surface->sourceImage = img;
      surface->sourceImageSurface = fallback;
      surface->sourceTransform = CGAffineTransformMakeTranslation (x0, y0);
      return DO_IMAGE;
  }
 +/*
 +Quartz does not support repeating radients. We handle repeating gradients
 +by manually extending the gradient and repeating color stops. We need to
 +minimize the number of repetitions since Quartz seems to sample our color
 +function across the entire range, even if part of that range is not needed
 +for the visible area of the gradient, and it samples with some fixed resolution,
 +so if the gradient range is too large it samples with very low resolution and
 +the gradient is very coarse. CreateRepeatingLinearGradientFunction and
 +CreateRepeatingRadialGradientFunction compute the number of repetitions needed
 +based on the extents of the object (the clip region cannot be used here since
 +we don't want the rasterization of the entire gradient to depend on the
 +clip region).
 +*/
  static cairo_quartz_action_t
  _cairo_quartz_setup_linear_source (cairo_quartz_surface_t *surface,
 -				   const cairo_linear_pattern_t *lpat)
 +				   const cairo_linear_pattern_t *lpat,
 +				   cairo_rectangle_int_t *extents)
  {
      const cairo_pattern_t *abspat = &lpat->base.base;
      cairo_matrix_t mat;
      CGPoint start, end;
      CGFunctionRef gradFunc;
      CGColorSpaceRef rgb;
      bool extend = abspat->extend == CAIRO_EXTEND_PAD;
      if (lpat->base.n_stops == 0) {
  	CGContextSetRGBStrokeColor (surface->cgContext, 0., 0., 0., 0.);
  	CGContextSetRGBFillColor (surface->cgContext, 0., 0., 0., 0.);
  	return DO_SOLID;
      }
 +    if (lpat->p1.x == lpat->p2.x &&
 +        lpat->p1.y == lpat->p2.y) {
 +	/* Quartz handles cases where the vector has no length very
 +	 * differently from pixman.
 +	 * Whatever the correct behaviour is, let's at least have only pixman's
 +	 * implementation to worry about.
 +	 */
 +	return _cairo_quartz_setup_fallback_source (surface, abspat);
 +    }
 +
      mat = abspat->matrix;
      cairo_matrix_invert (&mat);
      _cairo_quartz_cairo_matrix_to_quartz (&mat, &surface->sourceTransform);
      rgb = CGColorSpaceCreateDeviceRGB();
      start = CGPointMake (_cairo_fixed_to_double (lpat->p1.x),
  			 _cairo_fixed_to_double (lpat->p1.y));
@@ -1254,33 +1305,34 @@ _cairo_quartz_setup_linear_source (cairo
      if (abspat->extend == CAIRO_EXTEND_NONE ||
          abspat->extend == CAIRO_EXTEND_PAD)
      {
  	gradFunc = CreateGradientFunction (&lpat->base);
      } else {
  	gradFunc = CreateRepeatingLinearGradientFunction (surface,
  						          &lpat->base,
  						          &start, &end,
 -						          surface->sourceTransform);
 +						          extents);
      }
      surface->sourceShading = CGShadingCreateAxial (rgb,
  						   start, end,
  						   gradFunc,
  						   extend, extend);
      CGColorSpaceRelease(rgb);
      CGFunctionRelease(gradFunc);
      return DO_SHADING;
  }
  static cairo_quartz_action_t
  _cairo_quartz_setup_radial_source (cairo_quartz_surface_t *surface,
 -				   const cairo_radial_pattern_t *rpat)
 +				   const cairo_radial_pattern_t *rpat,
 +				   cairo_rectangle_int_t *extents)
  {
      const cairo_pattern_t *abspat = &rpat->base.base;
      cairo_matrix_t mat;
      CGPoint start, end;
      CGFunctionRef gradFunc;
      CGColorSpaceRef rgb;
      bool extend = abspat->extend == CAIRO_EXTEND_PAD;
      double c1x = _cairo_fixed_to_double (rpat->c1.x);
@@ -1322,17 +1374,18 @@ _cairo_quartz_setup_radial_source (cairo
      if (abspat->extend == CAIRO_EXTEND_NONE ||
          abspat->extend == CAIRO_EXTEND_PAD)
      {
  	gradFunc = CreateGradientFunction (&rpat->base);
      } else {
  	gradFunc = CreateRepeatingRadialGradientFunction (surface,
  						          &rpat->base,
  						          &start, &r1,
 -						          &end, &r2);
 +						          &end, &r2,
 +						          extents);
      }
      surface->sourceShading = CGShadingCreateRadial (rgb,
  						    start,
  						    r1,
  						    end,
  						    r2,
  						    gradFunc,
@@ -1341,17 +1394,18 @@ _cairo_quartz_setup_radial_source (cairo
      CGColorSpaceRelease(rgb);
      CGFunctionRelease(gradFunc);
      return DO_SHADING;
  }
  static cairo_quartz_action_t
  _cairo_quartz_setup_source (cairo_quartz_surface_t *surface,
 -			    const cairo_pattern_t *source)
 +			    const cairo_pattern_t *source,
 +			    cairo_rectangle_int_t *extents)
  {
      assert (!(surface->sourceImage || surface->sourceShading || surface->sourcePattern));
      surface->oldInterpolationQuality = CGContextGetInterpolationQuality (surface->cgContext);
      CGContextSetInterpolationQuality (surface->cgContext, _cairo_quartz_filter_to_quartz (source->filter));
      if (source->type == CAIRO_PATTERN_TYPE_SOLID) {
  	cairo_solid_pattern_t *solid = (cairo_solid_pattern_t *) source;
@@ -1367,24 +1421,22 @@ _cairo_quartz_setup_source (cairo_quartz
  				  solid->color.blue,
  				  solid->color.alpha);
  	return DO_SOLID;
      }
      if (source->type == CAIRO_PATTERN_TYPE_LINEAR) {
  	const cairo_linear_pattern_t *lpat = (const cairo_linear_pattern_t *)source;
 -	return _cairo_quartz_setup_linear_source (surface, lpat);
 -
 +	return _cairo_quartz_setup_linear_source (surface, lpat, extents);
      }
      if (source->type == CAIRO_PATTERN_TYPE_RADIAL) {
  	const cairo_radial_pattern_t *rpat = (const cairo_radial_pattern_t *)source;
 -	return _cairo_quartz_setup_radial_source (surface, rpat);
 -
 +	return _cairo_quartz_setup_radial_source (surface, rpat, extents);
      }
      if (source->type == CAIRO_PATTERN_TYPE_SURFACE &&
  	(source->extend == CAIRO_EXTEND_NONE || (CGContextDrawTiledImagePtr && source->extend == CAIRO_EXTEND_REPEAT)))
      {
  	const cairo_surface_pattern_t *spat = (const cairo_surface_pattern_t *) source;
  	cairo_surface_t *pat_surf = spat->surface;
  	CGImageRef img;
@@ -1852,17 +1904,17 @@ _cairo_quartz_surface_paint (void *abstr
      if (IS_EMPTY(surface))
  	return CAIRO_STATUS_SUCCESS;
      if (op == CAIRO_OPERATOR_DEST)
  	return CAIRO_STATUS_SUCCESS;
      CGContextSetCompositeOperation (surface->cgContext, _cairo_quartz_cairo_operator_to_quartz (op));
 -    action = _cairo_quartz_setup_source (surface, source);
 +    action = _cairo_quartz_setup_source (surface, source, NULL);
      if (action == DO_SOLID || action == DO_PATTERN) {
  	CGContextFillRect (surface->cgContext, CGRectMake(surface->extents.x,
  							  surface->extents.y,
  							  surface->extents.width,
  							  surface->extents.height));
      } else if (action == DO_SHADING) {
  	CGContextSaveGState (surface->cgContext);
@@ -1886,16 +1938,35 @@ _cairo_quartz_surface_paint (void *abstr
      }
      _cairo_quartz_teardown_source (surface, source);
      ND((stderr, "-- paint\n"));
      return rv;
  }
 +static cairo_bool_t
 +_cairo_quartz_source_needs_extents (const cairo_pattern_t *source)
 +{
 +    /* For repeating gradients we need to manually extend the gradient and
 +       repeat stops, since Quartz doesn't support repeating gradients natively.
 +       We need to minimze the number of repeated stops, and since rasterization
 +       depends on the number of repetitions we use (even if some of the
 +       repetitions go beyond the extents of the object or outside the clip
 +       region), it's important to use the same number of repetitions when
 +       rendering an object no matter what the clip region is. So the
 +       computation of the repetition count cannot depended on the clip region,
 +       and should only depend on the object extents, so we need to compute
 +       the object extents for repeating gradients. */
 +    return (source->type == CAIRO_PATTERN_TYPE_LINEAR ||
 +            source->type == CAIRO_PATTERN_TYPE_RADIAL) &&
 +           (source->extend == CAIRO_EXTEND_REPEAT ||
 +            source->extend == CAIRO_EXTEND_REFLECT);
 +}
 +
  static cairo_int_status_t
  _cairo_quartz_surface_fill (void *abstract_surface,
  			     cairo_operator_t op,
  			     const cairo_pattern_t *source,
  			     cairo_path_fixed_t *path,
  			     cairo_fill_rule_t fill_rule,
  			     double tolerance,
  			     cairo_antialias_t antialias,
@@ -1926,17 +1997,27 @@ _cairo_quartz_surface_fill (void *abstra
  	return CAIRO_STATUS_SUCCESS;
      }
      CGContextSaveGState (surface->cgContext);
      CGContextSetShouldAntialias (surface->cgContext, (antialias != CAIRO_ANTIALIAS_NONE));
      CGContextSetCompositeOperation (surface->cgContext, _cairo_quartz_cairo_operator_to_quartz (op));
 -    action = _cairo_quartz_setup_source (surface, source);
 +    if (_cairo_quartz_source_needs_extents (source))
 +    {
 +        /* We don't need precise extents since these are only used to
 +           compute the number of gradient reptitions needed to cover the
 +           object. */
 +        cairo_rectangle_int_t path_extents;
 +        _cairo_path_fixed_approximate_fill_extents (path, &path_extents);
 +        action = _cairo_quartz_setup_source (surface, source, &path_extents);
 +    } else {
 +        action = _cairo_quartz_setup_source (surface, source, NULL);
 +    }
      CGContextBeginPath (surface->cgContext);
      stroke.cgContext = surface->cgContext;
      stroke.ctm_inverse = NULL;
      rv = _cairo_quartz_cairo_path_to_quartz_context (path, &stroke);
      if (rv)
          goto BAIL;
@@ -2059,17 +2140,24 @@ _cairo_quartz_surface_stroke (void *abst
  	CGContextSetLineDash (surface->cgContext, style->dash_offset, fdash, max_dashes);
  	if (fdash != sdash)
  	    free (fdash);
      }
      CGContextSetCompositeOperation (surface->cgContext, _cairo_quartz_cairo_operator_to_quartz (op));
 -    action = _cairo_quartz_setup_source (surface, source);
 +    if (_cairo_quartz_source_needs_extents (source))
 +    {
 +        cairo_rectangle_int_t path_extents;
 +        _cairo_path_fixed_approximate_stroke_extents (path, style, ctm, &path_extents);
 +        action = _cairo_quartz_setup_source (surface, source, &path_extents);
 +    } else {
 +        action = _cairo_quartz_setup_source (surface, source, NULL);
 +    }
      CGContextBeginPath (surface->cgContext);
      stroke.cgContext = surface->cgContext;
      stroke.ctm_inverse = ctm_inverse;
      rv = _cairo_quartz_cairo_path_to_quartz_context (path, &stroke);
      if (rv)
  	goto BAIL;
@@ -2180,17 +2268,26 @@ _cairo_quartz_surface_show_glyphs (void
      if (op == CAIRO_OPERATOR_DEST)
  	return CAIRO_STATUS_SUCCESS;
      if (cairo_scaled_font_get_type (scaled_font) != CAIRO_FONT_TYPE_QUARTZ)
  	return CAIRO_INT_STATUS_UNSUPPORTED;
      CGContextSaveGState (surface->cgContext);
 -    action = _cairo_quartz_setup_source (surface, source);
 +    if (_cairo_quartz_source_needs_extents (source))
 +    {
 +        cairo_rectangle_int_t glyph_extents;
 +        _cairo_scaled_font_glyph_device_extents (scaled_font, glyphs, num_glyphs,
 +                                                 &glyph_extents);
 +        action = _cairo_quartz_setup_source (surface, source, &glyph_extents);
 +    } else {
 +        action = _cairo_quartz_setup_source (surface, source, NULL);
 +    }
 +
      if (action == DO_SOLID || action == DO_PATTERN) {
  	CGContextSetTextDrawingMode (surface->cgContext, kCGTextFill);
      } else if (action == DO_IMAGE || action == DO_TILED_IMAGE || action == DO_SHADING) {
  	CGContextSetTextDrawingMode (surface->cgContext, kCGTextClip);
  	isClipping = TRUE;
      } else {
  	if (action != DO_NOTHING)
  	    rv = CAIRO_INT_STATUS_UNSUPPORTED;

The Tor Browser / annotate

gfx/cairo/quartz-minimize-gradient-repeat.patch@97036ab72558 (annotated)

gfx/cairo/quartz-minimize-gradient-repeat.patch