зеркало из https://github.com/mozilla/gecko-dev.git
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
This commit is contained in:
Robert O'Callahan
Родитель
c0dc55c8da
Коммит
0fe322d9b1
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@ -715,72 +715,90 @@ CreateGradientFunction (const cairo_gradient_pattern_t *gpat)
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&gradient_callbacks);
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}
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static void
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UpdateLinearParametersToIncludePoint(double *min_t, double *max_t, CGPoint *start,
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double dx, double dy,
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double x, double y)
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{
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/* Compute a parameter t such that a line perpendicular to the (dx,dy)
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vector, passing through (start->x + dx*t, start->y + dy*t), also
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passes through (x,y).
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Let px = x - start->x, py = y - start->y.
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t is given by
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(px - dx*t)*dx + (py - dy*t)*dy = 0
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Solving for t we get
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numerator = dx*px + dy*py
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denominator = dx^2 + dy^2
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t = numerator/denominator
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In CreateRepeatingLinearGradientFunction we know the length of (dx,dy)
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is not zero. (This is checked in _cairo_quartz_setup_linear_source.)
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*/
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double px = x - start->x;
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double py = y - start->y;
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double numerator = dx*px + dy*py;
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double denominator = dx*dx + dy*dy;
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double t = numerator/denominator;
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if (*min_t > t) {
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*min_t = t;
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}
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if (*max_t < t) {
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*max_t = t;
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}
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}
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static CGFunctionRef
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CreateRepeatingLinearGradientFunction (cairo_quartz_surface_t *surface,
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const cairo_gradient_pattern_t *gpat,
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CGPoint *start, CGPoint *end,
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CGAffineTransform matrix)
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cairo_rectangle_int_t *extents)
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{
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cairo_pattern_t *pat;
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float input_value_range[2];
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double t_min = 0.;
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double t_max = 0.;
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double dx = end->x - start->x;
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double dy = end->y - start->y;
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double bounds_x1, bounds_x2, bounds_y1, bounds_y2;
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CGPoint mstart, mend;
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double dx, dy;
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int x_rep_start = 0, x_rep_end = 0;
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int y_rep_start = 0, y_rep_end = 0;
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int rep_start, rep_end;
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// figure out how many times we'd need to repeat the gradient pattern
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// to cover the whole (transformed) surface area
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mstart = CGPointApplyAffineTransform (*start, matrix);
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mend = CGPointApplyAffineTransform (*end, matrix);
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dx = fabs (mend.x - mstart.x);
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dy = fabs (mend.y - mstart.y);
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if (dx > 1e-6) {
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x_rep_start = (int) ceil(MIN(mstart.x, mend.x) / dx);
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x_rep_end = (int) ceil((surface->extents.width - MAX(mstart.x, mend.x)) / dx);
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if (mend.x < mstart.x) {
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int swap = x_rep_end;
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x_rep_end = x_rep_start;
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x_rep_start = swap;
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}
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if (!extents) {
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extents = &surface->extents;
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}
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bounds_x1 = extents->x;
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bounds_y1 = extents->y;
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bounds_x2 = extents->x + extents->width;
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bounds_y2 = extents->y + extents->height;
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_cairo_matrix_transform_bounding_box (&gpat->base.matrix,
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&bounds_x1, &bounds_y1,
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&bounds_x2, &bounds_y2,
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NULL);
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if (dy > 1e-6) {
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y_rep_start = (int) ceil(MIN(mstart.y, mend.y) / dy);
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y_rep_end = (int) ceil((surface->extents.width - MAX(mstart.y, mend.y)) / dy);
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UpdateLinearParametersToIncludePoint(&t_min, &t_max, start, dx, dy,
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bounds_x1, bounds_y1);
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UpdateLinearParametersToIncludePoint(&t_min, &t_max, start, dx, dy,
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bounds_x2, bounds_y1);
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UpdateLinearParametersToIncludePoint(&t_min, &t_max, start, dx, dy,
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bounds_x2, bounds_y2);
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UpdateLinearParametersToIncludePoint(&t_min, &t_max, start, dx, dy,
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bounds_x1, bounds_y2);
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if (mend.y < mstart.y) {
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int swap = y_rep_end;
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y_rep_end = y_rep_start;
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y_rep_start = swap;
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}
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}
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rep_start = MAX(x_rep_start, y_rep_start);
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rep_end = MAX(x_rep_end, y_rep_end);
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// extend the line between start and end by rep_start times from the start
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// and rep_end times from the end
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dx = end->x - start->x;
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dy = end->y - start->y;
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start->x = start->x - dx * rep_start;
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start->y = start->y - dy * rep_start;
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end->x = end->x + dx * rep_end;
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end->y = end->y + dy * rep_end;
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/* Move t_min and t_max to the nearest usable integer to try to avoid
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subtle variations due to numerical instability, especially accidentally
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cutting off a pixel. Extending the gradient repetitions is always safe. */
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t_min = floor (t_min);
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t_max = ceil (t_max);
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end->x = start->x + dx*t_max;
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end->y = start->y + dy*t_max;
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start->x = start->x + dx*t_min;
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start->y = start->y + dy*t_min;
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// set the input range for the function -- the function knows how to
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// map values outside of 0.0 .. 1.0 to that range for REPEAT/REFLECT.
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input_value_range[0] = 0.0 - 1.0 * rep_start;
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input_value_range[1] = 1.0 + 1.0 * rep_end;
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input_value_range[0] = t_min;
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input_value_range[1] = t_max;
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if (_cairo_pattern_create_copy (&pat, &gpat->base))
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/* quartz doesn't deal very well with malloc failing, so there's
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@ -845,10 +863,9 @@ static CGFunctionRef
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CreateRepeatingRadialGradientFunction (cairo_quartz_surface_t *surface,
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const cairo_gradient_pattern_t *gpat,
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CGPoint *start, double *start_radius,
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CGPoint *end, double *end_radius)
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CGPoint *end, double *end_radius,
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cairo_rectangle_int_t *extents)
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{
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CGRect clip = CGContextGetClipBoundingBox (surface->cgContext);
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CGAffineTransform transform;
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cairo_pattern_t *pat;
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float input_value_range[2];
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CGPoint *inner;
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@ -860,10 +877,19 @@ CreateRepeatingRadialGradientFunction (cairo_quartz_surface_t *surface,
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double t_min, t_max, t_temp;
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/* outer minus inner */
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double dr, dx, dy;
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double bounds_x1, bounds_x2, bounds_y1, bounds_y2;
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_cairo_quartz_cairo_matrix_to_quartz (&gpat->base.matrix, &transform);
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/* clip is in cairo device coordinates; get it into cairo user space */
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clip = CGRectApplyAffineTransform (clip, transform);
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if (!extents) {
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extents = &surface->extents;
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}
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bounds_x1 = extents->x;
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bounds_y1 = extents->y;
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bounds_x2 = extents->x + extents->width;
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bounds_y2 = extents->y + extents->height;
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_cairo_matrix_transform_bounding_box (&gpat->base.matrix,
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&bounds_x1, &bounds_y1,
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&bounds_x2, &bounds_y2,
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NULL);
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if (*start_radius < *end_radius) {
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/* end circle contains start circle */
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@ -883,6 +909,7 @@ CreateRepeatingRadialGradientFunction (cairo_quartz_surface_t *surface,
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dx = outer->x - inner->x;
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dy = outer->y - inner->y;
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/* We can't round or fudge t_min here, it has to be as accurate as possible. */
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t_min = -(*inner_radius/dr);
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inner->x += t_min*dx;
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inner->y += t_min*dy;
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@ -890,19 +917,19 @@ CreateRepeatingRadialGradientFunction (cairo_quartz_surface_t *surface,
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t_temp = 0.;
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UpdateRadialParameterToIncludePoint(&t_temp, inner, dr, dx, dy,
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clip.origin.x, clip.origin.y);
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bounds_x1, bounds_y1);
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UpdateRadialParameterToIncludePoint(&t_temp, inner, dr, dx, dy,
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clip.origin.x + clip.size.width, clip.origin.y);
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bounds_x2, bounds_y1);
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UpdateRadialParameterToIncludePoint(&t_temp, inner, dr, dx, dy,
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clip.origin.x + clip.size.width, clip.origin.y + clip.size.height);
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bounds_x2, bounds_y2);
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UpdateRadialParameterToIncludePoint(&t_temp, inner, dr, dx, dy,
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clip.origin.x, clip.origin.y + clip.size.height);
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bounds_x1, bounds_y2);
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/* UpdateRadialParameterToIncludePoint assumes t=0 means radius 0.
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But for the parameter values we use with Quartz, t_min means radius 0.
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Also, add a small fudge factor to avoid rounding issues. Since the
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circles are alway expanding and containing the earlier circles, this is
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OK. */
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t_temp += 1e-6;
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Since the circles are alway expanding and contain the earlier circles,
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it's safe to extend t_max/t_temp as much as we want, so round t_temp up
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to the nearest integer. This may help us give stable results. */
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t_temp = ceil (t_temp);
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t_max = t_min + t_temp;
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outer->x = inner->x + t_temp*dx;
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outer->y = inner->y + t_temp*dy;
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@ -1223,9 +1250,23 @@ _cairo_quartz_setup_fallback_source (cairo_quartz_surface_t *surface,
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return DO_IMAGE;
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}
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/*
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Quartz does not support repeating radients. We handle repeating gradients
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by manually extending the gradient and repeating color stops. We need to
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minimize the number of repetitions since Quartz seems to sample our color
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function across the entire range, even if part of that range is not needed
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for the visible area of the gradient, and it samples with some fixed resolution,
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so if the gradient range is too large it samples with very low resolution and
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the gradient is very coarse. CreateRepeatingLinearGradientFunction and
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CreateRepeatingRadialGradientFunction compute the number of repetitions needed
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based on the extents of the object (the clip region cannot be used here since
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we don't want the rasterization of the entire gradient to depend on the
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clip region).
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*/
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static cairo_quartz_action_t
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_cairo_quartz_setup_linear_source (cairo_quartz_surface_t *surface,
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const cairo_linear_pattern_t *lpat)
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const cairo_linear_pattern_t *lpat,
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cairo_rectangle_int_t *extents)
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{
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const cairo_pattern_t *abspat = &lpat->base.base;
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cairo_matrix_t mat;
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@ -1240,6 +1281,16 @@ _cairo_quartz_setup_linear_source (cairo_quartz_surface_t *surface,
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return DO_SOLID;
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}
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if (lpat->p1.x == lpat->p2.x &&
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lpat->p1.y == lpat->p2.y) {
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/* Quartz handles cases where the vector has no length very
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* differently from pixman.
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* Whatever the correct behaviour is, let's at least have only pixman's
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* implementation to worry about.
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*/
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return _cairo_quartz_setup_fallback_source (surface, abspat);
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}
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mat = abspat->matrix;
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cairo_matrix_invert (&mat);
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_cairo_quartz_cairo_matrix_to_quartz (&mat, &surface->sourceTransform);
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@ -1259,7 +1310,7 @@ _cairo_quartz_setup_linear_source (cairo_quartz_surface_t *surface,
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gradFunc = CreateRepeatingLinearGradientFunction (surface,
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&lpat->base,
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&start, &end,
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surface->sourceTransform);
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extents);
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}
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surface->sourceShading = CGShadingCreateAxial (rgb,
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@ -1275,7 +1326,8 @@ _cairo_quartz_setup_linear_source (cairo_quartz_surface_t *surface,
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static cairo_quartz_action_t
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_cairo_quartz_setup_radial_source (cairo_quartz_surface_t *surface,
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const cairo_radial_pattern_t *rpat)
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const cairo_radial_pattern_t *rpat,
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cairo_rectangle_int_t *extents)
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{
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const cairo_pattern_t *abspat = &rpat->base.base;
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cairo_matrix_t mat;
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@ -1327,7 +1379,8 @@ _cairo_quartz_setup_radial_source (cairo_quartz_surface_t *surface,
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gradFunc = CreateRepeatingRadialGradientFunction (surface,
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&rpat->base,
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&start, &r1,
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&end, &r2);
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&end, &r2,
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extents);
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}
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surface->sourceShading = CGShadingCreateRadial (rgb,
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@ -1346,7 +1399,8 @@ _cairo_quartz_setup_radial_source (cairo_quartz_surface_t *surface,
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static cairo_quartz_action_t
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_cairo_quartz_setup_source (cairo_quartz_surface_t *surface,
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const cairo_pattern_t *source)
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const cairo_pattern_t *source,
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cairo_rectangle_int_t *extents)
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{
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assert (!(surface->sourceImage || surface->sourceShading || surface->sourcePattern));
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@ -1372,14 +1426,12 @@ _cairo_quartz_setup_source (cairo_quartz_surface_t *surface,
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if (source->type == CAIRO_PATTERN_TYPE_LINEAR) {
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const cairo_linear_pattern_t *lpat = (const cairo_linear_pattern_t *)source;
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return _cairo_quartz_setup_linear_source (surface, lpat);
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return _cairo_quartz_setup_linear_source (surface, lpat, extents);
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}
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if (source->type == CAIRO_PATTERN_TYPE_RADIAL) {
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const cairo_radial_pattern_t *rpat = (const cairo_radial_pattern_t *)source;
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return _cairo_quartz_setup_radial_source (surface, rpat);
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return _cairo_quartz_setup_radial_source (surface, rpat, extents);
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}
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if (source->type == CAIRO_PATTERN_TYPE_SURFACE &&
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@ -1857,7 +1909,7 @@ _cairo_quartz_surface_paint (void *abstract_surface,
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CGContextSetCompositeOperation (surface->cgContext, _cairo_quartz_cairo_operator_to_quartz (op));
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action = _cairo_quartz_setup_source (surface, source);
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action = _cairo_quartz_setup_source (surface, source, NULL);
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if (action == DO_SOLID || action == DO_PATTERN) {
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CGContextFillRect (surface->cgContext, CGRectMake(surface->extents.x,
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@ -1891,6 +1943,25 @@ _cairo_quartz_surface_paint (void *abstract_surface,
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return rv;
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}
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static cairo_bool_t
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_cairo_quartz_source_needs_extents (const cairo_pattern_t *source)
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{
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/* For repeating gradients we need to manually extend the gradient and
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repeat stops, since Quartz doesn't support repeating gradients natively.
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We need to minimze the number of repeated stops, and since rasterization
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depends on the number of repetitions we use (even if some of the
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repetitions go beyond the extents of the object or outside the clip
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region), it's important to use the same number of repetitions when
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rendering an object no matter what the clip region is. So the
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computation of the repetition count cannot depended on the clip region,
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and should only depend on the object extents, so we need to compute
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the object extents for repeating gradients. */
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return (source->type == CAIRO_PATTERN_TYPE_LINEAR ||
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source->type == CAIRO_PATTERN_TYPE_RADIAL) &&
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(source->extend == CAIRO_EXTEND_REPEAT ||
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source->extend == CAIRO_EXTEND_REFLECT);
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}
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static cairo_int_status_t
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_cairo_quartz_surface_fill (void *abstract_surface,
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cairo_operator_t op,
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@ -1931,7 +2002,17 @@ _cairo_quartz_surface_fill (void *abstract_surface,
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CGContextSetShouldAntialias (surface->cgContext, (antialias != CAIRO_ANTIALIAS_NONE));
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CGContextSetCompositeOperation (surface->cgContext, _cairo_quartz_cairo_operator_to_quartz (op));
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action = _cairo_quartz_setup_source (surface, source);
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if (_cairo_quartz_source_needs_extents (source))
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{
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/* We don't need precise extents since these are only used to
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compute the number of gradient reptitions needed to cover the
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object. */
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cairo_rectangle_int_t path_extents;
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_cairo_path_fixed_approximate_fill_extents (path, &path_extents);
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action = _cairo_quartz_setup_source (surface, source, &path_extents);
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} else {
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action = _cairo_quartz_setup_source (surface, source, NULL);
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}
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CGContextBeginPath (surface->cgContext);
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@ -2064,7 +2145,14 @@ _cairo_quartz_surface_stroke (void *abstract_surface,
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CGContextSetCompositeOperation (surface->cgContext, _cairo_quartz_cairo_operator_to_quartz (op));
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action = _cairo_quartz_setup_source (surface, source);
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if (_cairo_quartz_source_needs_extents (source))
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{
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cairo_rectangle_int_t path_extents;
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_cairo_path_fixed_approximate_stroke_extents (path, style, ctm, &path_extents);
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action = _cairo_quartz_setup_source (surface, source, &path_extents);
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} else {
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action = _cairo_quartz_setup_source (surface, source, NULL);
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}
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CGContextBeginPath (surface->cgContext);
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@ -2185,7 +2273,16 @@ _cairo_quartz_surface_show_glyphs (void *abstract_surface,
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CGContextSaveGState (surface->cgContext);
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action = _cairo_quartz_setup_source (surface, source);
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if (_cairo_quartz_source_needs_extents (source))
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{
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cairo_rectangle_int_t glyph_extents;
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_cairo_scaled_font_glyph_device_extents (scaled_font, glyphs, num_glyphs,
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||||
&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) {
|
||||
|
|
|
|||
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Ссылка в новой задаче