/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */ /* * Copyright (C) 2015-2020 Red Hat * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA * 02111-1307, USA. * * Written by: * Jonas Ådahl */ #include "config.h" #include #include #include "core/meta-border.h" #include "meta-pointer-constraint-native.h" struct _MetaPointerConstraintImplNative { MetaPointerConstraintImpl parent; MetaPointerConstraint *constraint; cairo_region_t *region; }; G_DEFINE_TYPE (MetaPointerConstraintImplNative, meta_pointer_constraint_impl_native, META_TYPE_POINTER_CONSTRAINT_IMPL); typedef struct _MetaBox { int x1; int y1; int x2; int y2; } MetaBox; static MetaBorder * add_border (GArray *borders, float x1, float y1, float x2, float y2, MetaBorderMotionDirection blocking_directions) { MetaBorder border; border = (MetaBorder) { .line = (MetaLine2) { .a = (MetaVector2) { .x = x1, .y = y1, }, .b = (MetaVector2) { .x = x2, .y = y2, }, }, .blocking_directions = blocking_directions, }; g_array_append_val (borders, border); return &g_array_index (borders, MetaBorder, borders->len - 1); } static gint compare_lines_x (gconstpointer a, gconstpointer b) { const MetaBorder *border_a = a; const MetaBorder *border_b = b; if (border_a->line.a.x == border_b->line.a.x) return border_a->line.b.x < border_b->line.b.x; else return border_a->line.a.x > border_b->line.a.x; } static void add_non_overlapping_edges (MetaBox *boxes, unsigned int band_above_start, unsigned int band_below_start, unsigned int band_below_end, GArray *borders) { unsigned int i; GArray *band_merge; MetaBorder *border; MetaBorder *prev_border; MetaBorder *new_border; band_merge = g_array_new (FALSE, FALSE, sizeof *border); /* Add bottom band of previous row, and top band of current row, and * sort them so lower left x coordinate comes first. If there are two * borders with the same left x coordinate, the wider one comes first. */ for (i = band_above_start; i < band_below_start; i++) { MetaBox *box = &boxes[i]; add_border (band_merge, box->x1, box->y2, box->x2, box->y2, META_BORDER_MOTION_DIRECTION_POSITIVE_Y); } for (i = band_below_start; i < band_below_end; i++) { MetaBox *box= &boxes[i]; add_border (band_merge, box->x1, box->y1, box->x2, box->y1, META_BORDER_MOTION_DIRECTION_NEGATIVE_Y); } g_array_sort (band_merge, compare_lines_x); /* Combine the two combined bands so that any overlapping border is * eliminated. */ prev_border = NULL; for (i = 0; i < band_merge->len; i++) { border = &g_array_index (band_merge, MetaBorder, i); g_assert (border->line.a.y == border->line.b.y); g_assert (!prev_border || prev_border->line.a.y == border->line.a.y); g_assert (!prev_border || (prev_border->line.a.x != border->line.a.x || prev_border->line.b.x != border->line.b.x)); g_assert (!prev_border || prev_border->line.a.x <= border->line.a.x); if (prev_border && prev_border->line.a.x == border->line.a.x) { /* * ------------ + * ------- = * [ ]----- */ prev_border->line.a.x = border->line.b.x; } else if (prev_border && prev_border->line.b.x == border->line.b.x) { /* * ------------ + * ------ = * ------[ ] */ prev_border->line.b.x = border->line.a.x; } else if (prev_border && prev_border->line.b.x == border->line.a.x) { /* * -------- + * ------ = * -------------- */ prev_border->line.b.x = border->line.b.x; } else if (prev_border && prev_border->line.b.x >= border->line.a.x) { /* * --------------- + * ------ = * -----[ ]---- */ new_border = add_border (borders, border->line.b.x, border->line.b.y, prev_border->line.b.x, prev_border->line.b.y, prev_border->blocking_directions); prev_border->line.b.x = border->line.a.x; prev_border = new_border; } else { g_assert (!prev_border || prev_border->line.b.x < border->line.a.x); /* * First border or non-overlapping. * * ----- + * ----- = * ----- ----- */ g_array_append_val (borders, *border); prev_border = &g_array_index (borders, MetaBorder, borders->len - 1); } } g_array_free (band_merge, FALSE); } static void add_band_bottom_edges (MetaBox *boxes, int band_start, int band_end, GArray *borders) { int i; for (i = band_start; i < band_end; i++) { add_border (borders, boxes[i].x1, boxes[i].y2, boxes[i].x2, boxes[i].y2, META_BORDER_MOTION_DIRECTION_POSITIVE_Y); } } static void region_to_outline (cairo_region_t *region, GArray *borders) { MetaBox *boxes; int num_boxes; int i; int top_most, bottom_most; int current_roof; int prev_top; int band_start, prev_band_start; /* * Remove any overlapping lines from the set of rectangles. Note that * pixman regions are grouped as rows of rectangles, where rectangles * in one row never touch or overlap and are all of the same height. * * -------- --- -------- --- * | | | | | | | | * ----------====---- --- ----------- ----- --- * | | => | | * ----==========--------- ----- ---------- * | | | | * ------------------- ------------------- * */ num_boxes = cairo_region_num_rectangles (region); boxes = g_new (MetaBox, num_boxes); for (i = 0; i < num_boxes; i++) { cairo_rectangle_int_t rect; cairo_region_get_rectangle (region, i, &rect); boxes[i] = (MetaBox) { .x1 = rect.x, .y1 = rect.y, .x2 = rect.x + rect.width, .y2 = rect.y + rect.height, }; } prev_top = 0; top_most = boxes[0].y1; current_roof = top_most; bottom_most = boxes[num_boxes - 1].y2; band_start = 0; prev_band_start = 0; for (i = 0; i < num_boxes; i++) { /* Detect if there is a vertical empty space, and add the lower * level of the previous band if so was the case. */ if (i > 0 && boxes[i].y1 != prev_top && boxes[i].y1 != boxes[i - 1].y2) { current_roof = boxes[i].y1; add_band_bottom_edges (boxes, band_start, i, borders); } /* Special case adding the last band, since it won't be handled * by the band change detection below. */ if (boxes[i].y1 != current_roof && i == num_boxes - 1) { if (boxes[i].y1 != prev_top) { /* The last band is a single box, so we don't * have a prev_band_start to tell us when the * previous band started. */ add_non_overlapping_edges (boxes, band_start, i, i + 1, borders); } else { add_non_overlapping_edges (boxes, prev_band_start, band_start, i + 1, borders); } } /* Detect when passing a band and combine the top border of the * just passed band with the bottom band of the previous band. */ if (boxes[i].y1 != top_most && boxes[i].y1 != prev_top) { /* Combine the two passed bands. */ if (prev_top != current_roof) { add_non_overlapping_edges (boxes, prev_band_start, band_start, i, borders); } prev_band_start = band_start; band_start = i; } /* Add the top border if the box is part of the current roof. */ if (boxes[i].y1 == current_roof) { add_border (borders, boxes[i].x1, boxes[i].y1, boxes[i].x2, boxes[i].y1, META_BORDER_MOTION_DIRECTION_NEGATIVE_Y); } /* Add the bottom border of the last band. */ if (boxes[i].y2 == bottom_most) { add_border (borders, boxes[i].x1, boxes[i].y2, boxes[i].x2, boxes[i].y2, META_BORDER_MOTION_DIRECTION_POSITIVE_Y); } /* Always add the left border. */ add_border (borders, boxes[i].x1, boxes[i].y1, boxes[i].x1, boxes[i].y2, META_BORDER_MOTION_DIRECTION_NEGATIVE_X); /* Always add the right border. */ add_border (borders, boxes[i].x2, boxes[i].y1, boxes[i].x2, boxes[i].y2, META_BORDER_MOTION_DIRECTION_POSITIVE_X); prev_top = boxes[i].y1; } g_free (boxes); } static MetaBorder * get_closest_border (GArray *borders, MetaLine2 *motion, uint32_t directions) { MetaBorder *border; MetaVector2 intersection; MetaVector2 delta; float distance_2; MetaBorder *closest_border = NULL; float closest_distance_2 = DBL_MAX; unsigned int i; for (i = 0; i < borders->len; i++) { border = &g_array_index (borders, MetaBorder, i); if (!meta_border_is_blocking_directions (border, directions)) continue; if (!meta_line2_intersects_with (&border->line, motion, &intersection)) continue; delta = meta_vector2_subtract (intersection, motion->a); distance_2 = delta.x*delta.x + delta.y*delta.y; if (distance_2 < closest_distance_2) { closest_border = border; closest_distance_2 = distance_2; } } return closest_border; } static void clamp_to_border (MetaBorder *border, MetaLine2 *motion, uint32_t *motion_dir) { /* * When clamping either rightward or downward motions, the motion needs to be * clamped so that the destination coordinate does not end up on the border * (see weston_pointer_clamp_event_to_region). Do this by clamping such * motions to the border minus the smallest possible wl_fixed_t value. * * When clamping in either leftward or upward motion, the resulting coordinate * needs to be clamped so that it is enough on the inside to avoid the * inaccuracies of clutter's stage to actor transformation algorithm (the one * used in clutter_actor_transform_stage_point) to make it end up outside the * next motion. It also needs to be clamped so that to the wl_fixed_t * coordinate may still be right on the border (i.e. at .0). Testing shows * that the smallest wl_fixed_t value divided by 10 is small enough to make * the wl_fixed_t coordinate .0 and large enough to avoid the inaccuracies of * clutters transform algorithm. */ if (meta_border_is_horizontal (border)) { if (*motion_dir & META_BORDER_MOTION_DIRECTION_POSITIVE_Y) motion->b.y = border->line.a.y - wl_fixed_to_double (1); else motion->b.y = border->line.a.y + wl_fixed_to_double (1) / 10; *motion_dir &= ~(META_BORDER_MOTION_DIRECTION_POSITIVE_Y | META_BORDER_MOTION_DIRECTION_NEGATIVE_Y); } else { if (*motion_dir & META_BORDER_MOTION_DIRECTION_POSITIVE_X) motion->b.x = border->line.a.x - wl_fixed_to_double (1); else motion->b.x = border->line.a.x + wl_fixed_to_double (1) / 10; *motion_dir &= ~(META_BORDER_MOTION_DIRECTION_POSITIVE_X | META_BORDER_MOTION_DIRECTION_NEGATIVE_X); } } static uint32_t get_motion_directions (MetaLine2 *motion) { uint32_t directions = 0; if (motion->a.x < motion->b.x) directions |= META_BORDER_MOTION_DIRECTION_POSITIVE_X; else if (motion->a.x > motion->b.x) directions |= META_BORDER_MOTION_DIRECTION_NEGATIVE_X; if (motion->a.y < motion->b.y) directions |= META_BORDER_MOTION_DIRECTION_POSITIVE_Y; else if (motion->a.y > motion->b.y) directions |= META_BORDER_MOTION_DIRECTION_NEGATIVE_Y; return directions; } static void meta_pointer_constraint_impl_native_constraint (MetaPointerConstraintImpl *constraint_impl, ClutterInputDevice *device, uint32_t time, float prev_x, float prev_y, float *x_inout, float *y_inout) { MetaPointerConstraintImplNative *constraint_impl_native; cairo_region_t *region; float x, y; GArray *borders; MetaLine2 motion; MetaBorder *closest_border; uint32_t directions; constraint_impl_native = META_POINTER_CONSTRAINT_IMPL_NATIVE (constraint_impl); region = cairo_region_reference (constraint_impl_native->region); x = *x_inout; y = *y_inout; /* For motions in a positive direction on any axis, append the smallest * possible value representable in a Wayland absolute coordinate. This is * in order to avoid not clamping motion that as a floating point number * won't be clamped, but will be rounded up to be outside of the range * of wl_fixed_t. */ if (x > prev_x) x += (float) wl_fixed_to_double(1); if (y > prev_y) y += (float) wl_fixed_to_double(1); borders = g_array_new (FALSE, FALSE, sizeof (MetaBorder)); /* * Generate borders given the confine region we are to use. The borders * are defined to be the outer region of the allowed area. This means * top/left borders are "within" the allowed area, while bottom/right * borders are outside. This needs to be considered when clamping * confined motion vectors. */ region_to_outline (region, borders); cairo_region_destroy (region); motion = (MetaLine2) { .a = (MetaVector2) { .x = prev_x, .y = prev_y, }, .b = (MetaVector2) { .x = x, .y = y, }, }; directions = get_motion_directions (&motion); while (directions) { closest_border = get_closest_border (borders, &motion, directions); if (closest_border) clamp_to_border (closest_border, &motion, &directions); else break; } *x_inout = motion.b.x; *y_inout = motion.b.y; g_array_free (borders, FALSE); } static float point_to_border_distance_2 (MetaBorder *border, float x, float y) { float orig_x, orig_y; float dx, dy; if (meta_border_is_horizontal (border)) { if (x < border->line.a.x) orig_x = border->line.a.x; else if (x > border->line.b.x) orig_x = border->line.b.x; else orig_x = x; orig_y = border->line.a.y; } else { if (y < border->line.a.y) orig_y = border->line.a.y; else if (y > border->line.b.y) orig_y = border->line.b.y; else orig_y = y; orig_x = border->line.a.x; } dx = fabsf (orig_x - x); dy = fabsf (orig_y - y); return dx*dx + dy*dy; } static void closest_point_behind_border (MetaBorder *border, float *sx, float *sy) { switch (border->blocking_directions) { case META_BORDER_MOTION_DIRECTION_POSITIVE_X: case META_BORDER_MOTION_DIRECTION_NEGATIVE_X: if (border->blocking_directions == META_BORDER_MOTION_DIRECTION_POSITIVE_X) *sx = border->line.a.x - wl_fixed_to_double (1); else *sx = border->line.a.x + wl_fixed_to_double (1); if (*sy < border->line.a.y) *sy = border->line.a.y + wl_fixed_to_double (1); else if (*sy > border->line.b.y) *sy = border->line.b.y - wl_fixed_to_double (1); break; case META_BORDER_MOTION_DIRECTION_POSITIVE_Y: case META_BORDER_MOTION_DIRECTION_NEGATIVE_Y: if (border->blocking_directions == META_BORDER_MOTION_DIRECTION_POSITIVE_Y) *sy = border->line.a.y - wl_fixed_to_double (1); else *sy = border->line.a.y + wl_fixed_to_double (1); if (*sx < border->line.a.x) *sx = border->line.a.x + wl_fixed_to_double (1); else if (*sx > (border->line.b.x)) *sx = border->line.b.x - wl_fixed_to_double (1); break; } } static void meta_pointer_constraint_impl_native_ensure_constrained (MetaPointerConstraintImpl *constraint_impl, ClutterInputDevice *device) { MetaPointerConstraintImplNative *constraint_impl_native; graphene_point_t point; cairo_region_t *region; float x; float y; constraint_impl_native = META_POINTER_CONSTRAINT_IMPL_NATIVE (constraint_impl); region = cairo_region_reference (constraint_impl_native->region); clutter_seat_query_state (clutter_input_device_get_seat (device), device, NULL, &point, NULL); x = point.x; y = point.y; if (!cairo_region_contains_point (region, (int) x, (int) y)) { GArray *borders; float closest_distance_2 = FLT_MAX; MetaBorder *closest_border = NULL; ClutterSeat *seat; unsigned int i; borders = g_array_new (FALSE, FALSE, sizeof (MetaBorder)); region_to_outline (region, borders); for (i = 0; i < borders->len; i++) { MetaBorder *border = &g_array_index (borders, MetaBorder, i); float distance_2; distance_2 = point_to_border_distance_2 (border, x, y); if (distance_2 < closest_distance_2) { closest_border = border; closest_distance_2 = distance_2; } } closest_point_behind_border (closest_border, &x, &y); seat = clutter_backend_get_default_seat (clutter_get_default_backend ()); clutter_seat_warp_pointer (seat, x, y); } cairo_region_destroy (region); } static void meta_pointer_constraint_impl_native_finalize (GObject *object) { MetaPointerConstraintImplNative *constraint_impl_native; constraint_impl_native = META_POINTER_CONSTRAINT_IMPL_NATIVE (object); g_clear_pointer (&constraint_impl_native->region, cairo_region_destroy); G_OBJECT_CLASS (meta_pointer_constraint_impl_native_parent_class)->finalize (object); } static void meta_pointer_constraint_impl_native_init (MetaPointerConstraintImplNative *constraint_impl_native) { } static void meta_pointer_constraint_impl_native_class_init (MetaPointerConstraintImplNativeClass *klass) { MetaPointerConstraintImplClass *constraint_impl_class; GObjectClass *object_class = G_OBJECT_CLASS (klass); object_class->finalize = meta_pointer_constraint_impl_native_finalize; constraint_impl_class = META_POINTER_CONSTRAINT_IMPL_CLASS (klass); constraint_impl_class->constrain = meta_pointer_constraint_impl_native_constraint; constraint_impl_class->ensure_constrained = meta_pointer_constraint_impl_native_ensure_constrained; } MetaPointerConstraintImpl * meta_pointer_constraint_impl_native_new (MetaPointerConstraint *constraint, const cairo_region_t *region) { MetaPointerConstraintImplNative *constraint_impl; constraint_impl = g_object_new (META_TYPE_POINTER_CONSTRAINT_IMPL_NATIVE, NULL); constraint_impl->constraint = constraint; constraint_impl->region = cairo_region_copy (region); return META_POINTER_CONSTRAINT_IMPL (constraint_impl); }