Portability fixes, mostly from James for Palm purposes. Mostly
[sgt/puzzles] / loopy.c
diff --git a/loopy.c b/loopy.c
index 5b41d0a..e7fb6cb 100644 (file)
--- a/loopy.c
+++ b/loopy.c
@@ -107,7 +107,7 @@ enum {
 };
 
 struct game_state {
-    grid *game_grid;
+    grid *game_grid; /* ref-counted (internally) */
 
     /* Put -1 in a face that doesn't get a clue */
     signed char *clues;
@@ -201,16 +201,12 @@ static char const diffchars[] = DIFFLIST(ENCODE);
 SOLVERLIST(SOLVER_FN_DECL)
 static int (*(solver_fns[]))(solver_state *) = { SOLVERLIST(SOLVER_FN) };
 static int const solver_diffs[] = { SOLVERLIST(SOLVER_DIFF) };
-const int NUM_SOLVERS = sizeof(solver_diffs)/sizeof(*solver_diffs);
+static const int NUM_SOLVERS = sizeof(solver_diffs)/sizeof(*solver_diffs);
 
 struct game_params {
     int w, h;
     int diff;
     int type;
-
-    /* Grid generation is expensive, so keep a (ref-counted) reference to the
-     * grid for these parameters, and only generate when required. */
-    grid *game_grid;
 };
 
 /* line_drawstate is the same as line_state, but with the extra ERROR
@@ -247,29 +243,31 @@ static void check_caches(const solver_state* sstate);
 
 /* ------- List of grid generators ------- */
 #define GRIDLIST(A) \
-    A(Squares,grid_new_square,3,3) \
-    A(Triangular,grid_new_triangular,3,3) \
-    A(Honeycomb,grid_new_honeycomb,3,3) \
-    A(Snub-Square,grid_new_snubsquare,3,3) \
-    A(Cairo,grid_new_cairo,3,4) \
-    A(Great-Hexagonal,grid_new_greathexagonal,3,3) \
-    A(Octagonal,grid_new_octagonal,3,3) \
-    A(Kites,grid_new_kites,3,3) \
-    A(Floret,grid_new_floret,1,2) \
-    A(Dodecagonal,grid_new_dodecagonal,2,2) \
-    A(Great-Dodecagonal,grid_new_greatdodecagonal,2,2)
-
-#define GRID_NAME(title,fn,amin,omin) #title,
-#define GRID_CONFIG(title,fn,amin,omin) ":" #title
-#define GRID_FN(title,fn,amin,omin) &fn,
-#define GRID_SIZES(title,fn,amin,omin) \
+    A(Squares,GRID_SQUARE,3,3) \
+    A(Triangular,GRID_TRIANGULAR,3,3) \
+    A(Honeycomb,GRID_HONEYCOMB,3,3) \
+    A(Snub-Square,GRID_SNUBSQUARE,3,3) \
+    A(Cairo,GRID_CAIRO,3,4) \
+    A(Great-Hexagonal,GRID_GREATHEXAGONAL,3,3) \
+    A(Octagonal,GRID_OCTAGONAL,3,3) \
+    A(Kites,GRID_KITE,3,3) \
+    A(Floret,GRID_FLORET,1,2) \
+    A(Dodecagonal,GRID_DODECAGONAL,2,2) \
+    A(Great-Dodecagonal,GRID_GREATDODECAGONAL,2,2) \
+    A(Penrose (kite/dart),GRID_PENROSE_P2,3,3) \
+    A(Penrose (rhombs),GRID_PENROSE_P3,3,3)
+
+#define GRID_NAME(title,type,amin,omin) #title,
+#define GRID_CONFIG(title,type,amin,omin) ":" #title
+#define GRID_TYPE(title,type,amin,omin) type,
+#define GRID_SIZES(title,type,amin,omin) \
     {amin, omin, \
      "Width and height for this grid type must both be at least " #amin, \
      "At least one of width and height for this grid type must be at least " #omin,},
 static char const *const gridnames[] = { GRIDLIST(GRID_NAME) };
 #define GRID_CONFIGS GRIDLIST(GRID_CONFIG)
-static grid * (*(grid_fns[]))(int w, int h) = { GRIDLIST(GRID_FN) };
-#define NUM_GRID_TYPES (sizeof(grid_fns) / sizeof(grid_fns[0]))
+static grid_type grid_types[] = { GRIDLIST(GRID_TYPE) };
+#define NUM_GRID_TYPES (sizeof(grid_types) / sizeof(grid_types[0]))
 static const struct {
     int amin, omin;
     char *aerr, *oerr;
@@ -277,13 +275,10 @@ static const struct {
 
 /* Generates a (dynamically allocated) new grid, according to the
  * type and size requested in params.  Does nothing if the grid is already
- * generated.  The allocated grid is owned by the params object, and will be
- * freed in free_params(). */
-static void params_generate_grid(game_params *params)
+ * generated. */
+static grid *loopy_generate_grid(game_params *params, char *grid_desc)
 {
-    if (!params->game_grid) {
-        params->game_grid = grid_fns[params->type](params->w, params->h);
-    }
+    return grid_new(grid_types[params->type], params->w, params->h, grid_desc);
 }
 
 /* ----------------------------------------------------------------------
@@ -480,8 +475,6 @@ static game_params *default_params(void)
     ret->diff = DIFF_EASY;
     ret->type = 0;
 
-    ret->game_grid = NULL;
-
     return ret;
 }
 
@@ -490,44 +483,45 @@ static game_params *dup_params(game_params *params)
     game_params *ret = snew(game_params);
 
     *ret = *params;                       /* structure copy */
-    if (ret->game_grid) {
-        ret->game_grid->refcount++;
-    }
     return ret;
 }
 
 static const game_params presets[] = {
 #ifdef SMALL_SCREEN
-    {  7,  7, DIFF_EASY, 0, NULL },
-    {  7,  7, DIFF_NORMAL, 0, NULL },
-    {  7,  7, DIFF_HARD, 0, NULL },
-    {  7,  7, DIFF_HARD, 1, NULL },
-    {  7,  7, DIFF_HARD, 2, NULL },
-    {  5,  5, DIFF_HARD, 3, NULL },
-    {  7,  7, DIFF_HARD, 4, NULL },
-    {  5,  4, DIFF_HARD, 5, NULL },
-    {  5,  5, DIFF_HARD, 6, NULL },
-    {  5,  5, DIFF_HARD, 7, NULL },
-    {  3,  3, DIFF_HARD, 8, NULL },
-    {  3,  3, DIFF_HARD, 9, NULL },
-    {  3,  3, DIFF_HARD, 10, NULL },
+    {  7,  7, DIFF_EASY, 0 },
+    {  7,  7, DIFF_NORMAL, 0 },
+    {  7,  7, DIFF_HARD, 0 },
+    {  7,  7, DIFF_HARD, 1 },
+    {  7,  7, DIFF_HARD, 2 },
+    {  5,  5, DIFF_HARD, 3 },
+    {  7,  7, DIFF_HARD, 4 },
+    {  5,  4, DIFF_HARD, 5 },
+    {  5,  5, DIFF_HARD, 6 },
+    {  5,  5, DIFF_HARD, 7 },
+    {  3,  3, DIFF_HARD, 8 },
+    {  3,  3, DIFF_HARD, 9 },
+    {  3,  3, DIFF_HARD, 10 },
+    {  6,  6, DIFF_HARD, 11 },
+    {  6,  6, DIFF_HARD, 12 },
 #else
-    {  7,  7, DIFF_EASY, 0, NULL },
-    {  10,  10, DIFF_EASY, 0, NULL },
-    {  7,  7, DIFF_NORMAL, 0, NULL },
-    {  10,  10, DIFF_NORMAL, 0, NULL },
-    {  7,  7, DIFF_HARD, 0, NULL },
-    {  10,  10, DIFF_HARD, 0, NULL },
-    {  10,  10, DIFF_HARD, 1, NULL },
-    {  12,  10, DIFF_HARD, 2, NULL },
-    {  7,  7, DIFF_HARD, 3, NULL },
-    {  9,  9, DIFF_HARD, 4, NULL },
-    {  5,  4, DIFF_HARD, 5, NULL },
-    {  7,  7, DIFF_HARD, 6, NULL },
-    {  5,  5, DIFF_HARD, 7, NULL },
-    {  5,  5, DIFF_HARD, 8, NULL },
-    {  5,  4, DIFF_HARD, 9, NULL },
-    {  5,  4, DIFF_HARD, 10, NULL },
+    {  7,  7, DIFF_EASY, 0 },
+    {  10,  10, DIFF_EASY, 0 },
+    {  7,  7, DIFF_NORMAL, 0 },
+    {  10,  10, DIFF_NORMAL, 0 },
+    {  7,  7, DIFF_HARD, 0 },
+    {  10,  10, DIFF_HARD, 0 },
+    {  10,  10, DIFF_HARD, 1 },
+    {  12,  10, DIFF_HARD, 2 },
+    {  7,  7, DIFF_HARD, 3 },
+    {  9,  9, DIFF_HARD, 4 },
+    {  5,  4, DIFF_HARD, 5 },
+    {  7,  7, DIFF_HARD, 6 },
+    {  5,  5, DIFF_HARD, 7 },
+    {  5,  5, DIFF_HARD, 8 },
+    {  5,  4, DIFF_HARD, 9 },
+    {  5,  4, DIFF_HARD, 10 },
+    {  10, 10, DIFF_HARD, 11 },
+    {  10, 10, DIFF_HARD, 12 }
 #endif
 };
 
@@ -551,18 +545,11 @@ static int game_fetch_preset(int i, char **name, game_params **params)
 
 static void free_params(game_params *params)
 {
-    if (params->game_grid) {
-        grid_free(params->game_grid);
-    }
     sfree(params);
 }
 
 static void decode_params(game_params *params, char const *string)
 {
-    if (params->game_grid) {
-        grid_free(params->game_grid);
-        params->game_grid = NULL;
-    }
     params->h = params->w = atoi(string);
     params->diff = DIFF_EASY;
     while (*string && isdigit((unsigned char)*string)) string++;
@@ -641,7 +628,6 @@ static game_params *custom_params(config_item *cfg)
     ret->type = cfg[2].ival;
     ret->diff = cfg[3].ival;
 
-    ret->game_grid = NULL;
     return ret;
 }
 
@@ -702,14 +688,44 @@ static char *state_to_text(const game_state *state)
     return retval;
 }
 
+#define GRID_DESC_SEP '_'
+
+/* Splits up a (optional) grid_desc from the game desc. Returns the
+ * grid_desc (which needs freeing) and updates the desc pointer to
+ * start of real desc, or returns NULL if no desc. */
+static char *extract_grid_desc(char **desc)
+{
+    char *sep = strchr(*desc, GRID_DESC_SEP), *gd;
+    int gd_len;
+
+    if (!sep) return NULL;
+
+    gd_len = sep - (*desc);
+    gd = snewn(gd_len+1, char);
+    memcpy(gd, *desc, gd_len);
+    gd[gd_len] = '\0';
+
+    *desc = sep+1;
+
+    return gd;
+}
+
 /* We require that the params pass the test in validate_params and that the
  * description fills the entire game area */
 static char *validate_desc(game_params *params, char *desc)
 {
     int count = 0;
     grid *g;
-    params_generate_grid(params);
-    g = params->game_grid;
+    char *grid_desc, *ret;
+
+    /* It's pretty inefficient to do this just for validation. All we need to
+     * know is the precise number of faces. */
+    grid_desc = extract_grid_desc(&desc);
+    ret = grid_validate_desc(grid_types[params->type], params->w, params->h, grid_desc);
+    if (ret) return ret;
+
+    g = loopy_generate_grid(params, grid_desc);
+    if (grid_desc) sfree(grid_desc);
 
     for (; *desc; ++desc) {
         if ((*desc >= '0' && *desc <= '9') || (*desc >= 'A' && *desc <= 'Z')) {
@@ -728,6 +744,8 @@ static char *validate_desc(game_params *params, char *desc)
     if (count > g->num_faces)
         return "Description too long for board size";
 
+    grid_free(g);
+
     return NULL;
 }
 
@@ -809,16 +827,15 @@ static void game_changed_state(game_ui *ui, game_state *oldstate,
 static void game_compute_size(game_params *params, int tilesize,
                               int *x, int *y)
 {
-    grid *g;
     int grid_width, grid_height, rendered_width, rendered_height;
+    int g_tilesize;
+
+    grid_compute_size(grid_types[params->type], params->w, params->h,
+                      &g_tilesize, &grid_width, &grid_height);
 
-    params_generate_grid(params);
-    g = params->game_grid;
-    grid_width = g->highest_x - g->lowest_x;
-    grid_height = g->highest_y - g->lowest_y;
     /* multiply first to minimise rounding error on integer division */
-    rendered_width = grid_width * tilesize / g->tilesize;
-    rendered_height = grid_height * tilesize / g->tilesize;
+    rendered_width = grid_width * tilesize / g_tilesize;
+    rendered_height = grid_height * tilesize / g_tilesize;
     *x = rendered_width + 2 * BORDER(tilesize) + 1;
     *y = rendered_height + 2 * BORDER(tilesize) + 1;
 }
@@ -839,8 +856,14 @@ static float *game_colours(frontend *fe, int *ncolours)
     ret[COL_FOREGROUND * 3 + 1] = 0.0F;
     ret[COL_FOREGROUND * 3 + 2] = 0.0F;
 
-    ret[COL_LINEUNKNOWN * 3 + 0] = 0.8F;
-    ret[COL_LINEUNKNOWN * 3 + 1] = 0.8F;
+    /*
+     * We want COL_LINEUNKNOWN to be a yellow which is a bit darker
+     * than the background. (I previously set it to 0.8,0.8,0, but
+     * found that this went badly with the 0.8,0.8,0.8 favoured as a
+     * background by the Java frontend.)
+     */
+    ret[COL_LINEUNKNOWN * 3 + 0] = ret[COL_BACKGROUND * 3 + 0] * 0.9F;
+    ret[COL_LINEUNKNOWN * 3 + 1] = ret[COL_BACKGROUND * 3 + 1] * 0.9F;
     ret[COL_LINEUNKNOWN * 3 + 2] = 0.0F;
 
     ret[COL_HIGHLIGHT * 3 + 0] = 1.0F;
@@ -894,6 +917,8 @@ static game_drawstate *game_new_drawstate(drawing *dr, game_state *state)
 
 static void game_free_drawstate(drawing *dr, game_drawstate *ds)
 {
+    sfree(ds->textx);
+    sfree(ds->texty);
     sfree(ds->clue_error);
     sfree(ds->clue_satisfied);
     sfree(ds->lines);
@@ -1830,14 +1855,14 @@ static char *new_game_desc(game_params *params, random_state *rs,
                            char **aux, int interactive)
 {
     /* solution and description both use run-length encoding in obvious ways */
-    char *retval;
+    char *retval, *game_desc, *grid_desc;
     grid *g;
     game_state *state = snew(game_state);
     game_state *state_new;
-    int count = 0;
-    params_generate_grid(params);
-    state->game_grid = g = params->game_grid;
-    g->refcount++;
+
+    grid_desc = grid_new_desc(grid_types[params->type], params->w, params->h, rs);
+    state->game_grid = g = loopy_generate_grid(params, grid_desc);
+
     state->clues = snewn(g->num_faces, signed char);
     state->lines = snewn(g->num_edges, char);
     state->line_errors = snewn(g->num_edges, unsigned char);
@@ -1856,7 +1881,6 @@ static char *new_game_desc(game_params *params, random_state *rs,
      * preventing games smaller than 4x4 seems to stop this happening */
     do {
         add_full_clues(state, rs);
-        if (++count%100 == 0) printf("tried %d times to make a unique board\n", count);
     } while (!game_has_unique_soln(state, params->diff));
 
     state_new = remove_clues(state, rs, params->diff);
@@ -1871,10 +1895,19 @@ static char *new_game_desc(game_params *params, random_state *rs,
         goto newboard_please;
     }
 
-    retval = state_to_text(state);
+    game_desc = state_to_text(state);
 
     free_game(state);
 
+    if (grid_desc) {
+        retval = snewn(strlen(grid_desc) + 1 + strlen(game_desc) + 1, char);
+        sprintf(retval, "%s%c%s", grid_desc, (int)GRID_DESC_SEP, game_desc);
+        sfree(grid_desc);
+        sfree(game_desc);
+    } else {
+        retval = game_desc;
+    }
+
     assert(!validate_desc(params, retval));
 
     return retval;
@@ -1886,13 +1919,17 @@ static game_state *new_game(midend *me, game_params *params, char *desc)
     game_state *state = snew(game_state);
     int empties_to_make = 0;
     int n,n2;
-    const char *dp = desc;
+    const char *dp;
+    char *grid_desc;
     grid *g;
     int num_faces, num_edges;
 
-    params_generate_grid(params);
-    state->game_grid = g = params->game_grid;
-    g->refcount++;
+    grid_desc = extract_grid_desc(&desc);
+    state->game_grid = g = loopy_generate_grid(params, grid_desc);
+    if (grid_desc) sfree(grid_desc);
+
+    dp = desc;
+
     num_faces = g->num_faces;
     num_edges = g->num_edges;
 
@@ -2432,6 +2469,13 @@ static int trivial_deductions(solver_state *sstate)
         if (state->clues[i] < 0)
             continue;
 
+        /*
+         * This code checks whether the numeric clue on a face is so
+         * large as to permit all its remaining LINE_UNKNOWNs to be
+         * filled in as LINE_YES, or alternatively so small as to
+         * permit them all to be filled in as LINE_NO.
+         */
+
         if (state->clues[i] < current_yes) {
             sstate->solver_status = SOLVER_MISTAKE;
             return DIFF_EASY;
@@ -2453,6 +2497,57 @@ static int trivial_deductions(solver_state *sstate)
             sstate->face_solved[i] = TRUE;
             continue;
         }
+
+        if (f->order - state->clues[i] == current_no + 1 &&
+            f->order - current_yes - current_no > 2) {
+            /*
+             * One small refinement to the above: we also look for any
+             * adjacent pair of LINE_UNKNOWNs around the face with
+             * some LINE_YES incident on it from elsewhere. If we find
+             * one, then we know that pair of LINE_UNKNOWNs can't
+             * _both_ be LINE_YES, and hence that pushes us one line
+             * closer to being able to determine all the rest.
+             */
+            int j, k, e1, e2, e, d;
+
+            for (j = 0; j < f->order; j++) {
+                e1 = f->edges[j] - g->edges;
+                e2 = f->edges[j+1 < f->order ? j+1 : 0] - g->edges;
+
+                if (g->edges[e1].dot1 == g->edges[e2].dot1 ||
+                    g->edges[e1].dot1 == g->edges[e2].dot2) {
+                    d = g->edges[e1].dot1 - g->dots;
+                } else {
+                    assert(g->edges[e1].dot2 == g->edges[e2].dot1 ||
+                           g->edges[e1].dot2 == g->edges[e2].dot2);
+                    d = g->edges[e1].dot2 - g->dots;
+                }
+
+                if (state->lines[e1] == LINE_UNKNOWN &&
+                    state->lines[e2] == LINE_UNKNOWN) {
+                    for (k = 0; k < g->dots[d].order; k++) {
+                        int e = g->dots[d].edges[k] - g->edges;
+                        if (state->lines[e] == LINE_YES)
+                            goto found;    /* multi-level break */
+                    }
+                }
+            }
+            continue;
+
+          found:
+            /*
+             * If we get here, we've found such a pair of edges, and
+             * they're e1 and e2.
+             */
+            for (j = 0; j < f->order; j++) {
+                e = f->edges[j] - g->edges;
+                if (state->lines[e] == LINE_UNKNOWN && e != e1 && e != e2) {
+                    int r = solver_set_line(sstate, e, LINE_YES);
+                    assert(r);
+                    diff = min(diff, DIFF_EASY);
+                }
+            }
+        }
     }
 
     check_caches(sstate);
@@ -3342,10 +3437,8 @@ static void grid_to_screen(const game_drawstate *ds, const grid *g,
 /* Returns (into x,y) position of centre of face for rendering the text clue.
  */
 static void face_text_pos(const game_drawstate *ds, const grid *g,
-                          const grid_face *f, int *xret, int *yret)
+                          grid_face *f, int *xret, int *yret)
 {
-    int x, y, x0, y0, x1, y1, xbest, ybest, i, shift;
-    long bestdist;
     int faceindex = f - g->faces;
 
     /*
@@ -3359,154 +3452,11 @@ static void face_text_pos(const game_drawstate *ds, const grid *g,
     }
 
     /*
-     * Otherwise, try to find the point in the polygon with the
-     * maximum distance to any edge or corner.
-     *
-     * Start by working out the face's bounding box, in grid
-     * coordinates.
+     * Otherwise, use the incentre computed by grid.c and convert it
+     * to screen coordinates.
      */
-    x0 = x1 = f->dots[0]->x;
-    y0 = y1 = f->dots[0]->y;
-    for (i = 1; i < f->order; i++) {
-        if (x0 > f->dots[i]->x) x0 = f->dots[i]->x;
-        if (x1 < f->dots[i]->x) x1 = f->dots[i]->x;
-        if (y0 > f->dots[i]->y) y0 = f->dots[i]->y;
-        if (y1 < f->dots[i]->y) y1 = f->dots[i]->y;
-    }
-
-    /*
-     * If the grid is at excessive resolution, decide on a scaling
-     * factor to bring it within reasonable bounds so we don't have to
-     * think too hard or suffer integer overflow.
-     */
-    shift = 0;
-    while (x1 - x0 > 128 || y1 - y0 > 128) {
-        shift++;
-        x0 >>= 1;
-        x1 >>= 1;
-        y0 >>= 1;
-        y1 >>= 1;
-    }
-
-    /*
-     * Now iterate over every point in that bounding box.
-     */
-    xbest = ybest = -1;
-    bestdist = -1;
-    for (y = y0; y <= y1; y++) {
-        for (x = x0; x <= x1; x++) {
-            /*
-             * First, disqualify the point if it's not inside the
-             * polygon, which we work out by counting the edges to the
-             * right of the point. (For tiebreaking purposes when
-             * edges start or end on our y-coordinate or go right
-             * through it, we consider our point to be offset by a
-             * small _positive_ epsilon in both the x- and
-             * y-direction.)
-             */
-            int in = 0;
-            for (i = 0; i < f->order; i++) {
-                int xs = f->edges[i]->dot1->x >> shift;
-                int xe = f->edges[i]->dot2->x >> shift;
-                int ys = f->edges[i]->dot1->y >> shift;
-                int ye = f->edges[i]->dot2->y >> shift;
-                if ((y >= ys && y < ye) || (y >= ye && y < ys)) {
-                    /*
-                     * The line goes past our y-position. Now we need
-                     * to know if its x-coordinate when it does so is
-                     * to our right.
-                     *
-                     * The x-coordinate in question is mathematically
-                     * (y - ys) * (xe - xs) / (ye - ys), and we want
-                     * to know whether (x - xs) >= that. Of course we
-                     * avoid the division, so we can work in integers;
-                     * to do this we must multiply both sides of the
-                     * inequality by ye - ys, which means we must
-                     * first check that's not negative.
-                     */
-                    int num = xe - xs, denom = ye - ys;
-                    if (denom < 0) {
-                        num = -num;
-                        denom = -denom;
-                    }
-                    if ((x - xs) * denom >= (y - ys) * num)
-                        in ^= 1;
-                }
-            }
-
-            if (in) {
-                long mindist = LONG_MAX;
-
-                /*
-                 * This point is inside the polygon, so now we check
-                 * its minimum distance to every edge and corner.
-                 * First the corners ...
-                 */
-                for (i = 0; i < f->order; i++) {
-                    int xp = f->dots[i]->x >> shift;
-                    int yp = f->dots[i]->y >> shift;
-                    int dx = x - xp, dy = y - yp;
-                    long dist = (long)dx*dx + (long)dy*dy;
-                    if (mindist > dist)
-                        mindist = dist;
-                }
-
-                /*
-                 * ... and now also check the perpendicular distance
-                 * to every edge, if the perpendicular lies between
-                 * the edge's endpoints.
-                 */
-                for (i = 0; i < f->order; i++) {
-                    int xs = f->edges[i]->dot1->x >> shift;
-                    int xe = f->edges[i]->dot2->x >> shift;
-                    int ys = f->edges[i]->dot1->y >> shift;
-                    int ye = f->edges[i]->dot2->y >> shift;
-
-                    /*
-                     * If s and e are our endpoints, and p our
-                     * candidate circle centre, the foot of a
-                     * perpendicular from p to the line se lies
-                     * between s and e if and only if (p-s).(e-s) lies
-                     * strictly between 0 and (e-s).(e-s).
-                     */
-                    int edx = xe - xs, edy = ye - ys;
-                    int pdx = x - xs, pdy = y - ys;
-                    long pde = (long)pdx * edx + (long)pdy * edy;
-                    long ede = (long)edx * edx + (long)edy * edy;
-                    if (0 < pde && pde < ede) {
-                        /*
-                         * Yes, the nearest point on this edge is
-                         * closer than either endpoint, so we must
-                         * take it into account by measuring the
-                         * perpendicular distance to the edge and
-                         * checking its square against mindist.
-                         */
-
-                        long pdre = (long)pdx * edy - (long)pdy * edx;
-                        long sqlen = pdre * pdre / ede;
-
-                        if (mindist > sqlen)
-                            mindist = sqlen;
-                    }
-                }
-
-                /*
-                 * Right. Now we know the biggest circle around this
-                 * point, so we can check it against bestdist.
-                 */
-                if (bestdist < mindist) {
-                    bestdist = mindist;
-                    xbest = x;
-                    ybest = y;
-                }
-            }
-        }
-    }
-
-    assert(bestdist >= 0);
-
-    /* convert to screen coordinates */
-    grid_to_screen(ds, g, xbest << shift, ybest << shift,
+    grid_find_incentre(f);
+    grid_to_screen(ds, g, f->ix, f->iy,
                    &ds->textx[faceindex], &ds->texty[faceindex]);
 
     *xret = ds->textx[faceindex];
@@ -3598,7 +3548,6 @@ static void game_redraw_line(drawing *dr, game_drawstate *ds,
     grid *g = state->game_grid;
     grid_edge *e = g->edges + i;
     int x1, x2, y1, y2;
-    int xmin, ymin, xmax, ymax;
     int line_colour;
 
     if (state->line_errors[i])
@@ -3618,11 +3567,6 @@ static void game_redraw_line(drawing *dr, game_drawstate *ds,
     grid_to_screen(ds, g, e->dot1->x, e->dot1->y, &x1, &y1);
     grid_to_screen(ds, g, e->dot2->x, e->dot2->y, &x2, &y2);
 
-    xmin = min(x1, x2);
-    xmax = max(x1, x2);
-    ymin = min(y1, y2);
-    ymax = max(y1, y2);
-
     if (line_colour == COL_FAINT) {
        static int draw_faint_lines = -1;
        if (draw_faint_lines < 0) {
@@ -3673,9 +3617,11 @@ static void game_redraw_in_rect(drawing *dr, game_drawstate *ds,
     draw_rect(dr, x, y, w, h, COL_BACKGROUND);
 
     for (i = 0; i < g->num_faces; i++) {
-        face_text_bbox(ds, g, &g->faces[i], &bx, &by, &bw, &bh);
-        if (boxes_intersect(x, y, w, h, bx, by, bw, bh))
-            game_redraw_clue(dr, ds, state, i);
+        if (state->clues[i] >= 0) {
+            face_text_bbox(ds, g, &g->faces[i], &bx, &by, &bw, &bh);
+            if (boxes_intersect(x, y, w, h, bx, by, bw, bh))
+                game_redraw_clue(dr, ds, state, i);
+        }
     }
     for (phase = 0; phase < NPHASES; phase++) {
         for (i = 0; i < g->num_edges; i++) {
@@ -4098,3 +4044,5 @@ int main(int argc, char **argv)
 }
 
 #endif
+
+/* vim: set shiftwidth=4 tabstop=8: */