selector: implement maxdisplay. unit tests!

include/notcurses.h

@@ -2141,6 +2141,8 @@ API int ncselector_delitem(struct ncselector* n, const char* item);
 // Return a copy of the currently-selected option. NULL if there are no items.
 API char* ncselector_selected(const struct ncselector* n);
 
+API struct ncplane* ncselector_plane(struct ncselector* n);
+
 // Move up or down in the list. If 'newitem' is not NULL, the newly-selected
 // option will be strdup()ed and assigned to '*newitem' (and must be free()d by
 // the caller).

src/lib/internal.h

@@ -127,6 +127,7 @@ typedef struct ncselector {
   ncplane* ncp;                // backing ncplane
   unsigned selected;           // index of selection
   unsigned startdisp;          // index of first option displayed
+  unsigned maxdisplay;         // max number of items to display, 0 -> no limit
   size_t longop;               // length of longest option
   size_t longdesc;             // length of longest description
   struct selector_item* items; // list of items and descriptions, heap-copied

src/lib/selector.c

@@ -48,7 +48,11 @@ ncselector_draw(ncselector* n){
   ncplane_rounded_box_sized(n->ncp, 0, channels, dimy - yoff, bodywidth, 0);
   unsigned printidx = n->startdisp;
   int bodyoffset = dimx - bodywidth + 2;
+  unsigned printed = 0;
   for(yoff += 2 ; yoff < dimy - 2 ; ++yoff){
+    if(n->maxdisplay && printed == n->maxdisplay){
+      break;
+    }
     if(printidx == n->selected){
       ncplane_styles_on(n->ncp, CELL_STYLE_REVERSE);
     }
@@ -59,6 +63,7 @@ ncselector_draw(ncselector* n){
       ncplane_styles_off(n->ncp, CELL_STYLE_REVERSE);
     }
     ++printidx;
+    ++printed;
   }
   return notcurses_render(n->ncp->nc);
 }
@@ -79,7 +84,7 @@ ncselector_dim_yx(notcurses* nc, const ncselector* n, int* ncdimy, int* ncdimx){
   if(rows > dimy){ // insufficient height to display selector
     return -1;
   }
-  rows += n->itemcount - 1; // rows necessary to display all options
+  rows += (!n->maxdisplay || n->maxdisplay > n->itemcount ? n->itemcount : n->maxdisplay) - 1; // rows necessary to display all options
   if(rows > dimy){ // claw excess back
     rows = dimy;
   }
@@ -104,6 +109,7 @@ ncselector* ncselector_create(ncplane* n, int y, int x, const selector_options*
   ns->selected = 0;
   ns->startdisp = 0;
   ns->longop = 0;
+  ns->maxdisplay = opts->maxdisplay;
   ns->longdesc = 0;
   if(opts->itemcount){
     if(!(ns->items = malloc(sizeof(*ns->items) * opts->itemcount))){
@@ -185,6 +191,10 @@ int ncselector_delitem(ncselector* n, const char* item){
   return -1; // wasn't found
 }
 
+ncplane* ncselector_plane(ncselector* n){
+  return n->ncp;
+}
+
 char* ncselector_selected(const ncselector* n){
   if(n->itemcount == 0){
     return NULL;

tests/selector.cpp

@@ -23,6 +23,12 @@ TEST_CASE("SelectorTest") {
     REQUIRE(nullptr != ncs);
     CHECK(0 == notcurses_render(nc_));
     CHECK(nullptr == ncselector_selected(ncs));
+    struct ncplane* ncsp = ncselector_plane(ncs);
+    REQUIRE(nullptr != ncsp);
+    int dimy, dimx;
+    ncplane_dim_yx(ncsp, &dimy, &dimx);
+    CHECK(4 == dimy);
+    CHECK(5 == dimx);
     ncselector_destroy(ncs, nullptr);
   }
 
@@ -32,6 +38,12 @@ TEST_CASE("SelectorTest") {
     struct ncselector* ncs = ncselector_create(notcurses_stdplane(nc_), 0, 0, &opts);
     REQUIRE(nullptr != ncs);
     CHECK(0 == notcurses_render(nc_));
+    struct ncplane* ncsp = ncselector_plane(ncs);
+    REQUIRE(nullptr != ncsp);
+    int dimy, dimx;
+    ncplane_dim_yx(ncsp, &dimy, &dimx);
+    CHECK(6 == dimy);
+    CHECK(strlen(opts.title) + 4 == dimx);
     ncselector_destroy(ncs, nullptr);
   }
 
@@ -41,15 +53,27 @@ TEST_CASE("SelectorTest") {
     struct ncselector* ncs = ncselector_create(notcurses_stdplane(nc_), 0, 0, &opts);
     REQUIRE(nullptr != ncs);
     CHECK(0 == notcurses_render(nc_));
+    struct ncplane* ncsp = ncselector_plane(ncs);
+    REQUIRE(nullptr != ncsp);
+    int dimy, dimx;
+    ncplane_dim_yx(ncsp, &dimy, &dimx);
+    CHECK(4 == dimy);
+    CHECK(strlen(opts.secondary) + 2 == dimx);
     ncselector_destroy(ncs, nullptr);
   }
 
   SUBCASE("FooterSelector") {
     struct selector_options opts{};
-    opts.secondary = strdup("i am a lone footer, little old footer");
+    opts.footer = strdup("i am a lone footer, little old footer");
     struct ncselector* ncs = ncselector_create(notcurses_stdplane(nc_), 0, 0, &opts);
     REQUIRE(nullptr != ncs);
     CHECK(0 == notcurses_render(nc_));
+    struct ncplane* ncsp = ncselector_plane(ncs);
+    REQUIRE(nullptr != ncsp);
+    int dimy, dimx;
+    ncplane_dim_yx(ncsp, &dimy, &dimx);
+    CHECK(4 == dimy);
+    CHECK(strlen(opts.footer) + 2 == dimx);
     ncselector_destroy(ncs, nullptr);
   }
 
@@ -65,6 +89,12 @@ TEST_CASE("SelectorTest") {
     struct ncselector* ncs = ncselector_create(notcurses_stdplane(nc_), 0, 0, &opts);
     REQUIRE(nullptr != ncs);
     CHECK(0 == notcurses_render(nc_));
+    struct ncplane* ncsp = ncselector_plane(ncs);
+    REQUIRE(nullptr != ncsp);
+    int dimy, dimx;
+    ncplane_dim_yx(ncsp, &dimy, &dimx);
+    CHECK(7 == dimy);
+    CHECK(15 < dimx);
     ncselector_destroy(ncs, nullptr);
   }
 
@@ -95,29 +125,79 @@ TEST_CASE("SelectorTest") {
     opts.itemcount = sizeof(items) / sizeof(*items);
     struct ncselector* ncs = ncselector_create(notcurses_stdplane(nc_), 0, 0, &opts);
     REQUIRE(nullptr != ncs);
-    CHECK(0 == notcurses_render(nc_));
     auto sel = ncselector_selected(ncs);
     REQUIRE(nullptr != sel);
     CHECK(0 == strcmp(sel, items[0].option));
     free(sel);
+    CHECK(0 == notcurses_render(nc_));
     ncselector_nextitem(ncs, &sel);
     REQUIRE(nullptr != sel);
     CHECK(0 == strcmp(sel, items[1].option));
     free(sel);
+    CHECK(0 == notcurses_render(nc_));
     ncselector_previtem(ncs, &sel);
     REQUIRE(nullptr != sel);
     CHECK(0 == strcmp(sel, items[0].option));
     free(sel);
+    CHECK(0 == notcurses_render(nc_));
     // wrap around from the top to bottom...
     ncselector_previtem(ncs, &sel);
     REQUIRE(nullptr != sel);
     CHECK(0 == strcmp(sel, items[2].option));
     free(sel);
+    CHECK(0 == notcurses_render(nc_));
     // ...and back to the top
     ncselector_nextitem(ncs, &sel);
     REQUIRE(nullptr != sel);
     CHECK(0 == strcmp(sel, items[0].option));
     free(sel);
+    CHECK(0 == notcurses_render(nc_));
+    ncselector_destroy(ncs, nullptr);
+  }
+
+  // Provide three items, limited to 1 shown at a time
+  SUBCASE("ScrollingSelectorOne") {
+    selector_item items[] = {
+      { strdup("op1"), strdup("this is option 1"), },
+      { strdup("2ndop"), strdup("this is option #2"), },
+      { strdup("tres"), strdup("option the third"), },
+    };
+    struct selector_options opts{};
+    opts.maxdisplay = 1;
+    opts.items = items;
+    opts.itemcount = sizeof(items) / sizeof(*items);
+    struct ncselector* ncs = ncselector_create(notcurses_stdplane(nc_), 0, 0, &opts);
+    REQUIRE(nullptr != ncs);
+    CHECK(0 == notcurses_render(nc_));
+    auto sel = ncselector_selected(ncs);
+    REQUIRE(nullptr != sel);
+    struct ncplane* ncsp = ncselector_plane(ncs);
+    REQUIRE(nullptr != ncsp);
+    int dimy, dimx;
+    ncplane_dim_yx(ncsp, &dimy, &dimx);
+    CHECK(5 == dimy);
+    ncselector_destroy(ncs, nullptr);
+  }
+
+  // Provide three items, limited to 2 shown at a time
+  SUBCASE("ScrollingSelectorTwo") {
+    selector_item items[] = {
+      { strdup("op1"), strdup("this is option 1"), },
+      { strdup("2ndop"), strdup("this is option #2"), },
+      { strdup("tres"), strdup("option the third"), },
+    };
+    struct selector_options opts{};
+    opts.maxdisplay = 2;
+    opts.items = items;
+    opts.itemcount = sizeof(items) / sizeof(*items);
+    struct ncselector* ncs = ncselector_create(notcurses_stdplane(nc_), 0, 0, &opts);
+    REQUIRE(nullptr != ncs);
+    CHECK(0 == notcurses_render(nc_));
+    struct ncplane* ncsp = ncselector_plane(ncs);
+    REQUIRE(nullptr != ncsp);
+    int dimy, dimx;
+    ncplane_dim_yx(ncsp, &dimy, &dimx);
+    CHECK(6 == dimy);
     ncselector_destroy(ncs, nullptr);
   }