somewhat daring and dangerous scrolling for rendered mode #1823

src/lib/internal.h

@@ -458,6 +458,7 @@ typedef struct ncpile {
   struct ncpile *prev, *next; // circular list
   size_t crenderlen;          // size of crender vector
   int dimy, dimx;             // rows and cols at time of render
+  int scrolls;                // how many real lines need be scrolled at raster
   sprixel* sprixelcache;      // list of sprixels
 } ncpile;
 
@@ -496,6 +497,7 @@ typedef struct notcurses {
   ncpalette palette; // 256-indexed palette can be used instead of/with RGB
   bool palette_damage[NCPALETTESIZE];
   unsigned stdio_blocking_save; // was stdio blocking at entry? restore on stop.
+  uint64_t flags;  // copied from notcurses_options
 } notcurses;
 
 // this flag is used internally, by direct mode (which might want
@@ -815,7 +817,7 @@ sprite_destroy(const notcurses* nc, const ncpile* p, FILE* out, sprixel* s){
 // returns -1 on error, or the number of bytes written.
 static inline int
 sprite_draw(const notcurses* n, const ncpile* p, sprixel* s, FILE* out){
-//sprixel_debug(stderr, s);
+sprixel_debug(stderr, s);
   return n->tcache.pixel_draw(p, s, out);
 }
 
@@ -823,7 +825,7 @@ sprite_draw(const notcurses* n, const ncpile* p, sprixel* s, FILE* out){
 // returns -1 on error, or the number of bytes written.
 static inline int
 sprite_redraw(const notcurses* n, const ncpile* p, sprixel* s, FILE* out){
-//sprixel_debug(stderr, s);
+sprixel_debug(stderr, s);
   if(s->invalidated == SPRIXEL_MOVED && n->tcache.pixel_move){
     return n->tcache.pixel_move(p, s, out);
   }else{

src/lib/kitty.c

@@ -599,7 +599,7 @@ int kitty_destroy(const notcurses* nc __attribute__ ((unused)),
             // ideally, we wouldn't damage our annihilated sprixcells, but if
             // we're being annihilated only during this cycle, we need to go
             // ahead and damage it.
-            r->s.damaged = 1;
+            // r->s.damaged = 1;
           }
         }else{
           // need this to damage cells underneath a sprixel we're removing

src/lib/notcurses.c

@@ -357,6 +357,7 @@ make_ncpile(notcurses* nc, ncplane* n){
     ret->crender = NULL;
     ret->crenderlen = 0;
     ret->sprixelcache = NULL;
+    ret->scrolls = 0;
   }
   return ret;
 }
@@ -1034,6 +1035,7 @@ notcurses* notcurses_core_init(const notcurses_options* opts, FILE* outfp){
   if(outfp == NULL){
     outfp = stdout;
   }
+  ret->flags = opts->flags;
   ret->margin_t = opts->margin_t;
   ret->margin_b = opts->margin_b;
   ret->margin_l = opts->margin_l;
@@ -1237,13 +1239,17 @@ int notcurses_stop(notcurses* nc){
       fclose(nc->rstate.mstreamfp);
     }
     // if we were not using the alternate screen, our cursor's wherever we last
-    // wrote. move it to the bottom left of the screen.
-    if(!get_escape(&nc->tcache, ESCAPE_SMCUP)){
-      // if ldimy is 0, we've not yet written anything; leave it untouched
-      if(nc->lfdimy){
-        int targy = nc->lfdimy + nc->margin_t - 1;
-        // cup is required, no need to test for existence
-        tty_emit(tiparm(get_escape(&nc->tcache, ESCAPE_CUP), targy, 0), nc->ttyfd);
+    // wrote. move it to the bottom left of the screen, *unless*
+    // NCOPTION_PRESERVE_CURSOR was used, in which case it's right where we
+    // want it (i think?).
+    if(!(nc->flags & NCOPTION_PRESERVE_CURSOR)){
+      if(!get_escape(&nc->tcache, ESCAPE_SMCUP)){
+        // if ldimy is 0, we've not yet written anything; leave it untouched
+        if(nc->lfdimy){
+          int targy = nc->lfdimy + nc->margin_t - 1;
+          // cup is required, no need to test for existence
+          tty_emit(tiparm(get_escape(&nc->tcache, ESCAPE_CUP), targy, 0), nc->ttyfd);
+        }
       }
     }
     if(nc->ttyfd >= 0){
@@ -1484,8 +1490,12 @@ nccell_obliterate(ncplane* n, nccell* c){
 
 // increment y by 1 and rotate the framebuffer up one line. x moves to 0.
 void scroll_down(ncplane* n){
+//fprintf(stderr, "pre-scroll: %d/%d %d/%d log: %d\n", n->y, n->x, n->leny, n->lenx, n->logrow);
   n->x = 0;
   if(n->y == n->leny - 1){
+    if(n == notcurses_stdplane(ncplane_notcurses(n))){
+      ncplane_pile(n)->scrolls++;
+    }
     n->logrow = (n->logrow + 1) % n->leny;
     nccell* row = n->fb + nfbcellidx(n, n->y, 0);
     for(int clearx = 0 ; clearx < n->lenx ; ++clearx){

src/lib/render.c

@@ -942,6 +942,18 @@ clean_sprixels(notcurses* nc, ncpile* p, FILE* out){
   return bytesemitted;
 }
 
+static int
+rasterize_scrolls(ncpile* p, FILE* out){
+//fprintf(stderr, "%d tardies to work off, by far the most in the class\n", p->scrolls);
+  while(p->scrolls){
+    if(fprintf(out, "\n") < 0){
+      return -1;
+    }
+    --p->scrolls;
+  }
+  return 0;
+}
+
 // draw any invalidated sprixels. returns -1 on error, number of bytes written
 // on success. any material underneath them has already been updated.
 static int64_t
@@ -1116,6 +1128,9 @@ notcurses_rasterize_inner(notcurses* nc, ncpile* p, FILE* out, unsigned* asu){
   }
   update_palette(nc, out);
 //fprintf(stderr, "RASTERIZE CORE\n");
+  if(rasterize_scrolls(p, out)){
+    return -1;
+  }
   if(rasterize_core(nc, p, out, 0)){
     return -1;
   }