notcurses_refresh: always clear screen #1915

src/lib/internal.h

@@ -1131,8 +1131,6 @@ coerce_styles(FILE* out, const tinfo* ti, uint16_t* curstyle,
               uint16_t newstyle, unsigned* normalized){
   *normalized = 0; // we never currently use sgr0
   int ret = 0;
-  ret |= term_setstyle(out, *curstyle, newstyle, NCSTYLE_BLINK,
-                       get_escape(ti, ESCAPE_BLINK), get_escape(ti, ESCAPE_NOBLINK));
   ret |= term_setstyle(out, *curstyle, newstyle, NCSTYLE_BOLD,
                        get_escape(ti, ESCAPE_BOLD), get_escape(ti, ESCAPE_NOBOLD));
   ret |= term_setstyle(out, *curstyle, newstyle, NCSTYLE_ITALIC,
@@ -1179,38 +1177,39 @@ mouse_disable(FILE* out){
 // our understanding of our horizontal location is faulty.
 // FIXME fall back to synthesized moves in the absence of capabilities (i.e.
 // textronix lacks cup; fake it with horiz+vert moves)
-// if hardcursorpos is non-zero, we always perform a cup
+// if hardcursorpos is non-zero, we always perform a cup. this is done when we
+// don't know where the cursor currently is =].
 static inline int
 goto_location(notcurses* nc, FILE* out, int y, int x){
 //fprintf(stderr, "going to %d/%d from %d/%d hard: %u\n", y, x, nc->rstate.y, nc->rstate.x, hardcursorpos);
   int ret = 0;
   // if we don't have hpa, force a cup even if we're only 1 char away. the only
-  // terminal i know supporting cup sans hpa is vt100, and vt100 can suck it.
+  // TERM i know supporting cup sans hpa is vt100, and vt100 can suck it.
   // you can't use cuf for backwards moves anyway; again, vt100 can suck it.
   const char* hpa = get_escape(&nc->tcache, ESCAPE_HPA);
   if(nc->rstate.y == y && hpa && !nc->rstate.hardcursorpos){ // only need move x
     if(nc->rstate.x == x){ // needn't move shit
       return 0;
     }
-    const char* cuf1 = get_escape(&nc->tcache, ESCAPE_CUF1);
-    if(x == nc->rstate.x + 1 && cuf1){
-      ret = term_emit(cuf1, out, false);
-    }else{
-      ret = term_emit(tiparm(hpa, x), out, false);
+    if(term_emit(tiparm(hpa, x), out, false)){
+      return -1;
     }
   }else{
     // cup is required, no need to verify existence
-    ret = term_emit(tiparm(get_escape(&nc->tcache, ESCAPE_CUP), y, x), out, false);
-    nc->rstate.hardcursorpos = 0;
+    const char* cup = get_escape(&nc->tcache, ESCAPE_CUP);
+    if(term_emit(tiparm(cup, y, x), out, false)){
+      return -1;
+    }
   }
-  nc->rstate.x = x;
-  nc->rstate.y = y;
   if(nc->rstate.logendy >= 0){
     if(y > nc->rstate.logendy || (y == nc->rstate.logendy && x > nc->rstate.logendx)){
       nc->rstate.logendy = y;
       nc->rstate.logendx = x;
     }
   }
+  nc->rstate.x = x;
+  nc->rstate.y = y;
+  nc->rstate.hardcursorpos = 0;
   return ret;
 }
 

src/lib/notcurses.c

@@ -1181,14 +1181,12 @@ notcurses* notcurses_core_init(const notcurses_options* opts, FILE* outfp){
           goto err;
         }
       }
-      const char* clearscr = get_escape(&ret->tcache, ESCAPE_CLEAR);
-      // perform an explicit clear if the alternate screen was requested
-      // (smcup *might* clear, but who knows, and might not have been
+      // perform an explicit clear since the alternate screen was requested
+      // (smcup *might* clear, but who knows? and it might not have been
       // available in any case).
-      if(!clearscr || term_emit(clearscr, ret->ttyfp, true)){
-        // if we don't have a clear escape, clear via iterated writes
-        notcurses_refresh(ret, NULL, NULL);
-      }
+      notcurses_refresh(ret, NULL, NULL);
+      // no need to reestablish a preserved cursor -- that only affects the
+      // standard plane, not the physical cursor that was just disrupted.
     }
   }
   return ret;

src/lib/render.c

@@ -1206,28 +1206,41 @@ notcurses_rasterize(notcurses* nc, ncpile* p, FILE* out){
   return ret;
 }
 
-// get the cursor to the upper-left corner by one means or another. will clear
-// the screen if need be.
+// get the cursor to the upper-left corner by one means or another, clearing
+// the screen while doing so.
 static int
-home_cursor(notcurses* nc, bool flush){
-  int ret = -1;
-  const char* home = get_escape(&nc->tcache, ESCAPE_HOME);
-  if(home){
-    ret = term_emit(home, nc->ttyfp, flush);
-  }else{
-    const char* cup = get_escape(&nc->tcache, ESCAPE_CUP);
-    const char* clearscr = get_escape(&nc->tcache, ESCAPE_CLEAR);
-    if(cup){
-      ret = term_emit(tiparm(cup, 1, 1), nc->ttyfp, flush);
-    }else if(clearscr){
-      ret = term_emit(clearscr, nc->ttyfp, flush);
+clear_and_home(notcurses* nc, tinfo* ti, FILE* fp, unsigned flush){
+  // clear clears the screen and homes the cursor by itself
+  const char* clearscr = get_escape(ti, ESCAPE_CLEAR);
+  if(clearscr){
+    if(term_emit(clearscr, fp, flush) == 0){
+      goto success;
     }
   }
-  if(ret >= 0){
-    nc->rstate.x = 0;
-    nc->rstate.y = 0;
+  const ncplane* stdn = notcurses_stdplane_const(nc);
+  // clearscr didn't fly. try scrolling everything off. first, go to the
+  // bottom of the screen, then write N newlines.
+  if(goto_location(nc, fp, ncplane_dim_y(stdn) - 1, 0)){
+    return -1;
   }
-  return ret;
+  for(int y = 0 ; y < ncplane_dim_y(stdn) ; ++y){
+    if(ncfputc('\n', fp) == EOF){
+      return -1;
+    }
+  }
+  if(goto_location(nc, fp, 0, 0)){
+    return -1;
+  }
+  if(flush){
+    if(ncflush(fp)){
+      return -1;
+    }
+  }
+
+success:
+  nc->rstate.x = 0;
+  nc->rstate.y = 0;
+  return 0;
 }
 
 int notcurses_refresh(notcurses* nc, int* restrict dimy, int* restrict dimx){
@@ -1237,7 +1250,7 @@ int notcurses_refresh(notcurses* nc, int* restrict dimy, int* restrict dimx){
   if(nc->lfdimx == 0 || nc->lfdimy == 0){
     return 0;
   }
-  if(home_cursor(nc, true)){
+  if(clear_and_home(nc, &nc->tcache, nc->ttyfp, true)){
     return -1;
   }
   ncpile p = {};

src/lib/termdesc.c

@@ -534,7 +534,6 @@ build_supported_styles(tinfo* ti){
     { NCSTYLE_UNDERLINE, ESCAPE_SMUL, "smul", A_UNDERLINE },
     { NCSTYLE_ITALIC, ESCAPE_SITM, "sitm", A_ITALIC },
     { NCSTYLE_STRUCK, ESCAPE_SMXX, "smxx", 0 },
-    { NCSTYLE_BLINK, ESCAPE_BLINK, "blink", A_BLINK },
     { NCSTYLE_UNDERCURL, ESCAPE_SMULX, "Smulx", 0 },
     { 0, 0, NULL, 0 }
   };
@@ -620,11 +619,9 @@ int interrogate_terminfo(tinfo* ti, int fd, const char* termname, unsigned utf8,
     { ESCAPE_SITM, "sitm", },
     { ESCAPE_RITM, "ritm", },
     { ESCAPE_BOLD, "bold", },
-    { ESCAPE_BLINK, "blink", },
     { ESCAPE_CUD, "cud", },
     { ESCAPE_CUU, "cuu", },
     { ESCAPE_CUF, "cuf", },
-    { ESCAPE_CUF1, "cuf1", },
     { ESCAPE_CUB, "cub", },
     { ESCAPE_INITC, "initc", },
     { ESCAPE_GETM, "getm", },
@@ -636,7 +633,6 @@ int interrogate_terminfo(tinfo* ti, int fd, const char* termname, unsigned utf8,
     { ESCAPE_SC, "sc", },
     { ESCAPE_RC, "rc", },
     { ESCAPE_CLEAR, "clear", },
-    { ESCAPE_HOME, "home", },
     { ESCAPE_OC, "oc", },
     { ESCAPE_RMKX, "rmkx", },
     { ESCAPE_DSRCPR, "u7", },
@@ -689,11 +685,6 @@ int interrogate_terminfo(tinfo* ti, int fd, const char* termname, unsigned utf8,
       goto err;
     }
   }
-  if(get_escape(ti, ESCAPE_BLINK)){
-    if(grow_esc_table(ti, "\e[25m", ESCAPE_NOBLINK, &tablelen, &tableused)){
-      goto err;
-    }
-  }
   // if op is defined as ansi 39 + ansi 49, make the split definitions
   // available. this ought be asserted by extension capability "ax", but
   // no terminal i've found seems to do so. =[

src/lib/termdesc.h

@@ -45,10 +45,7 @@ typedef enum {
   ESCAPE_CUF,      // "cuf" move n cells forward (right)
   ESCAPE_BOLD,     // "bold" enter bold mode
   ESCAPE_NOBOLD,   // disable bold (ANSI but not terminfo, SGR 22)
-  ESCAPE_BLINK,    // "blink" enter blink mode
-  ESCAPE_NOBLINK,  // disable blink (ANSI but not terminfo, SGR 25)
   ESCAPE_CUD,      // "cud" move n cells down
-  ESCAPE_CUF1,     // "cuf1" move 1 cell forward (right)
   ESCAPE_SMKX,     // "smkx" keypad_xmit (keypad transmit mode)
   ESCAPE_RMKX,     // "rmkx" keypad_local
   ESCAPE_SMCUP,    // "smcup" enter alternate screen
@@ -62,7 +59,6 @@ typedef enum {
   ESCAPE_SC,       // "sc" push the cursor onto the stack
   ESCAPE_RC,       // "rc" pop the cursor off the stack
   ESCAPE_CLEAR,    // "clear" clear screen and home cursor
-  ESCAPE_HOME,     // "home" home cursor
   ESCAPE_INITC,    // "initc" set up palette entry
   ESCAPE_GETM,     // "getm" get mouse events
   ESCAPE_DSRCPR,   // "u7" cursor position report