Dragon demo #708 (#710)

* define dragon curve demo #708
* demo: distinguish abort from fail, color-wise
* dragon: ncvisual-based #708

doc/man/man1/notcurses-demo.1.md

@@ -25,6 +25,7 @@ The demonstrations include (see NOTES below):
 * (a)llglyph—scroll the glyphs of your font
 * (b)oxes—pulsating boxes with a transparent center
 * (c)hunli—the strongest woman in the world
+* (d)ragon—the Harter-Heighway dragon curve
 * (e)agle—they took some time off my life, back in the day
 * (f)allin'—the screen falls apart under heavy blows
 * (g)rid—a gradient of color lain atop a great grid
@@ -71,7 +72,7 @@ At any time, press 'q' to quit. The demo is best run in at least an 80x45 termin
 **-V**: Print the program name and version, and exit with success.
 
 demospec: Select which demos to run, and what order to run them in. The
-default is **ixeaythnbcgrwuvlsfjqo**. See above for a list of demos.
+default is **ixeaydthnbcgrwuvlsfjqo**. See above for a list of demos.
 
 Default margins are all 0, and thus the full screen will be rendered. Using
 **-m**, margins can be supplied. Provide a single number to set all four margins

src/demo/demo.c

@@ -19,7 +19,7 @@ static int democount;
 static demoresult* results;
 static char *datadir = NOTCURSES_SHARE;
 
-static const char DEFAULT_DEMO[] = "ixeaythnbcgrwuvlsfjqo";
+static const char DEFAULT_DEMO[] = "ixeaydthnbcgrwuvlsfjqo";
 
 atomic_bool interrupted = ATOMIC_VAR_INIT(false);
 // checked following demos, whether aborted, failed, or otherwise
@@ -76,19 +76,19 @@ static struct {
   { "allglyph", allglyphs_demo, false, },
   { "box", box_demo, false, },
   { "chunli", chunli_demo, true, },
-  { NULL, NULL, false, },
+  { "dragon", dragon_demo, false, },
   { "eagle", eagle_demo, true, },
   { "fallin'", fallin_demo, false, },
   { "grid", grid_demo, false, },
   { "highcon", highcontrast_demo, false, },
   { "intro", intro, false, },
   { "jungle", jungle_demo, true, },
-  { NULL, NULL, false, },
+  { NULL, NULL, false, }, // FIXME
   { "luigi", luigi_demo, true, },
-  { NULL, NULL, false, },
+  { NULL, NULL, false, }, // mojibake
   { "normal", normal_demo, false, },
   { "outro", outro, false, },
-  { NULL, NULL, false, },
+  { NULL, NULL, false, }, // pango
   { "qrcode", qrcode_demo, false, }, // is blank without USE_QRCODEGEN
   { "reel", reel_demo, false, },
   { "sliders", sliding_puzzle_demo, false, },
@@ -98,7 +98,7 @@ static struct {
   { "whiteout", witherworm_demo, false, },
   { "xray", xray_demo, false, },
   { "yield", yield_demo, false, },
-  { NULL, NULL, false, },
+  { NULL, NULL, false, }, // zoo
 };
 
 static void
@@ -360,8 +360,10 @@ summary_table(struct ncdirect* nc, const char* spec){
     qprefix(results[i].stats.render_ns, GIG, rtimebuf, 0);
     bprefix(results[i].stats.render_bytes, 1, totalbuf, 0);
     uint32_t rescolor;
-    if(results[i].result != 0){
+    if(results[i].result < 0){
       rescolor = 0xff303c;
+    }else if(results[i].result > 0){
+      rescolor = 0xffaa22;
     }else if(!results[i].stats.renders){
       rescolor = 0xbbbbbb;
     }else{

src/demo/demo.h

@@ -38,6 +38,7 @@ int witherworm_demo(struct notcurses* nc);
 int box_demo(struct notcurses* nc);
 int trans_demo(struct notcurses* nc);
 int chunli_demo(struct notcurses* nc);
+int dragon_demo(struct notcurses* nc);
 int qrcode_demo(struct notcurses* nc);
 int grid_demo(struct notcurses* nc);
 int fallin_demo(struct notcurses* nc);

src/demo/dragon.c

@@ -0,0 +1,108 @@
+#include "demo.h"
+
+// lame as fuck lol
+static bool done;
+static uint32_t pixel;
+static int y, x, dy, dx;
+
+static int
+dragonmayer(struct ncvisual* ncv, const char* str, int iters){
+  char c;
+  int r;
+  while( (c = *str++) ){
+    switch(c){
+      case 'X':
+        if(iters > 1){
+          if( (r = dragonmayer(ncv, "X+YF+", iters - 1)) ){
+            return r;
+          }
+        }
+        break;
+      case 'Y':
+        if(iters > 1){
+          if( (r = dragonmayer(ncv, "-FX-Y", iters - 1)) ){
+            return r;
+          }
+        }
+        break;
+      case '+': { int tmp = dy; dy = -dx; dx = tmp; break; }
+      case '-': { int tmp = -dy; dy = dx; dx = tmp; break; }
+      case 'F': // FIXME want a line
+        // FIXME some of these will fail...hella lame, check against dims
+        if(ncvisual_set_yx(ncv, y, x, pixel) < 0){
+          done = true;
+        }
+        x += dx;
+        y += dy;
+        break;
+      default:
+        return -1;
+    }
+  }
+  return 0;
+}
+
+int dragon_demo(struct notcurses* nc){
+  int dimy, dimx;
+  struct ncplane* n = notcurses_stddim_yx(nc, &dimy, &dimx);
+  // we use a Lindenmayer string rewriting system. the classic dragon curve
+  // system is X -> X+YF+, Y -> -FX-Y, where F is forward, - is turn left, and
+  // + is turn right.
+  const char LINDENSTART[] = "FX";
+  const int SCALE = 1;
+  dimy *= 2;
+  dimx *= 2;
+  int dxstart, dystart;
+  if(dimy > dimx){
+    dystart = 0;
+    dxstart = SCALE;
+  }else{
+    dystart = SCALE;
+    dxstart = 0;
+  }
+  size_t fbbytes = sizeof(uint32_t) * dimy * dimx;
+  uint32_t* rgba = malloc(fbbytes);
+  if(rgba == NULL){
+    return -1;
+  }
+  memset(rgba, 0, fbbytes);
+  for(int i = 0 ; i < dimy * dimx ; ++i){
+    ncpixel_set_a(&rgba[i], 0xff);
+  }
+  struct ncvisual* ncv = ncvisual_from_rgba(rgba, dimy, dimx * sizeof(uint32_t), dimx);
+  if(ncv == NULL){
+    free(rgba);
+    return -1;
+  }
+  free(rgba);
+  struct timespec scaled;
+  timespec_div(&demodelay, 4, &scaled);
+  int iters = 0;
+  do{
+    ++iters;
+    pixel = 0xffffffffull;
+    ncpixel_set_rgb(&pixel, 0, 0x11 * iters, 0);
+    dx = dxstart;
+    dy = dystart;
+    x = dimx / 2;
+    y = dimy / 2;
+    int r = dragonmayer(ncv, LINDENSTART, iters);
+    if(r){
+      ncvisual_destroy(ncv);
+      return r;
+    }
+    struct ncvisual_options vopts = {
+      .n = n,
+      .blitter = NCBLIT_2x2,
+    };
+    if(ncvisual_render(nc, ncv, &vopts) == NULL){
+      ncvisual_destroy(ncv);
+      return -1;
+    }
+    DEMO_RENDER(nc);
+    demo_nanosleep(nc, &scaled);
+    ncplane_erase(n);
+  }while(!done);
+  ncvisual_destroy(ncv);
+  return 0;
+}

src/lib/plot.h

@@ -82,6 +82,7 @@ class ncppplot {
      ncpp->maxy = maxy;
      ncpp->vertical_indep = opts->flags & NCPLOT_OPTION_VERTICALI;
      ncpp->exponentiali = opts->flags & NCPLOT_OPTION_EXPONENTIALD;
+     ncpp->detectonlymax = opts->flags & NCPLOT_OPTION_DETECTMAXONLY;
      if( (ncpp->detectdomain = (miny == maxy)) ){
        ncpp->maxy = 0;
        ncpp->miny = std::numeric_limits<T>::max();