qrcode: center qrcode

src/demo/qrcode.c

@@ -5,29 +5,51 @@
 #include <sys/libkern.h>
 #endif
 
+// FIXME duplicated--ought these just be exported?
+#define QR_BASE_SIZE 17
+#define PER_QR_VERSION 4
+static inline int
+qrcode_rows(int version){
+  return QR_BASE_SIZE + (version * PER_QR_VERSION / 2);
+}
+
+static inline int
+qrcode_cols(int version){
+  return QR_BASE_SIZE + (version * PER_QR_VERSION);
+}
+
 int qrcode_demo(struct notcurses* nc){
 #ifdef USE_QRCODEGEN
   char data[128];
   int dimy, dimx;
-  struct ncplane* n = notcurses_stddim_yx(nc, &dimy, &dimx);
+  struct ncplane *stdn = notcurses_stddim_yx(nc, &dimy, &dimx);
+  ncplane_erase(stdn);
+  struct ncplane* n = ncplane_dup(stdn, NULL);
   for(int i = 0 ; i < 1024 ; ++i){
     ncplane_erase(n);
     size_t len = random() % sizeof(data) + 1;
 #ifdef __linux__
     ssize_t got = getrandom(data, len, 0);
     if(got < 0 || (size_t)got != len){
+      ncplane_destroy(n);
       return -1;
     }
 #else
     arc4rand(data, len, 0);
 #endif
     if(ncplane_cursor_move_yx(n, 0, 0)){
+      ncplane_destroy(n);
       return -1;
     }
-    if(ncplane_qrcode(n, 0, data, len) <= 0){
+    int qlen = ncplane_qrcode(n, 0, data, len);
+    if(qlen <= 0){
+      ncplane_destroy(n);
       return -1;
     }
+    ncplane_move_yx(n, dimy / 2 - qrcode_rows(qlen) / 2,
+                   dimx / 2 - qrcode_cols(qlen) / 2);
     if(ncplane_cursor_move_yx(n, 0, 0)){
+      ncplane_destroy(n);
       return -1;
     }
     uint64_t tl = 0, bl = 0, br = 0, tr = 0;
@@ -36,12 +58,13 @@ int qrcode_demo(struct notcurses* nc){
     channels_set_fg_rgb(&bl, random() % 255 + 1, random() % 255 + 1, random() % 255 + 1);
     channels_set_fg_rgb(&br, random() % 255 + 1, random() % 255 + 1, random() % 255 + 1);
     if(ncplane_stain(n, dimy - 1, dimx - 1, tl, tr, bl, br) <= 0){
+      ncplane_destroy(n);
       return -1;
     }
     DEMO_RENDER(nc);
   }
 #endif
-  ncplane_erase(notcurses_stdplane(nc));
+  ncplane_destroy(n);
   DEMO_RENDER(nc);
   return 0;
 }