diff --git a/USAGE.md b/USAGE.md
index 76d208a27..2a982adba 100644
--- a/USAGE.md
+++ b/USAGE.md
@@ -98,6 +98,11 @@ typedef struct notcurses_options {
   int margin_t, margin_r, margin_b, margin_l;
 } notcurses_options;
 
+// Lex a margin argument according to the standard notcurses definition. There
+// can be either a single number, which will define all margins equally, or
+// there can be four numbers separated by commas.
+int notcurses_lex_margins(const char* op, notcurses_options* opts);
+
 // Initialize a notcurses context on the connected terminal at 'fp'. 'fp' must
 // be a tty. You'll usually want stdout. Returns NULL on error, including any
 // failure initializing terminfo.
diff --git a/doc/man/man1/notcurses-view.1.md b/doc/man/man1/notcurses-view.1.md
index 3b0a6b7d6..b5970301d 100644
--- a/doc/man/man1/notcurses-view.1.md
+++ b/doc/man/man1/notcurses-view.1.md
@@ -23,10 +23,17 @@ and videos to the terminal. Media will be scaled to the terminal's size.
 
 **-s scalemode**: Scaling mode, one of **none**, **scale**, or **stretch**.
 
+**-m margins**: Define rendering margins (see below).
+
 **-k**: Inhibit use of the alternate screen. Necessary if you want the output left on your terminal after the program exits.
 
 files: Select which files to render, and what order to render them in.
 
+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
+to the same value, or four comma-delimited values for the top, right, bottom,
+and left margins respectively. Negative margins are illegal.
+
 # NOTES
 
 Optimal display requires a terminal advertising the **rgb** terminfo(5)
diff --git a/doc/man/man3/notcurses.3.md b/doc/man/man3/notcurses.3.md
index 57cc62c33..b82a392b1 100644
--- a/doc/man/man3/notcurses.3.md
+++ b/doc/man/man3/notcurses.3.md
@@ -97,6 +97,7 @@ particular EGC is heavily reused within a plane.
 
 A few high-level widgets are included, all built atop ncplanes:
 
+* **notcurses_fds(3)** for dumping file descriptors/subprocesses to a plane
 * **notcurses_menu(3)** for menu bars at the top or bottom of the screen
 * **notcurses_multiselector(3)** for selecting one or more items from a set
 * **notcurses_plot(3)** for drawing histograms and lineplots
diff --git a/doc/man/man3/notcurses_init.3.md b/doc/man/man3/notcurses_init.3.md
index 3d579fa30..8920107e1 100644
--- a/doc/man/man3/notcurses_init.3.md
+++ b/doc/man/man3/notcurses_init.3.md
@@ -23,7 +23,9 @@ typedef struct notcurses_options {
 } notcurses_options;
 ```
 
-**struct notcurses* notcurses_init(const struct notcurses_options* opts, FILE* fp);**
+**int notcurses_lex_margins(const char* op, notcurses_options* opts);**
+
+**struct notcurses* notcurses_init(const notcurses_options* opts, FILE* fp);**
 
 # DESCRIPTION
 
@@ -67,7 +69,11 @@ the full screen cleared, followed by rendering to a subregion. Inhibiting the
 alternate screen plus margins will see rendering to a subregion, with the screen
 outside this region not cleared. This is the only means by which existing
 output can be undisturbed by notcurses. Margins are best-effort. Supplying any
-negative margin is an error.
+negative margin is an error. **notcurses_lex_margins** provides lexing a
+margin argument expression in one of two forms:
+
+* a single number, which will be applied to all sides, or
+* four comma-delimited numbers, applied to top, right, bottom, and left.
 
 ## Fatal signals
 
diff --git a/include/notcurses/notcurses.h b/include/notcurses/notcurses.h
index 1d5aba8d0..0e197821a 100644
--- a/include/notcurses/notcurses.h
+++ b/include/notcurses/notcurses.h
@@ -785,6 +785,11 @@ typedef struct notcurses_options {
   int margin_t, margin_r, margin_b, margin_l;
 } notcurses_options;
 
+// Lex a margin argument according to the standard notcurses definition. There
+// can be either a single number, which will define all margins equally, or
+// there can be four numbers separated by commas.
+API int notcurses_lex_margins(const char* op, notcurses_options* opts);
+
 // Initialize a notcurses context on the connected terminal at 'fp'. 'fp' must
 // be a tty. You'll usually want stdout. Returns NULL on error, including any
 // failure initializing terminfo.
diff --git a/python/src/notcurses/build_notcurses.py b/python/src/notcurses/build_notcurses.py
index af4d105c8..e205c764e 100644
--- a/python/src/notcurses/build_notcurses.py
+++ b/python/src/notcurses/build_notcurses.py
@@ -79,6 +79,7 @@ typedef struct notcurses_options {
   int margin_t, margin_r, margin_b, margin_l;
 } notcurses_options;
 struct notcurses* notcurses_init(const notcurses_options*, FILE*);
+int notcurses_lex_margins(const char* op, notcurses_options* opts);
 int notcurses_stop(struct notcurses*);
 int notcurses_render(struct notcurses*);
 struct ncplane* notcurses_stdplane(struct notcurses*);
diff --git a/src/demo/demo.c b/src/demo/demo.c
index 7aa605269..d08f414e8 100644
--- a/src/demo/demo.c
+++ b/src/demo/demo.c
@@ -127,53 +127,6 @@ usage(const char* exe, int status){
   exit(status);
 }
 
-// extract an integer, which must be non-negative, and followed by either a
-// comma or a NUL terminator.
-static int
-lex_long(const char* op, int* i, char** endptr){
-  errno = 0;
-  long l = strtol(op, endptr, 10);
-  if(l < 0 || (l == LONG_MAX && errno == ERANGE) || (l > INT_MAX)){
-    fprintf(stderr, "Invalid margin: %s\n", op);
-    return -1;
-  }
-  if((**endptr != ',' && **endptr) || *endptr == op){
-    fprintf(stderr, "Invalid margin: %s\n", op);
-    return -1;
-  }
-  *i = l;
-  return 0;
-}
-
-static int
-lex_margins(const char* op, notcurses_options* opts){
-  if(opts->margin_t || opts->margin_r || opts->margin_b || opts->margin_l){
-    fprintf(stderr, "Provided margins twice!\n");
-    return -1;
-  }
-  char* eptr;
-  if(lex_long(op, &opts->margin_t, &eptr)){
-    return -1;
-  }
-  if(!*eptr){ // allow a single value to be specified for all four margins
-    opts->margin_r = opts->margin_l = opts->margin_b = opts->margin_t;
-    return 0;
-  }
-  op = ++eptr; // once here, we require four values
-  if(lex_long(op, &opts->margin_r, &eptr) || !*eptr){
-    return -1;
-  }
-  op = ++eptr;
-  if(lex_long(op, &opts->margin_b, &eptr) || !*eptr){
-    return -1;
-  }
-  op = ++eptr;
-  if(lex_long(op, &opts->margin_l, &eptr) || *eptr){ // must end in NUL
-    return -1;
-  }
-  return 0;
-}
-
 static demoresult*
 ext_demos(struct notcurses* nc, const char* spec, bool ignore_failures){
   int ret = 0;
@@ -255,7 +208,11 @@ handle_opts(int argc, char** argv, notcurses_options* opts, bool* ignore_failure
         }
         break;
       }case 'm':{
-        if(lex_margins(optarg, opts)){
+        if(opts->margin_t || opts->margin_r || opts->margin_b || opts->margin_l){
+          fprintf(stderr, "Provided margins twice!\n");
+          usage(*argv, EXIT_FAILURE);
+        }
+        if(notcurses_lex_margins(optarg, opts)){
           usage(*argv, EXIT_FAILURE);
         }
         break;
diff --git a/src/lib/notcurses.c b/src/lib/notcurses.c
index b51070e37..56322455a 100644
--- a/src/lib/notcurses.c
+++ b/src/lib/notcurses.c
@@ -1897,3 +1897,45 @@ bool ncplane_set_scrolling(ncplane* n, bool scrollp){
   n->scrolling = scrollp;
   return old;
 }
+
+// extract an integer, which must be non-negative, and followed by either a
+// comma or a NUL terminator.
+static int
+lex_long(const char* op, int* i, char** endptr){
+  errno = 0;
+  long l = strtol(op, endptr, 10);
+  if(l < 0 || (l == LONG_MAX && errno == ERANGE) || (l > INT_MAX)){
+    fprintf(stderr, "Invalid margin: %s\n", op);
+    return -1;
+  }
+  if((**endptr != ',' && **endptr) || *endptr == op){
+    fprintf(stderr, "Invalid margin: %s\n", op);
+    return -1;
+  }
+  *i = l;
+  return 0;
+}
+
+int notcurses_lex_margins(const char* op, notcurses_options* opts){
+  char* eptr;
+  if(lex_long(op, &opts->margin_t, &eptr)){
+    return -1;
+  }
+  if(!*eptr){ // allow a single value to be specified for all four margins
+    opts->margin_r = opts->margin_l = opts->margin_b = opts->margin_t;
+    return 0;
+  }
+  op = ++eptr; // once here, we require four values
+  if(lex_long(op, &opts->margin_r, &eptr) || !*eptr){
+    return -1;
+  }
+  op = ++eptr;
+  if(lex_long(op, &opts->margin_b, &eptr) || !*eptr){
+    return -1;
+  }
+  op = ++eptr;
+  if(lex_long(op, &opts->margin_l, &eptr) || *eptr){ // must end in NUL
+    return -1;
+  }
+  return 0;
+}
diff --git a/src/view/view.cpp b/src/view/view.cpp
index 1e62f184b..8ce3e0275 100644
--- a/src/view/view.cpp
+++ b/src/view/view.cpp
@@ -17,10 +17,11 @@ static void usage(std::ostream& os, const char* name, int exitcode)
   __attribute__ ((noreturn));
 
 void usage(std::ostream& o, const char* name, int exitcode){
-  o << "usage: " << name << " [ -h ] [ -l loglevel ] [ -d mult ] [ -s scaletype ] [ -k ] files" << '\n';
+  o << "usage: " << name << " [ -h ] [ -m margins ] [ -l loglevel ] [ -d mult ] [ -s scaletype ] [ -k ] files" << '\n';
   o << " -k: don't use the alternate screen\n";
   o << " -l loglevel: integer between 0 and 9, goes to stderr'\n";
   o << " -s scaletype: one of 'none', 'scale', or 'stretch'\n";
+  o << " -m margins: margin, or 4 comma-separated margins\n";
   o << " -d mult: non-negative floating point scale for frame time" << std::endl;
   exit(exitcode);
 }
@@ -104,7 +105,7 @@ int handle_opts(int argc, char** argv, notcurses_options& opts, float* timescale
   *timescale = 1.0;
   *scalemode = NCScale::Scale;
   int c;
-  while((c = getopt(argc, argv, "hl:d:s:k")) != -1){
+  while((c = getopt(argc, argv, "hl:d:s:m:k")) != -1){
     switch(c){
       case 'h':
         usage(std::cout, argv[0], EXIT_SUCCESS);
@@ -121,6 +122,15 @@ int handle_opts(int argc, char** argv, notcurses_options& opts, float* timescale
       case 'k':{
         opts.inhibit_alternate_screen = true;
         break;
+      }case 'm':{
+        if(opts.margin_t || opts.margin_r || opts.margin_b || opts.margin_l){
+          std::cerr <<  "Provided margins twice!" << std::endl;
+          usage(std::cerr, argv[0], EXIT_FAILURE);
+        }
+        if(notcurses_lex_margins(optarg, &opts)){
+          usage(std::cerr, argv[0], EXIT_FAILURE);
+        }
+        break;
       }case 'd':{
         std::stringstream ss;
         ss << optarg;