Add TUI paneling example

Makefile

@@ -137,7 +137,6 @@ include libc/testlib/testlib.mk
 include tool/viz/lib/vizlib.mk
 include third_party/lua/lua.mk
 include third_party/quickjs/quickjs.mk
-include examples/examples.mk
 include third_party/lz4cli/lz4cli.mk
 include tool/build/lib/buildlib.mk
 include third_party/chibicc/chibicc.mk
@@ -145,6 +144,7 @@ include third_party/chibicc/test/test.mk
 include tool/build/emucrt/emucrt.mk
 include tool/build/emubin/emubin.mk
 include tool/build/build.mk
+include examples/examples.mk
 include tool/decode/lib/decodelib.mk
 include tool/decode/decode.mk
 include tool/hash/hash.mk

examples/examples.mk

@@ -74,6 +74,7 @@ EXAMPLES_DIRECTDEPS =						\
 	THIRD_PARTY_STB						\
 	THIRD_PARTY_XED						\
 	THIRD_PARTY_ZLIB					\
+	TOOL_BUILD_LIB						\
 	TOOL_VIZ_LIB
 
 EXAMPLES_DEPS :=						\

examples/panels.c

@@ -0,0 +1,177 @@
+#if 0
+/*─────────────────────────────────────────────────────────────────╗
+│ To the extent possible under law, Justine Tunney has waived      │
+│ all copyright and related or neighboring rights to this file,    │
+│ as it is written in the following disclaimers:                   │
+│   • http://unlicense.org/                                        │
+│   • http://creativecommons.org/publicdomain/zero/1.0/            │
+╚─────────────────────────────────────────────────────────────────*/
+#endif
+#include "libc/calls/calls.h"
+#include "libc/calls/ioctl.h"
+#include "libc/calls/struct/sigaction.h"
+#include "libc/calls/struct/termios.h"
+#include "libc/calls/struct/winsize.h"
+#include "libc/log/check.h"
+#include "libc/log/gdb.h"
+#include "libc/log/log.h"
+#include "libc/macros.internal.h"
+#include "libc/runtime/gc.internal.h"
+#include "libc/runtime/runtime.h"
+#include "libc/str/str.h"
+#include "libc/sysv/consts/sa.h"
+#include "libc/sysv/consts/sig.h"
+#include "libc/sysv/consts/termios.h"
+#include "libc/x/x.h"
+#include "tool/build/lib/panel.h"
+
+/**
+ * @fileoverview Cosmopolitan Paneling Demo.
+ *
+ * This is useful for creating terminal user interfaces. We take the
+ * simplest approach possible. The main thing we abstract is like,
+ * truncating the lines that overflow within a panel. In order to do
+ * that, we abstract the ANSI parsing and the implementation is able to
+ * tell how many cells wide each UNICODE character is.
+ *
+ * There are smarter ways for Cosmopolitan to do this. For example, it'd
+ * be great to have automatic flex boxes. It'd also be nice to be able
+ * to use dynamic programming for low bandwidth display updates, like
+ * Emacs does, but that's less of an issue these days and can actually
+ * make things slower, since for heavy workloads like printing videos,
+ * having ANSI codes bouncing around the display actually goes slower.
+ *
+ * Beyond basic paneling, a message box widget is also provided, which
+ * makes it easier to do modal dialogs.
+ */
+
+struct Panels {
+  union {
+    struct {
+      struct Panel left;
+      struct Panel right;
+    };
+    struct Panel p[2];
+  };
+} pan;
+
+long tyn;
+long txn;
+char key[8];
+bool shutdown;
+bool invalidated;
+struct termios oldterm;
+
+void OnShutdown(int sig) {
+  shutdown = true;
+}
+
+void OnInvalidate(int sig) {
+  invalidated = true;
+}
+
+void GetTtySize(void) {
+  struct winsize wsize;
+  wsize.ws_row = tyn;
+  wsize.ws_col = txn;
+  getttysize(1, &wsize);
+  tyn = wsize.ws_row;
+  txn = wsize.ws_col;
+}
+
+int Write(const char *s) {
+  return write(1, s, strlen(s));
+}
+
+void Setup(void) {
+  CHECK_NE(-1, ioctl(1, TCGETS, &oldterm));
+}
+
+void Enter(void) {
+  struct termios term;
+  memcpy(&term, &oldterm, sizeof(term));
+  term.c_cc[VMIN] = 1;
+  term.c_cc[VTIME] = 1;
+  term.c_iflag &= ~(INPCK | ISTRIP | PARMRK | INLCR | IGNCR | ICRNL | IXON);
+  term.c_lflag &= ~(IEXTEN | ICANON | ECHO | ECHONL);
+  term.c_cflag &= ~(CSIZE | PARENB);
+  term.c_cflag |= CS8;
+  term.c_iflag |= IUTF8;
+  CHECK_NE(-1, ioctl(1, TCSETS, &term));
+  Write("\e[?25l");
+}
+
+void Leave(void) {
+  Write(gc(xasprintf("\e[?25h\e[%d;%dH\e[S\r\n", tyn, txn)));
+  ioctl(1, TCSETS, &oldterm);
+}
+
+void Clear(void) {
+  long i, j;
+  for (i = 0; i < ARRAYLEN(pan.p); ++i) {
+    for (j = 0; j < pan.p[i].n; ++j) {
+      free(pan.p[i].lines[j].p);
+    }
+    free(pan.p[i].lines);
+    pan.p[i].lines = 0;
+    pan.p[i].n = 0;
+  }
+}
+
+void Layout(void) {
+  long i, j;
+  i = txn >> 1;
+  pan.left.top = 0;
+  pan.left.left = 0;
+  pan.left.bottom = tyn;
+  pan.left.right = i;
+  pan.right.top = 0;
+  pan.right.left = i + 1;
+  pan.right.bottom = tyn;
+  pan.right.right = txn;
+  pan.left.n = pan.left.bottom - pan.left.top;
+  pan.left.lines = xcalloc(pan.left.n, sizeof(*pan.left.lines));
+  pan.right.n = pan.right.bottom - pan.right.top;
+  pan.right.lines = xcalloc(pan.right.n, sizeof(*pan.right.lines));
+}
+
+void Append(struct Panel *p, int i, const char *s) {
+  if (i >= p->n) return;
+  AppendStr(p->lines + i, s);
+}
+
+void Draw(void) {
+  Append(&pan.left, 0, gc(xasprintf("you typed %`'s", key)));
+  Append(&pan.left, ((tyn + 1) >> 1) + 0, "hello left 1 𐌰𐌱𐌲𐌳𐌴𐌵𐌶𐌷");
+  Append(&pan.left, ((tyn + 1) >> 1) + 1, "hello left 2 (╯°□°)╯");
+  Append(&pan.right, ((tyn + 1) >> 1) + 0, "hello right 1");
+  Append(&pan.right, ((tyn + 1) >> 1) + 1, "hello right 2");
+  PrintPanels(1, ARRAYLEN(pan.p), pan.p, tyn, txn);
+}
+
+int main(int argc, char *argv[]) {
+  struct sigaction sa[2] = {
+      {.sa_handler = OnShutdown},
+      {.sa_handler = OnInvalidate, .sa_flags = SA_RESTART},
+  };
+  showcrashreports();
+  Setup();
+  Enter();
+  GetTtySize();
+  sigaction(SIGINT, &sa[0], 0);
+  sigaction(SIGCONT, &sa[1], 0);
+  sigaction(SIGWINCH, &sa[1], 0);
+  atexit(Leave);
+  do {
+    Clear();
+    Layout();
+    Draw();
+    if (invalidated) {
+      Enter();
+      GetTtySize();
+      invalidated = false;
+    } else {
+      readansi(0, key, sizeof(key));
+    }
+  } while (!shutdown);
+}