Initial import of xrectsel source

Note the prior history is left in FFcast.git

.gitattributes

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+.git* export-ignore

.gitignore

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+.deps/
+aclocal.m4
+autom4te.cache/
+build-aux/
+config.log
+config.status
+config.status.lineno
+configure
+configure.lineno
+Makefile
+Makefile.in
+xrectsel
+xrectsel-*.tar.gz
+*.o
+*~

Makefile.am

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+AM_CFLAGS = -std=c99 -pedantic -Wall -Wextra -Wno-variadic-macros
+bin_PROGRAMS = xrectsel

README.md

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+xrectsel
+========
+
+`xrectsel` is a small program that tells you the geometry of a rectangular
+screen region which you have selected by dragging the mouse / pointer.
+
+When arguments are passed to `xrectsel`, a limited set of `%` format strings
+are recognized and substituted. Look at the source to see what are supported.
+
+`xrectsel` requires `libX11` to build.
+
+To build and install from source,
+
+    ./bootstrap  # required if ./configure is not present
+    ./configure --prefix /usr
+    make
+    make DESTDIR="$directory" install

bootstrap

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+autoreconf -vi

configure.ac

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+AC_INIT([xrectsel], [0.3])
+AC_CONFIG_AUX_DIR([build-aux])
+AM_INIT_AUTOMAKE([foreign subdir-objects])
+AC_PROG_CC
+AC_SEARCH_LIBS([XOpenDisplay], [X11], , AC_MSG_ERROR([libx11 is required]))
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT

xrectsel.c

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+/* xrectsel.c -- print the geometry of a rectangular screen region.
+
+   Copyright (C) 2011-2014  lolilolicon <lolilolicon@gmail.com>
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+#include <X11/Xlib.h>
+#include <X11/cursorfont.h>
+
+#define die(args...) do {error(args); exit(EXIT_FAILURE); } while(0)
+
+typedef struct Region Region;
+struct Region {
+  Window root;
+  int x; /* offset from left of screen */
+  int y; /* offset from top of screen */
+  int X; /* offset from right of screen */
+  int Y; /* offset from bottom of screen */
+  unsigned int w; /* width */
+  unsigned int h; /* height */
+  unsigned int b; /* border_width */
+  unsigned int d; /* depth */
+};
+
+static void error(const char *errstr, ...);
+static int print_region_attr(const char *fmt, Region region);
+static int select_region(Display *dpy, Window root, Region *region);
+
+int main(int argc, const char *argv[])
+{
+  Display *dpy;
+  Window root;
+  Region sr; /* selected region */
+  const char *fmt; /* format string */
+
+  dpy = XOpenDisplay(NULL);
+  if (!dpy) {
+    die("failed to open display %s\n", getenv("DISPLAY"));
+  }
+
+  root = DefaultRootWindow(dpy);
+
+  fmt = argc > 1 ? argv[1] : "%wx%h+%x+%y\n";
+
+  /* interactively select a rectangular region */
+  if (select_region(dpy, root, &sr) != EXIT_SUCCESS) {
+    XCloseDisplay(dpy);
+    die("failed to select a rectangular region\n");
+  }
+
+  print_region_attr(fmt, sr);
+
+  XCloseDisplay(dpy);
+  return EXIT_SUCCESS;
+}
+
+static void error(const char *errstr, ...)
+{
+  va_list ap;
+
+  fprintf(stderr, "xrectsel: ");
+  va_start(ap, errstr);
+  vfprintf(stderr, errstr, ap);
+  va_end(ap);
+}
+
+static int print_region_attr(const char *fmt, Region region)
+{
+  const char *s;
+
+  for (s = fmt; *s; ++s) {
+    if (*s == '%') {
+      switch (*++s) {
+        case '%':
+          putchar('%');
+          break;
+        case 'x':
+          printf("%i", region.x);
+          break;
+        case 'y':
+          printf("%i", region.y);
+          break;
+        case 'X':
+          printf("%i", region.X);
+          break;
+        case 'Y':
+          printf("%i", region.Y);
+          break;
+        case 'w':
+          printf("%u", region.w);
+          break;
+        case 'h':
+          printf("%u", region.h);
+          break;
+        case 'b':
+          printf("%u", region.b);
+          break;
+        case 'd':
+          printf("%u", region.d);
+          break;
+      }
+    } else {
+      putchar(*s);
+    }
+  }
+
+  return 0;
+}
+
+static int select_region(Display *dpy, Window root, Region *region)
+{
+  XEvent ev;
+
+  GC sel_gc;
+  XGCValues sel_gv;
+
+  int done = 0, btn_pressed = 0;
+  int x = 0, y = 0;
+  unsigned int width = 0, height = 0;
+  int start_x = 0, start_y = 0;
+
+  Cursor cursor;
+  cursor = XCreateFontCursor(dpy, XC_crosshair);
+
+  /* Grab pointer for these events */
+  XGrabPointer(dpy, root, True, PointerMotionMask | ButtonPressMask | ButtonReleaseMask,
+               GrabModeAsync, GrabModeAsync, None, cursor, CurrentTime);
+
+  sel_gv.function = GXinvert;
+  sel_gv.subwindow_mode = IncludeInferiors;
+  sel_gv.line_width = 1;
+  sel_gc = XCreateGC(dpy, root, GCFunction | GCSubwindowMode | GCLineWidth, &sel_gv);
+
+  for (;;) {
+    XNextEvent(dpy, &ev);
+    switch (ev.type) {
+      case ButtonPress:
+        btn_pressed = 1;
+        x = start_x = ev.xbutton.x_root;
+        y = start_y = ev.xbutton.y_root;
+        width = height = 0;
+        break;
+      case MotionNotify:
+        /* Draw only if button is pressed */
+        if (btn_pressed) {
+          /* Re-draw last Rectangle to clear it */
+          XDrawRectangle(dpy, root, sel_gc, x, y, width, height);
+
+          x = ev.xbutton.x_root;
+          y = ev.xbutton.y_root;
+
+          if (x > start_x) {
+            width = x - start_x;
+            x = start_x;
+          } else {
+            width = start_x - x;
+          }
+          if (y > start_y) {
+            height = y - start_y;
+            y = start_y;
+          } else {
+            height = start_y - y;
+          }
+
+          /* Draw Rectangle */
+          XDrawRectangle(dpy, root, sel_gc, x, y, width, height);
+          XFlush(dpy);
+        }
+        break;
+      case ButtonRelease:
+        done = 1;
+        break;
+      default:
+        break;
+    }
+    if (done)
+      break;
+  }
+
+  /* Re-draw last Rectangle to clear it */
+  XDrawRectangle(dpy, root, sel_gc, x, y, width, height);
+  XFlush(dpy);
+
+  XUngrabPointer(dpy, CurrentTime);
+  XFreeCursor(dpy, cursor);
+  XFreeGC(dpy, sel_gc);
+  XSync(dpy, 1);
+
+  Region rr; /* root region */
+  Region sr; /* selected region */
+
+  if (False == XGetGeometry(dpy, root, &rr.root, &rr.x, &rr.y, &rr.w, &rr.h, &rr.b, &rr.d)) {
+    error("failed to get root window geometry\n");
+    return EXIT_FAILURE;
+  }
+  sr.x = x;
+  sr.y = y;
+  sr.w = width;
+  sr.h = height;
+  /* calculate right and bottom offset */
+  sr.X = rr.w - sr.x - sr.w;
+  sr.Y = rr.h - sr.y - sr.h;
+  /* those doesn't really make sense but should be set */
+  sr.b = rr.b;
+  sr.d = rr.d;
+  *region = sr;
+  return EXIT_SUCCESS;
+}