Misc #215: Reformat usage text & update docs

 - Reformat usage text by adding a blank line between descriptions of
   two switches. (#215)

 - Update documentation for a bit. Correct some wrong statements and
   clarify some others.
(cherry picked from commit 07b75620487436a0e693d3a13354dba346a463f2)

1 files changed, 87 insertions, 11 deletions

diff --git a/twin/compton-tde/compton.c b/twin/compton-tde/compton.c
index d8f6223f6..7b195f5b0 100644
--- a/twin/compton-tde/compton.c
+++ b/twin/compton-tde/compton.c
@@ -5153,88 +5153,126 @@ usage(int ret) {
     "\n"
     "-d display\n"
     "  Which display should be managed.\n"
+    "\n"
     "-r radius\n"
     "  The blur radius for shadows. (default 12)\n"
+    "\n"
     "-o opacity\n"
     "  The translucency for shadows. (default .75)\n"
+    "\n"
     "-l left-offset\n"
     "  The left offset for shadows. (default -15)\n"
+    "\n"
     "-t top-offset\n"
     "  The top offset for shadows. (default -15)\n"
+    "\n"
     "-I fade-in-step\n"
     "  Opacity change between steps while fading in. (default 0.028)\n"
+    "\n"
     "-O fade-out-step\n"
     "  Opacity change between steps while fading out. (default 0.03)\n"
+    "\n"
     "-D fade-delta-time\n"
     "  The time between steps in a fade in milliseconds. (default 10)\n"
+    "\n"
     "-m opacity\n"
     "  The opacity for menus. (default 1.0)\n"
+    "\n"
     "-c\n"
     "  Enabled client-side shadows on windows.\n"
+    "\n"
     "-C\n"
     "  Avoid drawing shadows on dock/panel windows.\n"
+    "\n"
     "-z\n"
-    "  Zero the part of the shadow's mask behind the window (experimental).\n"
+    "  Zero the part of the shadow's mask behind the window.\n"
+    "\n"
     "-f\n"
     "  Fade windows in/out when opening/closing and when opacity\n"
     "  changes, unless --no-fading-openclose is used.\n"
+    "\n"
     "-F\n"
-    "  Equals -f. Deprecated.\n"
+    "  Equals to -f. Deprecated.\n"
+    "\n"
     "-i opacity\n"
     "  Opacity of inactive windows. (0.1 - 1.0)\n"
+    "\n"
     "-e opacity\n"
     "  Opacity of window titlebars and borders. (0.1 - 1.0)\n"
+    "\n"
     "-G\n"
     "  Don't draw shadows on DND windows\n"
+    "\n"
     "-b\n"
     "  Daemonize process.\n"
+    "\n"
     "-S\n"
     "  Enable synchronous operation (for debugging).\n"
+    "\n"
     "--show-all-xerrors\n"
     "  Show all X errors (for debugging).\n"
+    "\n"
     "-v\n"
-    "  Print version Number and exit\\n"
+    "  Print version Number and exit\n"
     "--config path\n"
-    "  Look for configuration file at the path.\n"
+    "  Look for configuration file at the path. Use /dev/null to avoid\n"
+    "  loading configuration file.\n"
+    "\n"
     "--write-pid-path path\n"
     "  Write process ID to a file.\n"
+    "\n"
     "--shadow-red value\n"
     "  Red color value of shadow (0.0 - 1.0, defaults to 0).\n"
+    "\n"
     "--shadow-green value\n"
     "  Green color value of shadow (0.0 - 1.0, defaults to 0).\n"
+    "\n"
     "--shadow-blue value\n"
     "  Blue color value of shadow (0.0 - 1.0, defaults to 0).\n"
+    "\n"
     "--inactive-opacity-override\n"
     "  Inactive opacity set by -i overrides value of _NET_WM_OPACITY.\n"
+    "\n"
     "--inactive-dim value\n"
     "  Dim inactive windows. (0.0 - 1.0, defaults to 0)\n"
+    "\n"
     "--active-opacity opacity\n"
     "  Default opacity for active windows. (0.0 - 1.0)\n"
+    "\n"
     "--mark-wmwin-focused\n"
     "  Try to detect WM windows and mark them as active.\n"
+    "\n"
     "--shadow-exclude condition\n"
     "  Exclude conditions for shadows.\n"
+    "\n"
     "--fade-exclude condition\n"
     "  Exclude conditions for fading.\n"
+    "\n"
     "--mark-ovredir-focused\n"
     "  Mark windows that have no WM frame as active.\n"
+    "\n"
     "--no-fading-openclose\n"
     "  Do not fade on window open/close.\n"
+    "\n"
     "--no-fading-destroyed-argb\n"
     "  Do not fade destroyed ARGB windows with WM frame. Workaround of bugs\n"
     "  in Openbox, Fluxbox, etc.\n"
+    "\n"
     "--no-fading-opacitychange\n"
     "  Do not fade on window opacity change.\n"
+    "\n"
     "--shadow-ignore-shaped\n"
     "  Do not paint shadows on shaped windows. (Deprecated, use\n"
     "  --shadow-exclude \'bounding_shaped\' or\n"
     "  --shadow-exclude \'bounding_shaped && !rounded_corners\' instead.)\n"
+    "\n"
     "--detect-rounded-corners\n"
     "  Try to detect windows with rounded corners and don't consider\n"
     "  them shaped windows. Affects --shadow-ignore-shaped,\n"
     "  --unredir-if-possible, and possibly others. You need to turn this\n"
     "  on manually if you want to match against rounded_corners in\n"
     "  conditions.\n"
+    "\n"
     "--detect-client-opacity\n"
     "  Detect _NET_WM_OPACITY on client windows, useful for window\n"
     "  managers not passing _NET_WM_OPACITY of client windows to frame\n"
@@ -5244,11 +5282,14 @@ usage(int ret) {
 #else
 #define WARNING
 #endif
+    "\n"
     "--refresh-rate val\n"
     "  Specify refresh rate of the screen. If not specified or 0, compton\n"
     "  will try detecting this with X RandR extension."WARNING"\n"
+    "\n"
     "--vsync vsync-method\n"
-    "  Set VSync method. There are up to 4 VSync methods currently available.\n"
+    "  Set VSync method. There are (up to) 5 VSync methods currently\n"
+    "  available:\n"
     "    none = No VSync\n"
 #undef WARNING
 #ifndef CONFIG_VSYNC_DRM
@@ -5257,7 +5298,7 @@ usage(int ret) {
 #define WARNING
 #endif
     "    drm = VSync with DRM_IOCTL_WAIT_VBLANK. May only work on some\n"
-    "      drivers." WARNING "\n"
+    "      (DRI-based) drivers." WARNING "\n"
 #undef WARNING
 #ifndef CONFIG_VSYNC_OPENGL
 #define WARNING WARNING_DISABLED
@@ -5267,67 +5308,82 @@ usage(int ret) {
     "    opengl = Try to VSync with SGI_video_sync OpenGL extension. Only\n"
     "      work on some drivers." WARNING"\n"
     "    opengl-oml = Try to VSync with OML_sync_control OpenGL extension.\n"
-    "      Only work on some drivers. Experimental." WARNING"\n"
+    "      Only work on some drivers." WARNING"\n"
     "    opengl-swc = Try to VSync with SGI_swap_control OpenGL extension.\n"
-    "      Only work on some drivers. Works only with GLX backend.\n"
-    "      Does not actually control paint timing, only buffer swap is\n"
-    "      affected, so it doesn't have the effect of --sw-opti unlike\n"
-    "      other methods." WARNING "\n"
+    "      Only work on some drivers. Works only with GLX backend." WARNING "\n"
     "    opengl-mswc = Try to VSync with MESA_swap_control OpenGL\n"
     "      extension. Basically the same as opengl-swc above, except the\n"
     "      extension we use." WARNING "\n"
+    "\n"
     "--vsync-aggressive\n"
     "  Attempt to send painting request before VBlank and do XFlush()\n"
     "  during VBlank. This switch may be lifted out at any moment.\n"
+    "\n"
     "--alpha-step val\n"
     "  X Render backend: Step for pregenerating alpha pictures. \n"
     "  0.01 - 1.0. Defaults to 0.03.\n"
+    "\n"
     "--dbe\n"
     "  Enable DBE painting mode, intended to use with VSync to\n"
     "  (hopefully) eliminate tearing.\n"
+    "\n"
     "--paint-on-overlay\n"
     "  Painting on X Composite overlay window.\n"
+    "\n"
     "--sw-opti\n"
     "  Limit compton to repaint at most once every 1 / refresh_rate\n"
     "  second to boost performance.\n"
+    "\n"
     "--use-ewmh-active-win\n"
     "  Use _NET_WM_ACTIVE_WINDOW on the root window to determine which\n"
     "  window is focused instead of using FocusIn/Out events.\n"
+    "\n"
     "--respect-prop-shadow\n"
     "  Respect _TDE_WM_WINDOW_SHADOW. This a prototype-level feature, which\n"
     "  you must not rely on.\n"
+    "\n"
     "--unredir-if-possible\n"
     "  Unredirect all windows if a full-screen opaque window is\n"
     "  detected, to maximize performance for full-screen windows.\n"
+    "\n"
     "--unredir-if-possible-delay ms\n"
     "  Delay before unredirecting the window, in milliseconds.\n"
     "  Defaults to 0.\n"
+    "\n"
     "--unredir-if-possible-exclude condition\n"
     "  Conditions of windows that shouldn't be considered full-screen\n"
     "  for unredirecting screen.\n"
+    "\n"
     "--focus-exclude condition\n"
     "  Specify a list of conditions of windows that should always be\n"
     "  considered focused.\n"
+    "\n"
     "--inactive-dim-fixed\n"
     "  Use fixed inactive dim value.\n"
+    "\n"
     "--detect-transient\n"
     "  Use WM_TRANSIENT_FOR to group windows, and consider windows in\n"
     "  the same group focused at the same time.\n"
+    "\n"
     "--detect-client-leader\n"
     "  Use WM_CLIENT_LEADER to group windows, and consider windows in\n"
     "  the same group focused at the same time. WM_TRANSIENT_FOR has\n"
     "  higher priority if --detect-transient is enabled, too.\n"
+    "\n"
     "--blur-background\n"
     "  Blur background of semi-transparent / ARGB windows. Bad in\n"
     "  performance. The switch name may change without prior\n"
     "  notifications.\n"
+    "\n"
     "--blur-background-frame\n"
     "  Blur background of windows when the window frame is not opaque.\n"
     "  Implies --blur-background. Bad in performance. The switch name\n"
     "  may change.\n"
+    "\n"
     "--blur-background-fixed\n"
     "  Use fixed blur strength instead of adjusting according to window\n"
     "  opacity.\n"
+    "\n"
     "--blur-kern matrix\n"
     "  Specify the blur convolution kernel, with the following format:\n"
     "    WIDTH,HEIGHT,ELE1,ELE2,ELE3,ELE4,ELE5...\n"
@@ -5341,6 +5397,7 @@ usage(int ret) {
     "  May also be one the predefined kernels: 3x3box (default), 5x5box,\n"
     "  7x7box, 3x3gaussian, 5x5gaussian, 7x7gaussian, 9x9gaussian,\n"
     "  11x11gaussian.\n"
+    "\n"
     "--blur-background-exclude condition\n"
     "  Exclude conditions for background blur.\n"
     "--greyscale-background\n"
@@ -5348,20 +5405,24 @@ usage(int ret) {
     "  The switch name may change without prior notifications.\n"
     "--greyscale-background-exclude condition\n"
     "  Exclude conditions for greyscale background.\n"
+    "\n"
     "--resize-damage integer\n"
     "  Resize damaged region by a specific number of pixels. A positive\n"
     "  value enlarges it while a negative one shrinks it. Useful for\n"
     "  fixing the line corruption issues of blur. May or may not\n"
     "  work with --glx-no-stencil. Shrinking doesn't function correctly.\n"
+    "\n"
     "--invert-color-include condition\n"
     "  Specify a list of conditions of windows that should be painted with\n"
     "  inverted color. Resource-hogging, and is not well tested.\n"
+    "\n"
     "--opacity-rule opacity:condition\n"
     "  Specify a list of opacity rules, in the format \"PERCENT:PATTERN\",\n"
     "  like \'50:name *= \"Firefox\"'. compton-trans is recommended over\n"
     "  this. Note we do not distinguish 100% and unset, and we don't make\n"
     "  any guarantee about possible conflicts with other programs that set\n"
     "  _NET_WM_WINDOW_OPACITY on frame or client windows.\n"
+    "\n"
     "--shadow-exclude-reg geometry\n"
     "  Specify a X geometry that describes the region in which shadow\n"
     "  should not be painted in, such as a dock window region.\n"
@@ -5373,32 +5434,39 @@ usage(int ret) {
 #else
 #define WARNING
 #endif
+    "\n"
     "--xinerama-shadow-crop\n"
     "  Crop shadow of a window fully on a particular Xinerama screen to the\n"
     "  screen." WARNING "\n"
+    "\n"
     "--backend backend\n"
     "  Choose backend. Possible choices are xrender, glx, and\n"
     "  xr_glx_hybrid" WARNING ".\n"
+    "\n"
     "--glx-no-stencil\n"
     "  GLX backend: Avoid using stencil buffer. Might cause issues\n"
     "  when rendering transparent content. My tests show a 15% performance\n"
     "  boost.\n"
+    "\n"
     "--glx-copy-from-front\n"
     "  GLX backend: Copy unmodified regions from front buffer instead of\n"
     "  redrawing them all. My tests with nvidia-drivers show a 5% decrease\n"
     "  in performance when the whole screen is modified, but a 30% increase\n"
     "  when only 1/4 is. My tests on nouveau show terrible slowdown. Could\n"
     "  work with --glx-swap-method but not --glx-use-copysubbuffermesa.\n"
+    "\n"
     "--glx-use-copysubbuffermesa\n"
     "  GLX backend: Use MESA_copy_sub_buffer to do partial screen update.\n"
     "  My tests on nouveau shows a 200% performance boost when only 1/4 of\n"
     "  the screen is updated. May break VSync and is not available on some\n"
     "  drivers. Overrides --glx-copy-from-front.\n"
+    "\n"
     "--glx-no-rebind-pixmap\n"
     "  GLX backend: Avoid rebinding pixmap on window damage. Probably\n"
     "  could improve performance on rapid window content changes, but is\n"
     "  known to break things on some drivers (LLVMpipe, xf86-video-intel,\n"
     "  etc.).\n"
+    "\n"
     "--glx-swap-method undefined/copy/exchange/3/4/5/6/buffer-age\n"
     "  GLX backend: GLX buffer swap method we assume. Could be\n"
     "  undefined (0), copy (1), exchange (2), 3-6, or buffer-age (-1).\n"
@@ -5407,9 +5475,11 @@ usage(int ret) {
     "  but safer (6 is still faster than 0). -1 means auto-detect using\n"
     "  GLX_EXT_buffer_age, supported by some drivers. Useless with\n"
     "  --glx-use-copysubbuffermesa.\n"
+    "\n"
     "--glx-use-gpushader4\n"
     "  GLX backend: Use GL_EXT_gpu_shader4 for some optimization on blur\n"
     "  GLSL code. My tests on GTX 670 show no noticeable effect.\n"
+    "\n"
     "--xrender-sync\n"
     "  Attempt to synchronize client applications' draw calls with XSync(),\n"
     "  used on GLX backend to ensure up-to-date window content is painted.\n"
@@ -5419,6 +5489,7 @@ usage(int ret) {
 #else
 #define WARNING
 #endif
+    "\n"
     "--xrender-sync-fence\n"
     "  Additionally use X Sync fence to sync clients' draw calls. Needed\n"
     "  on nvidia-drivers with GLX backend for some users." WARNING "\n"
@@ -5428,17 +5499,22 @@ usage(int ret) {
 #else
 #define WARNING
 #endif
+    "\n"
     "--glx-fshader-win shader\n"
     "  GLX backend: Use specified GLSL fragment shader for rendering window\n"
     "  contents.\n"
+    "\n"
     "--force-win-blend\n"
     "  Force all windows to be painted with blending. Useful if you have a\n"
     "  --glx-fshader-win that could turn opaque pixels transparent.\n"
+    "\n"
     "--dbus\n"
     "  Enable remote control via D-Bus. See the D-BUS API section in the\n"
     "  man page for more details." WARNING "\n"
+    "\n"
     "--benchmark cycles\n"
     "  Benchmark mode. Repeatedly paint until reaching the specified cycles.\n"
+    "\n"
     "--benchmark-wid window-id\n"
     "  Specify window ID to repaint in benchmark mode. If omitted or is 0,\n"
     "  the whole screen is repainted.\n"