From 4da626639f5cf9b7916fff18f7d36cc0eebaecda Mon Sep 17 00:00:00 2001
From: Yuxuan Shui <yshuiv7@gmail.com>
Date: Mon, 24 Sep 2018 00:13:08 +0100
Subject: [PATCH] Update comments about clear-shadow

---
 dbus-examples/cdbus-driver.sh |  6 -----
 src/compton.c                 | 44 ++++++++++-------------------------
 src/win.c                     |  9 +++----
 3 files changed, 15 insertions(+), 44 deletions(-)

diff --git a/dbus-examples/cdbus-driver.sh b/dbus-examples/cdbus-driver.sh
index 157ac747..6215816f 100755
--- a/dbus-examples/cdbus-driver.sh
+++ b/dbus-examples/cdbus-driver.sh
@@ -41,12 +41,6 @@ else
   echo "Cannot find focused window."
 fi
 
-# Set the clear_shadow setting to true
-dbus-send --print-reply --dest="$service" "$object" "${interface}.opts_set" string:clear_shadow boolean:true
-
-# Get the clear_shadow setting
-dbus-send --print-reply --dest="$service" "$object" "${interface}.opts_get" string:clear_shadow
-
 # Reset compton
 sleep 3
 dbus-send --print-reply --dest="$service" "$object" "${interface}.reset"
diff --git a/src/compton.c b/src/compton.c
index d2b1f4c3..cf6ebb8f 100644
--- a/src/compton.c
+++ b/src/compton.c
@@ -532,20 +532,18 @@ make_shadow(session_t *ps, double opacity,
    * center (fill the complete data array)
    */
 
-  // If clear_shadow is enabled and the border & corner shadow (which
-  // later will be filled) could entirely cover the area of the shadow
-  // that will be displayed, do not bother filling other pixels. If it
-  // can't, we must fill the other pixels here.
-  /* if (!(clear_shadow && ps->o.shadow_offset_x <= 0 && ps->o.shadow_offset_x >= -ps->cgsize
-        && ps->o.shadow_offset_y <= 0 && ps->o.shadow_offset_y >= -ps->cgsize)) { */
-    if (ps->cgsize > 0) {
-      d = ps->shadow_top[opacity_int * (ps->cgsize + 1) + ps->cgsize];
-    } else {
-      d = sum_gaussian(ps->gaussian_map,
-        opacity, center, center, width, height);
-    }
-    memset(data, d, sheight * swidth);
-  // }
+  // XXX If the center part of the shadow would be entirely covered by
+  // the body of the window, we shouldn't need to fill the center here.
+  // XXX In general, we want to just fill the part that is not behind
+  // the window, in order to reduce CPU load and make transparent window
+  // look correct
+  if (ps->cgsize > 0) {
+    d = ps->shadow_top[opacity_int * (ps->cgsize + 1) + ps->cgsize];
+  } else {
+    d = sum_gaussian(ps->gaussian_map,
+      opacity, center, center, width, height);
+  }
+  memset(data, d, sheight * swidth);
 
   /*
    * corners
@@ -608,24 +606,6 @@ make_shadow(session_t *ps, double opacity,
     }
   }
 
-  /*
-  if (clear_shadow) {
-    // Clear the region in the shadow that the window would cover based
-    // on shadow_offset_{x,y} user provides
-    int xstart = normalize_i_range(- (int) ps->o.shadow_offset_x, 0, swidth);
-    int xrange = normalize_i_range(width - (int) ps->o.shadow_offset_x,
-        0, swidth) - xstart;
-    int ystart = normalize_i_range(- (int) ps->o.shadow_offset_y, 0, sheight);
-    int yend = normalize_i_range(height - (int) ps->o.shadow_offset_y,
-        0, sheight);
-    int y;
-
-    for (y = ystart; y < yend; y++) {
-      memset(&data[y * swidth + xstart], 0, xrange);
-    }
-  }
-  */
-
   return ximage;
 }
 
diff --git a/src/win.c b/src/win.c
index faf6c6d3..96833a40 100644
--- a/src/win.c
+++ b/src/win.c
@@ -407,12 +407,9 @@ void win_update_shape(session_t *ps, win *w) {
 
     win_on_factor_change(ps, w);
 
-    /*
-    // If clear_shadow state on the window possibly changed, destroy the old
-    // shadow_pict
-    if (ps->o.clear_shadow && w->bounding_shaped != bounding_shaped_old)
-      free_paint(ps, &w->shadow_paint);
-    */
+    // XXX Window shape changed, and if we didn't fill in the pixels
+    // behind the window (not implemented yet), we should rebuild
+    // the shadow_pict
   }
 }