[WIP] configurable dim rules over dbus

compton.sample.conf

@@ -28,8 +28,6 @@ inactive-opacity = 0.8;
 frame-opacity = 0.7;
 inactive-opacity-override = false;
 alpha-step = 0.06;
-# inactive-dim = 0.2;
-# inactive-dim-fixed = true;
 # blur-background = true;
 # blur-background-frame = true;
 blur-kern = "3x3box";
@@ -42,6 +40,11 @@ blur-background-exclude = [
 ];
 # opacity-rule = [ "80:class_g = 'URxvt'" ];
 
+# Dimming
+# inactive-dim = 0.2;
+# inactive-dim-fixed = true;
+# dim-rule = [ "50:!(class_g ~= '^(URxvt|mpv|Sxiv)$' || _NET_WM_WINDOW_TYPE@:a *= 'DOCK')" ];
+
 # Fading
 fading = true;
 # fade-delta = 30;

dbus-examples/ambient-dim.sh

@@ -0,0 +1,174 @@
+#!/bin/bash
+
+# === Get connection parameters ===
+
+dpy=$(echo -n "$DISPLAY" | tr -c '[:alnum:]' _)
+unbright="/dev/shm/unbright.$dpy"
+
+if [ -z "$dpy" ]; then
+    echo "Cannot find display."
+    exit 1;
+fi
+
+service="com.github.chjj.compton.${dpy}"
+interface="com.github.chjj.compton"
+
+compton_dbus="dbus-send --print-reply=literal --dest="${service}" / "${interface}"."
+compton_dbus_h="dbus-send --print-reply --dest="${service}" / "${interface}"."
+
+# === Get camera device ===
+if [[ -z "$1" ]] || [[ ! -c "$1" ]]; then
+    echo "usage: $0 <camera device>"
+    exit 1
+else
+    cam="$1"
+fi
+
+# === Sample parameters ===
+
+max_dim=65
+frame_ms=30
+rule='!(class_g ~= "^(URxvt|mpv|Sxiv|syncterm|XTerm|stellarium|XEphem)$" || _NET_WM_WINDOW_TYPE@:32a *= "DOCK")'
+
+# === Trap ===
+
+trap 'kill $(jobs -p); _remove; _repaint;' EXIT
+
+_insert() {
+    ${compton_dbus}dim_rule_update string:insert string:"${1}:${rule}" 2>/dev/null
+}
+
+_remove() {
+    if [ ! -z "$last_repr" ]; then
+        ${compton_dbus}dim_rule_update string:remove string:"$last_repr" >/dev/null 2>&1
+        if [[ $? -ne 0 ]]; then
+            # Exiting during set_dim(). Fingers crossed we're removing the
+            # right thing
+            last_repr=$(${compton_dbus_h}opts_get string:dim-rule | \
+                grep -m1 -Po '(?<=string ").*(?=")')
+            _remove
+        fi
+    fi
+}
+
+_replace() {
+    ${compton_dbus}dim_rule_update string:replace string:"$last_repr" string:"${1}:${rule}"
+}
+
+_repaint() {
+    ${compton_dbus}repaint >/dev/null
+}
+
+set_dim() {
+    local new
+    if [[ -z "$last_repr" ]]; then
+        new=$(_insert $1)
+    else
+        new=$(_replace $1)
+    fi
+    last_repr=${new:3}
+    last_dim="$1"
+    _repaint
+}
+
+_normalize() {
+    old_min=$1
+    old_max=$2
+    new_min=$3
+    new_max=$4
+    old_val=$5
+    new_val=$(( (((old_val - old_min) * (new_max - new_min)) / \
+        (old_max - old_min)) + new_min ))
+    if [[ $new_min -gt $new_max ]]; then
+        [[ $new_val -gt $new_min ]] && new_val=$new_min
+        [[ $new_val -lt $new_max ]] && new_val=$new_max
+    fi
+    echo $new_val
+}
+
+read_camera() {
+    exec ffmpeg \
+        -hide_banner \
+        -f video4linux2 \
+        -s 640x480 \
+        -i "$cam" \
+        -filter:v "fps=fps=30, showinfo" \
+        -f null - > >(stdbuf -oL grep -Po '(?<=mean:\[)[0-9]*' | \
+        while read -r brightness; do
+            echo $(_normalize 72 184 0 100 "$brightness") > "${unbright}_"
+            mv "${unbright}_" "${unbright}"
+        done) 2>&1
+}
+
+init_camera() {
+    [[ ! -c $cam ]] && exit 1
+
+    # Try changing this if you don't get good results
+    v4l2-ctl -d "$cam" -c exposure_auto=3 2>/dev/null
+    v4l2-ctl -d "$cam" -c exposure_auto=1 2>/dev/null
+
+    local expo=$(v4l2-ctl -d "$cam" -l | grep -m 1 exposure_absolute | grep -Po '(?<=default=)\d+')
+    local gain=$(v4l2-ctl -d "$cam" -l | grep -m 1 gain | grep -Po '(?<=default=)\d+')
+
+    if [ ! -z "$gain" ]; then
+        v4l2-ctl -d "$cam" -c gain=0 2>/dev/null
+        v4l2-ctl -d "$cam" -c exposure_absolute=1000 2>/dev/null
+    else
+        v4l2-ctl -d "$cam" -c exposure_absolute="$expo" 2>/dev/null
+    fi
+}
+
+set_ddc() {
+    local new="$1"
+    if [[ "$new" -ne "$last_ddc" ]]; then
+        if ! ps -p $ddc_pid >/dev/null 2>&1; then
+            ddccontrol -r 0x10 -w "$new" dev:/dev/i2c-2 >/dev/null 2>&1 &
+            ddc_pid=$!
+            last_ddc="$new"
+        fi
+    fi
+}
+
+dim_to() {
+    local new_aim="$1"
+    if [[ $new_aim -gt $(( last_dim + 1 )) ]]; then
+        set_dim $(( last_dim + 1 ))
+    elif [[ $new_aim -lt $(( $last_dim - 1 )) ]]; then
+        set_dim $(( last_dim - 1 ))
+    fi
+}
+
+echo > "$unbright"
+init_camera
+read_camera &
+
+last_dim=0
+last_ddc=0
+while :; do
+    # TODO Implement frame-dropping
+    start_date=$(date +%s%3N)
+
+    brightness=$(<"$unbright")
+    if [[ ! -z $brightness ]]; then
+
+        # DIM
+        dim_aim=$(_normalize 0 85 65 0 $brightness)
+        dim_to "$dim_aim"
+
+        # DDC
+        if [[ $brightness -gt 50 ]]; then
+            new_ddc=$(_normalize 50 100 20 100 $brightness)
+        else
+            new_ddc=20
+        fi
+        set_ddc $new_ddc
+
+        # echo "$brightness -> ($new_ddc, $dim_aim)"
+    fi
+
+    end_date=$(date +%s%3N)
+    diff_date=$(( end_date - start_date ))
+    # -1 is time spent on invoking `sleep` and `printf`, kind of
+    to_sleep=$(( frame_ms - diff_date - 1 ))
+    [[ $to_sleep -gt 0 ]] && sleep $(printf "0.0%02d" $to_sleep)
+done

man/compton.1.asciidoc

@@ -234,6 +234,9 @@ May also be one of the predefined kernels: `3x3box` (default), `5x5box`, `7x7box
 *--opacity-rule* 'OPACITY':'CONDITION'::
 	Specify a list of opacity rules, in the format `PERCENT:PATTERN`, like `50:name *= "Firefox"`. compton-trans is recommended over this. Note we do not distinguish 100% and unset, and we don't make any guarantee about possible conflicts with other programs that set '_NET_WM_WINDOW_OPACITY' on frame or client windows.
 
+*--dim-rule* 'VALUE':'CONDITION'::
+	Specify a list of dim rules, in the format `VALUE:PATTERN`, like `50:!class_g *= "URxvt"`, where `VALUE` is in the 0 - 100 range (0 means no dim).
+
 *--shadow-exclude-reg* 'GEOMETRY'::
 	Specify a X geometry that describes the region in which shadow should not be painted in, such as a dock window region.  Use `--shadow-exclude-reg x10+0-0`, for example, if the 10 pixels on the bottom of the screen should not have shadows painted on.