Skip to content

Instantly share code, notes, and snippets.

@ArianK16a

ArianK16a/gist:4720c51a80ddb7c4207ff677c53b987c

Last active February 19, 2026 11:13
Show Gist options

  • Select an option

    Learn more about clone URLs
  • Save ArianK16a/4720c51a80ddb7c4207ff677c53b987c to your computer and use it in GitHub Desktop.

Select an option

Learn more about clone URLs
Save ArianK16a/4720c51a80ddb7c4207ff677c53b987c to your computer and use it in GitHub Desktop.
Download ZIP
compare_auto_brightness.py
Raw
gistfile1.txt
import xml.etree.ElementTree as ET
from pathlib import Path
import matplotlib.pyplot as plt
import bisect
XML_CONFIGS = [
("overlay/Frameworks/res/values/config.xml", "unicorn", False),
("config.xml", "unicorn - old", False),
# ("../cupid/overlay/Frameworks/res/values/config.xml", "cupid"),
# ("pantah/panther/overlay/frameworks/base/core/res/res/values/config.xml", "pantah"),
# ("/home/arian/android/vendor/pixel/blazer/blazer-bp4a.260105.004.e1/framework-res__blazer__auto_generated_rro_vendor/res/values/arrays.xml", "blazer"),
]
LEVELS_NAME = "config_autoBrightnessLevels"
NITS_NAME = "config_autoBrightnessDisplayValuesNits"
MAX_LUX = 30000.0
SCALE_FROM_LUX = 15000.0
BASE_LUX = 15000.0
def adjust_curve(lux_levels, nits_values,
max_lux=MAX_LUX, base_lux=BASE_LUX):
"""
Adjust one auto-brightness config:
1. Remove all lux levels > max_lux
2. Let B_base = brightness at base_lux (15000).
For lux >= base_lux, only scale the *extra* brightness above B_base
so that the brightness at max_lux (30000) reaches the global max nits.
Assumes:
len(nits_values) == len(lux_levels) + 1
lux_levels sorted ascending.
"""
assert len(nits_values) == len(lux_levels) + 1
# Global max brightness before any changes (we want to reach this at 30000)
max_nits_global = max(nits_values)
# --- 1) Truncate all lux levels above max_lux ---
# cut_idx = number of lux levels <= max_lux
cut_idx = bisect.bisect_right(lux_levels, max_lux)
lux_trunc = lux_levels[:cut_idx]
nits_trunc = nits_values[:cut_idx + 1] # +1 because of the extra segment
# --- 2) Find the segment index for base_lux (15000) ---
# segment index i: nits_trunc[i] is used for lux in:
# [ 0, lux_trunc[0] ) -> i = 0
# [ lux_trunc[0], lux_trunc[1] ) -> i = 1
# ...
base_seg = bisect.bisect_right(lux_trunc, base_lux)
base_nits = nits_trunc[base_seg]
# Segment index for ">= last lux" (this contains 30000 after truncation)
last_idx = len(nits_trunc) - 1
last_nits_before = nits_trunc[last_idx]
tail_delta = last_nits_before - base_nits
if tail_delta <= 0:
# Nothing to scale above base (already flat or decreasing)
# -> just return with truncation applied.
return lux_trunc, nits_trunc
# Desired brightness at 30000 = global max
desired_last = max_nits_global
if desired_last <= base_nits:
# Would not make sense to scale if target <= base
return lux_trunc, nits_trunc
# --- 3) Scale only the *extra* brightness above base_nits ---
scale_factor = (desired_last - base_nits) / tail_delta
# Keep everything <= 15000 (incl. its segment) unchanged:
# start scaling from the *next* segment after base_seg
for i in range(base_seg + 1, len(nits_trunc)):
# old extra above base:
extra = nits_trunc[i] - base_nits
# scaled extra:
nits_trunc[i] = base_nits + extra * scale_factor
# clamp to [base_nits, desired_last]
if nits_trunc[i] < base_nits:
nits_trunc[i] = base_nits
if nits_trunc[i] > desired_last:
nits_trunc[i] = desired_last
# Make sure the last segment really hits desired_last
nits_trunc[-1] = desired_last
return lux_trunc, nits_trunc
def get_array(root, name, as_type=float):
arr_elem = root.find(f".//integer-array[@name='{name}']")
if arr_elem is None:
arr_elem = root.find(f".//array[@name='{name}']")
if arr_elem is None:
raise ValueError(f"Array with name '{name}' not found")
values = []
for item in arr_elem.findall("item"):
text = (item.text or "").strip()
if text:
values.append(as_type(text))
return values
def load_config(path):
tree = ET.parse(path)
root = tree.getroot()
lux_levels = get_array(root, LEVELS_NAME, as_type=float)
nits_values = get_array(root, NITS_NAME, as_type=float)
return lux_levels, nits_values
def plot_auto_brightness_curve(lux_levels, nits_values, label, ax):
"""Plot one auto-brightness curve as a step function onto ax."""
if len(nits_values) != len(lux_levels) + 1:
print(f"[{label}] WARNING: len(nits)={len(nits_values)} "
f"!= len(lux)+1={len(lux_levels)+1}; skipping this config.")
return
lower_bound = 0.0
last_lux = lux_levels[-1]
lux_bounds = [lower_bound] + lux_levels
y_step = list([n / nits_values[-1] for n in nits_values])
ax.step(lux_bounds, y_step, where="post", label=label)
def main():
fig, ax = plt.subplots()
for path_str, label, scale in XML_CONFIGS:
path = Path(path_str)
if not path.is_file():
print(f"[{label}] File not found: {path}")
continue
lux_levels, nits_values = load_config(path)
print(f"[{label}] lux_levels: {len(lux_levels)} entries")
print(f"[{label}] nits_values: {len(nits_values)} entries")
plot_auto_brightness_curve(lux_levels, nits_values, label, ax)
if scale:
lux_levels, nits_values = adjust_curve(lux_levels, nits_values)
plot_auto_brightness_curve(lux_levels, nits_values, label + " (scaled)", ax)
print('<integer-array name="config_autoBrightnessLevels">')
for v in lux_levels:
print(f' <item>{int(round(v))}</item>')
print('</integer-array>')
print('<array name="config_autoBrightnessDisplayValuesNits">')
for v in nits_values:
print(f' <item>{v:.1f}</item>')
print('</array>')
ax.set_xlabel("Ambient light (lux)")
ax.set_ylabel("Display brightness")
ax.set_title("Auto-brightness curve comparison")
ax.grid(True)
ax.legend()
ax.set_xlim(left=0)
ax.set_ylim(bottom=0)
plt.tight_layout()
plt.show()
if __name__ == "__main__":
main()
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment