Too dark or bright combo colours or slider borders

Although objects by default have a white border around them making them visible, the approach circles are affected by combo colour and will become impossible to see with colour 0,0,0. Stripping the game of important gameplay indicators or generally messing with them (see check for modified breaks) is not something beatmaps are expected to do, as they need to be consistent to work properly.

A slider whose approach circle is only visible on its borders and path, due to the rest blending into the dimmed bg.

As for bright colours, when outside of kiai they're fine, but while in kiai the game flashes them, attempting to make them even brighter without caring about them already being really bright, resulting in pretty strange behaviour for some monitors and generally just unpleasant contrast.

An example of a slider with colour 255,255,255 while in the middle of flashing.

This check uses the HSP colour system to better approximate the way humans perceive luminosity in colours, as opposed to the HSL system where green is regarded the same luminosity as deep blue, see image.

The HSP colour system compared to the in-game HSL system.

Outcomes

Problem Combo
Combo colour number is way too dark.
Cause: The HSP luminosity value of a combo colour is lower than 30. These values are visible in the overview section as tooltips for each colour if you want to check them manually.

Problem Border
Slider border is way too dark.
Cause: Same as the first check, except applies on the slider border instead.

Warning Combo
Combo colour number is really dark.
Cause: Same as the first check, but lower than 43 instead.

Warning Border
Slider border is really dark.
Cause: Same as the second check, except applies on the slider border instead.

Bright
Combo colour number is really bright in kiai sections, see example object.
Cause: Same as the first check, but higher than 250 and requires that at least one hit object with the combo is in a kiai section.

Slider tick rates not aligning with any common beat snap divisor

Table of contents

Too dark or bright combo colours or slider borders

Purpose

Reasoning

Outcomes