altalex531 / dwm_colorization_calculator

Converts HSB color and control panel color intensity slider or just ARGB color to the DWMCOLORIZATIONPARAMETERS structure

DWM Colorization Calculator

Converts HSB color and control panel color intensity slider or just ARGB color to the DWMCOLORIZATIONPARAMETERS structure used by DwmSetColorizationParameters.

You can read the code to understand how the Windows 7 Control Panel converts the values of several sliders into relevant DWM registry items.

Details

Windows 7 Control Panel colors are actually in HSB format, and the color intensity slider actually controls the alpha value of the converted CColorizationColor structure which is a DWORD stored in ARGB format.

When the user moves the sliders, the control panel reads the values of those sliders and performs a color format conversion. For some strange reasons, the value of the slider for color intensity is limited to 0x0D(13) to 0xD9(217).

Windows 10 only retains the last bit of calculations regarding color balance, however ColorizationAfterglowBalance is hardcoded to 10 and ColorizationBlurBalance is hardcoded to 1. Inside UxTheme.dll, new immersive color-related interfaces and functions have been introduced, which internally check if the calculated result of current color matches the value in the registry, and override the registry value if it doesn't, which is why Colorization*Balance is often reset to its default value.