Dynamic Multiply Modes

Objective

Make a beautiful brush stroke.

Design Revisions

Revision	Current Design	Issues	Changes
1. Apply a multiply to the dynamics output factor	dynamic output is summed	Enforcing a fine start and end to the brush stroke, with multiple dynamic elements in play can be difficult or impossible to achieve.	Paintbrush options to `Pressure Multiply` and `Fade Multiply` are available to be enabled. The pressure and fade dynamics can then be a defining factor on the overall character of the brush calligraphy.

Notes

Feature: The left side is with Pressure and Fade multiply enabled, right side is without feature

MR Description

This MR adds dynamic multiply modes (Pressure Multiply and Fade Multiply) to the gimp_dynamics_output_get_linear_value function, enabling finer control over brush strokes.

Changes

Pressure Dynamics:
- Added options->brush_pressure_multiply check.
- If enabled and there are existing factors, the pressure is multiplied. Otherwise, it’s added as usual.
Fade Dynamics:
- Added options->fade_options->fade_multiply check.
- If enabled and there are existing factors, the fade is multiplied. Otherwise, it’s added.

Benefit

Allows users to multiply or add pressure and fade dynamics for more precise brush control.

Dynamic Brush Spacing Dynamic Velocity Compression