horizontalProgressBar
Supplies one fixed-source horizontal progress-bar background and fill pair.
This declaration is an alternative to the three bundle progress-bar declarations and preserves older Minecraft releases whose native progress treatment uses equal-sized sprites rather than bundle nine-slices. The runtime scales the complete background to the requested component size and crops the fill horizontally by the normalized progress value.
Parameters
background
immutable nonempty background sprite.
fill
immutable fill sprite with the same size as background.
Throws
when either image is empty, their sizes differ, or any bundle progress-bar sprite was already declared.
when called from another thread or after the builder callback ends.