Color gradient using Postscript - Revision history

Lemzwerg: Lemzwerg moved page Color Gradient using Postscript to Color gradient using Postscript without leaving a redirect: Only the first letter of a title should be uppercase

2025-11-24T05:25:38Z

Lemzwerg moved page Color Gradient using Postscript to Color gradient using Postscript without leaving a redirect: Only the first letter of a title should be uppercase

← Older revision	Revision as of 05:25, 24 November 2025
(No difference)

Lemzwerg: New category

2025-11-21T23:37:26Z

New category

← Older revision		Revision as of 23:37, 21 November 2025
Line 86:		Line 86:
	[[Category:Paper and layout]]		[[Category:Paper and layout]]
	[[Category:Tweaks and overrides]]		[[Category:Tweaks and overrides]]
	[[Category:Syntax and expressions]][[Category:Snippet]]		[[Category:Syntax and expressions]]
			[[Category:Snippet]]

Lemzwerg at 22:49, 21 November 2025

2025-11-21T22:49:46Z

← Older revision		Revision as of 22:49, 21 November 2025
Line 86:		Line 86:
	[[Category:Paper and layout]]		[[Category:Paper and layout]]
	[[Category:Tweaks and overrides]]		[[Category:Tweaks and overrides]]
	[[Category:Syntax and expressions]]		[[Category:Syntax and expressions]][[Category:Snippet]]

Jean Abou Samra: Replace version="2.24.0" with version="2.24" now that the LilyWiki extension supports auto-selecting the latest release in a stable series

2025-11-16T18:45:20Z

Replace version="2.24.0" with version="2.24" now that the LilyWiki extension supports auto-selecting the latest release in a stable series

← Older revision		Revision as of 18:45, 16 November 2025
Line 3:		Line 3:
	It has NOT been tested with relative path commands.		It has NOT been tested with relative path commands.

	<lilypond version="2.24.0">		<lilypond version="2.24">
	#(define path->ps		#(define path->ps
	(lambda (cmds)		(lambda (cmds)

Jean Abou Samra: Import snippet from LSR

2025-10-26T22:50:44Z

Import snippet from LSR

New page

Lilypond has no way of creating color gradients. This markup function duplicates the path markup, converts it to postscript and uses postscript's rectclip to crop the duplicates, then colors each one a step to create a smooth gradient. The variable 'res' defines the resolution of the gradient. A larger number here makes the gradient smoother, but takes longer to compile. Bigger gradients and larger paths will need a larger resolution to look smooth.

It has NOT been tested with relative path commands.

<lilypond version="2.24.0">
#(define path->ps
(lambda (cmds)
(apply string-append
(map
(lambda (f)
(string-append
(apply string-append
(append
(map
(lambda (e)
(string-append
(number->string (exact->inexact e))
" "))
(cdr f))
(cons (symbol->string (car f)) '())))
" "))
cmds))))

#(define-markup-command
(gradient-path layout props startr startg startb endr endg endb path res)
(number? number? number? number? number? number? list? integer?)
(let*
((ps (path->ps path))
(markup-test
(ly:text-interface::interpret-markup
layout props (markup #:line (#:path 0.1 path))))
(xextnt (ly:stencil-extent markup-test X))
(yextnt (ly:stencil-extent markup-test Y))
(xlen (- (cdr xextnt) (car xextnt)))
(ylen (- (cdr yextnt) (car yextnt)))
(xstep (/ xlen res))
(rshadestep (/ (- endr startr) res))
(gshadestep (/ (- endg startg) res))
(bshadestep (/ (- endb startb) res))
(xlist (iota res (car xextnt) xstep))
(xextls (map (lambda (e) (cons e xlen)) xlist))
(rshadelist (iota res startr rshadestep))
(gshadelist (iota res startg gshadestep))
(bshadelist (iota res startb bshadestep))
(mkps
(map
(lambda (a)
(markup
#:line
(#:postscript
(string-append
(number->string (exact->inexact (car a)))
" -1000 "
(number->string (exact->inexact (- (cdr a) (car a))))
" 2000 rectclip "
ps
" fill"))))
xextls))
(colored
(map
(lambda (a r g b) (markup #:line (#:with-color (list r g b) a)))
(reverse mkps)
rshadelist
gshadelist
bshadelist))
(finalmkp (reduce make-combine-markup empty-markup colored)))
(interpret-markup layout props finalmkp)))

samplePath =
#'((moveto 0 0)
(lineto -10 10)
(lineto 10 10)
(lineto 10 -10)
(curveto -50 -50 -50 50 -10 0)
(closepath))

\markup
\translate #'(40 . -20)
%% \with-dimensions is needed to return a nice image in LSR
\with-dimensions #'(-40 . 10) #'(-20 . 15)
{ \gradient-path #1 #0 #0 #0 #0 #1 #samplePath #100 }
</lilypond>

[[Category:Non-music]]
[[Category:Symbols and glyphs]]
[[Category:Paper and layout]]
[[Category:Tweaks and overrides]]
[[Category:Syntax and expressions]]