1枚作成するコマンドは、
convert -size 100x100 xc:white -pointsize 10 -draw "text 10,10 xxxtextxxx" output.png
Rubyで回すと、
100.times do |i| filename = i.to_s.rjust(4,'0') + '.png' command = "convert -size 100x100 xc:yellow -pointsize 30 -draw \"text 20,60 \'ID:" + i.to_s + "\" " + filename system(command) print '.' hue = i * 10 command = 'convert ' + filename + ' -modulate 100,100,'+hue.to_s + ' ' + filename system(command) end