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元旦特刊 | 2020年元旦夜演：用R玩烟花，用心写代码
欢乐过新年，烟花灿九天。
新年伊始，数据Seminar全体人员，祝大家新年快乐，事事如意！本期特刊，我们用R语言绘制出“烟花夜景图”，与大家一同欢度佳节！烟花夜景
R绘制手工烟花
烟花图由Thomas Lin Pedersen开发，主要通过R语言中的ggplot2和gganimate包绘制而成。利用color（）函数采样颜色，并控制blast（）函数从中心到外围创建片段，然后用ggplot2包绘出静态图形，辅以gganimate包输出动画效果。下面是上图烟花的基本绘图代码，供参考：
##制作烟花(Making Fireworks)##加载包library(ggplot2)library(gganimate)
# Firework colourscolours <- c('lawngreen','gold','white','orchid','royalblue','yellow','orange')
# Produce data for a single blastblast <- function(n, radius, x0, y0, time) { u <- runif(n, -1, 1) rho <- runif(n, 0, 2*pi) x <- radius * sqrt(1 - u^2) * cos(rho) + x0 y <- radius * sqrt(1 - u^2) * sin(rho) + y0 id <- sample(.Machine$integer.max, n + 1) data.frame( x = c(x0, rep(x0, n), x0, x), y = c(0, rep(y0, n), y0, y), id = rep(id, 2), time = c((time - y0) * runif(1), rep(time, n), time, time + radius + rnorm(n)), colour = c('white', rep(sample(colours, 1), n), 'white', rep(sample(colours, 1), n)), stringsAsFactors = FALSE )}
# Make 20 blastsn <- round(rnorm(20, 30, 4))radius <- round(n + sqrt(n))x0 <- runif(20, -30, 30)y0 <- runif(20, 40, 80)time <- runif(20, max = 100)fireworks <- Map(blast, n = n, radius = radius, x0 = x0, y0 = y0, time = time)fireworks <- dplyr::bind_rows(fireworks)
# Make Fireworksggplot(fireworks) + geom_path(aes(x = x, y = y, group = id, colour = colour)) + scale_colour_identity()
ggplot(fireworks) + geom_point(aes(x, y, colour = colour, group = id), size = 0.5, shape = 20) + scale_colour_identity() + coord_fixed(xlim = c(-55, 55), expand = FALSE, clip = 'off') + theme_void() + theme(plot.background = element_rect(fill = 'black', colour = NA), panel.border = element_blank()) + # Here comes the gganimate code transition_components(time, exit_length = 20) + ease_aes(x = 'sine-out', y = 'sine-out') + shadow_wake(0.05, size = 3, alpha = TRUE, wrap = FALSE, falloff = 'sine-in', exclude_phase = 'enter') + exit_recolour(colour = 'black')左右滑动查看更多
烟花夜景调相
利用调相软件，我们还可以做出更加美观流畅的图形效果：
►一周热文
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作者：简华（何年华）审阅：杨奇明、谈佳辉编辑：青酱
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