英文:
Triangle with a color gradient from each vertex in r
问题
我想要为我的图形制作一个带有自定义颜色渐变的彩色三角形，从三角形的每个顶点开始。示例：
以下是我目前的代码。颜色是正确的，但我无法让每个首选颜色从顶点开始。目前的三角形看起来像这样：
我的当前代码：
## 创建一个单元格坐标的三角形cells.x <- cells.y <- vector()k <- 1asp <- abs(diff(par()$usr[4:3]) / diff(par()$usr[2:1])) * par()$pin[2] / par()$pin[1]for (i in 1:50) {for (j in i:(100 - i + 1)) {cells.x[k] <- 0.1 + (j - 1) * 0.1 / 100cells.y[k] <- (-1) + (i - 1) * 2 * 0.1 * asp / 100k <- k + 1}}# 定义渐变的三种颜色color1 <- "#1e88e5"color2 <- "#d81b60"color3 <- "#ffc107"# 创建三种颜色之间的渐变色函数color_gradient <- colorRampPalette(c(color1, color2, color3))# 计算点的数量num_points <- length(cells.x)# 基于点的数量生成渐变颜色gradient_colors <- color_gradient(num_points)## 画点dx <- diff(range(cells.x))dy <- diff(range(cells.y))red.x <- max(cells.x)red.y <- min(cells.y)red <- 1 - sqrt((((cells.x - red.x) / dx)^2 + ((cells.y - red.y) / dy)^2) / 2)green.x <- min(cells.x)green.y <- min(cells.y)green <- 1 - sqrt((((cells.x - green.x) / dx)^2 + ((cells.y - green.y) / dy)^2) / 2)blue.x <- min(cells.x)blue.y <- max(cells.y)blue <- 1 - sqrt((((cells.x - blue.x) / dx)^2 + ((cells.y - blue.y) / dy)^2) / 2)points(cells.x, cells.y, col = gradient_colors, pch = 15, cex = 0.5)
英文:
I am looking to make a colored triangle for my plot with a customized color gradient starting from each vertex of the triangle. Example:
Below is my code so far. The colors are correct but I am unable to have each of the preferred color start from the vertex. The triangle currently looks like that:
My current code:
## make a triangle of cell coordinatescells.x<-cells.y<-vector()k<-1asp<-abs(diff(par()$usr[4:3])/diff(par()$usr[2:1]))*par()$pin[2]/par()$pin[1]for(i in 1:50){for(j in i:(100-i+1)){cells.x[k]<-0.1+(j-1)*0.1/100cells.y[k]<-(-1)+(i-1)*2*0.1*asp/100k<-k+1}}# Define the three colors for the gradientcolor1 <- "#1e88e5"color2 <- "#d81b60"color3 <- "#ffc107"# Create a color gradient function between the three colorscolor_gradient <- colorRampPalette(c(color1, color2, color3))# Calculate the number of pointsnum_points <- length(cells.x)# Generate the gradient colors based on the number of pointsgradient_colors <- color_gradient(num_points)## draw pointsdx<-diff(range(cells.x))dy<-diff(range(cells.y))red.x<-max(cells.x)red.y<-min(cells.y)red<-1-sqrt((((cells.x-red.x)/dx)^2+((cells.y-red.y)/dy)^2)/2)green.x<-min(cells.x)green.y<-min(cells.y)green<-1-sqrt((((cells.x-green.x)/dx)^2+((cells.y-green.y)/dy)^2)/2)blue.x<-min(cells.x)blue.y<-max(cells.y)blue<-1-sqrt((((cells.x-blue.x)/dx)^2+((cells.y-blue.y)/dy)^2)/2)points(cells.x,cells.y,col=gradient_colors, pch=15,cex=0.5)
答案1
得分: 1
以下是使用重心坐标的解决方案：
# 三角形顶点A <- c(0, 0)B <- c(1, 0)C <- c(0.5, 1)# RGB颜色clrA <- c(1, 0, 0)clrB <- c(0, 1, 0)clrC <- c(0, 0, 1)clrs <- rbind(clrA, clrB, clrC)library(geometry)trgl <- rbind(A, B, C)cart2bary(trgl, rbind(c(1, 1)))M <- matrix(NA_character_, nrow = 512, ncol = 512)x <- y <- seq(0, 1, length.out = 512L)for(i in 1L:512L) {for(j in 1L:512L) {coords <- cart2bary(trgl, rbind(c(x[i], y[j])))[1L, ]if(all(coords >= 0)) {r <- crossprod(coords, clrs[1, ])g <- crossprod(coords, clrs[2, ])b <- crossprod(coords, clrs[3, ])M[i, j] <- rgb(r, g, b)}}}M[is.na(M)] <- "white"par(mar = c(0, 0, 0, 0))plot(NULL, asp = 1, xlim = c(0, 1), ylim = c(0, 1),xlab = NA, ylab = NA, axes = FALSE, xaxs = "i", yaxs = "i")rasterImage(M, 0, 0, 1, 1)
英文:
Here is a solution using barycentric coordinates:
# triangle verticesA <- c(0, 0)B <- c(1, 0)C <- c (0.5, 1)# rgb colorsclrA <- c(1, 0, 0)clrB <- c(0, 1, 0)clrC <- c(0, 0, 1)clrs <- rbind(clrA, clrB, clrC)library(geometry)trgl <- rbind(A, B, C)cart2bary(trgl, rbind(c(1,1)))M <- matrix(NA_character_, nrow = 512, ncol = 512)x <- y <- seq(0, 1, length.out = 512L)for(i in 1L:512L) {for(j in 1L:512L) {coords <- cart2bary(trgl, rbind(c(x[i], y[j])))[1L, ]if(all(coords >= 0)) {r <- crossprod(coords, clrs[1, ])g <- crossprod(coords, clrs[2, ])b <- crossprod(coords, clrs[3, ])M[i, j] <- rgb(r, g, b)}}}M[is.na(M)] <- "white"par(mar = c(0, 0, 0, 0))plot(NULL, asp = 1, xlim = c(0, 1), ylim = c(0, 1),xlab = NA, ylab = NA, axes = FALSE, xaxs = "i", yaxs = "i")rasterImage(M, 0, 0, 1, 1)
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