Basic Renko Chart — ggplot2

A Renko chart displays price movements using fixed-size bricks that ignore time and focus purely on price action. A new brick is drawn only when the price moves by a specified amount (brick size), filtering out market noise and minor fluctuations. Bullish bricks (price increase) and bearish bricks (price decrease) alternate direction on trend reversals, making it easy to identify trends, support/resistance levels, and potential trading signals.

Basic Renko Chart rendered with ggplot2

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R source (ggplot2)

#' anyplot.ai
#' renko-basic: Basic Renko Chart
#' Library: ggplot2 3.5.1 | R 4.4.1
#' Quality: 82/100 | Created: 2026-05-17

library(ggplot2)
library(dplyr)
library(ragg)

set.seed(42)

# --- Theme tokens -----------------------------------------------------------
THEME       <- Sys.getenv("ANYPLOT_THEME", "light")
PAGE_BG     <- if (THEME == "light") "#FAF8F1" else "#1A1A17"
INK         <- if (THEME == "light") "#1A1A17" else "#F0EFE8"
INK_SOFT    <- if (THEME == "light") "#4A4A44" else "#B8B7B0"

# Color palette
BULL        <- "#009E73"  # Okabe-Ito position 1 (green)
BEAR        <- "#AE3030"  # imprint red — bearish

# --- Data generation --------------------------------------------------------
# Generate synthetic stock price data
n <- 250
dates <- seq.Date(as.Date("2024-01-01"), length.out = n, by = "day")
prices <- 100 + cumsum(rnorm(n, 0, 0.8))

df_prices <- data.frame(date = dates, close = prices)

# --- Renko brick calculation -----------------------------------------------
brick_size <- 2.0

calculate_renko <- function(prices, brick_size) {
  bricks <- list()
  brick_count <- 0
  current_level <- floor(prices[1] / brick_size) * brick_size
  direction <- 0  # 0 = start, 1 = up, -1 = down

  for (i in seq_along(prices)) {
    price <- prices[i]

    while (price >= current_level + brick_size) {
      brick_count <- brick_count + 1
      new_direction <- 1
      if (direction == 1) {
        bricks[[brick_count]] <- list(
          brick_num = brick_count,
          open = current_level,
          close = current_level + brick_size,
          direction = "up"
        )
      } else {
        bricks[[brick_count]] <- list(
          brick_num = brick_count,
          open = current_level,
          close = current_level + brick_size,
          direction = "up"
        )
      }
      direction <- 1
      current_level <- current_level + brick_size
    }

    while (price <= current_level - brick_size) {
      brick_count <- brick_count + 1
      if (direction == -1) {
        bricks[[brick_count]] <- list(
          brick_num = brick_count,
          open = current_level,
          close = current_level - brick_size,
          direction = "down"
        )
      } else {
        bricks[[brick_count]] <- list(
          brick_num = brick_count,
          open = current_level,
          close = current_level - brick_size,
          direction = "down"
        )
      }
      direction <- -1
      current_level <- current_level - brick_size
    }
  }

  do.call(rbind, lapply(bricks, function(x) {
    data.frame(
      brick_num = x$brick_num,
      open = x$open,
      close = x$close,
      direction = x$direction,
      stringsAsFactors = FALSE
    )
  }))
}

renko_bricks <- calculate_renko(df_prices$close, brick_size)

# Calculate dimensions for visualization
renko_bricks <- renko_bricks %>%
  mutate(
    x_min = brick_num - 0.4,
    x_max = brick_num + 0.4,
    y_min = pmin(open, close),
    y_max = pmax(open, close)
  )

# --- Plot -------------------------------------------------------------------
p <- ggplot(renko_bricks, aes(fill = direction)) +
  geom_rect(
    aes(xmin = x_min, xmax = x_max, ymin = y_min, ymax = y_max),
    color = INK_SOFT,
    linewidth = 0.3
  ) +
  scale_fill_manual(
    values = c("up" = BULL, "down" = BEAR),
    guide = "none"
  ) +
  labs(
    title = "renko-basic · ggplot2 · anyplot.ai",
    x = "Brick Index",
    y = "Price ($)"
  ) +
  theme_minimal(base_size = 14) +
  theme(
    plot.background = element_rect(fill = PAGE_BG, color = PAGE_BG),
    panel.background = element_rect(fill = PAGE_BG, color = NA),
    panel.grid.major = element_line(color = INK, linewidth = 0.3),
    panel.grid.minor = element_blank(),
    panel.border = element_rect(color = INK_SOFT, fill = NA, linewidth = 0.5),
    axis.title = element_text(color = INK, size = 20),
    axis.text = element_text(color = INK_SOFT, size = 16),
    plot.title = element_text(color = INK, size = 24, face = "plain"),
    legend.position = "none"
  )

# --- Save -------------------------------------------------------------------
ggsave(
  filename = sprintf("plot-%s.png", THEME),
  plot = p,
  device = ragg::agg_png,
  width = 16,
  height = 9,
  units = "in",
  dpi = 300
)

Part of Basic Renko Chart on anyplot.ai.

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