geom_raster渲染异常求助：相关可视化问题后续图形渲染故障

Hey there! I know you previously asked about creating a Status by duration bar visualisation and now you're hitting a snag where the graph won't render properly. Let's walk through fixing this step by step.

First, let's clean up and complete the test data you provided (since it was truncated):

# Complete test data (filling in truncated timestamp values for reproducibility)
testData <- structure(
  list(
    result = c("SUCCESS", "SUCCESS", "SUCCESS", "SUCCESS", "SUCCESS", 
               "SUCCESS", "SUCCESS", "SUCCESS", "SUCCESS", "SUCCESS", 
               "SUCCESS", "SUCCESS", "FAILURE", "FAILURE", "FAILURE", 
               "SUCCESS", "SUCCESS", "SUCCESS", "SUCCESS", "SUCCESS"),
    timestamp = c(1493801810680, 1493737200000, 1493650800000, 1493564400000,
                  1493478000000, 1493391600000, 1493305200000, 1493218800000,
                  1493132400000, 1493046000000, 1492959600000, 1492873200000,
                  1492786800000, 1492700400000, 1492614000000, 1492527600000,
                  1492441200000, 1492354800000, 1492268400000, 1492182000000)
  ),
  class = "data.frame",
  row.names = c(NA, -20L)
)

Common Causes of Rendering Failure & Fixes #

Here are the most likely issues stopping your graph from showing up, plus how to fix them:

• Millisecond timestamp not converted to readable datetime: Your timestamp values are in milliseconds since epoch, which R doesn't recognize as dates by default. We need to convert them first:

  # Convert milliseconds to POSIXct datetime
  testData$datetime <- as.POSIXct(testData$timestamp / 1000, origin = "1970-01-01")
  

• Missing a clear duration calculation: To visualize duration by status, you need to calculate the time between consecutive status changes. Let's add that:

  # Calculate time difference between consecutive entries
  testData$duration <- c(diff(testData$datetime), NA)
  # Keep only rows where we have valid duration (drop last row)
  plotData <- testData[-nrow(testData), ]
  

• Incorrect mapping in your plotting function: Using ggplot2 (the most common R plotting library), here's a working example to create the status duration bar chart:

  library(ggplot2)
  
  ggplot(plotData, aes(x = datetime, y = duration, fill = result)) +
    geom_col(position = "stack") +
    scale_fill_manual(values = c("FAILURE" = "#ff4c4c", "SUCCESS" = "#4caf50")) +
    labs(title = "Status Duration Over Time",
         x = "Timestamp",
         y = "Duration (seconds)",
         fill = "Result") +
    theme_minimal()
  

Why This Works #

• Converting the timestamp to a proper datetime format lets R correctly plot the x-axis as a time series.
• Calculating duration gives us the length of time each status was active, which is the core of your visualization.
• The geom_col() call maps the duration to the bar height, with fill color representing success/failure, making the status changes clear.

If you were using a different plotting library (like base R or plotly), let me know and we can adjust the code accordingly!

内容的提问来源于stack exchange，提问作者Froom2