Graphics.Image.IO.Histogram

Documentation

data Histogram

A single channel histogram of an image.

Constructors

Histogram

Fields

hBins :: Vector Int

Vector containing pixel counts. Index of a vector serves as an original pixel value.

hName :: String

Name of the channel that will be displayed in the legend.

hColour :: AlphaColour Double

Color of a plotted line.

getHistograms :: forall arr cs e. (SequentialArray arr Gray e, SequentialArray arr cs e, Elevator e) => Image arr cs e -> [Histogram]

Create a histogram per channel with 256 bins each.

getHistogram :: (SequentialArray arr Gray e, Elevator e) => Image arr Gray e -> Histogram

Generate a histogram with 256 bins for a single channel Gray image.

displayHistograms :: [Histogram] -> IO (Maybe ThreadId)

Display image histograms using an external program. Works the same way as displayImage.

>>> frog <- readImageRGB "images/frog.jpg"
>>> displayHistograms $ getHistograms frog

writeHistograms :: FilePath -> [Histogram] -> IO ()

Write histograms into a PNG image file.

>>> frog <- readImageRGB "images/frog.jpg"
>>> writeHistograms "images/frog_histogram.png" $ getHistograms frog