geotrellis.raster.render.PngRenderMethods.scala Maven / Gradle / Ivy

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GeoTrellis is an open source geographic data processing engine for high performance applications.

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package geotrellis.raster.render

import geotrellis.raster._
import geotrellis.raster.render.png._
import geotrellis.raster.histogram.Histogram
import geotrellis.util.MethodExtensions


trait PngRenderMethods extends MethodExtensions[Tile] {
  /** Generate a PNG from a raster of RGBA integer values.
    *
    * Use this operation when you have created a raster whose values are already
    * RGBA color values that you wish to render into a PNG. If you have a raster
    * with data that you wish to render, you should use RenderPng instead.
    *
    * An RGBA value is a 32 bit integer with 8 bits used for each component:
    * the first 8 bits are the red value (between 0 and 255), then green, blue,
    * and alpha (with 0 being transparent and 255 being opaque).
    */
  def renderPng(): Png =
    renderPng(RgbaPngEncoding)

  /** Generate a PNG from a raster of color encoded values.
    *
    * Use this operation when you have created a raster whose values are already
    * encoded color values that you wish to render into a PNG.
    */
  def renderPng(colorEncoding: PngColorEncoding): Png =
    new PngEncoder(Settings(colorEncoding, PaethFilter)).writeByteArray(self)

  def renderPng(colorMap: ColorMap): Png = {
    val colorEncoding = PngColorEncoding(colorMap.colors, colorMap.options.noDataColor, colorMap.options.fallbackColor)
    val convertedColorMap = colorEncoding.convertColorMap(colorMap)
    renderPng(colorEncoding, convertedColorMap)
  }

  def renderPng(colorRamp: ColorRamp): Png = {
    if(self.cellType.isFloatingPoint) {
      val histogram = self.histogram
      val quantileBreaks = histogram.quantileBreaks(colorRamp.numStops)
      renderPng(new IntColorMap(quantileBreaks.zip(colorRamp.colors).toMap).cache(histogram))
    } else {
      val histogram = self.histogramDouble
      renderPng(ColorMap.fromQuantileBreaks(histogram, colorRamp))
    }
  }

  private
  def renderPng(colorEncoding: PngColorEncoding, colorMap: ColorMap): Png = {
    val encoder = new PngEncoder(Settings(colorEncoding, PaethFilter))
    encoder.writeByteArray(colorMap.render(self))
  }
}