geotrellis.raster.mapalgebra.local.Mask.scala Maven / Gradle / Ivy

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/*
 * Copyright (c) 2014 Azavea.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package geotrellis.raster.mapalgebra.local

import geotrellis.raster._

object Mask extends Serializable {
  /**
   * Generate a raster with the values from the first raster, but only include
   * cells in which the corresponding cell in the second raster *are not* set to the
   * "readMask" value.
   *
   * For example, if *all* cells in the second raster are set to the readMask value,
   * the output raster will be empty -- all values set to NODATA.
   */
  def apply(r1: Tile, r2: Tile, readMask: Int, writeMask: Int): Tile =
    r1.dualCombine(r2) { (z1,z2) => if (z2 == readMask) writeMask else z1 }
                       { (z1,z2) => if (d2i(z2) == readMask) i2d(writeMask) else z1 }
}