java/src/main/com/google/appengine/api/images/Resize.java

   1 // Copyright 2009 Google Inc. All Rights Reserved.
   2
   3 package com.google.appengine.api.images;
   4
   5 /**
   6  * A transform that will resize an image to fit within a bounding box.
   7  *
   8  */
   9 final class Resize extends Transform {
  10
  11   private static final long serialVersionUID = -889209644904728094L;
  12
  13   private final int width;
  14   private final int height;
  15   private final boolean cropToFit;
  16   private final float cropOffsetX;
  17   private final float cropOffsetY;
  18   private final boolean allowStretch;
  19
  20   /**
  21    * Creates a transform that will resize an image to fit within a rectangle
  22    * with the given dimensions. If {@code allowStretch} is true, then the image
  23    * is resized without maintaining the original aspect ratio.
  24    * @param width width of the bounding box
  25    * @param height height of the bounding box
  26    * @param allowStretch resize the image without maintaining the aspect ratio.
  27    * @throws IllegalArgumentException If {@code width} or {@code height} are
  28    * negative or greater than {@code MAX_RESIZE_DIMENSIONS}, if both
  29    * {@code width} and {@code height} are 0 or if {@code allowStretch} is
  30    * set and {@code width} or {@code height} is 0.
  31    */
  32   Resize(int width, int height, boolean allowStretch) {
  33     this(width, height, false, 0, 0, allowStretch);
  34   }
  35
  36   /**
  37    * Creates a transform that will resize an image to fit within a rectangle
  38    * with the given dimensions. If {@code cropToFit} is true, then the image is
  39    * cropped to fit, with the center specified by {@code cropOffsetX} and
  40    * {@code cropOffsetY}.
  41    * @param width width of the bounding box
  42    * @param height height of the bounding box
  43    * @param cropToFit whether the image should be cropped to fit
  44    * @param cropOffsetX the relative horizontal position of the center
  45    * @param cropOffsetY the relative vertical position of the center
  46    * @throws IllegalArgumentException If {@code width} or {@code height} are
  47    * negative or greater than {@code MAX_RESIZE_DIMENSIONS}, if both
  48    * {@code width} and {@code height} are 0 or if {@code cropToFit} is
  49    * set and {@code width} or {@code height} is 0 or {@code cropOffsetX} or
  50    * {@code cropOffsetY} is outside the range 0.0 to 1.0.
  51    */
  52   Resize(int width, int height, boolean cropToFit, float cropOffsetX, float cropOffsetY) {
  53     this(width, height, cropToFit, cropOffsetX, cropOffsetY, false);
  54   }
  55
  56   /**
  57    * Creates a transform that will resize an image to fit within a rectangle
  58    * with the given dimensions. If {@code cropToFit} is true, then the image is
  59    * cropped to fit, with the center specified by {@code cropOffsetX} and
  60    * {@code cropOffsetY}.
  61    * @param width width of the bounding box
  62    * @param height height of the bounding box
  63    * @param cropToFit whether the image should be cropped to fit
  64    * @param cropOffsetX the relative horizontal position of the center
  65    * @param cropOffsetY the relative vertical position of the center
  66    * @param allowStretch resize the image without maintaining the aspect ratio.
  67    * @throws IllegalArgumentException If {@code width} or {@code height} are
  68    * negative or greater than {@code MAX_RESIZE_DIMENSIONS}, if both
  69    * {@code width} and {@code height} are 0, if {@code allowStretch} is set and
  70    * and {@code width} or {@code height} is 0 or if {@code cropToFit} is
  71    * set and {@code width} or {@code height} is 0 or {@code cropOffsetX} or
  72    * {@code cropOffsetY} is outside the range 0.0 to 1.0.
  73    */
  74   Resize(int width, int height, boolean cropToFit, float cropOffsetX,
  75       float cropOffsetY, boolean allowStretch) {
  76     if (width > ImagesService.MAX_RESIZE_DIMENSIONS
  77         || height > ImagesService.MAX_RESIZE_DIMENSIONS) {
  78       throw new IllegalArgumentException("width and height must be <= "
  79                                          + ImagesService.MAX_RESIZE_DIMENSIONS);
  80     }
  81     if (width < 0 || height < 0) {
  82       throw new IllegalArgumentException("width and height must be >= 0");
  83     }
  84     if (width == 0 && height == 0) {
  85       throw new IllegalArgumentException("width and height must not both be == 0");
  86     }
  87     if (cropToFit) {
  88       if (width == 0 || height == 0) {
  89         throw new IllegalArgumentException(
  90             "neither of width and height can be == 0 with crop to fit enabled");
  91       }
  92       checkCropArgument(cropOffsetX);
  93       checkCropArgument(cropOffsetY);
  94     }
  95     if (allowStretch) {
  96       if (width == 0 || height == 0) {
  97         throw new IllegalArgumentException(
  98             "Resize requests with allowStretch as true require that both "
  99             + "width and hight are non zero");
 100       }
 101     }
 102     this.width = width;
 103     this.height = height;
 104     this.cropToFit = cropToFit;
 105     this.cropOffsetX = cropOffsetX;
 106     this.cropOffsetY = cropOffsetY;
 107     this.allowStretch = allowStretch;
 108   }
 109
 110   /** {@inheritDoc} */
 111   @Override
 112   void apply(ImagesServicePb.ImagesTransformRequest.Builder request) {
 113     request.addTransform(
 114         ImagesServicePb.Transform.newBuilder()
 115         .setWidth(width)
 116         .setHeight(height)
 117         .setCropToFit(cropToFit)
 118         .setCropOffsetX(cropOffsetX)
 119         .setCropOffsetY(cropOffsetY)
 120         .setAllowStretch(allowStretch));
 121   }
 122
 123   /**
 124    * Checks that a crop argument is in the valid range.
 125    * @param arg crop argument
 126    */
 127   private void checkCropArgument(float arg) {
 128     if (arg < 0.0) {
 129       throw new IllegalArgumentException("Crop offsets must be >= 0");
 130     }
 131     if (arg > 1.0) {
 132       throw new IllegalArgumentException("Crop offsets must be <= 1");
 133     }
 134   }
 135 }