| /* |
| |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You 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 org.apache.batik.ext.awt.image; |
| |
| |
| /** |
| * GammaTransfer.java |
| * |
| * This class defines the Gamma type transfer function for the |
| * feComponentTransfer filter, as defined in chapter 15, section 11 of the SVG |
| * specification. |
| * |
| * @author <a href="mailto:sheng.pei@sun.com">Sheng Pei</a> |
| * @version $Id$ |
| */ |
| public class GammaTransfer implements TransferFunction { |
| /** |
| * This byte array stores the lookuptable data |
| */ |
| public byte [] lutData; |
| |
| /** |
| * The amplitude of the Gamma function |
| */ |
| public float amplitude; |
| |
| /** |
| * The exponent of the Gamma function |
| */ |
| public float exponent; |
| |
| /** |
| * The offset of the Gamma function |
| */ |
| public float offset; |
| |
| /** |
| * Three floats as the input for the Gamma function |
| */ |
| public GammaTransfer(float amplitude, float exponent, float offset){ |
| this.amplitude = amplitude; |
| this.exponent = exponent; |
| this.offset = offset; |
| } |
| |
| /* |
| * This method will build the lut data. Each entry's |
| * value is in form of "amplitude*pow(C, exponent) + offset" |
| */ |
| private void buildLutData(){ |
| lutData = new byte [256]; |
| int j, v; |
| for (j=0; j<=255; j++){ |
| v = (int)Math.round(255*(amplitude*Math.pow(j/255f, exponent)+offset)); |
| if(v > 255){ |
| v = (byte)0xff; |
| } |
| else if(v < 0){ |
| v = (byte)0x00; |
| } |
| lutData[j] = (byte)(v & 0xff); |
| } |
| } |
| |
| |
| /** |
| * This method will return the lut data in order |
| * to construct a LookUpTable object |
| */ |
| public byte [] getLookupTable(){ |
| buildLutData(); |
| return lutData; |
| } |
| } |