Java tutorial
//package com.java2s; /* * Copyright Car Connectivity Consortium * * 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. * * You may decide to give the Car Connectivity Consortium input, suggestions * or feedback of a technical nature which may be implemented on the * Car Connectivity Consortium products (Feedback?). * * You agrees that any such Feedback is given on non-confidential * basis and Licensee hereby waives any confidentiality restrictions * for such Feedback. In addition, Licensee grants to the Car Connectivity Consortium * and its affiliates a worldwide, non-exclusive, perpetual, irrevocable, * sub-licensable, royalty-free right and license under Licensees copyrights to copy, * reproduce, modify, create derivative works and directly or indirectly * distribute, make available and communicate to public the Feedback * in or in connection to any CCC products, software and/or services. */ import android.graphics.Bitmap; import android.graphics.Color; public class Main { private static Bitmap trimTransparentRegions(Bitmap input, int alphaThreshold) { final int height = input.getHeight(); final int width = input.getWidth(); final int[] pixels = new int[height * width]; input.getPixels(pixels, 0, width, 0, 0, width, height); int boundTop = 0, boundBottom = 0, boundLeft = 0, boundRight = 0; int i = 0; topScan: for (i = 0; i < pixels.length; i++) { if (isTransparent(pixels[i], alphaThreshold) == false) { boundTop = i / width; break topScan; } } bottomScan: for (i = pixels.length - 1; i >= 0; i--) { if (isTransparent(pixels[i], alphaThreshold) == false) { boundBottom = (pixels.length - i) / width; break bottomScan; } } /* for each x, x <- 0, scan downwards until not transparent pixel is reached */ leftScan: for (i = 0; i < width; i++) { for (int j = i; j < pixels.length; j += width) { if (isTransparent(pixels[j], alphaThreshold) == false) { boundLeft = j % width; break leftScan; } } } /* for each x, x <- width, scan upwards until not transparent pixel is reached */ rightScan: for (i = pixels.length - 1; i >= 0; i--) { for (int j = i; j >= 0; j -= width) { if (isTransparent(pixels[j], alphaThreshold) == false) { boundRight = width - (j % width); break rightScan; } } } return Bitmap.createBitmap(input, boundLeft, boundTop, width - boundLeft - boundRight, height - boundTop - boundBottom); } private static boolean isTransparent(int color, int alphaThreshold) { return Color.alpha(color) <= alphaThreshold; } }