Java tutorial
//package com.java2s; /* * Copyright (C) 2006 The Android Open Source Project * Copyright (C) 2013 YIXIA.COM * * 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. */ import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Matrix; import android.graphics.Rect; public class Main { private static final int OPTIONS_SCALE_UP = 0x1; public static final int OPTIONS_RECYCLE_INPUT = 0x2; private static Bitmap transform(Matrix scaler, Bitmap source, int targetWidth, int targetHeight, int options) { boolean scaleUp = (options & OPTIONS_SCALE_UP) != 0; boolean recycle = (options & OPTIONS_RECYCLE_INPUT) != 0; int deltaX = source.getWidth() - targetWidth; int deltaY = source.getHeight() - targetHeight; if (!scaleUp && (deltaX < 0 || deltaY < 0)) { Bitmap b2 = Bitmap.createBitmap(targetWidth, targetHeight, Bitmap.Config.ARGB_8888); Canvas c = new Canvas(b2); int deltaXHalf = Math.max(0, deltaX / 2); int deltaYHalf = Math.max(0, deltaY / 2); Rect src = new Rect(deltaXHalf, deltaYHalf, deltaXHalf + Math.min(targetWidth, source.getWidth()), deltaYHalf + Math.min(targetHeight, source.getHeight())); int dstX = (targetWidth - src.width()) / 2; int dstY = (targetHeight - src.height()) / 2; Rect dst = new Rect(dstX, dstY, targetWidth - dstX, targetHeight - dstY); c.drawBitmap(source, src, dst, null); if (recycle) source.recycle(); return b2; } float bitmapWidthF = source.getWidth(); float bitmapHeightF = source.getHeight(); float bitmapAspect = bitmapWidthF / bitmapHeightF; float viewAspect = (float) targetWidth / targetHeight; float scale = bitmapAspect > viewAspect ? targetHeight / bitmapHeightF : targetWidth / bitmapWidthF; if (scale < .9F || scale > 1F) scaler.setScale(scale, scale); else scaler = null; Bitmap b1; if (scaler != null) b1 = Bitmap.createBitmap(source, 0, 0, source.getWidth(), source.getHeight(), scaler, true); else b1 = source; if (recycle && b1 != source) source.recycle(); int dx1 = Math.max(0, b1.getWidth() - targetWidth); int dy1 = Math.max(0, b1.getHeight() - targetHeight); Bitmap b2 = Bitmap.createBitmap(b1, dx1 / 2, dy1 / 2, targetWidth, targetHeight); if (b2 != b1 && (recycle || b1 != source)) b1.recycle(); return b2; } }