Java tutorial
//package com.java2s; import android.graphics.*; public class Main { /** * Transform source Bitmap to targeted width and height. */ private static Bitmap transform(Matrix scaler, Bitmap source, int targetWidth, int targetHeight, boolean recycle) { float bitmapWidthF = source.getWidth(); float bitmapHeightF = source.getHeight(); float bitmapAspect = bitmapWidthF / bitmapHeightF; float viewAspect = (float) targetWidth / targetHeight; if (bitmapAspect > viewAspect) { float scale = targetHeight / bitmapHeightF; if (scale < .9F || scale > 1F) { scaler.setScale(scale, scale); } else { scaler = null; } } else { float scale = targetWidth / bitmapWidthF; if (scale < .9F || scale > 1F) { scaler.setScale(scale, scale); } else { scaler = null; } } Bitmap b1; if (scaler != null) { // this is used for minithumb and crop, so we want to filter here. 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, null, true); if (b2 != b1) { if (recycle || b1 != source) { b1.recycle(); } } return b2; } }