private Bitmap comp(Bitmap image) { ByteArrayOutputStream baos = new ByteArrayOutputStream(); image.compress(Bitmap.CompressFormat.JPEG, 100, baos); if( baos.toByteArray().length / 1024>1024) {//判断如果图片大于1M,进行压缩避免在生成图片(BitmapFactory.decodeStream)时溢出 baos.reset();//重置baos即清空baos image.compress(Bitmap.CompressFormat.JPEG, 50, baos);//这里压缩50%,把压缩后的数据存放到baos中 } ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray()); BitmapFactory.Options newOpts = new BitmapFactory.Options(); //开始读入图片,此时把options.inJustDecodeBounds 设回true了 newOpts.inJustDecodeBounds = true; Bitmap bitmap = BitmapFactory.decodeStream(isBm, null, newOpts); newOpts.inJustDecodeBounds = false; int w = newOpts.outWidth; int h = newOpts.outHeight; //现在主流手机比较多是800*480分辨率,所以高和宽我们设置为 float hh = 800f;//这里设置高度为800f float ww =580f;//这里设置宽度为480f //缩放比。由于是固定比例缩放,只用高或者宽其中一个数据进行计算即可 int be = 1;//be=1表示不缩放 if (w > h && w > ww) {//如果宽度大的话根据宽度固定大小缩放 be = (int) (newOpts.outWidth / ww); } else if (w < h && h > hh) {//如果高度高的话根据宽度固定大小缩放 be = (int) (newOpts.outHeight / hh); } if (be <= 0) be = 1; newOpts.inSampleSize = be;//设置缩放比例 //重新读入图片,注意此时已经把options.inJustDecodeBounds 设回false了 isBm = new ByteArrayInputStream(baos.toByteArray()); bitmap = BitmapFactory.decodeStream(isBm, null, newOpts); return compressImage(bitmap);//压缩好比例大小后再进行质量压缩 } private Bitmap compressImage(Bitmap image) { ByteArrayOutputStream baos = new ByteArrayOutputStream(); image.compress(Bitmap.CompressFormat.JPEG, 100, baos);//质量压缩方法,这里100表示不压缩,把压缩后的数据存放到baos中 int options = 100; while ( baos.toByteArray().length / 1024>300) { //循环判断如果压缩后图片是否大于100kb,大于继续压缩 baos.reset();//重置baos即清空baos image.compress(Bitmap.CompressFormat.JPEG, options, baos);//这里压缩options%,把压缩后的数据存放到baos中 options -= 10;//每次都减少10 } ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray());//把压缩后的数据baos存放到ByteArrayInputStream中 Bitmap bitmap = BitmapFactory.decodeStream(isBm, null, null);//把ByteArrayInputStream数据生成图片 return bitmap; }
缩略图
public static Bitmap getImageThumbnail(String imagePath, int width, int height) { Bitmap bitmap = null; BitmapFactory.Options options = new BitmapFactory.Options(); options.inPreferredConfig = Bitmap.Config.ARGB_4444; options.inPurgeable = true; options.inInputShareable = true; options.inJustDecodeBounds = true; // 获取这个图片的宽和高,注意此处的bitmap为null bitmap = BitmapFactory.decodeFile(imagePath, options); options.inJustDecodeBounds = false; // 设为 false // 计算缩放比 int h = options.outHeight; int w = options.outWidth; int beWidth = w / width; int beHeight = h / height; int be = 1; if (beWidth < beHeight) { be = beWidth; } else { be = beHeight; } if (be <= 0) { be = 1; } options.inSampleSize = be; // 重新读入图片,读取缩放后的bitmap,注意这次要把options.inJustDecodeBounds 设为 false bitmap = BitmapFactory.decodeFile(imagePath, options); // 利用ThumbnailUtils来创建缩略图,这里要指定要缩放哪个Bitmap对象 bitmap = ThumbnailUtils.extractThumbnail(bitmap, width, height, ThumbnailUtils.OPTIONS_RECYCLE_INPUT); return bitmap; } // 可用于生成缩略图。 /** * Creates a centered bitmap of the desired size. Recycles the input. * * @param source */ public static Bitmap extractMiniThumb(String imagePath, int width, int height) { // return extractMiniThumb(source, width, height, true); return getImageThumbnail(imagePath, width, height); }