之前说过了 重叠部分图片合成,今天说一下html
canvas.drawBitmap拼接长图
先上效果gifjava
需求:多图拼接长图,长图大小 宽度为屏幕,高度本身不变造成比例android
核心源码1.:算法
final int mScreenWidth = getResources().getDisplayMetrics().widthPixels; LogUtil.log("mScreenWidth---" + mScreenWidth); new AsyncTask<List<String>, Void, Bitmap>() { @Override protected void onPreExecute() { super.onPreExecute(); showMyDialog(); } @Override protected Bitmap doInBackground(List<String>... lists) { List<String> list = lists[0]; Bitmap last = null; for (int i = 0; i < list.size(); i++) { if (last == null) { last = PhotoUtils.comp(BitmapFactory.decodeFile(list.get(0))); } else { last = PhotoUtils.newBitmap(mScreenWidth, last, PhotoUtils.comp(BitmapFactory.decodeFile(list.get(i)))); } } return last; } @Override protected void onPostExecute(Bitmap bitmap) { dismissMyDialog(); ivLong.setImageBitmap(bitmap); } }.execute(pathList);
1.压缩到不崩溃的加载质量canvas
//图片按比例大小压缩方法(根据Bitmap图片压缩) public static Bitmap comp(Bitmap image) { ByteArrayOutputStream baos = new ByteArrayOutputStream(); image.compress(Bitmap.CompressFormat.JPEG, 100, baos); if (baos.toByteArray().length / 1024 > 1024) {//判断若是图片大于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; //如今主流手机比较可能是800*480分辨率,因此高和宽咱们设置为 float hh = 800f;//这里设置高度为800f float ww = 480f;//这里设置宽度为480f //缩放比。因为是固定比例缩放,只用高或者宽其中一个数据进行计算便可 int be = 1;//be=1表示不缩放 if (w > h && w > ww) {//若是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) {//若是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 //从新读入图片,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);//压缩比如例大小后再进行质量压缩 } //1、质量压缩法 public static 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 > 100) { //循环判断若是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;//每次都减小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; }
2.具体拼接方法基本原理(下面有进一步优化)ide
public static Bitmap newBitmap(int width, Bitmap bit1, Bitmap bit2) { if (width <= 0) { return null; } int h1 = bit1.getHeight() * width / bit1.getWidth(); int h2 = bit2.getHeight() * width / bit2.getWidth(); int height = h1 + h2; //缩放到屏幕宽度时候 合成后的总高度 //建立一个空的Bitmap(内存区域),宽度等于第一张图片的宽度,高度等于两张图片高度总和 Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888); //缩放到指定大小的新bitmap Bitmap newSizeBitmap1 = getNewSizeBitmap(bit1, width, h1); Bitmap newSizeBitmap2 = getNewSizeBitmap(bit2, width, h2); //将bitmap放置到绘制区域,并将要拼接的图片绘制到指定内存区域 Canvas canvas = new Canvas(bitmap); canvas.drawBitmap(newSizeBitmap1, 0, 0, null); canvas.drawBitmap(newSizeBitmap2, 0, h1, null); return bitmap; }
/** * 以第一个图为准 * 优化算法 1.图片不须要铺满,只须要以统一合适的宽度。而后让imageview本身去铺满,否则长图合成长图会崩溃,这里以第一张图为例 *2.只缩放不相等宽度的图片。已经缩放过的不须要再次缩放 * @param bit1 * @param bit2 * @return */ public static Bitmap newBitmap(Bitmap bit1, Bitmap bit2) { Bitmap newBit = null; int width = bit1.getWidth(); if (bit2.getWidth() != width) { int h2 = bit2.getHeight() * width / bit2.getWidth(); newBit = Bitmap.createBitmap(width, bit1.getHeight() + h2, Bitmap.Config.ARGB_8888); Canvas canvas = new Canvas(newBit); Bitmap newSizeBitmap2 = getNewSizeBitmap(bit2, width, h2); canvas.drawBitmap(bit1, 0, 0, null); canvas.drawBitmap(newSizeBitmap2, 0, bit1.getHeight(), null); } else { newBit = Bitmap.createBitmap(width, bit1.getHeight() + bit2.getHeight(), Bitmap.Config.ARGB_8888); Canvas canvas = new Canvas(newBit); canvas.drawBitmap(bit1, 0, 0, null); canvas.drawBitmap(bit2, 0, bit1.getHeight(), null); } return newBit; }
public static Bitmap getNewSizeBitmap(Bitmap bitmap, int newWidth, int newHeight) { float scaleWidth = ((float) newWidth) / bitmap.getWidth(); float scaleHeight = ((float) newHeight) / bitmap.getHeight(); // 取得想要缩放的matrix参数 Matrix matrix = new Matrix(); matrix.postScale(scaleWidth, scaleHeight); // 获得新的图片 Bitmap bit1Scale = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true); return bit1Scale; }
3.xml显示post
<ScrollView android:layout_width="match_parent" android:layout_height="wrap_content"> <FrameLayout android:layout_width="match_parent" android:layout_height="wrap_content"> <ImageView android:id="@+id/iv_long" android:layout_width="match_parent" android:layout_height="wrap_content" android:adjustViewBounds="true" android:scaleType="fitXY" /> </FrameLayout> </ScrollView>