Android拼接合并图片生成长图 - 好文

Android拼接合并图片生成长图

代码实现合并两张图片，以第一张图片的宽度为标准，如果被合并的第二张图片宽度和第一张不同，那么就以第一张图片的宽度为准线，对第二张图片进行缩放。

假设根目录的Pictures下已经有两张图片zhang.jpg和phil.jpg，最终把这两张图片合并成zhangphil.jpg的长图：
package zhangphil.test; import android.graphics.Bitmap; import
android.graphics.BitmapFactory; import android.graphics.Canvas; import
android.graphics.Matrix; import android.os.Bundle; import
android.os.Environment; import android.support.annotation.Nullable; import
android.support.v7.app.AppCompatActivity; import android.view.View; import
java.io.BufferedOutputStream; import java.io.File; import
java.io.FileInputStream; import java.io.FileOutputStream; import
java.io.IOException; import java.io.OutputStream; public class JavaActivity
extends AppCompatActivity { @Override protected void onCreate(@Nullable Bundle
savedInstanceState) { super.onCreate(savedInstanceState);
setContentView(R.layout.drawable_activity);
findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
@Override public void onClick(View v) { merge(); } }); } private void merge() {
new Thread(new Runnable() { @Override public void run() { File zhang = new
File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
"zhang.jpg"); File phil = new
File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
"phil.jpg"); try { Bitmap bitmap1 = BitmapFactory.decodeStream(new
FileInputStream(zhang)); Bitmap bitmap2 = BitmapFactory.decodeStream(new
FileInputStream(phil)); Bitmap newBmp = newBitmap(bitmap1, bitmap2); File
zhangphil = new
File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
"zhangphil.jpg"); if (!zhangphil.exists()) zhangphil.createNewFile();
save(newBmp, zhangphil, Bitmap.CompressFormat.JPEG, true); } catch (Exception
e) { e.printStackTrace(); } } }).start(); } public static Bitmap
newBitmap(Bitmap bmp1, Bitmap bmp2) { Bitmap retBmp; int width =
bmp1.getWidth(); if (bmp2.getWidth() != width) { //以第一张图片的宽度为标准，对第二张图片进行缩放。 int
h2 = bmp2.getHeight() * width / bmp2.getWidth(); retBmp =
Bitmap.createBitmap(width, bmp1.getHeight() + h2, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(retBmp); Bitmap newSizeBmp2 = resizeBitmap(bmp2,
width, h2); canvas.drawBitmap(bmp1, 0, 0, null); canvas.drawBitmap(newSizeBmp2,
0, bmp1.getHeight(), null); } else { //两张图片宽度相等，则直接拼接。 retBmp =
Bitmap.createBitmap(width, bmp1.getHeight() + bmp2.getHeight(),
Bitmap.Config.ARGB_8888); Canvas canvas = new Canvas(retBmp);
canvas.drawBitmap(bmp1, 0, 0, null); canvas.drawBitmap(bmp2, 0,
bmp1.getHeight(), null); } return retBmp; } public static Bitmap
resizeBitmap(Bitmap bitmap, int newWidth, int newHeight) { float scaleWidth =
((float) newWidth) / bitmap.getWidth(); float scaleHeight = ((float) newHeight)
/ bitmap.getHeight(); Matrix matrix = new Matrix();
matrix.postScale(scaleWidth, scaleHeight); Bitmap bmpScale =
Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(),
matrix, true); return bmpScale; } /** * 保存图片到文件File。 * * @param src 源图片 *
@param file 要保存到的文件 * @param format 格式 * @param recycle 是否回收 * @return true 成功
false 失败 */ public static boolean save(Bitmap src, File file,
Bitmap.CompressFormat format, boolean recycle) { if (isEmptyBitmap(src)) return
false; OutputStream os; boolean ret = false; try { os = new
BufferedOutputStream(new FileOutputStream(file)); ret = src.compress(format,
100, os); if (recycle && !src.isRecycled()) src.recycle(); } catch (IOException
e) { e.printStackTrace(); } return ret; } /** * Bitmap对象是否为空。 */ public static
boolean isEmptyBitmap(Bitmap src) { return src == null || src.getWidth() == 0
|| src.getHeight() == 0; } }

合并后生成的长图：

添加权限：
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

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