android中的图片处理

2023-07-30 19:53:16

大图片处理

大图片处理是将原来像素高的转换为像素低的图片,比如原来图片是1024*768的，而手机屏幕是800*600的，这时候就需要进行转换。转换的方式很简单就是等比例缩放。

package xidian.dy.com.chujia;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.os.Bundle;

import android.os.Environment;

import android.support.v7.app.AppCompatActivity;

import android.view.Display;

import android.view.View;

import android.widget.ImageView;

import java.io.File;

public class MainActivity extends AppCompatActivity {

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

    }

    public void load(View v){

        BitmapFactory.Options options = new BitmapFactory.Options();

        File file = new File(Environment.getExternalStorageDirectory(), "a.dog");

        options.inJustDecodeBounds = true;

        BitmapFactory.decodeFile(file.toString(), options);

        //获取图片宽高

        int imgWidth = options.outWidth;

        int imgHeight = options.outHeight;

        //获取屏幕宽高

        Display dsp = getWindowManager().getDefaultDisplay();

        int screanWidth = dsp.getWidth();

        int screanHeight = dsp.getHeight();

        //计算缩放比例

        int scaleWidth = imgWidth / screanWidth;

        int scaleHeight = imgHeight / screanHeight;

        int scale = scaleHeight >= scaleWidth ? scaleHeight:scaleWidth;

        if(scale < 1)

            scale = 1;

        //设置缩放比例(scale应大于1缩放才能其作用)

        options.inSampleSize = scale;

        options.inJustDecodeBounds = false;

        Bitmap bm = BitmapFactory.decodeFile(file.toString(), options);

        ImageView img = (ImageView) findViewById(R.id.iv);

        if(img != null)

            img.setImageBitmap(bm);

    }

}

图片副本

创建图片副本是为了对图片进行修改,下面的代码将图片进行了水平反转

package xidian.dy.com.chujia;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.Canvas;

import android.graphics.Matrix;

import android.graphics.Paint;

import android.os.Bundle;

import android.support.v7.app.AppCompatActivity;

import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        Bitmap bm = BitmapFactory.decodeFile("/sdcard/a.dog");

        //创建一个与原图等宽高的bitmap对象,可以看作是画纸

        Bitmap bmcpy = Bitmap.createBitmap(bm.getWidth(), bm.getHeight(),bm.getConfig());

        //创建画笔对象

        Paint paint = new Paint();

        //创建画板对象,将画纸铺在画板上

        Canvas canvas = new Canvas(bmcpy);

        //开始作画

        //将图片水平翻转

        Matrix mt = new Matrix();

        mt.setScale(-1, 1);

        mt.postTranslate(bmcpy.getWidth(), 0);

        canvas.drawBitmap(bm, mt, paint);

        ImageView iv = (ImageView) findViewById(R.id.iv2);

        iv.setImageBitmap(bmcpy);

        ImageView iv1 = (ImageView) findViewById(R.id.iv1);

        iv1.setImageBitmap(bm);

    }

}

画画

让用户在画板上作画

package xidian.dy.com.chujia;

import android.content.Intent;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Matrix;

import android.graphics.Paint;

import android.net.Uri;

import android.os.Bundle;

import android.os.Environment;

import android.support.v7.app.AppCompatActivity;

import android.view.MotionEvent;

import android.view.View;

import android.widget.ImageView;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

public class MainActivity extends AppCompatActivity {

    int preX,preY;

    Bitmap bmcpy;

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        Bitmap bm = BitmapFactory.decodeResource(getResources(), R.drawable.bg);

        bmcpy = Bitmap.createBitmap(bm.getWidth(), bm.getHeight(), bm.getConfig());

        final Paint paint = new Paint();

        final Canvas canvas = new Canvas(bmcpy);

        //设置画笔的颜色为红色

        paint.setColor(Color.RED);

        canvas.drawBitmap(bm, new Matrix(), paint);

        final ImageView iv = (ImageView) findViewById(R.id.iv);

        iv.setImageBitmap(bmcpy);

        if(iv != null)

            iv.setOnTouchListener(new View.OnTouchListener() {

                @Override

                public boolean onTouch(View v, MotionEvent event) {

                    int action = event.getAction();

                    switch (action) {

                        case MotionEvent.ACTION_DOWN:

                            preX = (int) event.getX();

                            preY = (int) event.getY();

                            break;

                        case MotionEvent.ACTION_UP:

                            break;

                        case MotionEvent.ACTION_MOVE:

                            int x = (int) event.getX();

                            int y = (int) event.getY();

                            canvas.drawLine(preX, preY, x, y, paint);

                            iv.setImageBitmap(bmcpy);

                            preX = x;

                            preY = y;

                            break;

                    }

                    return true;

                }

            });

    }

    //将画好的图片进行保存

    public void save(){

        File file = new File("/sdcard/tmp.png");

        try {

            FileOutputStream fos = new FileOutputStream(file);

            bmcpy.compress(Bitmap.CompressFormat.PNG,10,fos);

            Intent intent = new Intent();

            //发出SDcard挂载广播来刷新MediaStore数据库

            intent.setAction(Intent.ACTION_MEDIA_MOUNTED);

            intent.setData(Uri.fromFile(Environment.getExternalStorageDirectory()));

            startActivity(intent);

        } catch (FileNotFoundException e) {

            e.printStackTrace();

        }

    }

}

码农公寓

大图片处理

图片副本

画画

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