[Android] 使用Matrix矩阵类对图像进行缩放、旋转、对照度、亮度处理

2022-08-02 08:12:56

前一篇文章讲述了Android拍照、截图、保存并显示在ImageView控件中,该篇文章继续讲述Android图像处理技术,主要操作包含:通过打开相冊里的图片,使用Matrix对图像进行缩放、旋转、移动、对照度、亮度、饱和度操作,希望对大家有所帮助.

一. 显示打开图片

首先,设置activity_main.xml布局例如以下所看到的：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:id="@+id/container"

    android:layout_width="match_parent"

    android:layout_height="wrap_content"

    tools:context="com.example.cangeimagetest.MainActivity"

    tools:ignore="MergeRootFrame" >

    <LinearLayout

        android:layout_width="match_parent"

    	android:layout_height="wrap_content"

    	android:orientation="vertical" >

	    <Button

	        android:id="@+id/button1"

	        android:layout_width="match_parent"

	        android:layout_height="wrap_content"

	        android:text="选择图片" />

	    <TextView

	        android:id="@+id/textView1"

	        android:layout_width="match_parent"

	        android:layout_height="wrap_content"

	        android:visibility="invisible"

	        android:text="原图显示" />

	    <ImageView

	        android:id="@+id/imageView1"

	        android:layout_width="wrap_content"

	        android:layout_gravity="center_horizontal"

	        android:layout_height="wrap_content" />

	    <TextView

	        android:id="@+id/textView2"

	        android:layout_width="match_parent"

	        android:layout_height="wrap_content"

	        android:visibility="invisible"

	        android:text="变化后的图片" />

	    <ImageView

	        android:id="@+id/imageView2"

	        android:layout_gravity="center_horizontal"

	        android:layout_marginBottom="20dp"

	        android:layout_width="wrap_content"

	        android:layout_height="wrap_content" />

    </LinearLayout>

    <LinearLayout

        android:layout_width="match_parent"

    	android:layout_height="wrap_content"

    	android:orientation="horizontal"

    	android:layout_alignParentBottom="true" >

        <Button

	        android:id="@+id/button2"

	        android:layout_width="wrap_content"

	        android:layout_height="match_parent"

	        android:layout_weight="1"

	        android:text="缩小" />

        <Button

	        android:id="@+id/button3"

	        android:layout_width="wrap_content"

	        android:layout_height="match_parent"

	        android:layout_weight="1"

	        android:text="放大" />

        <Button

	        android:id="@+id/button4"

	        android:layout_width="wrap_content"

	        android:layout_height="match_parent"

	        android:layout_weight="1"

	        android:text="旋转" />

        <Button

	        android:id="@+id/button5"

	        android:layout_width="wrap_content"

	        android:layout_height="match_parent"

	        android:layout_weight="1"

	        android:text="饱和" />

        <Button

	        android:id="@+id/button6"

	        android:layout_width="wrap_content"

	        android:layout_height="match_parent"

	        android:layout_weight="1"

	        android:text="对照" />

    </LinearLayout>

</RelativeLayout>

然后,在Mainctivity.java中public class MainActivity extends Activity函数加入代码例如以下：

private Button selectBn;

private ImageView imageShow;

private ImageView imageCreate;

private TextView textview1;

private TextView textview2;

private Bitmap bmp; //原始图片

@Override

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    selectBn = (Button) findViewById(R.id.button1);

    imageShow = (ImageView) findViewById(R.id.imageView1);

    imageCreate = (ImageView) findViewById(R.id.imageView2);

    textview1 = (TextView) findViewById(R.id.textView1);

    textview2 = (TextView) findViewById(R.id.textView2);

    //选择图片

    selectBn.setOnClickListener(new OnClickListener() {

    	@Override

    	public void onClick(View v) {

    		Intent intent = new Intent(Intent.ACTION_PICK,

    				android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

    		startActivityForResult(intent, 0 );

    	}

    });

    if (savedInstanceState == null) {

        getFragmentManager().beginTransaction()

                .add(R.id.container, new PlaceholderFragment())

                .commit();

    }

}

//显示两张图片

protected void onActivityResult(int requestCode, int resultCode, Intent data) {

	super.onActivityResult(requestCode, resultCode, data);

	if(resultCode==RESULT_OK) {

		ShowPhotoByImageView(data);     //显示照片

		CreatePhotoByImageView();          //创建图片

	}

}

再调用自己定义函数实现显示图片：

//自己定义函数 显示打开的照片在ImageView1中

public void ShowPhotoByImageView(Intent data) {

	Uri imageFileUri = data.getData();

	DisplayMetrics dm = new DisplayMetrics();

	getWindowManager().getDefaultDisplay().getMetrics(dm);

	int width = dm.widthPixels;    //手机屏幕水平分辨率

	int height = dm.heightPixels;  //手机屏幕垂直分辨率

	Log.v("height", ""+height );

	Log.v("width", ""+width);

	try {

		// Load up the image's dimensions not the image itself

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

		bmpFactoryOptions.inJustDecodeBounds = true;

		bmp = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageFileUri), null, bmpFactoryOptions);

		int heightRatio = (int)Math.ceil(bmpFactoryOptions.outHeight/(float)height);

		int widthRatio = (int)Math.ceil(bmpFactoryOptions.outWidth/(float)width);

		Log.v("bmpheight", ""+bmpFactoryOptions.outHeight);

		Log.v("bmpheight", ""+bmpFactoryOptions.outWidth);

		if(heightRatio>1&&widthRatio>1) {

			if(heightRatio>widthRatio) {

				bmpFactoryOptions.inSampleSize = heightRatio*2;

			}

			else {

				bmpFactoryOptions.inSampleSize = widthRatio*2;

			}

		}

		 //图像真正解码

	    bmpFactoryOptions.inJustDecodeBounds = false;

	    bmp = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageFileUri), null, bmpFactoryOptions);

	    imageShow.setImageBitmap(bmp); //将剪裁后照片显示出来

	    textview1.setVisibility(View.VISIBLE);

	} catch(FileNotFoundException e) {

		e.printStackTrace();

	}

}

//创建第二张图片并显示

public void CreatePhotoByImageView() {

	try {

	    Bitmap createBmp = Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(), bmp.getConfig());

    	Canvas canvas = new Canvas(createBmp); //画布 传入位图用于绘制

    	Paint paint = new Paint(); //画刷 改变颜色 对照度等属性

    	canvas.drawBitmap(bmp, 0, 0, paint);    //错误:没有图片 由于參数bmp写成createBmp

    	imageCreate.setImageBitmap(createBmp);

    	textview2.setVisibility(View.VISIBLE);

	} catch(Exception e) {

		e.printStackTrace();

	}

}

显示的效果例如以下图所看到的,该图叫莱娜图(Lenna),是图像处理中常常使用的例子图.

[Android] 使用Matrix矩阵类对图像进行缩放、旋转、对照度、亮度处理

二. Matrix操作

然后通过Matrix对图像进行处理操作,在onCreate函数中加入点击事件:

//缩小图片

Button button2=(Button)findViewById(R.id.button2);

button2.setOnClickListener(new OnClickListener() {

	@Override

	public void onClick(View v) {

		SmallPicture();

	}

});

//放大图片

    Button button3=(Button)findViewById(R.id.button3);

    button3.setOnClickListener(new OnClickListener() {

		@Override

		public void onClick(View v) {

			BigPicture();

		}

	});

   //旋转图片

Button button4=(Button)findViewById(R.id.button4);

button4.setOnClickListener(new OnClickListener() {

	@Override

	public void onClick(View v) {

		TurnPicture();

	}

});

//图片饱和度改变

Button button5=(Button)findViewById(R.id.button5);

button5.setOnClickListener(new OnClickListener() {

	@Override

	public void onClick(View v) {

		SaturationPicture();

	}

});

//图片对照度改变

Button button6=(Button)findViewById(R.id.button6);

button6.setOnClickListener(new OnClickListener() {

	@Override

	public void onClick(View v) {

		ContrastPicture();

	}

});

最后分别自己定义函数各操作实现,代码例如以下：

//缩小图片

private void SmallPicture() {

	Matrix matrix = new Matrix();

	//缩放区间 0.5-1.0

	if(smallbig>0.5f)

		smallbig=smallbig-0.1f;

	else

		smallbig=0.5f;

	//x y坐标同一时候缩放

	matrix.setScale(smallbig,smallbig,bmp.getWidth()/2,bmp.getHeight()/2);

	Bitmap createBmp = Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(), bmp.getConfig());

	Canvas canvas = new Canvas(createBmp); //画布 传入位图用于绘制

	Paint paint = new Paint(); //画刷 改变颜色 对照度等属性

    	canvas.drawBitmap(bmp, matrix, paint);

    	imageCreate.setBackgroundColor(Color.RED);

    	imageCreate.setImageBitmap(createBmp);

    	textview2.setVisibility(View.VISIBLE);

    }

  //放大图片

private void BigPicture() {

	Matrix matrix = new Matrix();

	//缩放区间 0.5-1.0

	if(smallbig<1.5f)

		smallbig=smallbig+0.1f;

	else

		smallbig=1.5f;

	//x y坐标同一时候缩放

	matrix.setScale(smallbig,smallbig,bmp.getWidth()/2,bmp.getHeight()/2);

	Bitmap createBmp = Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(), bmp.getConfig());

	Canvas canvas = new Canvas(createBmp);

	Paint paint = new Paint();

	canvas.drawBitmap(bmp, matrix, paint);

	imageCreate.setBackgroundColor(Color.RED);

	imageCreate.setImageBitmap(createBmp);

	textview2.setVisibility(View.VISIBLE);

}

//旋转图片

private void TurnPicture() {

	Matrix matrix = new Matrix();

	turnRotate=turnRotate+15;

	//选择角度 饶(0,0)点选择 正数顺时针 负数逆时针 中心旋转

	matrix.setRotate(turnRotate,bmp.getWidth()/2,bmp.getHeight()/2);

	Bitmap createBmp = Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(), bmp.getConfig());

	Canvas canvas = new Canvas(createBmp);

	Paint paint = new Paint();

	canvas.drawBitmap(bmp, matrix, paint);

	imageCreate.setBackgroundColor(Color.RED);

	imageCreate.setImageBitmap(createBmp);

	textview2.setVisibility(View.VISIBLE);

}

//改变图像饱和度

private void SaturationPicture() {

	//设置饱和度 0表示灰度图像 大于1饱和度添加 0-1饱和度减小

	ColorMatrix cm = new ColorMatrix();

	cm.setSaturation(saturation);

	Paint paint = new Paint();

	paint.setColorFilter(new ColorMatrixColorFilter(cm));

	//显示图片

	Matrix matrix = new Matrix();

	Bitmap createBmp = Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(), bmp.getConfig());

	Canvas canvas = new Canvas(createBmp);

	canvas.drawBitmap(bmp, matrix, paint);

	imageCreate.setImageBitmap(createBmp);

	textview2.setVisibility(View.VISIBLE);

	saturation=saturation+0.1f;

	if(saturation>=1.5f) {

		saturation=0f;

	}

}

//设置图片对照度

private void ContrastPicture() {

	ColorMatrix cm = new ColorMatrix();

	float brightness = -25;  //亮度

	float contrast = 2;        //对照度

	cm.set(new float[] {

		contrast, 0, 0, 0, brightness,

		0, contrast, 0, 0, brightness,

		0, 0, contrast, 0, brightness,

		0, 0, 0, contrast, 0

	});

	Paint paint = new Paint();

	paint.setColorFilter(new ColorMatrixColorFilter(cm));

	//显示图片

	Matrix matrix = new Matrix();

	Bitmap createBmp = Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(), bmp.getConfig());

	Canvas canvas = new Canvas(createBmp);

	canvas.drawBitmap(bmp, matrix, paint);

	imageCreate.setImageBitmap(createBmp);

	textview2.setVisibility(View.VISIBLE);

}

同一时候自己定义变量例如以下：

//图片变换參数

private float smallbig=1.0f;   //缩放比例

private int turnRotate=0;       //旋转度数

private float saturation=0f;    //饱和度

它的执行结果例如以下图所看到的：

watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvRWFzdG1vdW50/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast" width="240" height="320">

watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvRWFzdG1vdW50/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast" width="240" height="320">



watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvRWFzdG1vdW50/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast" width="240" height="320">

watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvRWFzdG1vdW50/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast" width="240" height="320">

    须要指出的是：该项目只讲述处理的过程,并没有考虑非常多因素,如:有的图像显示可能超出屏幕,没有加载图片点击处理button报错,横竖屏切换导致不显示图片,最以下button可能被遮挡,图像放大画布没有变,由于为觉得显示一张改变后的图片效果更好,而该project不过对照.图像缩放移动触屏变换更好,下一篇讲述.

    XML布局推荐：http://www.apkbus.com/forum.php?mod=viewthread&tid=44949

    解决画布跟着图片放大：http://www.eoeandroid.com/thread-3162-1-1.html

三. Matrix处理的原理

Android中能够通过Matrix和ColorMatrix对图像进行处理.

    1.Matrix

    图像空间变换,包含旋转、剪裁、缩放或移动.Matrix类中每一个数字都将应用于图像上每一个点的3个坐标x\y\z之中的一个.

    例如以下代码通过setValues设置值.(1,0,0)表示x坐标转换x=1x+0y+0z,相同y=0x+1y+0z,z=0x+0y+1z.该矩阵不做不论什么变换.假设第一行改为(.5f,0,0),那么图像在x轴上将图像压缩50%.移动见setTranslate()函数.

Matrix matrix = new Matrix();

matrix.setValues(new float[] {

        1, 0, 0,

        0, 1, 0,

        0, 0, 1

});

    2.ColorMatrix

    在Canvas(画布)对象上绘制时既可使用Matrix方法,也可使用ColorMatrix来改变在Canvas对象上绘制的Paint(画刷)对象.对图像的像素处理时,每一个像素由RGBA值组成(Red Green Blue Alpha).详细方法推荐博文:http://www.cnblogs.com/leon19870907/articles/1978065.html

    最后希望该文章对大家有所帮助,尤其是Android刚開始学习的人.该文章是讲述Android使用Matrix处理图片的基础文章,假设有不足或错误地方,请见谅~參考资料《Android多媒体开发高级编程著：Shawn Van Every》

    下载地址:http://download.csdn.net/detail/eastmount/8082043

(By:Eastmount 2014-10-26 夜2点 http://blog.csdn.net/eastmount)

码农公寓

一. 显示打开图片

二. Matrix操作

三. Matrix处理的原理

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