Android 中图像特效处理方法小结

﹏ヽ暗。殇╰゛Y 2022-10-01 03:55 196阅读 0赞

大家好,这一节给大家分享的是Android中几种图像特效处理的小技巧,比如圆角,倒影,还有就是图片缩放,Drawable转化为Bitmap,Bitmap转化为Drawable等等.

废话少说了,直接讲解今天的实例,本例主要是先获取壁纸(getWallpaper()),然后对当前壁纸的一些特效处理.大家按步骤一步一步来:

![0_1311215304B600.gif][]

**第二步:新建一个.java文件,命名为ImageUtil.java,在里面定义一些图片处理方法,代码如下:**

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package com.android.tutor;  
import android.graphics.Bitmap;  
import android.graphics.Canvas;  
import android.graphics.LinearGradient;  
import android.graphics.Matrix;  
import android.graphics.Paint;  
import android.graphics.PixelFormat;  
import android.graphics.PorterDuffXfermode;  
import android.graphics.Rect;  
import android.graphics.RectF;  
import android.graphics.Bitmap.Config;  
import android.graphics.PorterDuff.Mode;  
import android.graphics.Shader.TileMode;  
import android.graphics.drawable.Drawable;

public class ImageUtil \{  
  
//放大缩小图片  
public static Bitmap zoomBitmap(Bitmap bitmap,int w,int h)\{

int width = bitmap.getWidth(); //实际长宽  
int height = bitmap.getHeight();  
Matrix matrix = new Matrix();  
float scaleWidht = ((float)w / width);  
float scaleHeight = ((float)h / height);  
matrix.postScale(scaleWidht, scaleHeight);  
Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);  
return newbmp;

/\*\*  
\* Returns an immutable adj. 不变的；不可变的 bitmap from subset of the source bitmap,  
\* transformed by the optional matrix. It is  
\* initialized with the same density as the original bitmap.  
\*  
\* @param source The bitmap we are subsetting  
\* @param x The x coordinate of the first pixel in source  
\* @param y The y coordinate of the first pixel in source  
\* @param width The number of pixels in each row  
\* @param height The number of rows  
\* @param m Optional matrix to be applied to the pixels  
\* @param filter true if the source should be filtered.  
\* Only applies if the matrix contains more than just  
\* translation.  
\* @return A bitmap that represents the specified subset of source  
\* @throws IllegalArgumentException if the x, y, width, height values are  
\* outside of the dimensions of the source bitmap.  
\*/  
\*public static Bitmap createBitmap(Bitmap source, int x, int y, int width, int height,  
Matrix m, boolean filter)

\*/

\}  
//将Drawable转化为Bitmap  
public static Bitmap drawableToBitmap(Drawable drawable)\{  
int width = drawable.getIntrinsicWidth();  
int height = drawable.getIntrinsicHeight();  
Bitmap bitmap = Bitmap.createBitmap(width, height,  
drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB\_8888  
: Bitmap.Config.RGB\_565);  
Canvas canvas = new Canvas(bitmap);  
drawable.setBounds(0,0,width,height);  
drawable.draw(canvas);  
return bitmap;  
  
\}  
  
//获得圆角图片的方法  
public static Bitmap getRoundedCornerBitmap(Bitmap bitmap,float roundPx)\{  
  
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap  
.getHeight(), Config.ARGB\_8888);  
Canvas canvas = new Canvas(output);  
  
final int color = 0xff424242;  
final Paint paint = new Paint();  
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());  
final RectF rectF = new RectF(rect);  
  
paint.setAntiAlias(true);  
canvas.drawARGB(0, 0, 0, 0);  
paint.setColor(color);  
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);  
  
paint.setXfermode(new PorterDuffXfermode(Mode.SRC\_IN));  
canvas.drawBitmap(bitmap, rect, rect, paint);  
  
return output;  
\}  
//获得带倒影的图片方法   
public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap)\{  
final int reflectionGap = 4;  
int width = bitmap.getWidth();  
int height = bitmap.getHeight();  
  
Matrix matrix = new Matrix();  
matrix.preScale(1, -1);  
  
Bitmap reflectionImage = Bitmap.createBitmap(bitmap,  
0, height/2, width, height/2, matrix, false);  
  
Bitmap bitmapWithReflection = Bitmap.createBitmap(width, (height + height/2), Config.ARGB\_8888);  
  
Canvas canvas = new Canvas(bitmapWithReflection);  
canvas.drawBitmap(bitmap, 0, 0, null);  
Paint deafalutPaint = new Paint();  
canvas.drawRect(0, height,width,height + reflectionGap,  
deafalutPaint);  
  
canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);  
  
Paint paint = new Paint();  
LinearGradient shader = new LinearGradient(0,  
bitmap.getHeight(), 0, bitmapWithReflection.getHeight()  
\+ reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);  
paint.setShader(shader);  
// Set the Transfer mode to be porter duff and destination in  
paint.setXfermode(new PorterDuffXfermode(Mode.DST\_IN));  
// Draw a rectangle using the paint with our linear gradient  
canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()  
\+ reflectionGap, paint);  
  
return bitmapWithReflection;  
\}  
  
\}

**第三步:修改main.xml布局文件,主要放了两个ImageView控件,代码如下:**

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<?xml version="1.0" encoding="utf-8"?>  
<LinearLayout xmlns:android="[http://schemas.android.com/apk/res/android][http_schemas.android.com_apk_res_android]"  
android:orientation="vertical"  
android:layout\_width="fill\_parent"  
android:layout\_height="fill\_parent"  
>  
<ImageView  
android:id="@+id/image01"  
android:layout\_width="wrap\_content"  
android:layout\_height="wrap\_content"  
android:padding="10px"  
/>  
<ImageView  
android:id="@+id/image02"  
android:layout\_width="wrap\_content"  
android:layout\_height="wrap\_content"  
android:padding="10px"  
/>  
</LinearLayout>

**第四步:修改主核心程序,ImageDemo.java,代码如下:**

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package com.android.tutor;  
import android.app.Activity;  
import android.graphics.Bitmap;  
import android.graphics.drawable.Drawable;  
import android.os.Bundle;  
import android.widget.ImageView;  
public class Imagedemo extends Activity \{  
private ImageView mImageView01,mImageView02;  
  
public void onCreate(Bundle savedInstanceState) \{  
super.onCreate(savedInstanceState);  
setContentView(R.layout.main);  
setupViews();  
\}  
  
private void setupViews()\{  
mImageView01 = (ImageView)findViewById(R.id.image01);  
mImageView02 = (ImageView)findViewById(R.id.image02);  
  
//获取壁纸返回值是Drawable  
Drawable drawable = getWallpaper();  
//将Drawable转化为Bitmap  
Bitmap bitmap = ImageUtil.drawableToBitmap(drawable);  
//缩放图片  
Bitmap zoomBitmap = ImageUtil.zoomBitmap(bitmap, 100, 100);  
//获取圆角图片  
Bitmap roundBitmap = ImageUtil.getRoundedCornerBitmap(zoomBitmap, 10.0f);  
//获取倒影图片  
Bitmap reflectBitmap = ImageUtil.createReflectionImageWithOrigin(zoomBitmap);  
//这里可以让Bitmap再转化为Drawable  
// Drawable roundDrawable = new BitmapDrawable(roundBitmap);  
// Drawable reflectDrawable = new BitmapDrawable(reflectBitmap);  
// mImageView01.setBackgroundDrawable(roundDrawable);  
// mImageView02.setBackgroundDrawable(reflectDrawable);  
  
mImageView01.setImageBitmap(roundBitmap);  
mImageView02.setImageBitmap(reflectBitmap);  
\}  
\}

**第五步:运行上述工程,查看效果如下:**

**![0_1311215392m881.gif][]**

**OK大功告成了!!**

[0_1311215304B600.gif]: /images/20220705/5b7c5da3b5dd44febf3f1aae649c8933.png
[http_schemas.android.com_apk_res_android]: http://schemas.android.com/apk/res/android
[0_1311215392m881.gif]: /images/20220705/6119e2a7fb4940389444643645cadb74.png