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android 筆記 --- Android中幾種影象特效處理的集錦

Android中幾種影象特效處理的小技巧,比如圓角,倒影,還有就是圖片縮放,Drawable轉化為Bitmap,Bitmap轉化為Drawable等等.

廢話少說了,直接講解今天的例項,本例主要是先獲取桌布(getWallpaper()),然後對當前桌布的一些特效處理.大家按步驟一步一步來:

第一步:新建一個Android工程命名為ImageDemo,工程結構如下:

[img]http://disanji.net/wp-content/uploads/2010/12/20101222_structure.jpg[/img]

第二步:新建一個.java檔案,命名為ImageUtil.java,在裡面定義一些圖片處理方法,程式碼如下:

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 {

//放大縮小圖片
public static Bitmap zoomBitmap(Bitmap bitmap,int w,int h){
int width = bitmap.getWidth();
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;
}
//將Drawable轉化為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;

}

//獲得圓角圖片的方法
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;
}
//獲得帶倒影的圖片方法
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佈局檔案,主要放了兩個ImageView控制元件,程式碼如下:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns: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:修改主核心程式,ImageDemo.java,程式碼如下:

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);

//獲取桌布返回值是Drawable
Drawable drawable = getWallpaper();
//將Drawable轉化為Bitmap
Bitmap bitmap = ImageUtil.drawableToBitmap(drawable);
//縮放圖片
Bitmap zoomBitmap = ImageUtil.zoomBitmap(bitmap, 100, 100);
//獲取圓角圖片
Bitmap roundBitmap = ImageUtil.getRoundedCornerBitmap(zoomBitmap, 10.0f);
//獲取倒影圖片
Bitmap reflectBitmap = ImageUtil.createReflectionImageWithOrigin(zoomBitmap);
//這裡可以讓Bitmap再轉化為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:執行上述工程,檢視效果如下:

[img]http://disanji.net/wp-content/uploads/2010/12/20101222_runresult.jpg[/img]

OK大功告成了!!