目录结构:
contents structure [+]
- EmbossMaskFilter
- BlurMaskFilter
MaskFilter可以用来指定画笔的边缘效果。如果引用开启硬件加速的话,那么MaskFilter将不会起作用。
关闭硬件加速:
android:hardwareAccelerated="false"
Android中有两个已知的MaskFilter实现类,分别是:BlurMaskFilter和EmbossMaskFilter:
BlurMaskFilter:指定模糊样式和影响半径。
EmbossMaskFilter:指定浮雕的光源方向和周围光强度。
在实际中,使用不同的方法可能会有不同的硬件加速情况,比如笔者测试发现drawText默认是关闭硬件加速的,drawRect默认是开启硬件加速的。除了在Application.xml文件中指定硬件加速的开关情况,也可以通过代码来实现:
//不使用硬件加速 myview.setLayerType(View.LAYER_TYPE_SOFTWARE, null); //... //使用硬件加速 myview.setLayerType(View.LAYER_TYPE_HARDWARE,null);
1.EmbossMaskFilter
EmbossMaskFilter用于完成浮雕效果,通过PS可以更简单的完成类似的效果。EmbossMaskFilter的唯一构造方法是:
public EmbossMaskFilter (float[] direction,float ambient,float specular,float blurRadius)
这个构造方法在API 28(Android 9.0)中已经被废弃了。
在指定参数的时候需要指定光源方向(direction)、环境光强度(ambient)、镜面反射系数(specular)和模糊半径(blurRadius)。
float[] direction=new float[]{1,1,1};//指定光源方向 float light=0.4f;//指定环境光强度(0~1),0~1表示环境从暗到亮 float specular=6f;//指定镜面反射系数,越接近0,反射光越强。 float blur=3f;//指定模糊半径,值越大,越清晰。 EmbossMaskFilter emboss=new EmbossMaskFilter(direction,light,specular,blur); if(!canvas.isHardwareAccelerated()){//在未硬件加速的情况下设置效果 myPaint.setMaskFilter(emboss); }
如下代码:
protected void onDraw(Canvas canvas) {super.onDraw(canvas);Paint paint=new Paint();paint.setColor(Color.RED);paint.setStyle(Style.FILL);paint.setTextSize(70);float[] direction=new float[]{1,1,1};//指定光源方向float light=0.3f;//指定环境光强度float specular=5;//指定镜面反射强度float blur=5f;//指定模糊程度 EmbossMaskFilter emboss=new EmbossMaskFilter(direction,light,specular,blur);if(!canvas.isHardwareAccelerated()){//如果没有开启硬件加速,就设置浮雕效果 paint.setMaskFilter(emboss);}canvas.drawText("test测试", 200,200, paint);//绘制文本 }
效果图:
通过改变为不同的参数,可以得到不同的效果。
2.BlurMaskFilter
BlurMaskFilter有一个构造方法如下:
BlurMaskFilter(float radius, BlurMaskFilter.Blur style)
在构建BlurMaskFilter时,需要传入BlurMaskFilter.Blur枚举值,该枚举值有如下4种:
BlurMaskFilter.Blur.INNER 在边界内模糊,边界外不模糊
BlurMaskFilter.Blur.NORMAL 在边界内和边界外都模糊
BlurMaskFilter.Blur.OUTER 在边界外模糊,边界内不模糊
BlurMaskFilter.Blur.SOLID 在边边界内使用solid边框,边界外模糊
下面是使用示例:
activity_main.xml
<RelativeLayoutxmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:id="@+id/rl"android:layout_width="match_parent"android:layout_height="match_parent"android:padding="16dp"tools:context=".MainActivity"android:background="#ffffff"><TextViewandroid:id="@+id/tv"android:layout_width="match_parent"android:layout_height="wrap_content"android:layout_centerInParent="true"android:text="ANDROID"android:textSize="100dp"android:textStyle="bold"android:textColor="#ff0000"android:gravity="center"/><RadioGroupandroid:id="@+id/rg"android:layout_width="wrap_content"android:layout_height="wrap_content"android:orientation="horizontal"><RadioButtonandroid:id="@+id/rb_none"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="No blur"/><RadioButtonandroid:id="@+id/rb_inner"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="Inner blur"/><RadioButtonandroid:id="@+id/rb_normal"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="Normal blur"/><RadioButtonandroid:id="@+id/rb_outer"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="Outer blur"/><RadioButtonandroid:id="@+id/rb_solid"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="Solid blur"/></RadioGroup> </RelativeLayout>
MainActivity.jave
import android.app.Activity; import android.content.Context; import android.content.pm.ActivityInfo; import android.content.res.Resources; import android.graphics.BlurMaskFilter; import android.graphics.Paint; import android.os.Bundle; import android.view.View; import android.view.Window; import android.widget.RadioGroup; import android.widget.RelativeLayout; import android.widget.TextView;public class MainActivity extends Activity {Context mContext=null;Resources mResources=null;RelativeLayout mRelativeLayout=null;TextView mTextView=null;RadioGroup mRadioGroup=null;protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);//设置横屏 mContext = getApplicationContext();mResources = getResources();mRelativeLayout = (RelativeLayout) findViewById(R.id.rl);mTextView = (TextView) findViewById(R.id.tv);mRadioGroup = (RadioGroup) findViewById(R.id.rg);// Set a checked change listener for RadioGroupmRadioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {@Overridepublic void onCheckedChanged(RadioGroup radioGroup, int i) {if (i == R.id.rb_none) {// If no blur is checked// Set the TextView layer typemTextView.setLayerType(View.LAYER_TYPE_SOFTWARE,null);// Clear any previous MaskFiltermTextView.getPaint().setMaskFilter(null);}if(i == R.id.rb_inner){// If inner blur checked applyBlurMaskFilter(mTextView, BlurMaskFilter.Blur.INNER);}if(i == R.id.rb_normal){// If normal blur checked applyBlurMaskFilter(mTextView, BlurMaskFilter.Blur.NORMAL);}if(i == R.id.rb_outer){// If outer blur checked applyBlurMaskFilter(mTextView, BlurMaskFilter.Blur.OUTER);}if(i == R.id.rb_solid){// If solid blur checked applyBlurMaskFilter(mTextView, BlurMaskFilter.Blur.SOLID);}}});}// Custom method to apply BlurMaskFilter to a TextView textprotected void applyBlurMaskFilter(TextView tv, BlurMaskFilter.Blur style){// Define the blur effect radiusfloat radius = tv.getTextSize()/10;// Initialize a new BlurMaskFilter instanceBlurMaskFilter filter = new BlurMaskFilter(radius,style);/*public void setLayerType (int layerType, Paint paint)Specifies the type of layer backing this view. The layer can be LAYER_TYPE_NONE,LAYER_TYPE_SOFTWARE or LAYER_TYPE_HARDWARE.A layer is associated with an optional Paint instance that controls how thelayer is composed on screen.ParameterslayerType : The type of layer to use with this view, must be one ofLAYER_TYPE_NONE, LAYER_TYPE_SOFTWARE or LAYER_TYPE_HARDWAREpaint : The paint used to compose the layer. This argument is optional and can be null. It is ignored when the layer type is LAYER_TYPE_NONE*//*public static final int LAYER_TYPE_SOFTWAREIndicates that the view has a software layer. A software layer is backed bya bitmap and causes the view to be rendered using Android's software renderingpipeline, even if hardware acceleration is enabled.*/// Set the TextView layer typetv.setLayerType(View.LAYER_TYPE_SOFTWARE, new Paint());//取消硬件加速 tv.getPaint().setMaskFilter(filter);} }
效果图:
参考文章:
How to use BlurMaskFilter In Android