Android绘图机制二

来源：互联网发布：使用navicat连接mysql 编辑：程序博客网时间：2024/05/28 19:24

ColorMatrix

Android对图片处理时,最常用的数据结构是Bitmap,整个图是由包含像素的点阵和对应透明度,红,绿,蓝的颜色值组成的,在Android中,系统使用ColorMatrix类来处理图像的色彩效果,ColorMatrix其实就是一个4x5颜色矩阵.

        imageView = (ImageView)findViewById(R.id.icon_group);        ColorMatrix hueMatrix = new ColorMatrix();        hueMatrix.setRotate(0,1);//设置颜色色调,分别使用 0 1 2来代表红 绿 蓝        hueMatrix.setRotate(1,2);        hueMatrix.setRotate(2,1);        ColorMatrix saturationMatrix = new ColorMatrix();        saturationMatrix.setSaturation(0);//设置颜色的饱和度 0时,图像变为灰度        ColorMatrix lumMatrix = new ColorMatrix();        lumMatrix.setScale(0.33f,2f,91f,1);//设置图像的亮度 0时是全黑        ColorMatrix imageMatrix = new ColorMatrix();        imageMatrix.postConcat(hueMatrix);//将矩阵的作用混合,叠加处理效果        imageMatrix.postConcat(saturationMatrix);        imageMatrix.postConcat(lumMatrix);        Bitmap bm = BitmapFactory.decodeResource(getResources(),R.drawable.meijing);        Bitmap bitmap = Bitmap.createBitmap(bm.getWidth(),bm.getHeight(),Bitmap.Config.ARGB_8888);        Canvas canvas = new Canvas(bitmap);        Paint paint = new Paint();        paint.setColorFilter(new ColorMatrixColorFilter(imageMatrix));        canvas.drawBitmap(bm,0,0,paint);        imageView.setImageBitmap(bitmap);// 方式二 改变矩阵的系数来改变颜色        Bitmap bm = BitmapFactory.decodeResource(getResources(),R.drawable.meijing);        Bitmap bitmap = Bitmap.createBitmap(bm.getWidth(),bm.getHeight(),Bitmap.Config.ARGB_8888);        Canvas canvas = new Canvas(bitmap);        Paint paint = new Paint();        float[] mColorMatrix = new float[20];        for (int i = 0;i<20;i++){            mColorMatrix[i]= Float.valueOf(String.valueOf(i));//改变矩阵的系数        }        ColorMatrix colorMatrix = new ColorMatrix();        colorMatrix.set(mColorMatrix);//将系数变化后的4x5的ARGB矩阵设置进去        paint.setColorFilter(new ColorMatrixColorFilter(colorMatrix));        canvas.drawBitmap(bm,0,0,paint);        imageView.setImageBitmap(bitmap);

Matrix

Android对于图像的图形变换,通过一个3x3的矩阵来处理的,系统提供了Matrix类来处理图像的变形

        float[] mMatrix = new float[]{1,0,0,0,1,0,0,0,1};        Matrix matrix = new Matrix();        matrix.setValues(mMatrix);        matrix.setTranslate(200,200);//图像平移        matrix.setRotate(15);//图像旋转        matrix.setSkew(15,15);//图像错切        canvas.drawBitmap(bm,matrix,paint);//将图像以这个变换矩阵绘制出来        imageView.setImageBitmap(bitmap);

Paint画笔特效

普通的Paint可以设置其变宽,填充的样式,颜色,宽度以及抗锯齿等基本属性,以下是画笔的高级属性
1 PorterDuffxfermode
PorterDuffxfermode设置的是两个图层交集区域的显示方式,用的最多的就是,使用一张图片作为另一张图片的遮罩层,通过控制遮罩层的图像,来展现不同的被遮罩图形的显示效果.
举例1 对图形进行圆角处理

        Bitmap bm = BitmapFactory.decodeResource(getResources(),R.drawable.meijing);        Bitmap bitmap = Bitmap.createBitmap(bm.getWidth(),bm.getHeight(),Bitmap.Config.ARGB_8888);        Canvas canvas = new Canvas(bitmap);        Paint paint = new Paint();        paint.setAntiAlias(true);        canvas.drawRoundRect(0,0,bm.getWidth(),bm.getHeight(),80,80,paint);//画一个半径为80的圆角的矩形长宽为bm.getWidth(),bm.getHeight()        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));//给画笔添加模式为SRC_IN的PorterDuffXfermode        canvas.drawBitmap(bm,0,0,paint);        imageView.setImageBitmap(bitmap);

举例2 刮刮乐效果

    public XfermodeDemo(Context context, @Nullable AttributeSet attrs) {        super(context, attrs);        mPaint = new Paint();        mPaint.setAlpha(0);        mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));        mPaint.setStyle(Paint.Style.STROKE);        mPaint.setAntiAlias(true);        mPaint.setStrokeWidth(50);        mPaint.setStrokeCap(Paint.Cap.ROUND);        mPaint.setStrokeJoin(Paint.Join.ROUND);        mPath = new Path();        mBgBitmap = BitmapFactory.decodeResource(context.getResources(),R.drawable.meijing);        mbgBitmap = Bitmap.createBitmap(mBgBitmap.getWidth(),mBgBitmap.getHeight(), Bitmap.Config.ARGB_8888);        mCanvas = new Canvas(mbgBitmap);        mCanvas.drawColor(Color.GRAY);    }    public XfermodeDemo(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        canvas.drawBitmap(mBgBitmap,0,0,null);        canvas.drawBitmap(mbgBitmap,0,0,null);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        Log.i("niuniu ", " onTouchEvent");        switch (event.getAction()){            case MotionEvent.ACTION_DOWN:                mPath.reset();                mPath.moveTo(event.getX(),event.getY());                break;            case MotionEvent.ACTION_MOVE:                mPath.lineTo(event.getX(),event.getY());                break;        }        mCanvas.drawPath(mPath,mPaint);        invalidate();        return true;    }

2 Shader
Shader有着色器,渲染器之称,可以实现一些列渐变,渲染效果,包括以下几种:

BitmapShader ——— 位图Shader,与其他Shader产生的渐变不同的是,这个Shader是产生一个图像有三种不同的模式 CLAMP(拉伸),REAPT(重复,横向,纵向不断的重复),MIRROR(镜像,横向/纵向不断翻转重复)
LinearGradient ——– 线性Shader
RadialGradient——– 光束Shader
SweepGradient——- - 梯度Shader
ComposeShader——- 混合Shader

举例1 BitmapShader的使用

        Bitmap bm = BitmapFactory.decodeResource(getResources(),R.drawable.ic_launcher_android);        Bitmap bitmap = Bitmap.createBitmap(800,800,Bitmap.Config.ARGB_8888);        Canvas canvas = new Canvas(bitmap);        Paint paint = new Paint();        paint.setShader(new BitmapShader(bm, Shader.TileMode.REPEAT, Shader.TileMode.REPEAT));        canvas.drawCircle(180,200,100,paint);        imageView.setImageBitmap(bitmap);

举例2 LinearGradient 的使用

        Bitmap bm = BitmapFactory.decodeResource(getResources(),R.drawable.ic_launcher_android);        Bitmap bitmap = Bitmap.createBitmap(800,800,Bitmap.Config.ARGB_8888);        Canvas canvas = new Canvas(bitmap);        Paint paint = new Paint();        paint.setShader(new LinearGradient(0,0,400,400,Color.BLUE,Color.YELLOW, Shader.TileMode.REPEAT));        canvas.drawRoundRect(0,0,500,500,20,20,paint);        imageView.setImageBitmap(bitmap);

举例3 LinearGradient 与 PorterDuffXfermode综合使用,实现倒影的效果

    public ReflectView(Context context, @Nullable AttributeSet attrs) {        super(context, attrs);        mBgBitmap = BitmapFactory.decodeResource(context.getResources(),R.drawable.arrow_right);        Matrix matrix = new Matrix();        matrix.setScale(1f,-1f);//对mBgBitmap实现垂直翻转        mbgBitmap = Bitmap.createBitmap(mBgBitmap,0,0,mBgBitmap.getWidth(),mBgBitmap.getHeight(),matrix,true);        mPaint = new Paint();        mPaint.setShader(new LinearGradient(0,mBgBitmap.getHeight(),0,mBgBitmap.getHeight()+mBgBitmap.getHeight()/4,0XDD000000,0X10000000, Shader.TileMode.CLAMP));        porterDuffXfermode = new PorterDuffXfermode(PorterDuff.Mode.DST_IN);    }    public ReflectView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        canvas.drawColor(Color.BLACK);//添加黑色背景        canvas.drawBitmap(mBgBitmap,0,0,null);//画原图        canvas.drawBitmap(mbgBitmap,0,mBgBitmap.getHeight(),null);//在原图的正下方画倒影图        mPaint.setXfermode(porterDuffXfermode);        canvas.drawRect(0,mBgBitmap.getHeight(),mbgBitmap.getWidth(),mBgBitmap.getHeight()*2,mPaint);//使用带有PorterDuffXfermode模式的并有线性渲染的画笔在原图正下方画出倒影效果        mPaint.setXfermode(null);    }

PathEffect

PathEffect就是对各种画笔设置不同的效果

// 初始化        mPath = new Path();        mPath.moveTo(0,0);        for (int i =0;i<=30;i++){            mPath.lineTo(i*35,(float) Math.random()*100);        }    //添加不同画笔效果    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        mEffects[0]=null;// 没任何效果        mEffects[1]= new CornerPathEffect(30);//将拐角处处理的圆滑一些        mEffects[2]= new DiscretePathEffect(3.0F,5.0F);//在线段上产生一些杂点        mEffects[3]= new DashPathEffect(new float[]{20,10,5,10},0);//绘制虚线,数组代表各个点之间的间隔,另一个是参数偏移量        Path path = new Path();        path.addRect(0,0,100,100,Path.Direction.CCW);        mEffects[4] = new PathDashPathEffect(path,12,0, PathDashPathEffect.Style.ROTATE);//也是设置虚线的效果,但可以设置点的图形,比如方形点 圆形点        mEffects[5]= new ComposePathEffect(mEffects[3],mEffects[1]);//将这两种效果组合起来        for (int i = 0;i<mEffects.length;i++){            mPaint.setPathEffect(mEffects[i]);            canvas.drawPath(mPath,mPaint);            canvas.translate(0,200);        }    }

阅读全文

0 0