Android Api Demos登顶之路（九十三）Graphics-->Vertices

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/* * 这个demon演示了顶点的绘制 */public class MainActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(new SampleView(this));    }    private class SampleView extends View {        private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);        // 定义顶点的坐标数组        private float[] mVerts = new float[10];        // 定义纹理数组        private float[] mTexs = new float[10];        private float[] mTexs2 = new float[10];        // 定义顶点的绘制顺序数组        private short[] mIndices = new short[] { 0, 1, 2, 3, 4, 1 };        private Matrix mMatrix = new Matrix();        private Matrix mInverse = new Matrix();        private Bitmap bm;        private void setXY(float[] array, int index, float x, float y) {            array[index * 2] = x;            array[index * 2 + 1] = y;        }        public SampleView(Context context) {            super(context);            setFocusable(true);            bm = BitmapFactory.decodeResource(getResources(), R.drawable.beach);            Shader s = new BitmapShader(bm, Shader.TileMode.CLAMP,                    Shader.TileMode.CLAMP);            mPaint.setShader(s);            float w = bm.getWidth();            float h = bm.getHeight();            setXY(mTexs, 0, w / 2, h / 2);            setXY(mTexs, 1, 0, 0);            setXY(mTexs, 2, w, 0);            setXY(mTexs, 3, w, h);            setXY(mTexs, 4, 0, h);            setXY(mTexs2, 0, w / 3, h / 3);            setXY(mTexs2, 1, w, 0);            setXY(mTexs2, 2, 0, 0);            setXY(mTexs2, 3, 0, h);            setXY(mTexs2, 4, w, h);            setXY(mVerts, 0, w / 2, h / 2);            setXY(mVerts, 1, 0, 0);            setXY(mVerts, 2, w, 0);            setXY(mVerts, 3, w, h);            setXY(mVerts, 4, 0, h);            // 矩阵缩放            mMatrix.setScale(0.6f, 0.6f);            // 平移,参数为横向和纵向的平移距离            mMatrix.preTranslate(20, 20);            // 矩阵反转            mMatrix.invert(mInverse);        }        @Override        protected void onDraw(Canvas canvas) {            canvas.drawColor(0xffcccccc);            canvas.save();            canvas.concat(mMatrix);            // canvas.drawBitmap(bm, 0, 0, mPaint);            /*             * 绘制顶点：第一个参数表示顶点的模式。TRIANGLE_FAN表示以一个点为三角形公共顶点，组成一系列相邻的三角形。             * 第二个参数表示顶点坐标数组的长度，一个坐标由x和y两个值组成，所以该参数一定为偶数             * 第三个参数表示顶点坐标数组；第四个参数顶点坐标数组的偏移量； 第五个参数表示纹理坐标数组；第六个参数为纹理坐标数组的偏移量             * 第七个参数颜色数组，直接用颜色渲染顶点；第八个参数颜色数组的偏移量 第九个参数顶点绘制的索引；第十个参数顶点索引的偏移量             * 第十一个参数表示绘制的索引数量，第十二个参数表示画笔             */            canvas.drawVertices(Canvas.VertexMode.TRIANGLE_FAN, 10, mVerts, 0,                    mTexs, 0, null, 0, null, 0, 0, mPaint);            canvas.translate(200, 0);            canvas.drawVertices(Canvas.VertexMode.TRIANGLE_FAN, 10, mVerts, 0,                    mTexs2, 0, null, 0, null, 0, 0, mPaint);            canvas.translate(-200, 240);            canvas.drawVertices(Canvas.VertexMode.TRIANGLE_FAN, 10, mVerts, 0,                    mTexs, 0, null, 0, mIndices, 0,6, mPaint);            canvas.translate(200, 0);            canvas.drawVertices(Canvas.VertexMode.TRIANGLE_FAN, 10, mVerts, 0,                    mTexs2, 0, null, 0, mIndices, 0,6, mPaint);            canvas.restore();            /*             * canvas.save(); canvas.drawBitmap(bm, 10, 200, mPaint);             * canvas.restore();             */        }    }}
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