package com.android.bitmapmesh;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.os.Bundle;
import android.util.FloatMath;
import android.view.MotionEvent;
import android.view.View;

public class BitmapMesh extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.main);
        setContentView(new SampleView(this));
    }
    
    private static class SampleView extends View {
        private static final int WIDTH = 20;
        private static final int HEIGHT = 20;
        private static final int COUNT = (WIDTH + 1) * (HEIGHT + 1);

        private final Bitmap mBitmap;
        private final float[] mVerts = new float[COUNT*2];
        private final float[] mOrig = new float[COUNT*2];

        private final Matrix mMatrix = new Matrix();
        private final Matrix mInverse = new Matrix();

        private static void setXY(float[] array, int index, float x, float y) {
            array[index*2 + 0] = x;
            array[index*2 + 1] = y;
        }

        public SampleView(Context context) {
            super(context);
            setFocusable(true);

            mBitmap = BitmapFactory.decodeResource(getResources(),
                                                     R.drawable.beach);

            float w = mBitmap.getWidth();
            float h = mBitmap.getHeight();
            // construct our mesh
            int index = 0;
            for (int y = 0; y <= HEIGHT; y++) {
                float fy = h * y / HEIGHT;
                for (int x = 0; x <= WIDTH; x++) {
                    float fx = w * x / WIDTH;
                    setXY(mVerts, index, fx, fy);
                    setXY(mOrig, index, fx, fy);
                    index += 1;
                }
            }
            

            //mMatrix.setTranslate(10, 10);
            //mMatrix.invert(mInverse);
        }

        @Override protected void onDraw(Canvas canvas) {
            canvas.drawColor(0xFFCCCCCC);

            //canvas.concat(mMatrix);
            canvas.drawBitmapMesh(mBitmap, WIDTH, HEIGHT, mVerts, 0,
                                  null, 0, null);
        }
        
        private void warp(float cx, float cy) {
            final float K = 10000;
            float[] src = mOrig;
            float[] dst = mVerts;
            for (int i = 0; i < COUNT*2; i += 2) {
                float x = src[i+0];
                float y = src[i+1];
                float dx = cx - x;
                float dy = cy - y;
                float dd = dx*dx + dy*dy;
                float d = FloatMath.sqrt(dd);
                float pull = K / (dd + 0.000001f);

                pull /= (d + 0.000001f);
             //   android.util.Log.d("skia", "index " + i + " dist=" + d + " pull=" + pull);

                //dst[i+0] = x + dx * pull;
                //dst[i+1] = y + dy * pull;
                
                
                if (pull >= 1) {
                    dst[i+0] = cx;
                    dst[i+1] = cy;
                } else {
                    dst[i+0] = x + dx * pull;
                    dst[i+1] = y + dy * pull;
                }

            }
        }

        private int mLastWarpX = -9999; // don't match a touch coordinate
        private int mLastWarpY;

        @Override public boolean onTouchEvent(MotionEvent event) {
            float[] pt = { event.getX(), event.getY() };
            //mInverse.mapPoints(pt);

            int x = (int)pt[0];
            int y = (int)pt[1];
            if (mLastWarpX != x || mLastWarpY != y) {
                mLastWarpX = x;
                mLastWarpY = y;
                warp(pt[0], pt[1]);
                invalidate();
            }
            return true;
        }
    }

                
}

sample code: BitmapMesh

By admin-powenko

Dr. Powen Ko is a teacher and CEO on LoopTek LLC, and like to teaching. if you need to class, please let PowenKo know, he will love to service and sharing. LoopTek web site is www.looptek.com

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