Develop Reference

interpolate a given array to be in new lenght

in order to interpolate 2 values, I can use
lerp(int a, int b) {
return (a + b) / 2;
}
Now imagine I've an array(1, 30, 100, 300) and I want to interpolate it to array in size N (N=10 for example).
If N == 7, then:
1,15,30,65,100,200,300
I've no idea how to interpolate 4 values to be 10. I need a method that looks like:
interpolate(fina int[] input, final int newSize) {
int[] res = new int[newSize];
...
return res;
}
that works even on my example above with newSize of 7, 10 or whatever.
Any idea how to implement it?

SOLVED.
public static double[] interpolate(double[] x, int newLength) {
double[] y = null;
if (newLength > 0) {
int N = x.length;
if (N == 1) {
y = new double[1];
y[0] = x[0];
return y;
} else if (newLength == 1) {
y = new double[1];
int ind = (int) Math.floor(N * 0.5 + 0.5);
ind = Math.max(1, ind);
ind = Math.min(ind, N);
y[0] = x[ind - 1];
return y;
} else {
y = new double[newLength];
double Beta = ((double) newLength) / N;
double newBeta = 1.0;
if (newLength > 2)
newBeta = (N - 2.0) / (newLength - 2.0);
y[0] = x[0];
y[1] = x[1];
y[newLength - 1] = x[N - 1];
double tmp, alpha;
int i, j;
for (i = 2; i <= newLength - 2; i++) {
tmp = 1.0 + (i - 1) * newBeta;
j = (int) Math.floor(tmp);
alpha = tmp - j;
y[i] = (1.0 - alpha) * x[Math.max(0, j)] + alpha * x[Math.min(N - 1, j + 1)];
}
}
}
return y;
}
/**
* Find the maximum of all elements in the array, ignoring elements that are NaN.
* #param data
* #return
*/
public static double max(double[] data) {
double max = Double.NaN;
for (int i = 0; i < data.length; i++) {
if (Double.isNaN(data[i]))
continue;
if (Double.isNaN(max) || data[i] > max)
max = data[i];
}
return max;
}
public static int max(int[] data) {
int max = data[0];
for (int i = 1; i < data.length; i++) {
if (data[i] > max)
max = data[i];
}
return max;
}

How to fill the color gradually on drawn view canvas Android

I am having a WaveFormView on which I want to change the color of it while playing Audio file and as the Audio is paused it should be stopped coloring at that certain point and when resumed it should continue forward with coloring. I am not getting how to do it in my code..
This is the screen shot of my generated waveform. Now when I will click on Play button it should change the color of waveform gradually with red color (from start to end slowly).
Here is my code to draw waveform view.
WaveFormView.class
public class WaveformView extends View {
public interface WaveformListener {
public void waveformFling(float x);
public void waveformDraw();
}
;
// Colors
private Paint mGridPaint;
private Paint mSelectedLinePaint;
private Paint mUnselectedLinePaint;
private Paint mUnselectedBkgndLinePaint;
private Paint mBorderLinePaint;
private Paint mPlaybackLinePaint;
private Paint mTimecodePaint;
private SoundFile mSoundFile;
private int[] mLenByZoomLevel;
private double[][] mValuesByZoomLevel;
private double[] mZoomFactorByZoomLevel;
private int[] mHeightsAtThisZoomLevel;
private int mZoomLevel;
private int mNumZoomLevels;
private int mSampleRate;
private int mSamplesPerFrame;
private int mOffset;
private int mSelectionStart;
private int mSelectionEnd;
private int mPlaybackPos;
private float mDensity;
private float mInitialScaleSpan;
private WaveformListener mListener;
private GestureDetector mGestureDetector;
private ScaleGestureDetector mScaleGestureDetector;
private boolean mInitialized;
Color color;
public WaveformView(Context context, AttributeSet attrs) {
super(context, attrs);
// We don't want keys, the markers get these
setFocusable(false);
mGridPaint = new Paint();
mGridPaint.setAntiAlias(false);
mGridPaint.setColor(
getResources().getColor(R.color.grid_line));
mSelectedLinePaint = new Paint();
mSelectedLinePaint.setAntiAlias(false);
mSelectedLinePaint.setColor(
getResources().getColor(R.color.waveform_selected));
mUnselectedLinePaint = new Paint();
mUnselectedLinePaint.setAntiAlias(false);
mUnselectedLinePaint.setColor(
getResources().getColor(R.color.waveform_unselected));
mUnselectedBkgndLinePaint = new Paint();
mUnselectedBkgndLinePaint.setAntiAlias(false);
mUnselectedBkgndLinePaint.setColor(
getResources().getColor(
R.color.selection_border));
mBorderLinePaint = new Paint();
mBorderLinePaint.setAntiAlias(true);
mBorderLinePaint.setStrokeWidth(1.5f);
mBorderLinePaint.setPathEffect(
new DashPathEffect(new float[]{3.0f, 2.0f}, 0.0f));
mBorderLinePaint.setColor(
getResources().getColor(R.color.selection_border));
mPlaybackLinePaint = new Paint();
mPlaybackLinePaint.setAntiAlias(false);
mPlaybackLinePaint.setColor(
getResources().getColor(R.color.playback_indicator));
mTimecodePaint = new Paint();
mTimecodePaint.setTextSize(12);
mTimecodePaint.setAntiAlias(true);
mTimecodePaint.setColor(
getResources().getColor(R.color.timecode));
mTimecodePaint.setShadowLayer(
2, 1, 1,
getResources().getColor(R.color.timecode_shadow));
mGestureDetector = new GestureDetector(
context,
new GestureDetector.SimpleOnGestureListener() {
public boolean onFling(
MotionEvent e1, MotionEvent e2, float vx, float vy) {
mListener.waveformFling(vx);
return true;
}
});
mSoundFile = null;
mLenByZoomLevel = null;
mValuesByZoomLevel = null;
mHeightsAtThisZoomLevel = null;
mOffset = 0;
mPlaybackPos = -1;
mSelectionStart = 0;
mSelectionEnd = 0;
mDensity = 1.0f;
mInitialized = false;
}
public boolean hasSoundFile() {
return mSoundFile != null;
}
public void setSoundFile(SoundFile soundFile) {
mSoundFile = soundFile;
mSampleRate = mSoundFile.getSampleRate();
mSamplesPerFrame = mSoundFile.getSamplesPerFrame();
computeDoublesForAllZoomLevels();
mHeightsAtThisZoomLevel = null;
}
/**
* Called once when a new sound file is added
*/
private void computeDoublesForAllZoomLevels() {
int numFrames = mSoundFile.getNumFrames();
int[] frameGains = mSoundFile.getFrameGains();
double[] smoothedGains = new double[numFrames];
if (numFrames == 1) {
smoothedGains[0] = frameGains[0];
} else if (numFrames == 2) {
smoothedGains[0] = frameGains[0];
smoothedGains[1] = frameGains[1];
} else if (numFrames > 2) {
smoothedGains[0] = (double)(
(frameGains[0] / 2.0) +
(frameGains[1] / 2.0));
for (int i = 1; i < numFrames - 1; i++) {
smoothedGains[i] = (double)(
(frameGains[i - 1] / 3.0) +
(frameGains[i ] / 3.0) +
(frameGains[i + 1] / 3.0));
}
smoothedGains[numFrames - 1] = (double)(
(frameGains[numFrames - 2] / 2.0) +
(frameGains[numFrames - 1] / 2.0));
}
// Make sure the range is no more than 0 - 255
double maxGain = 1.0;
for (int i = 0; i < numFrames; i++) {
if (smoothedGains[i] > maxGain) {
maxGain = smoothedGains[i];
}
}
double scaleFactor = 1.0;
if (maxGain > 255.0) {
scaleFactor = 255 / maxGain;
}
// Build histogram of 256 bins and figure out the new scaled max
maxGain = 0;
int gainHist[] = new int[256];
for (int i = 0; i < numFrames; i++) {
int smoothedGain = (int)(smoothedGains[i] * scaleFactor);
if (smoothedGain < 0)
smoothedGain = 0;
if (smoothedGain > 255)
smoothedGain = 255;
if (smoothedGain > maxGain)
maxGain = smoothedGain;
gainHist[smoothedGain]++;
}
// Re-calibrate the min to be 5%
double minGain = 0;
int sum = 0;
while (minGain < 255 && sum < numFrames / 20) {
sum += gainHist[(int)minGain];
minGain++;
}
// Re-calibrate the max to be 99%
sum = 0;
while (maxGain > 2 && sum < numFrames / 100) {
sum += gainHist[(int)maxGain];
maxGain--;
}
// Compute the heights
double[] heights = new double[numFrames];
double range = maxGain - minGain;
for (int i = 0; i < numFrames; i++) {
double value = (smoothedGains[i] * scaleFactor - minGain) / range;
if (value < 0.0)
value = 0.0;
if (value > 1.0)
value = 1.0;
heights[i] = value * value;
}
mNumZoomLevels = 5;
mLenByZoomLevel = new int[5];
mZoomFactorByZoomLevel = new double[5];
mValuesByZoomLevel = new double[5][];
// Level 0 is doubled, with interpolated values
mLenByZoomLevel[0] = numFrames * 2;
mZoomFactorByZoomLevel[0] = 2.0;
mValuesByZoomLevel[0] = new double[mLenByZoomLevel[0]];
if (numFrames > 0) {
mValuesByZoomLevel[0][0] = 0.5 * heights[0];
mValuesByZoomLevel[0][1] = heights[0];
}
for (int i = 1; i < numFrames; i++) {
mValuesByZoomLevel[0][2 * i] = 0.5 * (heights[i - 1] + heights[i]);
mValuesByZoomLevel[0][2 * i + 1] = heights[i];
}
// Level 1 is normal
mLenByZoomLevel[1] = numFrames;
mValuesByZoomLevel[1] = new double[mLenByZoomLevel[1]];
mZoomFactorByZoomLevel[1] = 1.0;
for (int i = 0; i < mLenByZoomLevel[1]; i++) {
mValuesByZoomLevel[1][i] = heights[i];
}
// 3 more levels are each halved
for (int j = 2; j < 5; j++) {
mLenByZoomLevel[j] = mLenByZoomLevel[j - 1] / 2;
mValuesByZoomLevel[j] = new double[mLenByZoomLevel[j]];
mZoomFactorByZoomLevel[j] = mZoomFactorByZoomLevel[j - 1] / 2.0;
for (int i = 0; i < mLenByZoomLevel[j]; i++) {
mValuesByZoomLevel[j][i] =
0.5 * (mValuesByZoomLevel[j - 1][2 * i] +
mValuesByZoomLevel[j - 1][2 * i + 1]);
}
}
if (numFrames > 5000) {
mZoomLevel = 3;
} else if (numFrames > 1000) {
mZoomLevel = 2;
} else if (numFrames > 300) {
mZoomLevel = 1;
} else {
mZoomLevel = 0;
}
mInitialized = true;
}
public boolean canZoomIn() {
return (mZoomLevel > 0);
}
public void zoomIn() {
if (canZoomIn()) {
mZoomLevel--;
mSelectionStart *= 2;
mSelectionEnd *= 2;
mHeightsAtThisZoomLevel = null;
int offsetCenter = mOffset + getMeasuredWidth() / 2;
offsetCenter *= 2;
mOffset = offsetCenter - getMeasuredWidth() / 2;
if (mOffset < 0)
mOffset = 0;
invalidate();
}
}
public boolean canZoomOut() {
return (mZoomLevel < mNumZoomLevels - 1);
}
public void zoomOut() {
if (canZoomOut()) {
mZoomLevel++;
mSelectionStart /= 2;
mSelectionEnd /= 2;
int offsetCenter = mOffset + getMeasuredWidth() / 2;
offsetCenter /= 2;
mOffset = offsetCenter - getMeasuredWidth() / 2;
if (mOffset < 0)
mOffset = 0;
mHeightsAtThisZoomLevel = null;
invalidate();
}
}
public double pixelsToSeconds(int pixels) {
double z = mZoomFactorByZoomLevel[mZoomLevel];
return (pixels * (double)mSamplesPerFrame / (mSampleRate * z));
}
public void setListener(WaveformListener listener) {
mListener = listener;
}
public void recomputeHeights(float density) {
mHeightsAtThisZoomLevel = null;
mDensity = density;
mTimecodePaint.setTextSize((int)(12 * density));
invalidate();
}
protected void drawWaveformLine(Canvas canvas,
int x, int y0, int y1,
Paint paint) {
canvas.drawLine(x, y0, x, y1, paint);
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (mSoundFile == null)
return;
if (mHeightsAtThisZoomLevel == null)
computeIntsForThisZoomLevel();
DisplayMetrics displaymetrics = getContext().getResources().getDisplayMetrics();
int height = displaymetrics.heightPixels;
int widths = displaymetrics.widthPixels;
// Draw waveform
int measuredWidth = getMeasuredWidth();
int measuredHeight = getMeasuredHeight();
int start = mOffset;
int width = mHeightsAtThisZoomLevel.length - start;
int ctr = measuredHeight / 2;
Log.e("wid",String.valueOf(width));
Log.e("widCal",String.valueOf(mHeightsAtThisZoomLevel.length));
Log.e("widstart",String.valueOf(start));
if (width > measuredWidth)
width = measuredWidth;
Log.e("measured",String.valueOf(measuredWidth));
// Draw grid
double onePixelInSecs = pixelsToSeconds(1);
boolean onlyEveryFiveSecs = (onePixelInSecs > 1.0 / 50.0);
double fractionalSecs = mOffset * onePixelInSecs;
int integerSecs = (int) fractionalSecs;
int i = 0;
while (i < width) {
i++;
fractionalSecs += onePixelInSecs;
int integerSecsNew = (int) fractionalSecs;
if (integerSecsNew != integerSecs) {
integerSecs = integerSecsNew;
if (!onlyEveryFiveSecs || 0 == (integerSecs % 5)) {
canvas.drawLine(i, 0, i, measuredHeight, mGridPaint);
}
}
}
// Draw waveform
for ( i = 0; i < width; i++) {
Paint paint;
if (i + start >= mSelectionStart &&
i + start < mSelectionEnd) {
paint = mSelectedLinePaint;
// paint.setColor(color);
} else {
drawWaveformLine(canvas, ((widths/width)*i), 0, measuredHeight,
mUnselectedBkgndLinePaint);
paint = mUnselectedLinePaint;
}
drawWaveformLine(
canvas, ((widths/width)*i),
ctr - mHeightsAtThisZoomLevel[start + i],
ctr + 1 + mHeightsAtThisZoomLevel[start + i],
paint);
if (i + start == mPlaybackPos) {
canvas.drawLine(i, 0, i, measuredHeight, mPlaybackLinePaint);
}
}
if (mListener != null) {
mListener.waveformDraw();
}
}
private void computeIntsForThisZoomLevel() {
int halfHeight = (getMeasuredHeight() / 2) - 1;
mHeightsAtThisZoomLevel = new int[mLenByZoomLevel[mZoomLevel]];
for (int i = 0; i < mLenByZoomLevel[mZoomLevel]; i++) {
mHeightsAtThisZoomLevel[i] =
(int)(mValuesByZoomLevel[mZoomLevel][i] * halfHeight);
}
}
}
MainActivity.class
public class MainActivity extends AppCompatActivity implements WaveformView.WaveformListener {
WaveformView mWaveformView;
SoundFile mSoundFile;
private float mDensity;
private File mFile;
private String mFilename;
private long mLoadingLastUpdateTime;
boolean mLoadingKeepGoing;
boolean mFinishActivity;
private ProgressDialog mProgressDialog;
String mTitle,mArtist;
private Thread mLoadSoundFileThread;
private Thread mRecordAudioThread;
private Thread mSaveSoundFileThread;
private boolean mIsPlaying;
private SamplePlayer mPlayer;
private String mInfoContent;
private int mWidth;
private int mMaxPos;
private int mStartPos;
private int mEndPos;
private boolean mStartVisible;
private boolean mEndVisible;
private int mLastDisplayedStartPos;
private int mLastDisplayedEndPos;
private int mOffset;
private int mOffsetGoal;
private int mFlingVelocity;
private int mPlayStartMsec;
private int mPlayEndMsec;
private Handler mHandler;
Button pla;
MediaPlayer mediaPlayer;
boolean ismIsPlaying;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
pla = (Button)findViewById(R.id.play);
mWaveformView = (WaveformView)findViewById(R.id.waveform);
mWaveformView.setListener(this);
mHandler = new Handler();
Uri uri = Uri.parse("/sdcard/audio_file.mp3");
mediaPlayer = new MediaPlayer();
mediaPlayer = MediaPlayer.create(getApplicationContext(),uri);
loadGui();
loadFromFile();
}
/**
* Called from both onCreate and onConfigurationChanged
* (if the user switched layouts)
*/
private void loadGui() {
// Inflate our UI from its XML layout description.
setContentView(R.layout.activity_main);
DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
mDensity = metrics.density;
mWaveformView = (WaveformView)findViewById(R.id.waveform);
mWaveformView.setListener(this);
if (mSoundFile != null && !mWaveformView.hasSoundFile()) {
mWaveformView.setSoundFile(mSoundFile);
mWaveformView.recomputeHeights(mDensity);
}
}
private void loadFromFile() {
mFilename = "/sdcard/audio_file.mp3";
mFile = new File(mFilename);
SongMetadataReader metadataReader = new SongMetadataReader(
this, mFilename);
mTitle = metadataReader.mTitle;
mArtist = metadataReader.mArtist;
String titleLabel = mTitle;
if (mArtist != null && mArtist.length() > 0) {
titleLabel += " - " + mArtist;
}
setTitle(titleLabel);
mLoadingLastUpdateTime = getCurrentTime();
mLoadingKeepGoing = true;
mFinishActivity = false;
mProgressDialog = new ProgressDialog(MainActivity.this);
mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
mProgressDialog.setTitle("Loading...");
mProgressDialog.setCancelable(true);
mProgressDialog.setOnCancelListener(
new DialogInterface.OnCancelListener() {
public void onCancel(DialogInterface dialog) {
mLoadingKeepGoing = false;
mFinishActivity = true;
}
});
mProgressDialog.show();
final SoundFile.ProgressListener listener =
new SoundFile.ProgressListener() {
public boolean reportProgress(double fractionComplete) {
long now = getCurrentTime();
if (now - mLoadingLastUpdateTime > 100) {
mProgressDialog.setProgress(
(int) (mProgressDialog.getMax() * fractionComplete));
mLoadingLastUpdateTime = now;
}
return mLoadingKeepGoing;
}
};
// Load the sound file in a background thread
mLoadSoundFileThread = new Thread() {
public void run() {
try {
mSoundFile = SoundFile.create(mFile.getAbsolutePath(), listener);
if (mSoundFile == null) {
mProgressDialog.dismiss();
String name = mFile.getName().toLowerCase();
String[] components = name.split("\\.");
String err;
if (components.length < 2) {
err = getResources().getString(
R.string.no_extension_error);
} else {
err = getResources().getString(
R.string.bad_extension_error) + " " +
components[components.length - 1];
}
final String finalErr = err;
Runnable runnable = new Runnable() {
public void run() {
showFinalAlert(new Exception(), finalErr);
}
};
mHandler.post(runnable);
return;
}
mPlayer = new SamplePlayer(mSoundFile);
} catch (final Exception e) {
mProgressDialog.dismiss();
e.printStackTrace();
mInfoContent = e.toString();
runOnUiThread(new Runnable() {
public void run() {
}
});
Runnable runnable = new Runnable() {
public void run() {
showFinalAlert(e, getResources().getText(R.string.read_error));
}
};
mHandler.post(runnable);
return;
}
mProgressDialog.dismiss();
if (mLoadingKeepGoing) {
Runnable runnable = new Runnable() {
public void run() {
finishOpeningSoundFile();
}
};
mHandler.post(runnable);
} else if (mFinishActivity){
MainActivity.this.finish();
}
}
};
mLoadSoundFileThread.start();
}
private void finishOpeningSoundFile() {
mWaveformView.setSoundFile(mSoundFile);
mWaveformView.recomputeHeights(mDensity);
Log.e("sound file",mFilename);
Log.e("sound", String.valueOf(mSoundFile));
}
/**
* Show a "final" alert dialog that will exit the activity
* after the user clicks on the OK button. If an exception
* is passed, it's assumed to be an error condition, and the
* dialog is presented as an error, and the stack trace is
* logged. If there's no exception, it's a success message.
*/
private void showFinalAlert(Exception e, CharSequence message) {
CharSequence title;
if (e != null) {
Log.e("Ringdroid", "Error: " + message);
Log.e("Ringdroid", getStackTrace(e));
title = getResources().getText(R.string.alert_title_failure);
setResult(RESULT_CANCELED, new Intent());
} else {
Log.v("Ringdroid", "Success: " + message);
title = getResources().getText(R.string.alert_title_success);
}
new AlertDialog.Builder(MainActivity.this)
.setTitle(title)
.setMessage(message)
.setPositiveButton(
R.string.alert_ok_button,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int whichButton) {
finish();
}
})
.setCancelable(false)
.show();
}
private void showFinalAlert(Exception e, int messageResourceId) {
showFinalAlert(e, getResources().getText(messageResourceId));
}
#Override
public void waveformTouchStart(float x) {
}
#Override
public void waveformTouchMove(float x) {
}
#Override
public void waveformTouchEnd() {
}
#Override
public void waveformFling(float x) {
}
#Override
public void waveformDraw() {
mWidth = mWaveformView.getMeasuredWidth();
if (mOffsetGoal != mOffset) {
// updateDisplay();
}
else if (mIsPlaying) {
// updateDisplay();
} else if (mFlingVelocity != 0) {
// updateDisplay();
}
}
private long getCurrentTime() {
return System.nanoTime() / 1000000;
}
private String getStackTrace(Exception e) {
StringWriter writer = new StringWriter();
e.printStackTrace(new PrintWriter(writer));
return writer.toString();
}
public void buttonClick(View view) {
Toast.makeText(MainActivity.this, "test", Toast.LENGTH_SHORT).show();
mediaPlayer.start();
ismIsPlaying = true;
}
}

In your onDraw(Canvas canvas) add the following lines
if (i + start <= mPlaybackPos) {
Paint mPaint = new Paint(paint);
mPaint.setColor(Color.RED);
drawWaveformLine(
canvas, ((widths/width)*i),
ctr - mHeightsAtThisZoomLevel[start + i],
ctr + 1 + mHeightsAtThisZoomLevel[start + i],
mPaint);
}
add them above the line:
if (i + start == mPlaybackPos) {
And if this works, consider to allocate the Paint-object outside the onDraw() method.

mosaic bitmap in android

Hi I need to make mosaic effect in android.
Convert this:
To this:
How can i do this?
Thank you

/**
* 效果能实现，但是是个耗时的操作
*
* #param bmp
* #param precent 马赛克的程度（0-1）
* 300*300 precent=1 time=57ms
* #return
*/
public static Bitmap getMosaicsBitmap(Bitmap bmp, double precent) {
long start = System.currentTimeMillis();
int bmpW = bmp.getWidth();
int bmpH = bmp.getHeight();
Bitmap resultBmp = Bitmap.createBitmap(bmpW, bmpH, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(resultBmp);
Paint paint = new Paint();
double unit;
if (precent == 0) {
unit = bmpW;
} else {
unit = 1 / precent;
}
double resultBmpW = bmpW / unit;
double resultBmpH = bmpH / unit;
for (int i = 0; i < resultBmpH; i++) {
for (int j = 0; j < resultBmpW; j++) {
int pickPointX = (int) (unit * (j + 0.5));
int pickPointY = (int) (unit * (i + 0.5));
int color;
if (pickPointX >= bmpW || pickPointY >= bmpH) {
color = bmp.getPixel(bmpW / 2, bmpH / 2);
} else {
color = bmp.getPixel(pickPointX, pickPointY);
}
paint.setColor(color);
canvas.drawRect((int) (unit * j), (int) (unit * i), (int) (unit * (j + 1)), (int) (unit * (i + 1)), paint);
}
}
canvas.setBitmap(null);
long end = System.currentTimeMillis();
Log.v(TAG, "DrawTime:" + (end - start));
return resultBmp;
}
/**
* 和上面的函数同样的功能，效率远高于上面
*
* #param bmp
* #param precent
* #return
*/
public static Bitmap getMosaicsBitmaps(Bitmap bmp, double precent) {
long start = System.currentTimeMillis();
int bmpW = bmp.getWidth();
int bmpH = bmp.getHeight();
int[] pixels = new int[bmpH * bmpW];
bmp.getPixels(pixels, 0, bmpW, 0, 0, bmpW, bmpH);
int raw = (int) (bmpW * precent);
int unit;
if (raw == 0) {
unit = bmpW;
} else {
unit = bmpW / raw; //原来的unit*unit像素点合成一个，使用原左上角的值
}
if (unit >= bmpW || unit >= bmpH) {
return getMosaicsBitmap(bmp, precent);
}
for (int i = 0; i < bmpH; ) {
for (int j = 0; j < bmpW; ) {
int leftTopPoint = i * bmpW + j;
for (int k = 0; k < unit; k++) {
for (int m = 0; m < unit; m++) {
int point = (i + k) * bmpW + (j + m);
if (point < pixels.length) {
pixels[point] = pixels[leftTopPoint];
}
}
}
j += unit;
}
i += unit;
}
long end = System.currentTimeMillis();
Log.v(TAG, "DrawTime:" + (end - start));
return Bitmap.createBitmap(pixels, bmpW, bmpH, Bitmap.Config.ARGB_8888);
}
when you want change a bitmap to mosaic bitmap,just invoke function
getMosaicsBitmaps(bmp,0.1)

Android: Adaptive Thresholding

I'm trying to implement adaptive thresholding algorithm by Derek Bradley using Android. But it is returning black pixels all the time. Here is my code snippet. Please suggest me about what should I do. Thanks in advance.
public static Bitmap GrayscaleToBin(Bitmap bm2)
{
Bitmap bm;
bm=bm2.copy(Config.ARGB_8888, true);
final int width = bm.getWidth();
final int height = bm.getHeight();
int[] pixels;
pixels = new int[width*height];
bm.getPixels(pixels,0,width,0,0,width,height);
//Bradley AdaptiveThrsholdging
int []intImg= new int[width*height];
int sum=0;
for(int i=0;i<width;++i){
sum=0;
for(int j=0;j<height;++j)
{
sum=sum+pixels[i+j*width];
if(i==0){intImg[i+j*width]=sum;}
else
{
intImg[i+j*width]= intImg[i-1+j*width]+sum;
}
}
}
int x1,x2,y1,y2=0,count=0;
int s=width >> 3;
int t=15;
for(int i=0;i<width;++i)
{
for(int j=0;j<height;++j)
{
x1=i-s/2;
x2=i+s/2;
y1=j-s/2;
y2=j+s/2;
if (x1 <0) x1 = 0;
if (x2>= width) x2 = width-1;
if (y1 <0) y1 = 0;
if (y2>= height) y2 = height-1;
count = (x2-x1) * (y2-y1);
sum = intImg [y2 * width + x2] -
intImg [y1 * width + x2] -
intImg [y2 * width + x1] +
intImg [y1 * width + x1];
if((pixels[i+j*width]*count)<=(sum*(100-t)/100))
{
pixels[i+j*width]=0;
}
else
{
pixels[i+j*width]=255;
}
}
}
/*---------------------------------------------------------------------------*/
bm.setPixels(pixels,0,width,0,0,width,height);
// Log.d("cdsfss","afterloop");
return bm;
}

After a Long struggle I have solved the issue with the following code.
public static Bitmap GrayscaleToBin(Bitmap bm2)
{
Bitmap bm;
bm=bm2.copy(Config.RGB_565, true);
final int width = bm.getWidth();
final int height = bm.getHeight();
int pixel1,pixel2,pixel3,pixel4,A,R;
int[] pixels;
pixels = new int[width*height];
bm.getPixels(pixels,0,width,0,0,width,height);
int size=width*height;
int s=width/8;
int s2=s>>1;
double t=0.15;
double it=1.0-t;
int []integral= new int[size];
int []threshold=new int[size];
int i,j,diff,x1,y1,x2,y2,ind1,ind2,ind3;
int sum=0;
int ind=0;
while(ind<size)
{
sum+=pixels[ind] & 0xFF;
integral[ind]=sum;
ind+=width;
}
x1=0;
for(i=1;i<width;++i)
{
sum=0;
ind=i;
ind3=ind-s2;
if(i>s)
{
x1=i-s;
}
diff=i-x1;
for(j=0;j<height;++j)
{
sum+=pixels[ind] & 0xFF;
integral[ind]=integral[(int)(ind-1)]+sum;
ind+=width;
if(i<s2)continue;
if(j<s2)continue;
y1=(j<s ? 0 : j-s);
ind1=y1*width;
ind2=j*width;
if (((pixels[ind3]&0xFF)*(diff * (j - y1))) < ((integral[(int)(ind2 + i)] - integral[(int)(ind1 + i)] - integral[(int)(ind2 + x1)] + integral[(int)(ind1 + x1)])*it)) {
threshold[ind3] = 0x00;
} else {
threshold[ind3] = 0xFFFFFF;
}
ind3 += width;
}
}
y1 = 0;
for( j = 0; j < height; ++j )
{
i = 0;
y2 =height- 1;
if( j <height- s2 )
{
i = width - s2;
y2 = j + s2;
}
ind = j * width + i;
if( j > s2 ) y1 = j - s2;
ind1 = y1 * width;
ind2 = y2 * width;
diff = y2 - y1;
for( ; i < width; ++i, ++ind )
{
x1 = ( i < s2 ? 0 : i - s2);
x2 = i + s2;
// check the border
if (x2 >= width) x2 = width - 1;
if (((pixels[ind]&0xFF)*((x2 - x1) * diff)) < ((integral[(int)(ind2 + x2)] - integral[(int)(ind1 + x2)] - integral[(int)(ind2 + x1)] + integral[(int)(ind1 + x1)])*it)) {
threshold[ind] = 0x00;
} else {
threshold[ind] = 0xFFFFFF;
}
}
}
/*-------------------------------
* --------------------------------------------*/
bm.setPixels(threshold,0,width,0,0,width,height);
return bm;
}

You can use Catalano Framework. There's an example using Bradley for Android in samples folder.
FastBitmap fb = new FastBitmap(bitmap);
fb.toGrayscale();
BradleyLocalThreshold bradley = new BradleyLocalThreshold();
bradley.applyInPlace(fb);
bitmap = fb.toBitmap();

Android Tile Bitmap

I'm trying to load a bitmap in Android which I want to tile. I'm currently using the following in my view to display a bitmap:
canvas.drawBitmap(bitmap, srcRect, destRect, null)
I essentially want to use this bitmap as a background image in my app and would like to repeat the bitmap in both the X and Y directions.
I've seen the TileMode.REPEAT constant for the BitmapShader class but i am not sure if this is to be used for repeating the actual bitmap or is used for applying a filter to the bitmap.

You would do this in the xml instead of the java code. I haven't attempted this myself but I did find this example.
<xml version="1.0" encoding="utf-8"?>
<LinearLayout
android:id="#+id/MainLayout"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:background="#drawable/backrepeat"
>
then in an xml called backrepeat.xml
<bitmap xmlns:android="http://schemas.android.com/apk/res/android"
android:src="#drawable/back"
android:tileMode="repeat" />
reference

Figured out the code version:
BitmapDrawable TileMe = new BitmapDrawable(MyBitmap);
TileMe.setTileModeX(Shader.TileMode.REPEAT);
TileMe.setTileModeY(Shader.TileMode.REPEAT);
ImageView Item = new ImageView(this);
Item.setBackgroundDrawable(TileMe);
Then if you have a drawable to tile, this can be used instead to make the BitmapDrawable:
BitmapDrawable TileMe = new BitmapDrawable(BitmapFactory.decodeResource(getResources(), R.drawable.tile));

The backrepeat.xml above is buggy
<bitmap
xmlns:android="http://schemas.android.com/apk/res/android"
android:src="#drawable/tile"
android:tileMode="repeat"
android:dither="true" />

It seems that some people are interested in doing this in a View, at the onDraw method. The following code has worked for me:
bgTile = BitmapFactory.decodeResource(context.getResources(), R.drawable.bg_tile);
float left = 0, top = 0;
float bgTileWidth = bgTile.getWidth();
float bgTileHeight = bgTile.getHeight();
while (left < screenWidth) {
while (top < screenHeight) {
canvas.drawBitmap(bgTile, left, top, null);
top += bgTileHeight;
}
left += bgTileWidth;
top = 0;
}

<xml version="1.0" encoding="utf-8"?>
<LinearLayout
android:id="#+id/MainLayout"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:background="#drawable/back"
android:tileMode="repeat"
>
This worked fine for me. I did not have to create the bitmap seperately. I used the tileMode attribute in the layout.

Just put this line of codes in the onCreate():-
final Bitmap bmp = BitmapFactory.decodeResource(getResources(),R.drawable.actionbar_bg);
final BitmapDrawable bitmapDrawable = new BitmapDrawable(bmp);
bitmapDrawable.setTileModeXY(Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);
final ActionBar bar = getSupportActionBar();
bar.setBackgroundDrawable(bitmapDrawable);

If you want to repeat the background only vertically you can set the width of your layout to "wrap_content", whereas if you want to set the background to repeat horizontally set the height to "wrap_content". If both height and width are set to "fill_parent" then it will tile in the X and Y directions.
For example, the following code will repeat your background vertically:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:background="#drawable/news_detail_activity_bg">
</LinearLayout>

/* Tiled Layer Bitmap*/
public class TiledLayer {
private int cellWidth;
private int cellHeight;
private int yPosition = 0, xPosition = 0;
private int[][] grid;
private Image image;
private int[] tileXPositions;
private int[] tileYPositions;
private ArrayList animatedTiles;
private int numberOfTiles;
private int numberOfColumns;
private int numberOfRows;
private int gridColumns;
private int gridRows, width, height;
public TiledLayer(Image image, int columns, int rows, int tileWidth,
int tileHeight, int width, int height) {
this.grid = new int[columns][rows];
this.gridColumns = columns;
this.gridRows = rows;
this.width = columns * tileWidth;
this.height = rows * tileHeight;
this.animatedTiles = new ArrayList();
setStaticTileSet(image, tileWidth, tileHeight);
}
public void setStaticTileSet(Image image, int tileWidth, int tileHeight) {
this.image = image;
this.cellWidth = tileWidth;
this.cellHeight = tileHeight;
int columns = 64;//image.getWidth() / tileWidth;
int rows =40;// image.getHeight() / tileHeight;
this.tileXPositions = new int[columns];
int pos = 0;
for (int i = 0; i < columns; i++) {
this.tileXPositions[i] = pos;
pos += tileWidth;
}
this.tileYPositions = new int[rows];
pos = 0;
for (int i = 0; i < rows; i++) {
this.tileYPositions[i] = pos;
pos += tileHeight;
}
if (columns * rows < this.numberOfTiles) {
// clear the grid, when there are not as many tiles as in the
// previous set:
for (int i = 0; i < this.grid.length; i++) {
for (int j = 0; j < this.grid[i].length; j++) {
this.grid[i][j] = 0;
}
}
}
this.numberOfTiles = columns * rows;
this.numberOfColumns = columns;
this.numberOfRows = rows;
}
public int createAnimatedTile(int staticTileIndex) {
if (staticTileIndex >= this.numberOfTiles) {
throw new IllegalArgumentException("invalid static tile index: "
+ staticTileIndex + " (there are only ["
+ this.numberOfTiles + "] tiles available.");
}
this.animatedTiles.add(new Integer(staticTileIndex));
return -1 * (this.animatedTiles.size() - 1);
}
public void setAnimatedTile(int animatedTileIndex, int staticTileIndex) {
if (staticTileIndex >= this.numberOfTiles) {
}
int animatedIndex = (-1 * animatedTileIndex) - 1;
this.animatedTiles.set(animatedIndex, new Integer(staticTileIndex));
}
public int getAnimatedTile(int animatedTileIndex) {
int animatedIndex = (-1 * animatedTileIndex) - 1;
Integer animatedTile = (Integer) this.animatedTiles.get(animatedIndex);
return animatedTile.intValue();
}
public void setCell(int col, int row, int tileIndex) {
if (tileIndex >= this.numberOfTiles) {
throw new IllegalArgumentException("invalid static tile index: "
+ tileIndex + " (there are only [" + this.numberOfTiles
+ "] tiles available.");
}
this.grid[col][row] = tileIndex;
}
public int getCell(int col, int row) {
return this.grid[col][row];
}
public void fillCells(int col, int row, int numCols, int numRows,
int tileIndex) {
if (tileIndex >= this.numberOfTiles) {
throw new IllegalArgumentException("invalid static tile index: "
+ tileIndex + " (there are only [" + this.numberOfTiles
+ "] tiles available.");
}
int endCols = col + numCols;
int endRows = row + numRows;
for (int i = col; i < endCols; i++) {
for (int j = row; j < endRows; j++) {
this.grid[i][j] = tileIndex;
}
}
}
public final int getCellWidth() {
return this.cellWidth;
}
public final int getCellHeight() {
return this.cellHeight;
}
public final int getColumns() {
return this.gridColumns;
}
public final int getRows() {
return this.gridRows;
}
public final void paint(Graphics g) {
int clipX = 0;// g.getClipX();
int clipY = 0;// g.getClipY();
int clipWidth = width;// g.getClipWidth();
int clipHeight = height;// g.getClipHeight();
// jmt restore clip to previous state
int x = this.xPosition;
int y = this.yPosition;
int[][] gridTable = this.grid;
for (int i = 0; i < this.gridColumns; i++) {
int[] gridRow = gridTable[i];
for (int j = 0; j < gridRow.length; j++) {
int cellIndex = gridRow[j];
if (cellIndex != 0) {
// okay this cell needs to be rendered:
int tileIndex;
if (cellIndex < 0) {
Integer tile = (Integer) this.animatedTiles
.get((-1 * cellIndex) - 1);
tileIndex = tile.intValue() - 1;
} else {
tileIndex = cellIndex - 1;
}
// now draw the tile:
g.save(Canvas.CLIP_SAVE_FLAG);
// jmt: clear the screen
Rect r = new Rect(0, 0, cellWidth, cellHeight);
g.clipRect(r);
g.setClip(x, y, this.cellWidth, this.cellHeight);
int column = tileIndex % this.numberOfColumns;
int row = tileIndex / this.numberOfColumns;
int tileX = x - this.tileXPositions[column];
int tileY = y - this.tileYPositions[row];
g.drawImage(this.image, tileX, tileY);
g.restore();
}
y += this.cellHeight;
} // for each row
y = this.yPosition;
x += this.cellWidth;
} // for each column
// reset original clip:
g.setClip(clipX, clipY, clipWidth, clipHeight);
}
}