Android Open Source - BLEMeshChat Identicon

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Back to project page BLEMeshChat.
License

The source code is released under:
GNU General Public License
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Java Source Code

package im.delight.android.identicons;
//from ww w .  j a  v a2 s  . c  o m
/**
 * Copyright 2014 www.delight.im <info@delight.im>
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Build;
import android.util.AttributeSet;
import android.view.View;

import java.security.MessageDigest;

abstract public class Identicon extends View {
  
  private static final String HASH_ALGORITHM = "SHA-256";
  private final int mRowCount;
  private final int mColumnCount;
  private final Paint mPaint;
  private volatile int mCellWidth;
  private volatile int mCellHeight;
  private volatile byte[] mHash;
  private volatile int[][] mColors;
  private volatile boolean mReady;

  public Identicon(Context context) {
    super(context);

    mRowCount = getRowCount();
    mColumnCount = getColumnCount();
    mPaint = new Paint();

    init();
  }

  public Identicon(Context context, AttributeSet attrs) {
    super(context, attrs);

    mRowCount = getRowCount();
    mColumnCount = getColumnCount();
    mPaint = new Paint();

    init();
  }

  public Identicon(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);

    mRowCount = getRowCount();
    mColumnCount = getColumnCount();
    mPaint = new Paint();

    init();
  }
    
  @SuppressLint("NewApi")
  protected void init() {
    mPaint.setStyle(Paint.Style.FILL);
    mPaint.setAntiAlias(true);
    mPaint.setDither(true);
    
    setWillNotDraw(false);
    if (Build.VERSION.SDK_INT >= 11) {
      setLayerType(View.LAYER_TYPE_SOFTWARE, null);
    }
  }

  public void show(String input) {
    // if the input was null
    if (input == null) {
      // we can't create a hash value and have nothing to show (draw to the view)
      mHash = null;
    }
    // if the input was a proper string (non-null)
    else {
      // generate a hash from the string to get unique but deterministic byte values 
      try {
        final MessageDigest digest = MessageDigest.getInstance(HASH_ALGORITHM);
        digest.update(input == null ? new byte[0] : input.getBytes());
        mHash = digest.digest();
      }
      catch (Exception e) {
        mHash = null;
      }
    }
    
    // set up the cell colors according to the input that was provided via show(...)
    setupColors();
    
    // this view may now be drawn (and thus must be re-drawn)
    mReady = true;
    invalidate();
  }
  
  public void show(int input) {
    show(String.valueOf(input));
  }
  
  public void show(long input) {
    show(String.valueOf(input));
  }
  
  public void show(float input) {
    show(String.valueOf(input));
  }
  
  public void show(double input) {
    show(String.valueOf(input));
  }
  
  public void show(byte input) {
    show(String.valueOf(input));
  }
  
  public void show(char input) {
    show(String.valueOf(input));
  }
  
  public void show(boolean input) {
    show(String.valueOf(input));
  }
  
  public void show(Object input) {
    if (input == null) {
      mHash = null;
    }
    else {
      show(String.valueOf(input));
    }
  }
  
  protected void setupColors() {
    mColors = new int[mRowCount][mColumnCount];
    int colorVisible = getIconColor();

    for (int r = 0; r < mRowCount; r++) {
      for (int c = 0; c < mColumnCount; c++) {
        if (isCellVisible(r, c)) {
          mColors[r][c] = colorVisible;
        }
        else {
          mColors[r][c] = Color.TRANSPARENT;
        }
      }
    }
  }
  
  protected byte getByte(int index) {
    if (mHash == null) {
      return -128;
    }
    else {
      return mHash[index % mHash.length];
    }
  }
  
  abstract protected int getRowCount();
  
  abstract protected int getColumnCount();

  abstract protected boolean isCellVisible(int row, int column);

  abstract protected int getIconColor();
  
  @Override
  protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);
    
    mCellWidth = w / mColumnCount;
    mCellHeight = h / mRowCount;
  }
  
  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    int size = Math.min(getMeasuredWidth(), getMeasuredHeight());
    setMeasuredDimension(size, size);
  }
  
  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    if (mReady) {
      int x, y;
      for (int r = 0; r < mRowCount; r++) {
        for (int c = 0; c < mColumnCount; c++) {
          x = mCellWidth * c;
          y = mCellHeight * r;
          
          mPaint.setColor(mColors[r][c]);

          canvas.drawRect(x, y + mCellHeight, x + mCellWidth, y, mPaint);
        }
      }
    }
  }

}
Java Source Code List
