Android Open Source - FreeSketch Sketch View

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Back to project page FreeSketch.

License

The source code is released under:

GNU General Public License

Java Source Code

/* FreeSketch - A simple Android app for sketching out ideas etc
 * /*from  w  ww  . ja  va 2 s  . c om*/
 * Copyright (C) 2012  Nathan Sullivan (nathan.sullivan@gmail.com)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.nmsbox.freesketch;

import android.app.AlertDialog;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.Log;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;

public class SketchView extends SurfaceView implements SurfaceHolder.Callback {
  private static final String TAG = "SketchView";
  private static final int BACKGROUND_COLOR = Color.WHITE;
  private static final long STROKE_TIMEOUT_MILLIS = 100;
  private static final int SETTINGS_REQUEST = 0;
  private float mPrevX;
  private float mPrevY;
  private long mPrevTime;
  private Bitmap mBitmap;
  private Paint mPaint;
  private boolean mEnableTripleTouch;
  
  public SketchView(Context context) {
    super(context);
    setFocusable(true);
    getHolder().addCallback(this);
    mPaint = new Paint();
    mPaint.setAntiAlias(true);
    mPaint.setColor(Color.RED);
    mPaint.setStrokeWidth(5.0f);
    mPaint.setStyle(Paint.Style.STROKE);
    mPrevTime = 0;
    mEnableTripleTouch = true;
  }
  
  private void doDraw(Canvas canvas) {
    if (mBitmap != null) {
      canvas.drawBitmap(mBitmap, 0, 0, null);
    }
  }
  
  public void showSettings(View view) {
      Intent intent = new Intent(this.getContext(), SettingsActivity.class);
      this.getContext().startActivity(intent);
    }
  
  @Override
  protected void onVisibilityChanged (View changedView, int visibility) {
    if (visibility == View.VISIBLE) {
      mEnableTripleTouch = true;
    }
  }
    
  @Override
  public boolean onTouchEvent(MotionEvent e) {
    final float x = e.getX();
    final float y = e.getY();
    final int historySize = e.getHistorySize();
    final int pointerCount = e.getPointerCount(); // this is essentially the number of fingers/touches
    
    if (pointerCount == 3 && mEnableTripleTouch) {
      mEnableTripleTouch = false;
      showSettings(this);
      return true;
    }
    
    switch (e.getAction()) {
    case MotionEvent.ACTION_MOVE:
      if (pointerCount > 1) {
        return true;
      }
      long time = e.getEventTime();
      Path path = new Path();
      boolean firstPoint = true;
      
      // Continue current stroke if last motion event was less than STROKE_TIMEOUT_MILLIS ago
      if (time - mPrevTime < STROKE_TIMEOUT_MILLIS) {
        path.moveTo(mPrevX, mPrevY);
        firstPoint = false;
      }
      
      for (int h = 0; h < historySize; h++) {
        for (int p = 0; p < pointerCount; p++) {
          float histX = e.getHistoricalX(p, h);
          float histY = e.getHistoricalY(p, h);
          if (firstPoint) {
            path.moveTo(histX, histY);
            firstPoint = false;
          } else {
            path.lineTo(histX, histY);
          }
        }
      }

      if (firstPoint) {
        path.moveTo(x, y);
      }
      path.lineTo(x, y);
      
            if (mBitmap != null) {
              Canvas canvas = new Canvas(mBitmap);
               canvas.drawPath(path, mPaint);
              /*Paint p = new Paint();
              p.setColor(Color.BLACK);
              p.setStrokeWidth(10.0f);
              p.setAntiAlias(true);
              canvas.drawPoint(x, y, p);
              p.setColor(Color.GREEN);
              canvas.drawPoint(mPrevX, mPrevY, p);*/
              canvas = getHolder().lockCanvas();
              if (canvas != null) {
                doDraw(canvas);
                getHolder().unlockCanvasAndPost(canvas);
              }
            }
            mPrevX = x;
            mPrevY = y;
            mPrevTime = time;
            break;
    }
    return true;
  }

  @Override
  public void surfaceChanged(SurfaceHolder holder, int format, int width,
      int height) {
    if (mBitmap == null) {
      mBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
      Canvas canvas = new Canvas(mBitmap);
      Paint paint = new Paint();
      paint.setColor(BACKGROUND_COLOR);
      canvas.drawPaint(paint);
    }
    
    Canvas canvas = holder.lockCanvas();
    if (canvas != null) {
      doDraw(canvas);
      holder.unlockCanvasAndPost(canvas);
    }
  }

  @Override
  public void surfaceCreated(SurfaceHolder holder) {
  }

  @Override
  public void surfaceDestroyed(SurfaceHolder holder) {
  }
}

Java Source Code List

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