Android Open Source - bdb-simple Drawing View

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Back to project page bdb-simple.

License

The source code is released under:

MIT License

Java Source Code

package com.liaufscar.simplebdb;
//from  ww w.j  ava 2  s . co  m

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.MotionEvent;
import android.view.View;

/**
*** This code is based on the Mobiletuts+ tutorial
*** Android SDK: Create a Drawing App, by Sue Smith
**/

public class DrawingView extends View {

  // Drawing path
  private Path drawPath;
  // Drawing and canvas paint
  private Paint drawPaint, canvasPaint;
  // Initial color
  private int paintColor = 0xFF0000FF; // KKCCMMYY
  // Canvas
  private Canvas drawCanvas;
  // Canvas bitmap
  private Bitmap canvasBitmap;
  // Brush sizes
  private float brushSize;

  public DrawingView(Context context, AttributeSet attrs){
    super(context, attrs);
    setupDrawing();
  }

  //setup drawing
  private void setupDrawing(){

    //prepare for drawing and setup paint stroke properties
    brushSize = getResources().getInteger(R.integer.medium_size);
    drawPath = new Path();
    drawPaint = new Paint();
    drawPaint.setColor(paintColor);
    drawPaint.setAntiAlias(true);
    drawPaint.setStrokeWidth(brushSize);
    drawPaint.setStyle(Paint.Style.STROKE);
    drawPaint.setStrokeJoin(Paint.Join.ROUND);
    drawPaint.setStrokeCap(Paint.Cap.ROUND);
    canvasPaint = new Paint(Paint.DITHER_FLAG);
  }

  //size assigned to view
  @Override
  protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);
    canvasBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
    drawCanvas = new Canvas(canvasBitmap);
  }

  //draw the view - will be called after touch event
  @Override
  protected void onDraw(Canvas canvas) {
    canvas.drawBitmap(canvasBitmap, 0, 0, canvasPaint);
    canvas.drawPath(drawPath, drawPaint);
  }

  // Register user touches as drawing action
  @Override
  public boolean onTouchEvent(MotionEvent event) {
    float touchX = event.getX();
    float touchY = event.getY();
    //respond to down, move and up events
    switch (event.getAction()) {
    case MotionEvent.ACTION_DOWN:
      drawPath.moveTo(touchX, touchY);
      break;
    case MotionEvent.ACTION_MOVE:
      drawPath.lineTo(touchX, touchY);
      break;
    case MotionEvent.ACTION_UP:
      drawPath.lineTo(touchX, touchY);
      drawCanvas.drawPath(drawPath, drawPaint);
      drawPath.reset();
      break;
    default:
      return false;
    }
    // Redraw
    invalidate();
    return true;

  }

  // Update color
  public void setColor(int newColor){
    invalidate();
    paintColor = newColor;
    drawPaint.setColor(newColor);
  }

  // Set brush size
  public void setBrushSize(float newSize){
    float pixelAmount = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 
        newSize, getResources().getDisplayMetrics());
    brushSize = pixelAmount;
    drawPaint.setStrokeWidth(brushSize);
  }

  // Set erase true or false
  public void setErase(boolean isErase){
    if (isErase) drawPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
    else drawPaint.setXfermode(null);
  }

  // Start new drawing
  public void startNew() {
    drawCanvas.drawColor(0, PorterDuff.Mode.CLEAR);
    invalidate();
  }
}

Java Source Code List

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