Gauge.java

/*******************************************************************************
 * Copyright 2013-2014 alladin-IT GmbH
 * 
 * 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.
 ******************************************************************************/
package at.alladin.rmbt.android.test;

import java.text.Format;
import java.text.NumberFormat;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Region;
import android.graphics.drawable.Drawable;
import android.util.Log;

public class Gauge extends Drawable
{
    
    /*
     * init: 14 1 ping: 14 1 down: 33 1 up: 32
     */
    
    final static String LOG = "Gauge";
    
    final Bitmap background;
    final Bitmap foreground;
    final Bitmap dynamic;
    final Bitmap drawBitmap;
    final Canvas drawCanvas;
    final Paint paint = new Paint();
    final Paint erasePaint;
    final RectF ovalRect;
    final float startAngle;
    final float maxAngle;
    
    final Format formatter = NumberFormat.getPercentInstance();
    
    final int width;
    final int height;
    
    Rect bounds;
    
    double value = 0;
    
    public Gauge(final float startAngle, final float maxAngle, final Bitmap background, final Bitmap dynamic,
            final Bitmap foreground, final float x1, final float y1, final float x2, final float y2)
    {
        this.startAngle = startAngle;
        this.maxAngle = maxAngle;
        this.background = background;
        this.dynamic = dynamic;
        this.foreground = foreground;
        width = background.getWidth();
        height = background.getHeight();
        drawBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        drawCanvas = new Canvas(drawBitmap);
        
        paint.setFilterBitmap(true);
        
        Log.d(LOG, "density background: " + background.getDensity());
        
        erasePaint = new Paint();
        erasePaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));
        erasePaint.setAntiAlias(true);
        // erasePaint.setAlpha(0);
        
        ovalRect = new RectF(width * x1, height * y1, width * x2, height * y2);
    }
    
    public void setValue(double value)
    {
        if (value < 0)
            value = 0;
        else if (value > 1)
            value = 1;
        this.value = value;
        
        invalidateSelf();
    }
    
    @Override
    public void draw(final Canvas canvas)
    {
        final Rect r = getBounds();
        
        final int saveCount = canvas.save();
        
        canvas.clipRect(r, Region.Op.REPLACE);
        canvas.translate(r.left, r.top);
        
        canvas.drawBitmap(background, 0, 0, paint);
        
        drawCanvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
        drawCanvas.drawBitmap(dynamic, 0, 0, null);
        final float angle;
        if (maxAngle >= 0)
            angle = -(float) (360d - (maxAngle * value));
        else
            angle = (float) (360d - (-maxAngle * value));
        drawCanvas.drawArc(ovalRect, startAngle, angle, true, erasePaint);
        
        canvas.drawBitmap(drawBitmap, 0, 0, paint);
        
        canvas.drawBitmap(foreground, 0, 0, paint);
        
        // canvas.drawText(formatter.format(value), textX, textY, textPaint);
        
        canvas.restoreToCount(saveCount);
    }
    
    @Override
    public int getMinimumHeight()
    {
        return height;
    }
    
    @Override
    public int getMinimumWidth()
    {
        return width;
    }
    
    @Override
    public int getIntrinsicHeight()
    {
        return height;
    }
    
    @Override
    public int getIntrinsicWidth()
    {
        return width;
    }
    
    @Override
    public int getOpacity()
    {
        return PixelFormat.TRANSLUCENT;
    }
    
    @Override
    public void setAlpha(final int alpha)
    {
        paint.setAlpha(alpha);
        // textPaint.setAlpha(alpha);
        invalidateSelf();
    }
    
    @Override
    public void setColorFilter(final ColorFilter cf)
    {
        paint.setColorFilter(cf);
        // textPaint.setColorFilter(cf);
        invalidateSelf();
    }
    
    public void recycle()
    {
        background.recycle();
        foreground.recycle();
        dynamic.recycle();
        drawBitmap.recycle();
    }
    
}