Android Open Source - WATisRain Map Draw

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License

The source code is released under:

MIT License

Java Source Code

package com.lucky.watisrain.map;
/*from w  w  w .  j a va  2  s  . c o m*/
import java.util.List;

import com.lucky.watisrain.Global;
import com.lucky.watisrain.backend.data.Path;
import com.lucky.watisrain.backend.data.Waypoint;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.RectF;

/**
 * This class handles drawing things to map-specific coordinates. This is necessary because
 * by default, we can only draw to screen coordinates, which is not useful when we want
 * an overlay over the map of the campus.
 */
public class MapDraw {

  private Canvas canvas;
  private RectF rct;
  
  private float offset_x;
  private float offset_y;
  private float scale;
  
  /**
   * Constructs a MapDraw. This is specific to one rendering of the screen.
   * @param canvas the canvas object to draw to
   * @param displayRectangle the current field of view
   */
  public MapDraw(Canvas canvas, RectF displayRectangle){
    this.canvas = canvas;
    rct = displayRectangle;
    
    // Compute offsets given display rectangle
    scale = (rct.right-rct.left) / Global.MAP_WIDTH * Global.MAP_ADJUST_SCALING;
    offset_x = -rct.left + Global.MAP_ADJUST_X*scale;
    offset_y = -rct.top + Global.MAP_ADJUST_Y*scale;
  }
  
  
  /**
   * Draws a Path object, including all waypoints.
   * @param linewidth the width of the path (in map relative pixels)
   */
  public void drawPathOnMap(Path path, float linewidth, Paint paint){
    
    List<Waypoint> wps = path.getWaypoints();
    
    for(int i=0; i<wps.size()-1; i++){
      drawLineOnMap(wps.get(i).getX(), wps.get(i).getY(), wps.get(i+1).getX(), wps.get(i+1).getY(), linewidth, paint);
    }
    
  }
  
  
  /*
   * More primitive routines here
   */
  
  /**
   * Draw a circle in map relative units
   */
  public void drawCircleOnMap(float x, float y, float radius, Paint paint){
    
    float adjust_x = x * scale - offset_x;
    float adjust_y = y * scale - offset_y;
    
    canvas.drawCircle(adjust_x, adjust_y, radius*scale, paint);
  }
  
  /**
   * Draw a line in map relative units. The line goes from the point
   * (x1,y1) to the point (x2,y2).
   * @param linewidth how wide is the line (map relative pixels)
   */
  public void drawLineOnMap(float x1, float y1, float x2, float y2, float linewidth, Paint paint){
    
    // Don't draw a line from a point to itself. Doing so causes a
    // problem on some devices.
    if(x1 == x2 && y1 == y2)
      return;
    
    float adjust_x1 = x1 * scale - offset_x;
    float adjust_y1 = y1 * scale - offset_y;
    float adjust_x2 = x2 * scale - offset_x;
    float adjust_y2 = y2 * scale - offset_y;
    
    paint.setStrokeWidth(linewidth*scale);
    
    canvas.drawLine(adjust_x1, adjust_y1, adjust_x2, adjust_y2, paint);
  }
  
  
  /**
   * Draws a bitmap in map relative units. Assumes the image is square.
   */
  public void drawImageOnMap(Bitmap bitmap, float x, float y, float width){
    
    float adjust_x = x * scale - offset_x;
    float adjust_y = y * scale - offset_y;
    float scwidth = scale*width;
    
    // Scale image down
    int img_width = bitmap.getWidth();
    int img_height = bitmap.getHeight();
    
    Matrix scaleMatrix = new Matrix();
    scaleMatrix.setRectToRect(
        new RectF(0,0,img_width,img_height),
        new RectF(adjust_x-scwidth/2,adjust_y-scwidth/2,adjust_x+scwidth/2,adjust_y+scwidth/2),
        Matrix.ScaleToFit.CENTER);
    canvas.drawBitmap(bitmap, scaleMatrix, null);
  }
  
}

Java Source Code List

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