Android 绘制心形

MyLove

package org.wp.activity;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.graphics.Typeface;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

/**
 * ================================================
 * setTypeface
 * ================================================
 * public Typeface setTypeface (Typeface typeface) 
 * Since: API Level 1 Set or clear the typeface object. 
 * Pass null to clear any previous typeface. 
 * As a convenience, the parameter passed is also returned.
 * 
 * Parameters
 * typeface  May be null. The typeface to be installed in the paint 
 * Returns
 * typeface 
 * 
 * 
 * ================================================
 * create
 * ================================================
 * public static Typeface create (Typeface family, int style) 
 * Since: API Level 1 Create a typeface object that best matches 
 * the specified existing typeface and the specified Style. 
 * Use this call if you want to pick a new style from the same family 
 * of an existing typeface object. 
 * If family is null, this selects from the default font's family.
 * 
 * Parameters
 * family  May be null. The name of the existing type face. 
 * style  The style (normal, bold, italic) of the typeface. 
 * 		  e.g. NORMAL, BOLD, ITALIC, BOLD_ITALIC 
 * Returns 
 * The best matching typeface. 
 * 
 * Typeface.create(Typeface family, int style)
 * 创建一个混合型新的字体：有4*5种搭配
 * 
 * Typeface类型
 * DEFAULT                   默认字体
 * DEFAULT_BOLD              默认粗体
 * MONOSPACE                 单间隔字体
 * SANS_SERIF                单间隔字体
 * SERIF                     衬线字体
 * 
 * int Style类型
 * BOLD                      粗体
 * BOLD_ITALIC               粗斜体          
 * ITALIC                    斜体
 * NORMAL                    普通字体
 * 
 * 
 * ================================================
 * drawRoundRect 画一个圆角矩形
 * ================================================
 * public void drawRoundRect (RectF rect, float rx, float ry, Paint paint)
 * Since: API Level 1 Draw the specified round-rect using the specified paint. 
 * The roundrect will be filled or framed based on the Style in the paint.
 * Parameters
 * rect  The rectangular bounds of the roundRect to be drawn 
 * rx  The x-radius of the oval used to round the corners 
 * ry  The y-radius of the oval used to round the corners 
 * paint  The paint used to draw the roundRect  
 * 
 * @author wp
 *
 */
public class MyLove extends SurfaceView implements SurfaceHolder.Callback,
		Runnable {
	private SurfaceHolder sfh = null;
	private Paint paint = null;
	private Canvas canvas = null;
	private int SH = 0, SW = 0;
	private int miCount = 0;
	private boolean loop = false;

	public MyLove(Context context) {
		super(context);
		this.setKeepScreenOn(true);
		this.setFocusable(true);
		sfh = this.getHolder();
		sfh.addCallback(this);
		paint = new Paint();
		paint.setAntiAlias(true);
		paint.setTextSize(32);
		paint.setTypeface(Typeface.create(Typeface.SERIF, Typeface.ITALIC));
		loop = true;
	}

	@Override
	public void surfaceCreated(SurfaceHolder holder) {
		SW = getWidth();
		SH = getHeight();
		new Thread(this).start();
	}

	@Override
	public void surfaceChanged(SurfaceHolder holder, int format, int width,
			int height) {
	}

	@Override
	public void surfaceDestroyed(SurfaceHolder holder) {
		loop = false;
	}

	@Override
	public void run() {
		while (loop) {
			try {
				Thread.sleep(300);
			} catch (Exception e) {
				e.printStackTrace();
			}
			/*
			 * synchronized 关键字,代表这个方法加锁
			 * 相当于不管哪一个线程A每次运行到这个方法时, 
			 * 都要检查有没有其它正在用这个方法的线程B(或者C D等)
			 * 
			 * 有的话要等正在使用这个方法的线程B(或者C D) 
			 * 运行完这个方法后再运行此线程A, 
			 * 
			 * 没有的话,直接运行
			 * 
			 * 它包括两种用法：synchronized 方法和 synchronized 块。
			 */
			synchronized (sfh) {
				draw();
			}
		}
	}

	private void draw() {
		canvas = sfh.lockCanvas();
		try {
			if (canvas == null)
				return;

			/** 刷屏 **/
			paint.setColor(Color.BLACK);
			canvas.drawRect(0, 0, SW, SH, paint);

			/** 变换画笔的颜色 **/
			if (miCount < 100) {
				miCount++;
			} else {
				miCount = 0;
			}
			switch (miCount % 6) {
			case 0:
				paint.setColor(Color.BLUE);
				break;
			case 1:
				paint.setColor(Color.GREEN);
				break;
			case 2:
				paint.setColor(Color.RED);
				break;
			case 3:
				paint.setColor(Color.YELLOW);
				break;
			case 4:
				paint.setColor(Color.argb(255, 255, 181, 216));
				break;
			case 5:
				paint.setColor(Color.argb(255, 0, 255, 255));
				break;
			default:
				paint.setColor(Color.WHITE);
				break;
			}

			/** 画一个心 **/
			int i, j;
			double x, y, r;
			for (i = 0; i <= 90; i++) {
				for (j = 0; j <= 90; j++) {
					r = Math.PI / 45 * i * (1 - Math.sin(Math.PI / 45 * j))
							* 20;
					x = r * Math.cos(Math.PI / 45 * j)
							* Math.sin(Math.PI / 45 * i) + 320 / 2;
					y = -r * Math.sin(Math.PI / 45 * j) + 400 / 4;
					canvas.drawPoint((float) x, (float) y, paint);
				}
			}
			/** 绘制文字 **/
			canvas.drawText("Loving You", 75, 400, paint);
			/** 绘制圆角矩形 **/
			RectF rect = new RectF(60, 403, 260, 408);
			canvas.drawRoundRect(rect, (float) 1.0, (float) 1.0, paint);

			sfh.unlockCanvasAndPost(canvas);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}