Android 游戏开发之Canvas画布

得到canvas画布对象
[java]
Canvas canvas = getHolder().lockCanvas();

画布的一些属性和方法以及一些应用
[java]
if (canvas != null) {
    //----设置画布绘图无锯齿
    canvas.setDrawFilter(pfd);
    //----利用填充画布，刷屏
    canvas.drawColor(Color.BLACK);
    //----绘制文本
    canvas.drawText("drawText", 10, 10, paint);
    //----绘制像素点
    canvas.drawPoint(10, 20, paint);
    //----绘制多个像素点
    canvas.drawPoints(new float[] { 10, 30, 30, 30 }, paint);
    //----绘制直线
    canvas.drawLine(10, 40, 50, 40, paint);
    //----绘制多条直线
    canvas.drawLines(new float[] { 10, 50, 50, 50, 70, 50, 110, 50 }, paint);
    //----绘制矩形
    canvas.drawRect(10, 60, 40, 100, paint);
    //----绘制矩形2
    Rect rect = new Rect(10, 110, 60, 130);
    canvas.drawRect(rect, paint);
    canvas.drawRect(rect, paint);
    //----绘制圆角矩形
    RectF rectF = new RectF(10, 140, 60, 170);
    canvas.drawRoundRect(rectF, 20, 20, paint);
    //----绘制圆形
    canvas.drawCircle(20, 200, 20, paint);
    //----绘制弧形
    canvas.drawArc(new RectF(150, 20, 200, 70), 0, 230, true, paint);
    //----绘制椭圆
    canvas.drawOval(new RectF(150, 80, 180, 100), paint);
    //----绘制指定路径图形
    Path path = new Path();
    //设置路径起点
    path.moveTo(160, 150);
    //路线1
    path.lineTo(200, 150);
    //路线2
    path.lineTo(180, 200);
    //路径结束
    path.close();
    canvas.drawPath(path, paint);
    //----绘制指定路径图形
    Path pathCircle = new Path();
    //添加一个圆形的路径
    pathCircle.addCircle(130, 260, 20, Path.Direction.CCW);
    //----绘制带圆形的路径文本
    canvas.drawTextOnPath("PathText", pathCircle, 10, 20, paint);
}

注：以上代码参考自《Android游戏编程之从零开始》

得到自定义图片宽高的bitmap（参数一：上下文对象，参数二：资源ID，参数三：自定义宽度，参数四：自定义高度）
[java]
public static Bitmap loadBallView(Context context,int resId,int width,int height) {

    Resources resources = context.getResources();

    Drawable image = resources.getDrawable(resId);

    Bitmap bitmap = Bitmap.createBitmap(width,height, Bitmap.Config.ARGB_8888);

         Canvas canvas = new Canvas(bitmap);
         image.setBounds(0, 0, width,height);
         image.draw(canvas);

         return bitmap;
    }

利用canvas绘制bitmap
[java]
Bitmap bitmap = loadBallView(context,R.drawable.image,100,100);

Paint paint = new Paint();

canvas.drawBitmap(bitmap, startX, startY, paint); //参数一：bitmap资源,参数二：起始X坐标，参数三：起始Y坐标，参数四：画笔paint对象

补充：移动开发 , Android ,