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