Android(安卓)倒车影像车道线，3D效果
16lz
2022-04-11
Android 倒车影像车道线
1、直接上代码
public class LaneLineView extends View { private Paint paint; private Camera camera; private Matrix matrix; //尺度标记得长短，可调整 private int tran = 200; //笔粗细，由近到远是由粗到细，变化跟倾斜得角度有关，可调整 private int strokeWidth = 70; public LaneLineView(Context context) { super(context); init(); } public LaneLineView(Context context, @Nullable AttributeSet attrs) { super(context, attrs); init(); } private void init(){ paint = new Paint(); paint.setAntiAlias(true); paint.setStyle(Paint.Style.FILL_AND_STROKE); paint.setStrokeWidth(strokeWidth); //矩阵变化所需要的东西 camera = new Camera(); matrix = new Matrix(); }}2、然后开始画线，重写onDraw方法
@Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); nt height = getHeight(); int width = getWidth(); //每个刻度之间的长度，可调整 int h_coefficient = 1000; //左右边界距离，可调整 int w_coefficient = width / 6; //可适当调整俩条线之间的角度 int skewing = 300; //计算画布旋转角度 double v = Math.sqrt(Math.pow(h_coefficient, 2) - Math.pow(skewing, 2)); double angle = angle(v, skewing, h_coefficient); long round = Math.round(angle); //需要将画布旋转得角度 if(round != 0){ canvas.rotate(-round, w_coefficient, height); } paint.setColor(Color.parseColor("#dc474e")); canvas.drawLine(w_coefficient, height, w_coefficient, height - h_coefficient, paint); paint.setColor(Color.parseColor("#f2f542")); canvas.drawLine(w_coefficient, height - h_coefficient, w_coefficient, height - h_coefficient * 2, paint); paint.setColor(Color.parseColor("#4ee826")); canvas.drawLine(w_coefficient, height - h_coefficient * 2, w_coefficient, height - h_coefficient * 3, paint); canvas.drawLine(w_coefficient, height - h_coefficient * 3, w_coefficient, height - h_coefficient * 4, paint); paint.setColor(Color.parseColor("#dc474e")); canvas.drawLine(w_coefficient - strokeWidth / 2, height - h_coefficient, w_coefficient - strokeWidth / 2 + tran, height - h_coefficient, paint); paint.setColor(Color.parseColor("#f2f542")); canvas.drawLine(w_coefficient - strokeWidth / 2, height - h_coefficient * 2, w_coefficient - strokeWidth / 2 + tran, height - h_coefficient * 2, paint); paint.setColor(Color.parseColor("#4ee826")); canvas.drawLine(w_coefficient - strokeWidth / 2, height - h_coefficient * 3, w_coefficient - strokeWidth / 2 + tran, height - h_coefficient * 3, paint); canvas.drawLine(w_coefficient - strokeWidth / 2, height - h_coefficient * 4, w_coefficient - strokeWidth / 2 + tran, height - h_coefficient * 4, paint); if(round != 0){ //上面画布被逆时针旋转了，所以先要把画布归位，再旋转画布 canvas.rotate(round, w_coefficient, height); canvas.rotate(round, getWidth() - w_coefficient, height); } paint.setColor(Color.parseColor("#dc474e")); canvas.drawLine(getWidth() - w_coefficient, height, getWidth() - w_coefficient, height - h_coefficient, paint); paint.setColor(Color.parseColor("#f2f542")); canvas.drawLine(getWidth() - w_coefficient, height - h_coefficient, getWidth() - w_coefficient, height - h_coefficient * 2, paint); paint.setColor(Color.parseColor("#4ee826")); canvas.drawLine(getWidth() - w_coefficient, height - h_coefficient * 2, getWidth() - w_coefficient, height - h_coefficient * 3, paint); canvas.drawLine(getWidth() - w_coefficient, height - h_coefficient * 3, getWidth() - w_coefficient, height - h_coefficient * 4, paint); paint.setColor(Color.parseColor("#dc474e")); canvas.drawLine(getWidth() - w_coefficient + strokeWidth / 2, height - h_coefficient, getWidth() - w_coefficient + strokeWidth / 2 - tran, height - h_coefficient, paint); paint.setColor(Color.parseColor("#f2f542")); canvas.drawLine(getWidth() - w_coefficient + strokeWidth / 2, height - h_coefficient * 2, getWidth() - w_coefficient + strokeWidth / 2 - tran, height - h_coefficient * 2, paint); paint.setColor(Color.parseColor("#4ee826")); canvas.drawLine(getWidth() - w_coefficient + strokeWidth / 2, height - h_coefficient * 3, getWidth() - w_coefficient + strokeWidth / 2 - tran, height - h_coefficient * 3, paint); canvas.drawLine(getWidth() - w_coefficient + strokeWidth / 2, height - h_coefficient * 4, getWidth() - w_coefficient + strokeWidth / 2 - tran, height - h_coefficient * 4, paint); if(round != 0){ //将画布转回原位 canvas.rotate(-round, getWidth() - w_coefficient, height); } } //计算旋转的角度，余弦公式应该知道吧 private double angle(double a, int b, int c){ if(b == 0)return 0; double a2 = Math.pow(a, 2); double b2 = Math.pow(b, 2); double c2 = Math.pow(c, 2); double acos = Math.acos((a2 + c2 - b2) / (2 * a * c)); double v = Math.toDegrees(acos); return v; }3、到这里指示线就画完了，接下来用矩阵旋转画布，达到3D的效果
@Overrideprotected void onDraw(Canvas canvas) { super.onDraw(canvas); camera.save(); matrix.reset(); //z轴移动，z可调整，-放大，+缩小 camera.translate(0, 0, 0); //旋转度数可以调整 camera.rotateX(50); camera.getMatrix(matrix); camera.restore(); //设置坐标位置 matrix.preTranslate(-(getWidth() / 2), -getHeight()); matrix.postTranslate(getWidth() / 2, getHeight()); //将变换后的矩阵给canvashao canvas.concat(matrix);}没了，是不是很简单，最后附上代码地址
https://download.csdn.net/download/itacmen1vip/11584446
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