Question

我尝试执行捏合以放大自定义视图，并在其上显示路径。路径应相应缩放。

以下代码正常工作，直到放大级别达到应用崩溃并显示的关键点：

A / libc：致命信号11（SIGSEGV），代码2，故障地址0xb88799c0 in tid 25828（RenderThread）

此外，在粉碎之前显示：

W / OpenGLRenderer：路径太大而无法渲染到纹理

public class TestView extends View implements ScaleGestureDetector.OnScaleGestureListener {
    private String DEBUG_TAG = "TestView";
    private ScaleGestureDetector mScaleDetector;
    private Path mPath;
    private Paint mPaint;
    private float mScaleFactor = 1.f;
    private float mScaleMax = 2f;
    private float mScaleMin = 0.5f;
    private Matrix mMatrix;
    private boolean mScaling = false;
    private PointF mScaleFocus = new PointF();

    public TestView(Context context) {
        super(context);
        setupDrawing();
    }

    public TestView(Context context, AttributeSet attrs) {
        super(context, attrs);
        setupDrawing();
    }

    public TestView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        setupDrawing();
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public TestView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        setupDrawing();
    }

    private void setupDrawing(){
        mPath = new Path();

        mPaint = new Paint();
        mPaint.setColor(0xFF660000);
        mPaint.setAntiAlias(true);
        mPaint.setStrokeWidth(10);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeJoin(Paint.Join.ROUND);
        mPaint.setStrokeCap(Paint.Cap.ROUND);

        mMatrix = new Matrix();

        mScaleDetector = new ScaleGestureDetector(getContext(), this);

        mPath = new Path();
        int width = 100;
        int start = 20;
        mPath.moveTo(start,start);
        mPath.lineTo(start + width, start);
        mPath.lineTo(start + width, start + width);
        mPath.lineTo(start,start+width);
        mPath.close();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        canvas.save();

        mPath.transform(mMatrix);
        canvas.drawPath(mPath, mPaint);
        canvas.restore();
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        mScaleDetector.onTouchEvent(event);

        if(mScaling) return true;

        if (event.getPointerCount() > 1){
            return true;
        }

        invalidate();
        return true;
    }

    @Override
    public boolean onScale(ScaleGestureDetector detector) {
        mScaleFactor = detector.getScaleFactor();
        mScaleFactor = Math.max(mScaleMin, Math.min(mScaleFactor, mScaleMax));
        mScaleFocus.set(detector.getFocusX(), detector.getFocusY());
        Log.d(DEBUG_TAG, "onScale: " + mScaleFactor);
        mMatrix.setScale(mScaleFactor, mScaleFactor, mScaleFocus.x, mScaleFocus.y);
        invalidate();
        return true;
    }

    @Override
    public boolean onScaleBegin(ScaleGestureDetector detector) {
        Log.d(DEBUG_TAG, "onScaleBegin: " + mScaleFactor);
        mScaling = true;
        return true;
    }

    @Override
    public void onScaleEnd(ScaleGestureDetector detector) {
        Log.d(DEBUG_TAG, "onScaleEnd: " + mScaleFactor);
        mScaling = false;
    }
}

我尝试缩放画布，而不是缩放路径。这很好用，但是在放大时路径线会变形，这不是理想的行为。

Answer 1

问题与硬件加速有关。

在活动中设置android:hardwareAccelerated="false"解决了问题。

如何在缩放时正确缩放和Android路径

1 个答案: