java - Android 在 Canvas 上操作图像 - 使用触摸、移动、放大 - 放大/缩小、缩放

Question

我正在开发这样的摄影应用程序: https://play.google.com/store/apps/details?id=com.photo.editor.collage.maker.photoblender&hl=en

我必须实现这样的功能:

这个 View 有 2 个功能...

1) 带有飞溅背景

2) 背景模糊

两者都使用 2 种形状....现在您正在使用路径绘制形状....我想像上面那样绘制图像位图形状。

我有更多如下形状(所有有 2 个图像，如上):

3)

我想替换您正在使用的这部分代码:

private void createPath() {
            path.reset();
            path.moveTo(114, 156);
            float[] points = {68, 138, 19, 136, 21, 87, 8, 39, 56, 26, 97, -2, 123, 40, 163, 71, 131, 109};
            for (int i = 0; i < points.length; i += 2) {
                path.lineTo(points[i], points[i + 1]);
            }
            path.close();
            Matrix m = new Matrix();
            m.setRectToRect(new RectF(0, 0, 160, 160), clip, Matrix.ScaleToFit.CENTER);
            path.transform(m);
            transformedPath.set(path);
        }

我通过添加形状作为路径来实现上述功能，但是当我尝试将形状用作位图时，我没有得到完整的结果....这是我的 View 代码。

class MotionImageView extends View implements MatrixGestureDetector.OnMatrixChangeListener {
    private final Bitmap shapeMaskBitmap;
    private final Bitmap shapeShadowBitmap;
    Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    Paint monoPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    Paint borderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    Bitmap bitmap, blur;
    Matrix matrix = new Matrix();
    Matrix pathMatrix = new Matrix();
//    Path path = new Path();
//    Path transformedPath = new Path();
    MatrixGestureDetector detector;
    RectF clip = new RectF();

    public MotionImageView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        Log.e("~~~~", "1111");
        bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.model);
        blur = blur(context, bitmap, 8);
        ColorMatrix cm = new ColorMatrix();
        cm.setSaturation(0.25f);
        monoPaint.setColorFilter(new ColorMatrixColorFilter(cm));
        borderPaint.setStyle(Paint.Style.STROKE);
        borderPaint.setColor(0xccffffff);
        borderPaint.setStrokeWidth(4);
        borderPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        detector = new MatrixGestureDetector(pathMatrix, this);

        shapeMaskBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.shape_mask);
        shapeShadowBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.shape_shadow);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        Shader shader = new BitmapShader(bitmap, Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);
        RectF src = new RectF(0, 0, bitmap.getWidth(), bitmap.getHeight());
        RectF dst = new RectF(0, 0, w, h);
        matrix.setRectToRect(src, dst, Matrix.ScaleToFit.CENTER);
        shader.setLocalMatrix(matrix);
        paint.setShader(shader);
        matrix.mapRect(clip, src);
//        createPath();
    }

    /*private void createPath() {
        path.reset();
        path.moveTo(114, 156);
        float[] points = {68, 138, 19, 136, 21, 87, 8, 39, 56, 26, 97, -2, 123, 40, 163, 71, 131, 109};
        for (int i = 0; i < points.length; i += 2) {
            path.lineTo(points[i], points[i + 1]);
        }
        path.close();
        Matrix m = new Matrix();
        m.setRectToRect(new RectF(0, 0, 160, 160), clip, Matrix.ScaleToFit.CENTER);
        path.transform(m);
        transformedPath.set(path);
    }*/

    @Override
    protected void onDraw(Canvas canvas) {
        canvas.drawBitmap(blur, matrix, monoPaint);
        canvas.save();
        canvas.clipRect(clip);
//        canvas.drawPath(transformedPath, paint);
        canvas.drawBitmap(shapeMaskBitmap, pathMatrix, paint);
        canvas.restore();
//        canvas.drawPath(transformedPath, borderPaint);
        canvas.drawBitmap(shapeShadowBitmap, pathMatrix, borderPaint);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        detector.onTouchEvent(event);
        return true;
    }

    @Override
    public void onChange(Matrix matrix) {
//        path.transform(matrix, transformedPath);
        pathMatrix.set(matrix);
        invalidate();
    }

    Bitmap blur(Context ctx, Bitmap src, float radius) {
        Bitmap bitmap = src.copy(src.getConfig(), true);

        RenderScript renderScript = RenderScript.create(ctx);
        Allocation blurInput = Allocation.createFromBitmap(renderScript, src);
        Allocation blurOutput = Allocation.createFromBitmap(renderScript, bitmap);

        ScriptIntrinsicBlur blur = ScriptIntrinsicBlur.create(renderScript, Element.U8_4(renderScript));
        blur.setInput(blurInput);
        blur.setRadius(radius);
        blur.forEach(blurOutput);

        blurOutput.copyTo(bitmap);
        renderScript.destroy();
        return bitmap;
    }
}

我的输出是这样的:

Answer 1

如果您想要这样的效果，您尝试使用 PorterDuff.Mode.CLEAR 和 BlurMaskFilter 进行的操作将不起作用:

或者这个:

您必须使用 BitmapShader 和 ScriptIntrinsicBlur，请参阅此示例自定义 View:

class V extends View implements MatrixGestureDetector.OnMatrixChangeListener {
    Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    Paint monoPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    Paint borderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    Bitmap bitmap, blur;
    Matrix matrix = new Matrix();
    Matrix pathMatrix = new Matrix();
    Path path = new Path();
    Path transformedPath = new Path();
    MatrixGestureDetector detector;
    RectF clip = new RectF();

    public V(Context context) {
        super(context);
        bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.forest);
        blur = blur(context, bitmap, 8);
        ColorMatrix cm = new ColorMatrix();
        cm.setSaturation(0.25f);
        monoPaint.setColorFilter(new ColorMatrixColorFilter(cm));
        borderPaint.setStyle(Paint.Style.STROKE);
        borderPaint.setColor(0xccffffff);
        borderPaint.setStrokeWidth(4);
        detector = new MatrixGestureDetector(pathMatrix, this);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        Shader shader = new BitmapShader(bitmap, Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);
        RectF src = new RectF(0, 0, bitmap.getWidth(), bitmap.getHeight());
        RectF dst = new RectF(0, 0, w, h);
        matrix.setRectToRect(src, dst, Matrix.ScaleToFit.CENTER);
        shader.setLocalMatrix(matrix);
        paint.setShader(shader);
        matrix.mapRect(clip, src);
        createPath();
    }

    private void createPath() {
        path.reset();
        path.moveTo(114, 156);
        float[] points = {68, 138, 19, 136, 21, 87, 8, 39, 56, 26, 97, -2, 123, 40, 163, 71, 131, 109};
        for (int i = 0; i < points.length; i += 2) {
            path.lineTo(points[i], points[i + 1]);
        }
        path.close();
        Matrix m = new Matrix();
        m.setRectToRect(new RectF(0, 0, 160, 160), clip, Matrix.ScaleToFit.CENTER);
        path.transform(m);
        transformedPath.set(path);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        canvas.drawBitmap(blur, matrix, monoPaint);
        canvas.save();
        canvas.clipRect(clip);
        canvas.drawPath(transformedPath, paint);
        canvas.restore();
        canvas.drawPath(transformedPath, borderPaint);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        detector.onTouchEvent(event);
        return true;
    }

    @Override
    public void onChange(Matrix matrix) {
        path.transform(matrix, transformedPath);
        invalidate();
    }

    Bitmap blur(Context ctx, Bitmap src, float radius) {
        Bitmap bitmap = src.copy(src.getConfig(), true);

        RenderScript renderScript = RenderScript.create(ctx);
        Allocation blurInput = Allocation.createFromBitmap(renderScript, src);
        Allocation blurOutput = Allocation.createFromBitmap(renderScript, bitmap);

        ScriptIntrinsicBlur blur = ScriptIntrinsicBlur.create(renderScript, Element.U8_4(renderScript));
        blur.setInput(blurInput);
        blur.setRadius(radius);
        blur.forEach(blurOutput);

        blurOutput.copyTo(bitmap);
        renderScript.destroy();
        return bitmap;
    }
}

class MatrixGestureDetector {
    private static final String TAG = "MatrixGestureDetector";

    interface OnMatrixChangeListener {
        void onChange(Matrix matrix);
    }

    private int ptpIdx = 0;
    private Matrix mTempMatrix = new Matrix();
    private Matrix mMatrix;
    private OnMatrixChangeListener mListener;
    private float[] mSrc = new float[4];
    private float[] mDst = new float[4];
    private int mCount;

    public MatrixGestureDetector(Matrix matrix, MatrixGestureDetector.OnMatrixChangeListener listener) {
        if (matrix == null) throw new RuntimeException("Matrix cannot be null");
        if (listener == null) throw new RuntimeException("OnMatrixChangeListener cannot be null");
        mMatrix = matrix;
        mListener = listener;
    }

    public void onTouchEvent(MotionEvent event) {
        if (event.getPointerCount() > 2) {
            return;
        }

        int action = event.getActionMasked();
        int index = event.getActionIndex();

        switch (action) {
            case MotionEvent.ACTION_DOWN:
            case MotionEvent.ACTION_POINTER_DOWN:
                int idx = index * 2;
                mSrc[idx] = event.getX(index);
                mSrc[idx + 1] = event.getY(index);
                mCount++;
                ptpIdx = 0;
                break;

            case MotionEvent.ACTION_MOVE:
                for (int i = 0; i < mCount; i++) {
                    idx = ptpIdx + i * 2;
                    mDst[idx] = event.getX(i);
                    mDst[idx + 1] = event.getY(i);
                }
                mTempMatrix.setPolyToPoly(mSrc, ptpIdx, mDst, ptpIdx, mCount);
                mMatrix.postConcat(mTempMatrix);
                mListener.onChange(mMatrix);
                System.arraycopy(mDst, 0, mSrc, 0, mDst.length);
                break;

            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_POINTER_UP:
                if (event.getPointerId(index) == 0) ptpIdx = 2;
                mCount--;
                break;
        }
    }
}

编辑:当使用Bitmap而不是Path时，代码缩短了几行:

class V extends View implements MatrixGestureDetector.OnMatrixChangeListener {
    Paint monoPaint = new Paint();
    Paint srcInPaint = new Paint();
    Bitmap mask, maskShadow, bitmap, blur;
    Matrix matrix = new Matrix();
    Matrix maskMatrix = new Matrix();
    MatrixGestureDetector detector;
    RectF clip = new RectF();

    public V(Context context) {
        super(context);
        mask = BitmapFactory.decodeResource(context.getResources(), R.drawable.mask).extractAlpha();
        maskShadow = BitmapFactory.decodeResource(context.getResources(), R.drawable.mask_shadow);
        bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.forest);
        blur = blur(context, bitmap, 8);
        ColorMatrix cm = new ColorMatrix();
        cm.setSaturation(0.25f);
        monoPaint.setColorFilter(new ColorMatrixColorFilter(cm));
        srcInPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        detector = new MatrixGestureDetector(maskMatrix, this);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        RectF src = new RectF(0, 0, bitmap.getWidth(), bitmap.getHeight());
        RectF dst = new RectF(0, 0, w, h);
        matrix.setRectToRect(src, dst, Matrix.ScaleToFit.CENTER);
        matrix.mapRect(dst, src);

        src.set(0, 0, mask.getWidth(), mask.getHeight());
        maskMatrix.setRectToRect(src, dst, Matrix.ScaleToFit.CENTER);
        setupClip();
    }

    private void setupClip() {
        clip.set(0, 0, mask.getWidth(), mask.getHeight());
        maskMatrix.mapRect(clip);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        canvas.drawBitmap(blur, matrix, monoPaint);
        drawMask(canvas);
    }

    private void drawMask(Canvas canvas) {
        canvas.clipRect(clip);
        canvas.saveLayer(clip, null, 0);
        canvas.drawBitmap(mask, maskMatrix, null);
        canvas.drawBitmap(bitmap, matrix, srcInPaint);
        canvas.drawBitmap(maskShadow, maskMatrix, null);
        canvas.restore();
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        detector.onTouchEvent(event);
        return true;
    }

    @Override
    public void onChange(Matrix matrix) {
        setupClip();
        invalidate();
    }

    Bitmap blur(Context ctx, Bitmap src, float radius) {
        Bitmap bitmap = src.copy(src.getConfig(), true);

        RenderScript renderScript = RenderScript.create(ctx);
        Allocation blurInput = Allocation.createFromBitmap(renderScript, src);
        Allocation blurOutput = Allocation.createFromBitmap(renderScript, bitmap);

        ScriptIntrinsicBlur blur = ScriptIntrinsicBlur.create(renderScript, Element.U8_4(renderScript));
        blur.setInput(blurInput);
        blur.setRadius(radius);
        blur.forEach(blurOutput);

        blurOutput.copyTo(bitmap);
        renderScript.destroy();
        return bitmap;
    }
}

结果是这样的: