从图像视图中捏和图像并获得它的特定部分？

Posted 2023-02-25

【中文标题】从图像视图中捏和图像并获得它的特定部分？

【英文标题】：pinch and Image from Image View and get particular part of it?

【发布时间】：2014-06-12 08:19:38

【问题描述】：

我正在开发一个安卓应用程序。图像视图中有一个图像。我想在它上面添加捏和拖动功能。我想在这个视图上放置圆形图像视图。并选择出现在这个视图 android 中的特定区域。我尝试了很多例子，但都没有成功。

public class ImageCropScreen extends Activity 
ImageView cropImage;
ImageView imageUser;
@Override
protected void onCreate(Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.image_crop_screen);

imageUser = (ImageView)findViewById(R.id.imageUser);
    Touch img = new Touch(this);
    img.setImageURI(Uri.parse(GetApplicationContext.getApplicationInstance().getImagePath()));
    img.setMaxZoom(4f);
    setContentView(img);

触摸类代码：-

公共类 Touch 扩展 ImageView

Matrix matrix;

// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;

// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 3f;
float[] m;

int viewWidth, viewHeight;
static final int CLICK = 3;
float saveScale = 1f;
protected float origWidth, origHeight;
int oldMeasuredWidth, oldMeasuredHeight;

ScaleGestureDetector mScaleDetector;

Context context;

public Touch(Context context) 
    super(context);
    sharedConstructing(context);


public Touch(Context context, AttributeSet attrs) 
    super(context, attrs);
    sharedConstructing(context);


private void sharedConstructing(Context context) 
    super.setClickable(true);
    this.context = context;
    mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
    matrix = new Matrix();
    m = new float[9];
    setImageMatrix(matrix);
    setScaleType(ScaleType.MATRIX);

    setOnTouchListener(new OnTouchListener() 

        @Override
        public boolean onTouch(View v, MotionEvent event) 
            mScaleDetector.onTouchEvent(event);
            PointF curr = new PointF(event.getX(), event.getY());

            switch (event.getAction()) 
            case MotionEvent.ACTION_DOWN:
                last.set(curr);
                start.set(last);
                mode = DRAG;
                break;

            case MotionEvent.ACTION_MOVE:
                if (mode == DRAG) 
                    float deltaX = curr.x - last.x;
                    float deltaY = curr.y - last.y;
                    float fixTransX = getFixDragTrans(deltaX, viewWidth,
                            origWidth * saveScale);
                    float fixTransY = getFixDragTrans(deltaY, viewHeight,
                            origHeight * saveScale);
                    matrix.postTranslate(fixTransX, fixTransY);
                    fixTrans();
                    last.set(curr.x, curr.y);
                
                break;

            case MotionEvent.ACTION_UP:
                mode = NONE;
                int xDiff = (int) Math.abs(curr.x - start.x);
                int yDiff = (int) Math.abs(curr.y - start.y);
                if (xDiff < CLICK && yDiff < CLICK)
                    performClick();
                break;

            case MotionEvent.ACTION_POINTER_UP:
                mode = NONE;
                break;
            

            setImageMatrix(matrix);
            invalidate();
            return true; // indicate event was handled
        

    );


public void setMaxZoom(float x) 
    maxScale = x;


private class ScaleListener extends
        ScaleGestureDetector.SimpleOnScaleGestureListener 
    @Override
    public boolean onScaleBegin(ScaleGestureDetector detector) 
        mode = ZOOM;
        return true;
    

    @Override
    public boolean onScale(ScaleGestureDetector detector) 
        float mScaleFactor = detector.getScaleFactor();
        float origScale = saveScale;
        saveScale *= mScaleFactor;
        if (saveScale > maxScale) 
            saveScale = maxScale;
            mScaleFactor = maxScale / origScale;
         else if (saveScale < minScale) 
            saveScale = minScale;
            mScaleFactor = minScale / origScale;
        

        if (origWidth * saveScale <= viewWidth
                || origHeight * saveScale <= viewHeight)
            matrix.postScale(mScaleFactor, mScaleFactor, viewWidth / 2,
                    viewHeight / 2);
        else
            matrix.postScale(mScaleFactor, mScaleFactor,
                    detector.getFocusX(), detector.getFocusY());

        fixTrans();
        return true;
    


void fixTrans() 
    matrix.getValues(m);
    float transX = m[Matrix.MTRANS_X];
    float transY = m[Matrix.MTRANS_Y];

    float fixTransX = getFixTrans(transX, viewWidth, origWidth * saveScale);
    float fixTransY = getFixTrans(transY, viewHeight, origHeight
            * saveScale);

    if (fixTransX != 0 || fixTransY != 0)
        matrix.postTranslate(fixTransX, fixTransY);


float getFixTrans(float trans, float viewSize, float contentSize) 
    float minTrans, maxTrans;

    if (contentSize <= viewSize) 
        minTrans = 0;
        maxTrans = viewSize - contentSize;
     else 
        minTrans = viewSize - contentSize;
        maxTrans = 0;
    

    if (trans < minTrans)
        return -trans + minTrans;
    if (trans > maxTrans)
        return -trans + maxTrans;
    return 0;


float getFixDragTrans(float delta, float viewSize, float contentSize) 
    if (contentSize <= viewSize) 
        return 0;
    
    return delta;


@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) 
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    viewWidth = MeasureSpec.getSize(widthMeasureSpec);
    viewHeight = MeasureSpec.getSize(heightMeasureSpec);

    //
    // Rescales image on rotation
    //
    if (oldMeasuredHeight == viewWidth && oldMeasuredHeight == viewHeight
            || viewWidth == 0 || viewHeight == 0)
        return;
    oldMeasuredHeight = viewHeight;
    oldMeasuredWidth = viewWidth;

    if (saveScale == 1) 
        // Fit to screen.
        float scale;

        Drawable drawable = getDrawable();
        if (drawable == null || drawable.getIntrinsicWidth() == 0
                || drawable.getIntrinsicHeight() == 0)
            return;
        int bmWidth = drawable.getIntrinsicWidth();
        int bmHeight = drawable.getIntrinsicHeight();

        Log.d("bmSize", "bmWidth: " + bmWidth + " bmHeight : " + bmHeight);

        float scaleX = (float) viewWidth / (float) bmWidth;
        float scaleY = (float) viewHeight / (float) bmHeight;
        scale = Math.min(scaleX, scaleY);
        matrix.setScale(scale, scale);

        // Center the image
        float redundantYSpace = (float) viewHeight
                - (scale * (float) bmHeight);
        float redundantXSpace = (float) viewWidth
                - (scale * (float) bmWidth);
        redundantYSpace /= (float) 2;
        redundantXSpace /= (float) 2;

        matrix.postTranslate(redundantXSpace, redundantYSpace);

        origWidth = viewWidth - 2 * redundantXSpace;
        origHeight = viewHeight - 2 * redundantYSpace;
        setImageMatrix(matrix);
    
    fixTrans();

【问题讨论】：

仔细阅读 Matrix 文档以及如何将它与 Canvas 对象一起使用

向我们展示您已经尝试过什么？

@Kanak sony 我添加了代码

我们是否应该运行您的代码来检查哪些工作正常，哪些不工作？

你可以查看我的答案。我已经添加了 belove..它有你需要的功能..

【参考方案1】：

您可以使用以下自定义 imageView..这将满足您所需的所有功能

CustomImageVieew