如何在Android中对图像应用缩放、拖动和旋转[关闭]

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【中文标题】如何在Android中对图像应用缩放、拖动和旋转[关闭]【英文标题】:How to apply zoom, drag and rotation to an image in Android [closed] 【发布时间】:2011-09-28 12:44:00 【问题描述】:

有人可以告诉我在 android 应用程序中应用缩放、拖动和旋转图像的教程吗?

【问题讨论】:

【参考方案1】:

试试下面的代码,它对我有用。

    float[] lastEvent = null;
    float d = 0f;
    float newRot = 0f;
    private Matrix matrix = new Matrix();
    private Matrix savedMatrix = new Matrix();
    public static String fileNAME;
    public static int framePos = 0;

    private float scale = 0;
    private float newDist = 0;

    // Fields
    private String TAG = this.getClass().getSimpleName();

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

    // Remember some things for zooming
    private PointF start = new PointF();
    private PointF mid = new PointF();
    float oldDist = 1f;

     public boolean onTouch(View v, MotionEvent event) 
                ImageView view = (ImageView) v;

                // Handle touch events here...
                switch (event.getAction() & MotionEvent.ACTION_MASK) 
                case MotionEvent.ACTION_DOWN:
                    savedMatrix.set(matrix);
                    start.set(event.getX(), event.getY());
                    mode = DRAG;
                    lastEvent = null;
                    break;
                case MotionEvent.ACTION_POINTER_DOWN:
                    oldDist = spacing(event);
                    if (oldDist > 10f) 
                        savedMatrix.set(matrix);
                        midPoint(mid, event);
                        mode = ZOOM;
                    
                    lastEvent = new float[4];
                    lastEvent[0] = event.getX(0);
                    lastEvent[1] = event.getX(1);
                    lastEvent[2] = event.getY(0);
                    lastEvent[3] = event.getY(1);
                    d = rotation(event);
                    break;
                case MotionEvent.ACTION_UP:
                case MotionEvent.ACTION_POINTER_UP:
                    mode = NONE;
                    lastEvent = null;
                    break;
                case MotionEvent.ACTION_MOVE:
                    if (mode == DRAG) 
                        // ...
                        matrix.set(savedMatrix);
                        matrix.postTranslate(event.getX() - start.x, event.getY()
                                - start.y);
                     else if (mode == ZOOM && event.getPointerCount() == 2) 
                        float newDist = spacing(event);
                        matrix.set(savedMatrix);
                        if (newDist > 10f) 
                            float scale = newDist / oldDist;
                            matrix.postScale(scale, scale, mid.x, mid.y);
                        
                        if (lastEvent != null) 
                            newRot = rotation(event);
                            float r = newRot - d;
                            matrix.postRotate(r, view.getMeasuredWidth() / 2,
                                    view.getMeasuredHeight() / 2);
                        
                    
                    break;
                

                view.setImageMatrix(matrix);

                return true;
            

//用于在多点触控时旋转图像。

private float rotation(MotionEvent event) 
        double delta_x = (event.getX(0) - event.getX(1));
        double delta_y = (event.getY(0) - event.getY(1));
        double radians = Math.atan2(delta_y, delta_x);

        return (float) Math.toDegrees(radians);
    
private float spacing(MotionEvent event) 
        float x = event.getX(0) - event.getX(1);
        float y = event.getY(0) - event.getY(1);
        return FloatMath.sqrt(x * x + y * y);
    

private void midPoint(PointF point, MotionEvent event) 
        float x = event.getX(0) + event.getX(1);
        float y = event.getY(0) + event.getY(1);
        point.set(x / 2, y / 2);
    

【讨论】:

出色的工作人员!像任何东西一样工作。 它工作得很好..它还支持旋转..哇...谢谢@kyogs【参考方案2】:

这里是捏缩放和平移的完整代码(Touch.java 有一些可以实际使用的修改)

public class Touch implements OnTouchListener   

 // These matrices will be used to move and zoom image  
public static Matrix matrix = new Matrix();  
public static Matrix savedMatrix = new 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;
private static final float MAX_ZOOM = (float) 3;
private static final float MIN_ZOOM = 1;  
 int mode = NONE;  

 // Remember some things for zooming  
 PointF start = new PointF();  
 PointF mid = new PointF();  
 float oldDist = 1f;  

 int width,height;

 @Override  
 public boolean onTouch(View v, MotionEvent event) 


  ImageView view = (ImageView) v;
  Rect bounds = view.getDrawable().getBounds();

  width = bounds.right - bounds.left;
  height = bounds.bottom - bounds.top;
  // Dump touch event to log  
  dumpEvent(event);  

  // Handle touch events here...  
  switch (event.getAction() & MotionEvent.ACTION_MASK)   
  case MotionEvent.ACTION_DOWN:  
   savedMatrix.set(matrix);  
   start.set(event.getX(), event.getY());  
   mode = DRAG;  
   break;  
  case MotionEvent.ACTION_POINTER_DOWN:  
   oldDist = spacing(event);  
   if (oldDist > 10f)   
    savedMatrix.set(matrix);  
    midPoint(mid, event);  
    mode = ZOOM;  
     
   break;  
  case MotionEvent.ACTION_UP:  
  case MotionEvent.ACTION_POINTER_UP:  
   mode = NONE;  
   break;  
  case MotionEvent.ACTION_MOVE:  
   if (mode == DRAG)   
    // ...      
    matrix.set(savedMatrix);  
    matrix.postTranslate(event.getX() - start.x, event.getY() - start.y);      
    else if (mode == ZOOM)   
    float newDist = spacing(event);  
    if (newDist > 10f)   
     matrix.set(savedMatrix);  
     float scale = newDist / oldDist;  
     matrix.postScale(scale, scale, mid.x, mid.y);  
      
     
   break;  
    
//----------------------------------------------------
  limitZoom(matrix);
  limitDrag( matrix);
//----------------------------------------------------  
  view.setImageMatrix(matrix);  
  return true; // indicate event was handled  
   

 /** Show an event in the LogCat view, for debugging */  
 private void dumpEvent(MotionEvent event)   
  String names[] =  "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE",  
    "POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" ;  
  StringBuilder sb = new StringBuilder();  
  int action = event.getAction();  
  int actionCode = action & MotionEvent.ACTION_MASK;  
  sb.append("event ACTION_").append(names[actionCode]);  
  if (actionCode == MotionEvent.ACTION_POINTER_DOWN  
    || actionCode == MotionEvent.ACTION_POINTER_UP)   
   sb.append("(pid ").append(  
     action >> MotionEvent.ACTION_POINTER_ID_SHIFT);  
   sb.append(")");  
    
  sb.append("[");  
  for (int i = 0; i < event.getPointerCount(); i++)   
   sb.append("#").append(i);  
   sb.append("(pid ").append(event.getPointerId(i));  
   sb.append(")=").append((int) event.getX(i));  
   sb.append(",").append((int) event.getY(i));  
   if (i + 1 < event.getPointerCount())  
    sb.append(";");  
    
  sb.append("]");  
   

 /** Determine the space between the first two fingers */  
 private float spacing(MotionEvent event)   
  float x = event.getX(0) - event.getX(1);  
  float y = event.getY(0) - event.getY(1);  
  return FloatMath.sqrt(x * x + y * y);  
   

 /** Calculate the mid point of the first two fingers */  
 private void midPoint(PointF point, MotionEvent event)   
  float x = event.getX(0) + event.getX(1);  
  float y = event.getY(0) + event.getY(1);  
  point.set(x / 2, y / 2);  
   

 private void limitZoom(Matrix m) 

        float[] values = new float[9];
        m.getValues(values);
        float scaleX = values[Matrix.MSCALE_X];
        float scaleY = values[Matrix.MSCALE_Y];
        if(scaleX > MAX_ZOOM) 
            scaleX = MAX_ZOOM;
         else if(scaleX < MIN_ZOOM) 
            scaleX = MIN_ZOOM;
        

        if(scaleY > MAX_ZOOM) 
            scaleY = MAX_ZOOM;
         else if(scaleY < MIN_ZOOM) 
            scaleY = MIN_ZOOM;
        

        values[Matrix.MSCALE_X] = scaleX;
        values[Matrix.MSCALE_Y] = scaleY; 
        m.setValues(values);
    


 private void limitDrag(Matrix m) 

        float[] values = new float[9];
        m.getValues(values);
        float transX = values[Matrix.MTRANS_X];
        float transY = values[Matrix.MTRANS_Y];
        float scaleX = values[Matrix.MSCALE_X];
        float scaleY = values[Matrix.MSCALE_Y];
//--- limit moving to left ---
        float minX = (-width + 0) * (scaleX-1); 
        float minY = (-height + 0) * (scaleY-1);
//--- limit moving to right ---     
        float maxX=minX+width*(scaleX-1);
        float maxY=minY+height*(scaleY-1);
        if(transX>maxX)transX = maxX;
        if(transX<minX)transX = minX;
        if(transY>maxY)transY = maxY;
        if(transY<minY)transY = minY;
        values[Matrix.MTRANS_X] = transX;
        values[Matrix.MTRANS_Y] = transY; 
        m.setValues(values);
    


【讨论】:

【参考方案3】:

检查这些可能对您有帮助 Rotate zoom drag image in android imageview

zooming and dragging images using matrix in android

【讨论】:

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