Funzione di zoom e trascinamento in SurfaceView

Question

Sto provando a creare un SurfaceView che può essere ingrandito e trascinato. Implementa un flusso di immagini HTTP che attinge direttamente nella tela

Ho provato il seguente codice e funziona un po '... ma mi dà problemi nei confini. Non ho idea del motivo per cui. Qualsiasi aiuto?

flusso completa:

immagine ingrandita:

Nella seconda immagine si possono vedere più righe verdi che non ha bisogno di essere lì.

Questa è la classe che gestisce questo flusso:

import android.content.Context; 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 
import android.graphics.Canvas; 
import android.graphics.Paint; 
import android.graphics.Rect; 
import android.graphics.RectF; 
import android.graphics.drawable.BitmapDrawable; 
import android.graphics.drawable.Drawable; 
import android.util.AttributeSet; 
import android.view.Display; 
import android.view.MotionEvent; 
import android.view.ScaleGestureDetector; 
import android.view.SurfaceView; 
import android.view.WindowManager; 

/** 
* Created by fil on 07/12/15. 
*/ 
public class ZoomSurfaceView extends SurfaceView { 
    //These two constants specify the minimum and maximum zoom 
    private static float MIN_ZOOM = 1f; 
    private static float MAX_ZOOM = 5f; 

    private float scaleFactor = 1.f; 
    private ScaleGestureDetector detector; 

    //These constants specify the mode that we're in 
    private static int NONE = 0; 
    private static int DRAG = 1; 
    private static int ZOOM = 2; 

    private boolean dragged = false; 
    private float displayWidth; 
    private float displayHeight; 

    private int mode; 

    //These two variables keep track of the X and Y coordinate of the finger when it first 
    //touches the screen 
    private float startX = 0f; 
    private float startY = 0f; 

    //These two variables keep track of the amount we need to translate the canvas along the X 
    //and the Y coordinate 
    private float translateX = 0f; 
    private float translateY = 0f; 

    //These two variables keep track of the amount we translated the X and Y coordinates, the last time we 
    //panned. 
    private float previousTranslateX = 0f; 
    private float previousTranslateY = 0f; 

    private final Paint p = new Paint(); 

    private void init(Context context){ 
     detector = new ScaleGestureDetector(getContext(), new ScaleListener()); 
     WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE); 
     Display display = wm.getDefaultDisplay(); 

     displayWidth = display.getWidth(); 
     displayHeight = display.getHeight(); 
    } 

    public ZoomSurfaceView(Context context) { 
     super(context); 
     init(context); 
    } 

    public ZoomSurfaceView(Context context, AttributeSet attrs) { 
     super(context, attrs); 
     init(context); 
    } 

    public ZoomSurfaceView(Context context, AttributeSet attrs, int defStyleAttr) { 
     super(context, attrs, defStyleAttr); 
     init(context); 
    } 

    public ZoomSurfaceView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { 
     super(context, attrs, defStyleAttr, defStyleRes); 
     init(context); 
    } 

    public void resetZoom() { 

    } 

    public void drawBitmap(Canvas canvas, Bitmap b, Rect rect){ 

     canvas.save(); 

     //If translateX times -1 is lesser than zero, letfs set it to zero. This takes care of the left bound 
     if((translateX * -1) > (scaleFactor - 1) * displayWidth) 
     { 
      translateX = (1 - scaleFactor) * displayWidth; 
     } 

     if(translateY * -1 > (scaleFactor - 1) * displayHeight) 
     { 
      translateY = (1 - scaleFactor) * displayHeight; 
     } 

     //We need to divide by the scale factor here, otherwise we end up with excessive panning based on our zoom level 
     //because the translation amount also gets scaled according to how much we've zoomed into the canvas. 
     canvas.translate(translateX/scaleFactor, translateY/scaleFactor); 

     //We're going to scale the X and Y coordinates by the same amount 
     canvas.scale(scaleFactor, scaleFactor); 

     canvas.drawBitmap(b, null, rect, p); 

     /* The rest of your canvas-drawing code */ 
     canvas.restore(); 
    } 

    private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener 
    { 
     @Override 
     public boolean onScale(ScaleGestureDetector detector) 
     { 
      scaleFactor *= detector.getScaleFactor(); 
      scaleFactor = Math.max(MIN_ZOOM, Math.min(scaleFactor, MAX_ZOOM)); 
      return true; 
     } 
    } 

    @Override 
    public boolean onTouchEvent(MotionEvent event) 
    { 
     switch (event.getAction() & MotionEvent.ACTION_MASK) 
     { 
      case MotionEvent.ACTION_DOWN: 
       mode = DRAG; 

       //We assign the current X and Y coordinate of the finger to startX and startY minus the previously translated 
       //amount for each coordinates This works even when we are translating the first time because the initial 
       //values for these two variables is zero. 
       startX = event.getX() - previousTranslateX; 
       startY = event.getY() - previousTranslateY; 
       break; 

      case MotionEvent.ACTION_MOVE: 
       translateX = event.getX() - startX; 
       translateY = event.getY() - startY; 

       //We cannot use startX and startY directly because we have adjusted their values using the previous translation values. 
       //This is why we need to add those values to startX and startY so that we can get the actual coordinates of the finger. 
       double distance = Math.sqrt(Math.pow(event.getX() - (startX + previousTranslateX), 2) + 
         Math.pow(event.getY() - (startY + previousTranslateY), 2)); 

       if(distance > 0) 
       { 
        dragged = true; 
        distance *= scaleFactor; 
       } 
       break; 

      case MotionEvent.ACTION_POINTER_DOWN: 
       break; 

      case MotionEvent.ACTION_UP: 
       mode = NONE; 
       dragged = false; 

       //All fingers went up, so letfs save the value of translateX and translateY into previousTranslateX and 
       //previousTranslate 
       previousTranslateX = translateX; 
       previousTranslateY = translateY; 
       break; 

      case MotionEvent.ACTION_POINTER_UP: 
       mode = DRAG; 

       //This is not strictly necessary; we save the value of translateX and translateY into previousTranslateX 
       //and previousTranslateY when the second finger goes up 
       previousTranslateX = translateX; 
       previousTranslateY = translateY; 
       break; 
     } 

     detector.onTouchEvent(event); 

     //We redraw the canvas only in the following cases: 
     // 
     // o The mode is ZOOM 
     // OR 
     // o The mode is DRAG and the scale factor is not equal to 1 (meaning we have zoomed) and dragged is 
     // set to true (meaning the finger has actually moved) 
     if ((mode == DRAG && scaleFactor != 1f && dragged) || mode == ZOOM) 
     { 
      invalidate(); 
     } 

     return true; 
    } 
} 

Il codice per aggiungere i fotogrammi in superficie è il seguente:

if (!b.isRecycled()){ 
    try { 
     Rect rect = new Rect(0, 0, frame.getWidth(), frame.getHeight()); 
     Canvas canvas = frame.getHolder().lockCanvas(); 
     synchronized (frame.getHolder()) { 
      if (!b.isRecycled()) { 
       frame.drawBitmap(canvas, b, rect); 
       b.recycle(); 
      } 
     } 
     frame.getHolder().unlockCanvasAndPost(canvas); 
    } catch (java.lang.RuntimeException exc){ 
     Dbg.d("ERROR", exc); 
    } 
    lastBitmap = b; 
} 

Answer 1

Il codice che hai postato è incompleto così la sua difficile dì qual è il problema Ho fatto cadere il tuo codice in un rapido progetto dimostrativo e non ho visto alcun problema con i bordi.

Basta guardare gli screenshot: qualche possibilità che i dati delle immagini siano in qualche modo avvolgenti? Il secondo screenshot sembra che il bordo inferiore sia disegnato nella parte superiore dell'immagine. Ancora difficile da dire senza codice riproducibile.

potrebbe provare a ridipingere il fondo prima di ridisegnare la bitmap

canvas.drawRect(rect, backgroundPaint); 
frame.drawBitmap(canvas, b, rect);