Zoom- und Ziehfunktion in SurfaceView

Question

Ich versuche, eine SurfaceView zu erstellen, die gezoomt und gezogen werden kann. Es implementiert einen HTTP-Bild-Stream, der direkt in die Zeichenfläche

Ich habe den folgenden Code versucht und es funktioniert irgendwie ... aber es gibt mir Probleme in den Grenzen. Keine Ahnung warum. Irgendeine Hilfe?

Vollstrom:

gezoomte Bild:

Im zweiten Bild können Sie mehrere grüne Linien sehen, die nicht da sein muss.

Dies ist die Klasse, die diesen Strom behandelt:

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; 
    } 
} 

Der Code zum Hinzufügen der Rahmen auf der Oberfläche ist die folgende:

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

Der Code, den Sie unvollständig so seine schwer gepostet Sag, was das Problem ist. Ich habe Ihren Code in ein schnelles Demo-Projekt eingefügt und sah keine Probleme mit den Rahmen.

Nur mit Blick auf die Screenshots: eine Chance, dass Ihre Bilddaten irgendwie wickeln? Der zweite Screenshot sieht so aus, als ob der untere Rand oben im Bild gezeichnet wird. Wiederum ohne reproduzierbaren Code schwer zu sagen.

könnten versuchen, den Hintergrund neu zu streichen, bevor die Bitmap neu gezeichnet

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