Android：停止縮小圖像

Question

我試圖在視圖中繪製圖像，但嘗試維持原始圖像的縮放比例存在問題。基本上，我有一個小視圖，我想在視圖中顯示部分圖像。然後，意圖是在圖像上執行翻譯，以便在視圖中顯示不同的部分。

無論我嘗試什麼，圖像都會自動縮小以適合視圖或整個圖像可見。我試着玩了BitmapDrawable，ImageView和Layout的設置無濟於事。

任何人都知道一個很好的方法來實現這一目標？

Answer 1

這可能不會是最有效的方式，但如果你不打算太多，它會做的。 將它視爲一張spritesheet，使用Bitmap.createBitmap（位圖源，int x，int y，int width，int height）從原始位圖中獲取想要的部分作爲其自己的位圖，然後將其傳入。然後通過它而不是整個位圖，它只會與你想要顯示的部分一起工作。

Answer 2

聽起來就像你想要在一個較小的視圖內（像一個窗口一樣）有一個大的ImageView控件，然後在裏面移動ImageView控件，因此一次只能看到它的一部分。

不完全確定你會怎麼做，但很確定它可能與AbsoluteLayout和一些修補。

Answer 3

希望這段代碼有幫助。我在一個月前搜索了它。它爲更大的圖像滾動性能。這裏整個顯示大小被設置爲視圖的高度和寬度。你可以改變你的知道。也可以保持縮放控制。

public class LargeImageScroller extends Activity { 

// Physical display width and height. 
private static int displayWidth = 0; 
private static int displayHeight = 0; 

/** Called when the activity is first created. */ 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    // displayWidth and displayHeight will change depending on screen 
    // orientation. To get these dynamically, we should hook onSizeChanged(). 
    // This simple example uses only landscape mode, so it's ok to get them 
    // once on startup and use those values throughout. 
    Display display = ((WindowManager) 
      getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay(); 
    displayWidth = display.getWidth(); 
    displayHeight = display.getHeight(); 

    // SampleView constructor must be constructed last as it needs the 
    // displayWidth and displayHeight we just got. 
    setContentView(new SampleView(this)); 
} 

private static class SampleView extends View { 
    private static Bitmap bmLargeImage; //bitmap large enough to be scrolled 
    private static Rect displayRect = null; //rect we display to 
    private Rect scrollRect = null; //rect we scroll over our bitmap with 
    private int scrollRectX = 0; //current left location of scroll rect 
    private int scrollRectY = 0; //current top location of scroll rect 
    private float scrollByX = 0; //x amount to scroll by 
    private float scrollByY = 0; //y amount to scroll by 
    private float startX = 0; //track x from one ACTION_MOVE to the next 
    private float startY = 0; //track y from one ACTION_MOVE to the next 

    public SampleView(Context context) { 
      super(context); 

      // Destination rect for our main canvas draw. It never changes. 
      displayRect = new Rect(0, 0, displayWidth, displayHeight); 
      // Scroll rect: this will be used to 'scroll around' over the 
      // bitmap in memory. Initialize as above. 
      scrollRect = new Rect(0, 0, displayWidth, displayHeight); 

      // Load a large bitmap into an offscreen area of memory. 
      bmLargeImage = BitmapFactory.decodeResource(getResources(), 
       R.drawable.testlargeimage); 
    } 

    @Override 
    public boolean onTouchEvent(MotionEvent event) { 

      switch (event.getAction()) { 
       case MotionEvent.ACTION_DOWN: 
        // Remember our initial down event location. 
        startX = event.getRawX(); 
        startY = event.getRawY(); 
        break; 

       case MotionEvent.ACTION_MOVE: 
        float x = event.getRawX(); 
        float y = event.getRawY(); 
        // Calculate move update. This will happen many times 
        // during the course of a single movement gesture. 
        scrollByX = x - startX; //move update x increment 
        scrollByY = y - startY; //move update y increment 
        startX = x; //reset initial values to latest 
        startY = y; 
        invalidate(); //force a redraw 
        break; 
      } 
      return true; //done with this event so consume it 
    } 

    @Override 
    protected void onDraw(Canvas canvas) { 

      // Our move updates are calculated in ACTION_MOVE in the opposite direction 
      // from how we want to move the scroll rect. Think of this as dragging to 
      // the left being the same as sliding the scroll rect to the right. 
      int newScrollRectX = scrollRectX - (int)scrollByX; 
      int newScrollRectY = scrollRectY - (int)scrollByY; 

      // Don't scroll off the left or right edges of the bitmap. 
      if (newScrollRectX < 0) 
       newScrollRectX = 0; 
      else if (newScrollRectX > (bmLargeImage.getWidth() - displayWidth)) 
       newScrollRectX = (bmLargeImage.getWidth() - displayWidth); 

      // Don't scroll off the top or bottom edges of the bitmap. 
      if (newScrollRectY < 0) 
       newScrollRectY = 0; 
      else if (newScrollRectY > (bmLargeImage.getHeight() - displayHeight)) 
       newScrollRectY = (bmLargeImage.getHeight() - displayHeight); 

      // We have our updated scroll rect coordinates, set them and draw. 
      scrollRect.set(newScrollRectX, newScrollRectY, 
       newScrollRectX + displayWidth, newScrollRectY + displayHeight); 
      Paint paint = new Paint(); 
      canvas.drawBitmap(bmLargeImage, scrollRect, displayRect, paint); 

      // Reset current scroll coordinates to reflect the latest updates, 
      // so we can repeat this update process. 
      scrollRectX = newScrollRectX; 
      scrollRectY = newScrollRectY; 

    } 
} 
}