Black Screen when stretching Bitmap to fit with screen height

Question

I try to load the bitmap to a custom SurfaceView in my first image editor application. It will try to scale the image (up or down) to fit with the screen height (yeah, I know it is stupid function, but I am learning android as well). This is the code in the activity

private RelativeLayout topLayout; 
private CustomeSurfaceView customeSurfaceView; 

public void onCreate(Bundle onSaveBundle) {
    // initialize all the views
    ......

    // Scale image to screen
    Display display = getWindowManager().getDefaultDisplay();
    Point size = new Point();
    display.getSize(size);

    screenWidth = size.x;
    screenHeight = size.y;

    if (path != null && bmp == null) {
        bmp = AppUtils.loadBitmapFromPath(this, path);
    }

    Log.d(TAG, "Before scaled: " + bmp.getWidth() + " " + bmp.getHeight());

    int scaleHeight = screenHeight;
    int scaleWidth = (int) (((float) screenHeight / bmp.getHeight() * 1.0) * bmp.getWidth());

    Bitmap scaledBitmap = Bitmap.createScaledBitmap(bmp, scaleWidth, scaleHeight, false);

    if (scaledBitmap != bmp) {
        bmp.recycle();
    }

    Log.d(TAG, "After scaled: " + scaledBitmap.getWidth() + " " + scaledBitmap.getHeight());

    // Create the work space and load the bitmap
    customSurfaceView = new CustomeSurfaceView(this, scaledBitmap);
    topLayout.addView(customSurfaceView);

}

And this is the code of the SurfaceView

public class CustomeSurfaceView extends SurfaceView implements SurfaceHolder.Callback {

    private Bitmap mainImage; 
    int maxX;
    int maxY;

    private int scrollByX;
    private int scrollByY;
    private int maxLeft;
    private int maxRight;
    private int maxTop;
    private int maxBottom;
    private float downX, downY;
    private int totalX, totalY;
    private float currentXPos;
    private float currentYPos;
    private int screenHeight;
    private int screenWidth;

    public CustomeSurfaceView(Context context, Bitmap bitmap) {
        super(context);

        Display display = ((Activity) context).getWindowManager().getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);

        screenWidth = size.x;
        screenHeight = size.y;

        // set maximum scroll amount (based on center of image)
        maxX = (mainImage.getWidth() / 2) - (screenWidth / 2);
        maxY = (mainImage.getHeight() / 2) - (screenHeight / 2);

        // set scroll limits
        maxLeft = (maxX * -1);
        maxRight = maxX;
        maxTop = (maxY * -1);
        maxBottom = maxY;

        this.mainImage = bitmap;
        setWillNotDraw(false);
        getHolder().addCallback(this);
        .....
    }

    /**
     *
     * @param canvas
     */
    @Override
    public void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        canvas.drawBitmap(mainImage, maxLeft, 0, null);
    }
}

If I try to scale up, say from 1280 * 800 to 2048 * 1280, then SurfaceView happily load my scaled bitmap

enter image description here

However, if I try to scale down from 3264 * 1840 to 2270 * 1280, I end up with a black screen

enter image description here

My questions are :

What did I do wrong here?
If this is not a good way to load the image (for example, can lead to out of memory), what can I do to optimize it? The whole image needs to be loaded so user can scroll, edit on that image

score 1 · Answer 1 · edited May 23 '17 at 10:31

1

When ever working with bitmap or any type of images on Android the one of the biggest risk is the OutOfMemoryError which might not come when you are testing and later on appear. Due to lack of Memory avaialable in Android device.

The problem have been discused many times on SO and on Android Page Reference

My personal favourite way to tackle image problem is by using ImageLoader. Try going through ImageLoader, its the best.

PS: My app loads around 50-100 pics to ListView. Never it crashes.

edited May 23 '17 at 10:31

Community

1
1

answered Mar 03 '14 at 18:30

MDMalik

3,951
2
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Please see my edited question. For the `ListView` loading, I used `Android Image Universal Loader` which is pretty awesome already. I just need to load the full image to the screen in a efficient way since user has to do everything with the whole image – Thai Tran Mar 04 '14 at 03:53

Black Screen when stretching Bitmap to fit with screen height

1 Answers1