Question

I would like to know if I can make an image opaque if set in image view or set as background of relative layout.

How can I make image opaque using image view or relative layout for setting the image dynamically or Is there any other option to set image and its opacity dynamically?

I also want the same image to rotate in both directions and also can zoomin and zoomout to anylevel.

Thanks in advance

Answer 1

Working and tested code below.

private void applyTransformToImageView(int code)
{
    Bitmap bmpOriginal = BitmapFactory.decodeResource(this.getResources(), R.drawable.image2);
    Bitmap bmResult = Bitmap.createBitmap(bmpOriginal.getWidth(), bmpOriginal.getHeight(), Bitmap.Config.ARGB_8888);
    Canvas tempCanvas = new Canvas(bmResult); 

    switch (code)
    {
        case CHANGE_TRANSPARENCY:
        {
            Paint alphaPaint = new Paint();
            alphaPaint.setAlpha(128);
            tempCanvas.drawBitmap(bmpOriginal, 0, 0, alphaPaint);               
        }
        break;

        case ROTATE:
        {
            tempCanvas.rotate(90, bmpOriginal.getWidth()/2, bmpOriginal.getHeight()/2);
            tempCanvas.drawBitmap(bmpOriginal, 0, 0, null);
        }
        break;

        case ZOOM_IN:
        {               
            Rect zoomRegion = new Rect();
            zoomRegion.left = 0;
            zoomRegion.top = 0;
            zoomRegion.right = bmpOriginal.getWidth()/2;
            zoomRegion.bottom = bmpOriginal.getHeight()/2;

            Rect display = new Rect();
            display.left = 0;
            display.top = 0;
            display.right = bmpOriginal.getWidth();
            display.bottom = bmpOriginal.getHeight();

            tempCanvas.drawBitmap(bmpOriginal, zoomRegion, display, null);
        }
        break;

        default:
    }

    mImageView.setImageBitmap(bmResult);            
}

• sets alpha to semi-transparent – value 128
• rotates around original image center for 90 degrees
• zoom into top left quadrant of the original image