Android: How to overlay a bitmap and draw over a bitmap?

by

I can’t believe no one has answered this yet! A rare occurrence on SO!

1

The question doesn’t quite make sense to me. But I’ll give it a stab.
If you’re asking about direct drawing to a canvas (polygons, shading, text etc…) vs. loading a bitmap and blitting it onto the canvas that would depend on the complexity of your drawing.
As the drawing gets more complex the CPU time required will increase accordingly.
However, blitting a bitmap onto a canvas will always be a constant time which is proportional to the size of the bitmap.

2

Without knowing what “something” is how can I show you how to do it?
You should be able to figure out #2 from the answer for #3.

3

Assumptions:

  • bmp1 is larger than bmp2.

  • You want them both overlaid from the top left corner.

        private Bitmap overlay(Bitmap bmp1, Bitmap bmp2) {
        Bitmap bmOverlay = Bitmap.createBitmap(bmp1.getWidth(), bmp1.getHeight(), bmp1.getConfig());
        Canvas canvas = new Canvas(bmOverlay);
        canvas.drawBitmap(bmp1, new Matrix(), null);
        canvas.drawBitmap(bmp2, new Matrix(), null);
        return bmOverlay;
    }

More Related Contents:

  1. Creating an empty bitmap and drawing though canvas in Android
  2. Save bitmap to location
  3. Strange OutOfMemory issue while loading an image to a Bitmap object
  4. Convert view to bitmap on Android
  5. converting a canvas into bitmap image in android
  6. How to downsample images correctly?
  7. How to convert Views to bitmaps?
  8. Failed binder transaction when putting an bitmap dynamically in a widget
  9. Bitmaps in Android
  10. Android take screen shot programmatically
  11. Converting bitmap to byteArray android
  12. How to cache bitmaps into native memory
  13. How to change Bitmap image color in android?
  14. Overlay images onto Camera preview SurfaceView
  15. Android: how to convert whole ImageView to Bitmap?
  16. How can I tell if a closed path contains a given point?
  17. Android 2.1 View’s getDrawingCache() method always returns null
  18. Take a screenshot using MediaProjection
  19. How to make an image fit into a circular frame in android
  20. Rotate zoom drag image in android imageview
  21. Suggestions to avoid bitmap Out of Memory error
  22. Using drawable resources
  23. How does Bitmap allocation work on Oreo, and how to investigate their memory?
  24. how to change the color of certain pixels in bitmap android
  25. BitmapFactory.decodeStream out of memory despite using reduced sample size
  26. Android – Reduce image file size
  27. Resize Drawable in Android
  28. Android SkImageDecoder::Factory returned null Error
  29. How to pass bitmap from one activity to another
  30. Can I draw outside the bounds of an Android Canvas

Leave a Comment