CODEWITHSUNDEEP
javaandroidmatrix
Oliver Dixon
Oliver Dixon

Reputation: 7405

How to re-scale bitmap to different screen sizes but keep it square?

Hello great people of stackoverflow.com, I have a stumbled upon a great difficulty in my code; that being not being able to resize my images in-line with my screen size.

I have an image that is SAY 65 pixels by 65 pixels but I want this image to be a certain percentage of the screen say 6% while keeping square.

My brain cannot process the mathematics for this (because it is slow :-( )

(_width & _height is the screen width and height)

What I've got so far is:

int width = bitmap.getWidth();
int height = bitmap.getHeight();

int avg_screen_dimension = (_width + _height) / 2;

float scaleWidth =
    ((float) width + (avg_screen_dimension - _width)) / width;
float scaleHeight =
    ((float) height + (avg_screen_dimension - _height)) / height;

// CREATE A MATRIX FOR THE MANIPULATION
Matrix matrix = new Matrix();

// RESIZE THE BIT MAP
matrix.postScale(scaleWidth, scaleHeight);

// RECREATE THE NEW BITMAP

Bitmap resizedBitmap =
    Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, false);

return resizedBitmap;

Any help would be greatly appreciated!

Upvotes: 0

Views: 1167

Answers (2)

Clive van Hilten
Clive van Hilten

Reputation: 881

(Just as an aside - in your pasted code, you've mixed up the variable names : you declare them as height and width but pass them as _width and _height

Upvotes: 0

duffymo
duffymo

Reputation: 308753

It's little more than simple algebra - no complex math needed.

You'll have to choose between fraction of the width or height of your screen, unless they're equal.

Let h = screen height, w = screen width, f = fraction of screen dimension, x = image size.

Then x = h*f. If you want to make it a fraction of the width, substitute w for h.

Upvotes: 2

Related Questions