How to calculate the same position on different bitmaps?

Question

I have 2 photos, one is size 300x300

and the other is 1200x1200

. I have drawn one text at a position A = (50, 40)

in the image 300x300

.

How can I calculate the same A position in the image 1200x1200

?

UPDATE 2:

IF size is not round (e.g. 523 x 412 ...) - x, y after multiplication will deviate

+3

Thanh le May 20 '15 at 2:53

2 answers

Amit K. Saha · Answer 1 · 2015-05-20T03:53:05+0000

you can go with relative position calculation as follows.

AAx = (50/300)*1200; 

AAy = (50/300)*1200;

so your new position will be AA = (200,200)

Kling klang · Answer 2 · 2015-05-20T04:38:38+0000

The scaling factor for x and y is 1200/300 = 4

.
Then just multiply x and y by 4

(your scaling factor).

int scaleFactor = 1200 / 300;
int newX = oldX * scaleFactor;
int newY = oldY * scaleFactor;

So, given that oldX = 50 and oldY = 40, the expectex values for newX and newY are 200 and 160, respectively.