Image re sizing

Question

I have an image which 330 px width and 472 px height . I want to plot this image inn to a bigger canvas which is 55% bigger than the current picture .. How can I fount the final image width and height .

Answer 1

This is more of a math problem than a programming problem. Let's work on it abstractly to get a formula:

Our variables are:

oldWidth, oldHeight, newWidth, newHeight, percentBigger

The original canvas size is

oldCanvasSize = oldWidth * oldHeight

The new canvas size is

newCanvasSize = newWidth + newHeight

55% bigger means 155% or 1.55 so

percent = (percentBigger + 1)

The new canvas is some percent of the old canvas so we have

newCanvasSize = percent * oldCanvasSize

or

newCanvasSize = (percentBigger + 1) * oldCanvasSize

I'll assume we want the proportions to stay the same so

oldWidth / oldHeight = newWidth / newHeight

By substitution and solving the above equations we get

newWidth = SquareRoot(percentBigger + 1) * oldWidth

newHeight = SquareRoot(percentBigger + 1) * oldHeight

I'll let the reader plug in the values.