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```
```/*! IntegerScaling by Marat Tanalin | http://tanalin.com/en/projects/integer-scaling/ */

#![allow(non_snake_case)]

pub struct Ratios {
pub x : u32,
pub y : u32
}

/// Calculates an integer scaling ratio common for X/Y axes (square pixels).
pub fn calculateRatio(areaWidth : u32, areaHeight : u32,
imageWidth : u32, imageHeight : u32) -> u32
{
let (areaSize, imageSize);

if areaHeight * imageWidth < areaWidth * imageHeight {
areaSize  = areaHeight;
imageSize = imageHeight;
}
else {
areaSize  = areaWidth;
imageSize = imageWidth;
}

let mut ratio = areaSize / imageSize;

if ratio < 1 {
ratio = 1;
}

ratio
}

/// Calculates integer scaling ratios potentially different for X/Y axes
/// as a result of aspect-ratio correction (rectangular pixels).
pub fn calculateRatios(areaWidth : u32, areaHeight : u32,
imageWidth : u32, imageHeight : u32,
aspectX : f64, aspectY : f64) -> Ratios
{
if imageWidth as f64 * aspectY == imageHeight as f64 * aspectX {
let ratio = calculateRatio(areaWidth, areaHeight, imageWidth, imageHeight);

return Ratios {
x: ratio,
y: ratio
};
}

let maxRatioX        = areaWidth  / imageWidth;
let maxRatioY        = areaHeight / imageHeight;
let maxWidth         = imageWidth  * maxRatioX;
let maxHeight        = imageHeight * maxRatioY;
let maxWidthAspectY  = maxWidth  as f64 * aspectY;
let maxHeightAspectX = maxHeight as f64 * aspectX;

let mut ratioX : u32;
let mut ratioY : u32;

if maxWidthAspectY == maxHeightAspectX {
ratioX = maxRatioX;
ratioY = maxRatioY;
}
else {
let maxAspectLessThanTarget = maxWidthAspectY < maxHeightAspectX;

let (ratioA, maxSizeA, imageSizeB, aspectA, aspectB) : (u32, u32, u32, f64, f64);

if maxAspectLessThanTarget {
ratioA     = maxRatioX;
maxSizeA   = maxWidth;
imageSizeB = imageHeight;
aspectA    = aspectX;
aspectB    = aspectY;
}
else {
ratioA     = maxRatioY;
maxSizeA   = maxHeight;
imageSizeB = imageWidth;
aspectA    = aspectY;
aspectB    = aspectX;
}

let ratioBFract = maxSizeA as f64 * aspectB / aspectA / imageSizeB as f64;
let ratioBFloor = ratioBFract.floor();
let ratioBCeil  = ratioBFract.ceil();

let mut parFloor = ratioBFloor / ratioA as f64;
let mut parCeil  = ratioBCeil  / ratioA as f64;

if maxAspectLessThanTarget {
parFloor = 1.0 / parFloor;
parCeil  = 1.0 / parCeil;
}

let commonFactor = imageWidth as f64 * aspectY / aspectX / imageHeight as f64;
let errorFloor   = (1.0 - commonFactor * parFloor).abs();
let errorCeil    = (1.0 - commonFactor * parCeil).abs();

let ratioB : u32;

if (errorFloor - errorCeil).abs() < 0.001 {
ratioB = if (ratioA as f64 - ratioBFloor).abs() < (ratioA as f64 - ratioBCeil).abs()
{ratioBFloor as u32}
else
{ratioBCeil as u32};
}
else {
ratioB = if errorFloor < errorCeil
{ratioBFloor as u32}
else
{ratioBCeil as u32};
}

if maxAspectLessThanTarget {
ratioX = ratioA;
ratioY = ratioB;
}
else {
ratioX = ratioB;
ratioY = ratioA;
}
}

if ratioX < 1 {
ratioX = 1;
}

if ratioY < 1 {
ratioY = 1;
}

Ratios {
x: ratioX,
y: ratioY
}
}```