Resize with lwip

lwip.utils.js

// resolution is [width, height] structure

// Evaluate resolution by width (height doesn't matter, just keep it proportional)
function evalResolutionByWidth(requiredWidth, actualResolution) {
  var actualWidth = actualResolution[0];
  var actualHeight = actualResolution[1];
  if (actualWidth > requiredWidth) {
    var scale = actualWidth / requiredWidth;
    return [requiredWidth, Math.round(actualHeight / scale)];
  } else {
    return actualResolution;
  }
}

// Evaluate resolution by height (width doesn't matter, just keep it proportional)
function evalResolutionByHeight(requiredHeight, actualResolution) {
  var actualWidth = actualResolution[0];
  var actualHeight = actualResolution[1];
  if (actualHeight > requiredHeight) {
    var scale = actualHeight / requiredHeight;
    return [Math.round(actualWidth / scale), requiredHeight];
  } else {
    return actualResolution;
  }
}

// Like `image.contain` but without "black borders"
function evalResolution(requiredResolution, actualResolution) {
  if (actualResolution[0] >= actualResolution[1]) {
    // width >= height
    if (actualResolution[0] > requiredResolution[0]) {
      return evalResolutionByWidth(requiredResolution[0], actualResolution);
    } else {
      return actualResolution;
    }
  } else {
    // height > width
    if (actualResolution[1] > requiredResolution[1]) {
      return evalResolutionByHeight(requiredResolution[1], actualResolution);
    } else {
      return actualResolution;
    }
  }
}

// You may use `.bind` for partial application. Just for example:
// exports.evalSmallResolution = evalResolutionByHeight.bind(null, SMALL_HEIGHT);   // this = null, requiredHeight = SMALL_HEIGHT
// exports.evalMediumResolution = evalResolutionByHeight.bind(null, MEDIUM_HEIGHT); // this = null, requiredHeight = MEDIUM_HEIGHT
// exports.evalBigResolution = evalResolution.bind(null, [BIG_WIDTH, BIG_HEIGHT]);  // this = null, requiredResolution = [BIG_WIDTH, BIG_HEIGHT]