spee.ch/server/controllers/assets/utils/transformImage.js
2019-02-21 01:56:27 -05:00

76 lines
2.1 KiB
JavaScript

const gm = require('gm');
const logger = require('winston');
const imageMagick = gm.subClass({ imageMagick: true });
const { getImageHeightAndWidth } = require('../../../utils/imageProcessing');
module.exports = function transformImage(path, queryObj) {
return new Promise((resolve, reject) => {
let { h: cHeight = null } = queryObj;
let { w: cWidth = null } = queryObj;
let { t: transform = null } = queryObj;
let { x: xOrigin = null } = queryObj;
let { y: yOrigin = null } = queryObj;
let oHeight,
oWidth = null;
try {
getImageHeightAndWidth(path).then(hwarr => {
oHeight = hwarr[0];
oWidth = hwarr[1];
// conditional logic here
if (transform === 'crop') {
resolve(_cropCenter(path, cWidth, cHeight, oWidth, oHeight));
} else if (transform === 'stretch') {
imageMagick(path)
.resize(cWidth, cHeight, '!')
.toBuffer(null, (err, buf) => {
resolve(buf);
});
} else {
// resize scaled
imageMagick(path)
.resize(cWidth, cHeight)
.toBuffer(null, (err, buf) => {
resolve(buf);
});
}
});
} catch (e) {
logger.error(e);
reject(e);
}
});
};
function _cropCenter(path, cropWidth, cropHeight, originalWidth, originalHeight) {
let oAspect = originalWidth / originalHeight;
let cAspect = cropWidth / cropHeight;
let resizeX,
resizeY,
xpoint,
ypoint = null;
if (oAspect >= cAspect) {
// if crop is narrower aspect than original
resizeY = cropHeight;
xpoint = (oAspect * cropHeight) / 2 - cropWidth / 2;
ypoint = 0;
} else {
// if crop is wider aspect than original
resizeX = cropWidth;
xpoint = 0;
ypoint = cropWidth / oAspect / 2 - cropHeight / 2;
}
return new Promise((resolve, reject) => {
try {
imageMagick(path)
.resize(resizeX, resizeY)
.crop(cropWidth, cropHeight, xpoint, ypoint)
.toBuffer(null, (err, buf) => {
resolve(buf);
});
} catch (e) {
logger.error(e);
reject(e);
}
});
}