1  const fs = require('fs');
 2  const {promisify} = require('util');
 3  const execa = require('execa');
 4  const tempy = require('tempy');
 5  const gm = require('gm').subClass({imageMagick: true});
 6  const icns = require('icns-lib');
 7  
 8  const readFile = promisify(fs.readFile);
 9  const writeFile = promisify(fs.writeFile);
10  
11  const filterMap = (map, filterFn) => Object.entries(map).filter(filterFn).reduce((out, [key, item]) => ({...out, [key]: item}), {});
12  
13  // Drive icon from `/System/Library/Extensions/IOStorageFamily.kext/Contents/Resources/Removable.icns``
14  const baseDiskIconPath = `${__dirname}/disk-icon.icns`;
15  
16  async function composeIcon(type, appIcon, mountIcon, composedIcon) {
17  	mountIcon = gm(mountIcon);
18  	appIcon = gm(appIcon);
19  	const appIconSize = await promisify(appIcon.size.bind(appIcon))();
20  	const mountIconSize = appIconSize;
21  
22  	// Change the perspective of the app icon to match the mount drive icon
23  	appIcon = appIcon.out('-matte').out('-virtual-pixel', 'transparent').out('-distort', 'Perspective', `1,1  ${appIconSize.width * 0.08},1     ${appIconSize.width},1  ${appIconSize.width * 0.92},1     1,${appIconSize.height}  1,${appIconSize.height}     ${appIconSize.width},${appIconSize.height}  ${appIconSize.width},${appIconSize.height}`);
24  
25  	// Resize the app icon to fit it inside the mount icon, aspect ration should not be kept to create the perspective illution
26  	appIcon = appIcon.resize(appIconSize.width / 1.7, appIconSize.height / 1.78, '!');
27  
28  	const tempAppIconPath = tempy.file({extension: 'png'});
29  	await promisify(appIcon.write.bind(appIcon))(tempAppIconPath);
30  
31  	// Compose the two icons
32  	const iconGravityFactor = mountIconSize.height * 0.155;
33  	mountIcon = mountIcon.composite(tempAppIconPath).gravity('Center').geometry(`+0-${iconGravityFactor}`);
34  
35  	composedIcon[type] = await promisify(mountIcon.toBuffer.bind(mountIcon))();
36  }
37  
38  const hasGm = async () => {
39  	try {
40  		await execa('gm', ['-version']);
41  		return true;
42  	} catch (error) {
43  		if (error.code === 'ENOENT') {
44  			return false;
45  		}
46  
47  		throw error;
48  	}
49  };
50  
51  module.exports = async appIconPath => {
52  	if (!await hasGm()) {
53  		return baseDiskIconPath;
54  	}
55  
56  	const baseDiskIcons = filterMap(icns.parse(await readFile(baseDiskIconPath)), ([key]) => icns.isImageType(key));
57  	const appIcon = filterMap(icns.parse(await readFile(appIconPath)), ([key]) => icns.isImageType(key));
58  
59  	const composedIcon = {};
60  	await Promise.all(Object.entries(appIcon).map(async ([type, icon]) => {
61  		if (baseDiskIcons[type]) {
62  			return composeIcon(type, icon, baseDiskIcons[type], composedIcon);
63  		}
64  
65  		console.warn('There is no base image for this type', type);
66  	}));
67  
68  	const tempComposedIcon = tempy.file({extension: 'icns'});
69  
70  	await writeFile(tempComposedIcon, icns.format(composedIcon));
71  
72  	return tempComposedIcon;
73  };