feat(linux): ability to specify custom path to linux icon set

Close #1176

docs/Auto Update.md

@@ -10,11 +10,13 @@ Simplified auto-update is not supported for Squirrel.Windows.
 
 2. [Configure publish](https://github.com/electron-userland/electron-builder/wiki/Publishing-Artifacts#PublishConfiguration).
 
-3. Use `autoUpdater` from `electron-updater` instead of `electron`, e.g. (ES 6):
+3. Use `autoUpdater` from `electron-updater` instead of `electron`:
 
     ```js
-    import {autoUpdater} from "electron-updater"
-    ```    
+    import { autoUpdater } from "electron-updater"
+    ```
+
+    Or if you don't use ES6: `const autoUpdater = require("electron-updater").autoUpdater`
 
 4. Do not call `setFeedURL`. electron-builder automatically creates `app-update.yml` file for you on build in the `resources` (this file is internal, you don't need to be aware of it). 
 

docs/Options.md

@@ -133,6 +133,7 @@ On Windows works only if [nsis.perMachine](https://github.com/electron-userland/
 | compression | <a name="LinuxBuildOptions-compression"></a>*deb-only.* The compression type, one of `gz`, `bzip2`, `xz`. Defaults to `xz`.
 | depends | <a name="LinuxBuildOptions-depends"></a>Package dependencies. Defaults to `["gconf2", "gconf-service", "libnotify4", "libappindicator1", "libxtst6", "libnss3"]` for `deb`.
 | executableName | <a name="LinuxBuildOptions-executableName"></a><p>The executable name. Defaults to <code>productName</code>.</p> <p>Cannot be specified per target, allowed only in the <code>linux</code>.</p>
+| icon | <a name="LinuxBuildOptions-icon"></a><p>The path to icon set directory, relative to <code>build</code> (build resources directory). The icon filename must contain the size (e.g. 32x32.png) of the icon. By default will be generated automatically based on the macOS icns file.</p>
 
 <a name="MacOptions"></a>
 ### `mac` macOS Specific Options

packages/electron-builder/src/options/linuxOptions.ts

@@ -68,6 +68,12 @@ export interface LinuxBuildOptions extends PlatformSpecificBuildOptions {
    Cannot be specified per target, allowed only in the `linux`.
    */
   readonly executableName?: string | null
+
+  /*
+   The path to icon set directory, relative to `build` (build resources directory). The icon filename must contain the size (e.g. 32x32.png) of the icon.
+   By default will be generated automatically based on the macOS icns file.
+   */
+  readonly icon?: string
 }
 
 /*

packages/electron-builder/src/targets/LinuxTargetHelper.ts

@@ -18,6 +18,21 @@ export class LinuxTargetHelper {
 
   // must be name without spaces and other special characters, but not product name used
   private async computeDesktopIcons(): Promise<Array<Array<string>>> {
+    if (this.packager.platformSpecificBuildOptions.icon != null) {
+      const iconDir = path.resolve(this.packager.buildResourcesDir, this.packager.platformSpecificBuildOptions.icon)
+      try {
+        return await this.iconsFromDir(iconDir)
+      }
+      catch (e) {
+        if (e.code === "ENOENT") {
+          throw new Error(`Icon set directory ${iconDir} doesn't exist`)
+        }
+        else {
+          throw e
+        }
+      }
+    }
+
     const resourceList = await this.packager.resourceList
     if (resourceList.includes("icons")) {
       return await this.iconsFromDir(path.join(this.packager.buildResourcesDir, "icons"))
@@ -29,17 +44,17 @@ export class LinuxTargetHelper {
     }
   }
 
-  private async iconsFromDir(iconsDir: string) {
+  private async iconsFromDir(iconDir: string) {
     const mappings: Array<Array<string>> = []
     let maxSize = 0
-    for (const file of (await readdir(iconsDir))) {
+    for (const file of (await readdir(iconDir))) {
       if (file.endsWith(".png") || file.endsWith(".PNG")) {
         // If parseInt encounters a character that is not a numeral in the specified radix,
         // it returns the integer value parsed up to that point
         try {
           const size = parseInt(file!, 10)
           if (size > 0) {
-            const iconPath = `${iconsDir}/${file}`
+            const iconPath = `${iconDir}/${file}`
             mappings.push([iconPath, `${size}x${size}/apps/${this.packager.executableName}.png`])
 
             if (size > maxSize) {
@@ -53,6 +68,11 @@ export class LinuxTargetHelper {
         }
       }
     }
+
+    if (mappings.length === 0) {
+      throw new Error(`Icon set directory ${iconDir} doesn't contain icons`)
+    }
+
     return mappings
   }