Application icon has low visual quality when displayed in Linux dock

[per1234]

Describe the problem

When the Arduino IDE is running, an application icon is shown in the operating system's "dock" (referred to as "taskbar" on Windows).

🐛 The visual quality of the image is poor when it is displayed in the Linux dock.

To reproduce

1. Start Arduino IDE on a Linux machine.

🐛 The visual quality of the icon is poor when it is displayed in the Linux dock even though the source image is fine:

Source image:

Appearance in dock:

With Settings > Appearance > Dock > Icon size set to 64 px:

With Settings > Appearance > Dock > Icon size set to 16 px:

Expected behavior

Application icon has a reasonable visual quality when displayed in the dock.

Arduino IDE version

e08439b

Operating system

• Linux

Operating system version

• Ubuntu 22.04
• Ubuntu 20.04

Additional context

The problem does not occur on macOS and Windows.

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I see a mention of the problem here:

electron-userland/electron-builder#4617 (comment)

I found that a 64x64 png icon looked best in the docks in Linux. Larger sizes are jagged.

Ubuntu allows the user to configure the dock icon size from 16 to 64 px via the Settings > Appearance > Dock > Icon size setting.

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The problem also occurs in Theia Blueprint (verified using version 1.32.0 due to the loss of the icon in the latest Blueprint versions: https://github.com/eclipse-theia/theia-blueprint/issues/296):

Source image:

https://github.com/eclipse-theia/theia-blueprint/blob/a022cad9e6031842ee9a67a1b1f492761446a929/theia-extensions/theia-blueprint-product/icons/512-512.png

Appearance in dock:

Related

• fix: missing app icon for AppImage on Linux #2190

Issue checklist

• I searched for previous reports in the issue tracker
• I verified the problem still occurs when using the latest nightly build
• My report contains all necessary details