krita: add linux appimage support

Author: SMillerDev

Casks/k/krita.rb

@@ -1,8 +1,11 @@
 cask "krita" do
   version "5.2.11"
-  sha256 "c38443656c017e299264473c9d11f4f92aca63b1475bda325a0a0f969973a147"
+  sha256 arm: "c38443656c017e299264473c9d11f4f92aca63b1475bda325a0a0f969973a147",
+         x86_64: "c38443656c017e299264473c9d11f4f92aca63b1475bda325a0a0f969973a147",
+         x86_64_linux: "09c0c325bdf9b1e8494ce9ae8322b6ca5fcb337a7d4b08c8f3b98b8ab95c5bfd"
+  download_suffix = on_system_conditional linux: "-x86_64.AppImage", macos: ".dmg"
 
-  url "https://download.kde.org/stable/krita/#{version}/krita-#{version}.dmg",
+  url "https://download.kde.org/stable/krita/#{version}/krita-#{version}#{download_suffix}",
       verified: "download.kde.org/stable/krita/"
   name "Krita"
   desc "Free and open-source painting and sketching program"
@@ -13,9 +16,16 @@
     regex(/href=.*?krita[._-]v?(\d+(?:\.\d+)+)(?:-signed|-release)?\.dmg/i)
   end
 
-  depends_on macos: ">= :high_sierra"
+  on_macos do
+    depends_on macos: ">= :high_sierra"
 
-  app "krita.app"
+    app "krita.app"
+  end
+
+  on_linux do
+    depends_on arch: [:x86_64]
+    app_image "krita-#{version}#{download_suffix}"
+  end
 
   zap trash: [
     "~/Library/Application Support/krita",