Replace ImageMagick with a custom tool written in swift.

fastlane/Fastfile

@@ -14,14 +14,14 @@ before_all do
   ENV["SENTRY_LOG_LEVEL"] = "DEBUG"
 end
 
-lane :alpha do
+lane :build_alpha do
   app_store_connect_api_key(
     key_id: ENV["APPSTORECONNECT_KEY_ID"],
     issuer_id: ENV["APPSTORECONNECT_KEY_ISSUER_ID"],
     key_content: ENV["APPSTORECONNECT_KEY_CONTENT"]
   )
 
-  config_xcodegen_alpha()
+  config_alpha()
 
   code_signing_identity = "Apple Distribution: Vector Creations Limited (7J4U792NQT)"
   
@@ -184,7 +184,9 @@ lane :config_nightly do |options|
 
   release_version = get_version_number(target: "ElementX")
 
-  update_app_icon(caption_text: "#{release_version} (#{build_number})", modulate: "100,20,100")
+  Dir.chdir ".." do
+    sh("swift run tools app-icon-banner Variants/Nightly/Resources/Nightly.xcassets/NightlyAppIcon.appiconset/AppIcon.png --banner-text '#{release_version} (#{build_number})'")
+  end
 end
 
 $sentry_retry=0
@@ -311,7 +313,7 @@ private_lane :git_push do |options|
   sh("git push https://#{api_token}@#{repo_url}")
 end
 
-private_lane :config_xcodegen_alpha do
+lane :config_alpha do
   target_file_path = "../project.yml"
   data = YAML.load_file target_file_path
   data["include"].append({ "path" => "Variants/Alpha/alpha.yml" })
@@ -321,7 +323,9 @@ private_lane :config_xcodegen_alpha do
 
   version = ENV["GITHUB_PR_NUMBER"]
 
-  update_app_icon(caption_text: "PR #{version}", modulate: "100,100,200")
+  Dir.chdir ".." do
+    sh("swift run tools app-icon-banner Variants/Alpha/Resources/Alpha.xcassets/AlphaAppIcon.appiconset/AppIcon.png --banner-text 'PR #{version}'")
+  end
 
   bump_build_number()
 end
@@ -371,26 +375,6 @@ private_lane :bump_build_number do
   increment_build_number(build_number: build_number)
 end
 
-private_lane :update_app_icon do |options|
-  caption_text = options[:caption_text]
-  UI.user_error!("Invalid caption text.") unless !caption_text.to_s.empty?
-
-  modulate = options[:modulate]
-  UI.user_error!("Invalid icon modulate parameters.") unless !modulate.to_s.empty?
-
-  Dir.glob("../ElementX/Resources/Assets.xcassets/AppIcon.appiconset/**/*.png") do |file_name|
-    # Change the icons color
-    sh("convert '#{file_name}' -modulate #{modulate} '#{file_name}'")
-
-    image_width = sh("identify -format %w '#{file_name}'")
-    image_height = sh("identify -format %h '#{file_name}'").to_i
-    caption_height = image_height / 5
-
-    # Add a label on top
-    sh("convert -background '#0008' -fill white -gravity center -size '#{image_width}'x'#{caption_height}' caption:'#{caption_text}' '#{file_name}' +swap -gravity south -composite '#{file_name}'")
-  end
-end
-
 private_lane :create_simulator_if_necessary do |options|
   simulator_name = options[:name]
   UI.user_error!("Invalid simulator name") unless !simulator_name.to_s.empty?