Update HDRMerge

Now only checks for binary proper install once the functionality of the program is actually utilized. This avoids to many external command calls at dt startup just to check if certain things are installed.

contrib/HDRMerge.lua

@@ -52,14 +52,9 @@ local dsys = require "lib/dtutils.system"
 require "official/yield"
 
 --Check if HDRMerge is installed--
-local not_installed = 0
-dt.print_log("HDRMerge - Executable Path Preference: "..df.get_executable_path_preference("HDRMerge"))
-local HDRMerge_path = df.check_if_bin_exists("HDRMerge")
-if not HDRMerge_path then
-	dt.print_error("HDRMerge not found")
-	dt.print("ERROR - HDRMerge not found")
-	not_installed = 1
-end
+local first_run = true
+local not_installed = false
+local HDRMerge_path
 
 --Detect OS and modify accordingly--	
 local os_path_seperator = "/"
@@ -101,7 +96,16 @@ local function build_execute_command(cmd, args, file_list)
 	return result
 end
 local function HDRMerge()
-	if not_installed == 1 then
+	if first_run then
+		HDRMerge_path = df.check_if_bin_exists("HDRMerge")
+		if not HDRMerge_path then
+			dt.print_error("HDRMerge not found")
+			dt.print("ERROR - HDRMerge not found")
+			not_installed = true
+		end
+		first_run = false
+	end
+	if not_installed then
 		dt.print("Required software not found")
 		dt.print_log("Required software not found - HDRMerge did not run")
 		return
@@ -350,15 +354,6 @@ dt.preferences.register("module_HDRMerge", "bits_per_sample",	-- name
 	"16",	-- default
 	"24","32"	--value
 )
-
-if not HDRMerge_path then 
-	HDRMerge_path = ""
-end
-HDRMerge_path_widget = dt.new_widget("file_chooser_button"){
-	title = "Select HDRMerge[.exe] file",
-	value = HDRMerge_path,
-	is_directory = false,
-}
 dt.preferences.register("executable_paths", "HDRMerge",	-- name
 	"file",	-- type
 	'HDRMerge: Binary Location',	-- label