Move to .NET 5, fix -help error

.gitignore

@@ -337,4 +337,5 @@ ASALocalRun/
 .localhistory/
 
 # BeatPulse healthcheck temp database
-healthchecksdb
+healthchecksdb
+/Properties/launchSettings.json

GDStoSVG/GDStoSVG.csproj

@@ -2,8 +2,9 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <TargetFramework>net5.0</TargetFramework>
     <Nullable>enable</Nullable>
+    <StartupObject>GDStoSVG.Program</StartupObject>
   </PropertyGroup>
 
 </Project>

GDStoSVG/Program.cs

@@ -25,7 +25,8 @@ static void Main(string[] args)
 
             for(int i = 0; i < args.Length; i++)
             {
-                if (i == 0) { GDSFile = args[i]; }
+                if (args[i].Equals("-help", StringComparison.OrdinalIgnoreCase)) { PrintHelp(); return; }
+                else if (i == 0) { GDSFile = args[i]; }
                 else if (args[i].Equals("-csv", StringComparison.OrdinalIgnoreCase) && args.Length > i + 1) { CSVFile = args[i + 1]; }
                 else if (args[i].Equals("-svg", StringComparison.OrdinalIgnoreCase) && args.Length > i + 1) { SVGFile = args[i + 1]; }
                 else if (args[i].Equals("-unit", StringComparison.OrdinalIgnoreCase) && args.Length > i + 1) { TopUnit = args[i + 1]; }

README.md

@@ -3,14 +3,15 @@
 Fully integrated system to convert GDSII format files, such as the ones exported from Cadence Virtuoso, into SVG graphics for printing or display.
 
 Prerequisites:
-- [.NET Core 3.1](https://dotnet.microsoft.com/download/dotnet-core)
+- [.NET 5](https://dotnet.microsoft.com/download/dotnet)
 
 Should work on Windows, Linux, and Mac. Theoretically big-endian platforms are also supported (untested).
 
 ## Usage
 1) Export your layout as GDSII format from the CAD software you're using. (see below)
 2) Run this utility in info mode to determine layers, by running `GDStoSVG.exe <myfile.gds> -info`
 3) It will output design units and layer info to the console. Using this layer list, and the generated SVG file (same name as the input GDS), locate components on a specific layer (all items on a layer are grouped together), and determine what each layer ID corresponds to.
+    - If your SVG file is too large to open, you may want to export only a sub-unit to start, by using the `-unit <UNIT>` parameter, with one of the units listed from step 2.
 4) Create a CSV file with your layer IDs, names, colours, and opacities in the required format (see `GDStoSVG.exe -help` for info).
 5) Test your CSV file by running `GDStoSVG.exe <myfile.gds> -csv <layers.csv> -info`.
 6) Repeat until you are happy with the layer assignments, and there are no unassigned layers remaining (unless you don't care about those layers).