make size configurable via cli arg

README.md

@@ -23,6 +23,16 @@ GitHub and sourcehut:
 
 Sourcehut doesn't have macOS builds though.
 
+# Usage
+
+Simply run the provided binary for your OS. Mac & Linux users may need to first
+make the file executable with `chmod +x <file-name>`.
+
+If run from a terminal, use the `-h` argument to see available options.
+Currently there's only a `-size` argument which changes how big your shark will
+be rendered. Windows users can create a shortcut which lets you specify your
+desired arguments.
+
 # Compile from source
 
 - Follow [ebitengine's install guide][6]

main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"bytes"
 	"embed"
+	"flag"
 	_ "image/png"
 	"log"
 
@@ -160,18 +161,24 @@ func init() {
 }
 
 func main() {
+	var sizeFlag int
+	flag.IntVar(
+		&sizeFlag, "size", 2, "Size multiplier: make Gura as big as you want.",
+	)
+	flag.Parse()
+
 	var game Game
 	game.CurrentAnim = Idle
 
-	ebiten.SetWindowSize(SPRITE_X*2, SPRITE_Y*2)
+	ebiten.SetWindowSize(SPRITE_X*sizeFlag, SPRITE_Y*sizeFlag)
 	ebiten.SetWindowTitle("Shark!")
 	ebiten.SetWindowDecorated(false)
 	ebiten.SetScreenTransparent(true)
 	ebiten.SetWindowPosition(9999, 9999)
 	ebiten.SetWindowFloating(true)
-	if err := ebiten.RunGame(&game); err != nil {
-		log.Fatal(err)
-	}
+
+	err := ebiten.RunGame(&game)
+	PanicIfErr(err)
 }
 
 func PanicIfErr(err error) {