diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5f72794..fea9dca 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,6 +8,7 @@ set(SOURCES
 	src/main.c
 	src/options.c
 	src/mouse.c
+	src/strtoint.c
 	src/editing_area/main.c
 	src/editing_area/level.c
 	src/editing_area/draw.c
diff --git a/include/options.h b/include/options.h
index c9ee047..c45a92e 100644
--- a/include/options.h
+++ b/include/options.h
@@ -11,8 +11,8 @@ struct Options {
 	int tile_height;
 	int tileset_width;
 	int tileset_height;
-	int editor_window_width;
-	int editor_window_height;
+	int editor_width;
+	int editor_height;
 	int editor_target_fps;
 	int editor_draw_offset_x;
 	int editor_draw_offset_y;
diff --git a/include/strtoint.h b/include/strtoint.h
new file mode 100644
index 0000000..b5b9d13
--- /dev/null
+++ b/include/strtoint.h
@@ -0,0 +1,6 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/* Copyright (C) 2021 KikooDX */
+#pragma once
+
+/* Attempt to convert a string to positive integer. Return -1 on error. */
+int strtoint(char *string);
diff --git a/src/editing_area/main.c b/src/editing_area/main.c
index ed4b6eb..6f7b046 100644
--- a/src/editing_area/main.c
+++ b/src/editing_area/main.c
@@ -27,8 +27,8 @@ int editing_area_main(struct Options options,
 	Texture2D tileset;
 
 	/* initialize raylib */
-	InitWindow(options.editor_window_width,
-	           options.editor_window_height, "SLE main window");
+	InitWindow(options.editor_width,
+	           options.editor_height, "SLE main window");
 	SetTargetFPS(options.editor_target_fps);
 	init_mouse(options);
 	/* load textures */
diff --git a/src/main.c b/src/main.c
index 131b29f..efde1ac 100644
--- a/src/main.c
+++ b/src/main.c
@@ -5,6 +5,7 @@
 #include "options.h"
 #include "shared_data.h"
 #include "tile_picker/main.h"
+#include "strtoint.h"
 #include <getopt.h>
 #include <raylib.h>
 #include <stdbool.h>
@@ -89,6 +90,10 @@ static void process_arguments(int argc, char **argv,
 		static struct option long_options[] = {
 		    {"level", required_argument, 0, 'l'},
 		    {"tileset", required_argument, 0, 't'},
+		    {"tile-width", required_argument, 0, 'w'},
+		    {"tile-height", required_argument, 0, 'h'},
+		    {"editor-width", required_argument, 0, 'W'},
+		    {"editor-height", required_argument, 0, 'H'},
 		    {0, 0, 0, 0},
 		};
 		/* getopt_long stores the option index here */
@@ -101,14 +106,34 @@ static void process_arguments(int argc, char **argv,
 			break;
 
 		switch (opt) {
-		case 'l':
+		case 'l': /* level */
 			overflow_prevention();
 			strcpy(options->level_path, optarg);
 			break;
-		case 't':
+		case 't': /* tileset */
 			overflow_prevention();
 			strcpy(options->tileset_path, optarg);
 			break;
+		case 'w': /* tile width */
+			options->tile_width = strtoint(optarg);
+			if (options->tile_width <= 0)
+				exit(EXIT_FAILURE);
+			break;
+		case 'h': /* tile height */
+			options->tile_height = strtoint(optarg);
+			if (options->tile_height <= 0)
+				exit(EXIT_FAILURE);
+			break;
+		case 'W': /* editor width */
+			options->editor_width = strtoint(optarg);
+			if (options->editor_width <= 0)
+				exit(EXIT_FAILURE);
+			break;
+		case 'H': /* editor height */
+			options->editor_height = strtoint(optarg);
+			if (options->editor_height <= 0)
+				exit(EXIT_FAILURE);
+			break;
 		case '?':
 			/* getopt_long already printed an error message
 			 */
diff --git a/src/options.c b/src/options.c
index f8fd94d..220b74c 100644
--- a/src/options.c
+++ b/src/options.c
@@ -10,8 +10,8 @@ struct Options options_defaults(void)
 	    .tile_height = TILE_HEIGHT,
 	    .tileset_width = 0,
 	    .tileset_height = 0,
-	    .editor_window_width = EDITOR_WINDOW_WIDTH,
-	    .editor_window_height = EDITOR_WINDOW_HEIGHT,
+	    .editor_width = EDITOR_WINDOW_WIDTH,
+	    .editor_height = EDITOR_WINDOW_HEIGHT,
 	    .editor_target_fps = EDITOR_TARGET_FPS,
 	    .editor_draw_offset_x = EDITOR_DRAW_OFFSET_X,
 	    .editor_draw_offset_y = EDITOR_DRAW_OFFSET_Y,
diff --git a/src/strtoint.c b/src/strtoint.c
new file mode 100644
index 0000000..87eb414
--- /dev/null
+++ b/src/strtoint.c
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/* Copyright (C) 2021 KikooDX */
+
+#include "strtoint.h"
+#include <string.h>
+#include <stdio.h>
+
+/* Attempt to convert a string to positive integer. Return -1 on error. */
+int strtoint(char *string) {
+	char character;
+	int i;
+	const size_t string_len = strlen(string);
+	int sum = 0;
+	int multiplier = 1;
+	for (i = string_len - 1; i >= 0; i -= 1) {
+		character = string[i];
+		if (character < '0' || character > '9') {
+			fprintf(stderr, "ERROR: flag expected a positive number argument, got \"%s\"\n", string);
+			return -1;
+		}
+		sum += multiplier * (character - '0');
+		multiplier *= 10;
+	}
+	return sum;
+}