From 19a7b3b57317a28363fec3e4c6ce1100459d2e8e Mon Sep 17 00:00:00 2001
From: Michael Orlitzky <michael@orlitzky.com>
Date: Thu, 3 Aug 2023 20:13:13 -0400
Subject: [PATCH] example.c: take INPUT/OUTPUT filenames as arguments.

---
 example.c | 42 ++++++++++++++++++++++++++++++++----------
 1 file changed, 32 insertions(+), 10 deletions(-)

diff --git a/example.c b/example.c
index 1f54a00..f582682 100644
--- a/example.c
+++ b/example.c
@@ -1,8 +1,13 @@
+#include <fcntl.h> /* open */
+#include <stdio.h> /* printf, fprintf */
+#include <stdlib.h> /* malloc */
+#include <sys/stat.h> /* fstat */
+#include <unistd.h> /* read */
+
 #include <cairo.h>
-#include <stdio.h>
-#include <stdlib.h>
 #include <svgtiny.h>
 
+
 /**
  * Render an svgtiny path using cairo.
  */
@@ -67,13 +72,14 @@ int main(int argc, char** argv) {
   /* Initial viewport width and height */
   int width = 1024, height = 1024;
   float scale = 1.0;
-  char* svgpath = "Ghostscript_Tiger.svg";
-  char* pngpath = "Ghostscript_Tiger.png";
-  size_t svgsize = 68630;
+  char* svgpath;
+  char* pngpath;
 
-  FILE *fd;
+  int fd;
+  size_t svgsize;
   char *buffer;
   size_t bytesread;
+  struct stat sb;
 
   svgtiny_code code;
   struct svgtiny_diagram *diagram;
@@ -83,12 +89,28 @@ int main(int argc, char** argv) {
 
   unsigned int i;
 
+  /* Parse arguments, and maybe print usage */
+  if (argc < 3) {
+    printf("Usage: %s INPUT OUTPUT\n", argv[0]);
+    printf("Convert an SVG file (INPUT) to a PNG file (OUTPUT)\n");
+    return 2;
+  }
+
+  svgpath = argv[1];
+  pngpath = argv[2];
+
   /* load file into memory buffer */
-  fd = fopen(svgpath, "rb");
-  if (!fd) {
+  fd = open(svgpath, O_RDONLY);
+  if (fd == -1) {
+    perror(svgpath);
+    return 1;
+  }
+
+  if (fstat(fd, &sb)) {
     perror(svgpath);
     return 1;
   }
+  svgsize = sb.st_size;
 
   buffer = malloc(svgsize);
   if (!buffer) {
@@ -96,12 +118,12 @@ int main(int argc, char** argv) {
     return 1;
   }
 
-  bytesread = fread(buffer, 1, svgsize, fd);
+  bytesread = read(fd, buffer, svgsize);
   if (bytesread != svgsize) {
     perror(svgpath);
     return 1;
   }
-  fclose(fd);
+  close(fd);
 
 
   /* create svgtiny object */
-- 
2.43.2