image_new(): Support "-" file name for stdout

2 files changed, 17 insertions, 6 deletions

diff --git a/src/image.c b/src/image.c
index d85c9fd..3c5d98f 100644
--- a/src/image.c
+++ b/src/image.c
@@ -46,10 +46,13 @@ image_new(const char *file_name)
 		return NULL;
 	}
 
-	image->fp = fopen(file_name, "wb");
-	if (!image->fp) {
-		printf(_("Error: Cannot open \"%s\" for writing\n"), file_name);
-		return image_destroy(&image);
+	if (strcmp(file_name, "-") != 0) {
+		image->fp = fopen(file_name, "wb");
+		if (!image->fp) {
+			printf(_("Error: Cannot open \"%s\" for writing\n"),
+					file_name);
+			return image_destroy(&image);
+		}
 	}
 
 	image->png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
@@ -63,7 +66,11 @@ image_new(const char *file_name)
 		return image_destroy(&image);
 	}
 
-	png_init_io(image->png_ptr, image->fp);
+	if (image->fp) {
+		png_init_io(image->png_ptr, image->fp);
+	} else {
+		png_init_io(image->png_ptr, stdout);
+	}
 
 	return image;
 }
@@ -107,7 +114,9 @@ image_destroy(struct image **image_p)
 
 	image = *image_p;
 
-	fclose(image->fp);
+	if (image->fp) {
+		fclose(image->fp);
+	}
 	png_destroy_write_struct(&image->png_ptr, &image->info_ptr);
 	free(image);
 	return image = NULL;
diff --git a/src/image.h b/src/image.h
index 1177cd0..b303c23 100644
--- a/src/image.h
+++ b/src/image.h
@@ -24,6 +24,8 @@
 
 #include "text.h"
 
+#include <string.h>
+
 #include "font.h"
 
 #define IMAGE_BIT_DEPTH  8