From 8ac67db24ff4c8a1364c3cc3278fe75642514706 Mon Sep 17 00:00:00 2001
From: Patrick McDermott <patrick.mcdermott@libiquity.com>
Date: Wed, 17 Jul 2019 03:51:11 -0400
Subject: image_render(): Allocate and free row buffers

Move code from image_new() and image_destroy() and drop rows member from
struct image.
---
diff --git a/src/image.c b/src/image.c
index 3b653f8..b2cefc9 100644
--- a/src/image.c
+++ b/src/image.c
@@ -35,7 +35,6 @@
 struct image {
 	png_structp  png_ptr;
 	png_infop    info_ptr;
-	png_bytepp   rows;
 };
 
 static png_color palette[PALETTE_SIZE];
@@ -45,9 +44,6 @@ image_new(const char *file_name)
 {
 	struct image *image;
 	FILE         *fp;
-	size_t        i;
-	size_t        width  = 32;
-	size_t        height = 32;
 
 	image = calloc(1, sizeof(*image));
 	if (!image) {
@@ -73,39 +69,44 @@ image_new(const char *file_name)
 
 	png_init_io(image->png_ptr, fp);
 
+	return image;
+}
+
+void
+image_render(struct image *image)
+{
+	size_t     width  = 32;
+	size_t     height = 32;
+	png_bytepp rows;
+	size_t     i;
+
 	png_set_IHDR(image->png_ptr, image->info_ptr, width, height,
 			BIT_DEPTH, PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
 			PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
 	png_set_PLTE(image->png_ptr, image->info_ptr, palette, PALETTE_SIZE);
 
-	image->rows = png_malloc(image->png_ptr, height * sizeof(*image->rows));
+	rows = png_malloc(image->png_ptr, height * sizeof(*rows));
 	for (i = 0; i < height; ++i) {
-		image->rows[i] = png_malloc(image->png_ptr, width * PIXEL_SIZE);
+		rows[i] = png_malloc(image->png_ptr, width * PIXEL_SIZE);
 	}
-	png_set_rows(image->png_ptr, image->info_ptr, image->rows);
+	png_set_rows(image->png_ptr, image->info_ptr, rows);
 
-	return image;
-}
-
-void
-image_render(struct image *image)
-{
 	png_write_png(image->png_ptr, image->info_ptr, PNG_TRANSFORM_IDENTITY,
 			NULL);
+
+	for (i = 0; i < height; ++i) {
+		png_free(image->png_ptr, rows[i]);
+	}
+	png_free(image->png_ptr, rows);
 }
 
 struct image *
 image_destroy(struct image **image_p)
 {
 	struct image *image;
-	size_t        i;
 
 	image = *image_p;
 
-	for (i = 0; i < 32; ++i) {
-		png_free(image->png_ptr, image->rows[i]);
-	}
-	png_free(image->png_ptr, image->rows);
 	png_destroy_write_struct(&image->png_ptr, &image->info_ptr);
 	free(image);
 	return image = NULL;
--
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