From b9100222a146b61badcde313d589d8688a3c88ef Mon Sep 17 00:00:00 2001
From: Patrick McDermott <patrick.mcdermott@libiquity.com>
Date: Wed, 17 Jul 2019 02:38:18 -0400
Subject: image_*(): New functions

---
(limited to 'src/image.c')

diff --git a/src/image.c b/src/image.c
new file mode 100644
index 0000000..4cf7905
--- /dev/null
+++ b/src/image.c
@@ -0,0 +1,91 @@
+#include "image.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <png.h>
+
+#include "i18n.h"
+
+#define BIT_DEPTH    4
+#define PALETTE_SIZE (1 << BIT_DEPTH)
+#define PIXEL_SIZE   ((BIT_DEPTH + 7) / 8)
+
+struct image {
+	png_structp  png_ptr;
+	png_infop    info_ptr;
+	png_bytepp   rows;
+};
+
+static png_color palette[PALETTE_SIZE];
+
+struct image *
+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) {
+		return NULL;
+	}
+
+	fp = fopen(file_name, "wb");
+	if (!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,
+			NULL, NULL, NULL);
+	if (!image->png_ptr) {
+		return image_destroy(&image);
+	}
+
+	image->info_ptr = png_create_info_struct(image->png_ptr);
+	if (!image->info_ptr) {
+		return image_destroy(&image);
+	}
+
+	png_init_io(image->png_ptr, fp);
+
+	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));
+	for (i = 0; i < height; ++i) {
+		image->rows[i] = png_malloc(image->png_ptr, width * PIXEL_SIZE);
+	}
+	png_set_rows(image->png_ptr, image->info_ptr, image->rows);
+
+	return image;
+}
+
+void
+image_render(struct image *image)
+{
+	png_write_png(image->png_ptr, image->info_ptr, PNG_TRANSFORM_IDENTITY,
+			NULL);
+}
+
+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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