From 22db7ab4cb3b2928095bd9775fb015a5e28487f6 Mon Sep 17 00:00:00 2001
From: Christian C <cc@localhost>
Date: Wed, 5 Mar 2025 21:57:20 -0800
Subject: Save to PNG

---
 src/lib/png.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 src/lib/png.c

(limited to 'src/lib/png.c')

diff --git a/src/lib/png.c b/src/lib/png.c
new file mode 100644
index 0000000..d12a765
--- /dev/null
+++ b/src/lib/png.c
@@ -0,0 +1,64 @@
+#include <lib/png.h>
+
+#include <stdio.h>
+#include <png.h>
+
+// Save bitmap to file
+void save_png(struct bitmap_t* bitmap, char* fname)
+{
+  FILE *fp;
+  png_structp png_ptr = NULL;
+  png_infop info_ptr = NULL;
+  uint8_t pixel_size = 3;
+  uint8_t pixel_depth = 8;
+  png_byte ** row_pointers = NULL;
+  size_t x, y;
+  fp = fopen(fname, "wb");
+  if (fp == NULL) {
+    fprintf(stderr, "Error opening file\n");
+    return;
+  }
+  png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+  if (png_ptr == NULL) {
+    fprintf(stderr, "Error creating write structure\n");
+    fclose(fp);
+    return;
+  }
+  info_ptr = png_create_info_struct(png_ptr);
+  if (info_ptr == NULL) {
+    fprintf(stderr, "Error creating info structure\n");
+    fclose(fp);
+    return;
+  }
+  if (setjmp(png_jmpbuf(png_ptr))) {
+    fprintf(stderr, "Error setting jmp\n");
+    fclose(fp);
+    return;
+  }
+  png_set_IHDR(png_ptr, info_ptr,
+	       bitmap->width, bitmap->height,
+	       pixel_depth,
+	       PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT,
+	       PNG_FILTER_TYPE_DEFAULT);
+
+  row_pointers = png_malloc(png_ptr, bitmap->height*sizeof(png_byte*));
+  for (y = 0; y < bitmap->height; y++) {
+    png_byte *row = png_malloc(png_ptr, sizeof(uint8_t)*bitmap->width*pixel_size);
+    row_pointers[y] = row;
+    for (x = 0; x < bitmap->width; x++) {
+      *row++ = bitmap->image_buffer[x + y*bitmap->width].red;
+      *row++ = bitmap->image_buffer[x + y*bitmap->width].green;
+      *row++ = bitmap->image_buffer[x + y*bitmap->width].blue;
+    }
+  }
+  png_init_io(png_ptr, fp);
+  png_set_rows(png_ptr, info_ptr, row_pointers);
+  png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
+  for (y = 0; y < bitmap->height; y++) {
+    png_free(png_ptr, row_pointers[y]);
+  }
+  png_free(png_ptr, row_pointers);
+  png_destroy_write_struct(&png_ptr, &info_ptr);
+  fclose(fp);
+}
+
-- 
cgit v1.2.1