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 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/lib/seg/util.c | 30 +++++++++++++++++++++++++
 src/main.c         |  7 +++++-
 3 files changed, 100 insertions(+), 1 deletion(-)
 create mode 100644 src/lib/png.c

(limited to 'src')

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);
+}
+
diff --git a/src/lib/seg/util.c b/src/lib/seg/util.c
index 530c326..10b8fa8 100644
--- a/src/lib/seg/util.c
+++ b/src/lib/seg/util.c
@@ -1,5 +1,6 @@
 #include <lib/seg/util.h>
 #include <lib/algo/flood_fill.h>
+#include <lib/png.h>
 #include <tiffio.h>
 #include <assert.h>
 #include <stdio.h>
@@ -260,3 +261,32 @@ uint16_t* tif_to_labels(char* tif_file_name, uint32_t *width, uint32_t *height,
   TIFFClose(tif);
   return labels;
 }
+
+// Convert mask to bitmap
+struct bitmap_t* uint16_to_bitmap(uint16_t* buffer, uint32_t width, uint32_t height)
+{
+  struct pixel_t* out_buffer = (struct pixel_t*)calloc(width*height, sizeof(struct pixel_t));
+  if (out_buffer == NULL) {
+    return NULL;
+  }
+  struct bitmap_t* bitmap = (struct bitmap_t*)malloc(sizeof(struct bitmap_t));
+  if (bitmap == NULL) {
+    free(out_buffer);
+    return NULL;
+  }
+  for (size_t y = 0; y < height; y++) {
+    for (size_t x = 0; x < width; x++) {
+      size_t coord = x + y*width;
+      uint8_t red   = (buffer[coord] & 0xF00) >> 4*2;
+      uint8_t green = (buffer[coord] & 0x0F0) >> 4*1;
+      uint8_t blue  = (buffer[coord] & 0x00F) >> 4*0;
+      out_buffer[coord].red = red | (red << 4);
+      out_buffer[coord].green = green | (green << 4);
+      out_buffer[coord].blue = blue | (blue << 4);
+    }
+  }
+  bitmap->image_buffer = out_buffer;
+  bitmap->width = (size_t)width;
+  bitmap->height = (size_t)height;
+  return bitmap;
+}
diff --git a/src/main.c b/src/main.c
index 7c914e5..c77d7f5 100644
--- a/src/main.c
+++ b/src/main.c
@@ -4,6 +4,7 @@
 #include <raylib.h>
 
 #include <lib/lib.h>
+#include <lib/png.h>
 #include <lib/bool.h>
 #include <lib/monad.h>
 #include <lib/dir.h>
@@ -191,7 +192,6 @@ int main(int argc, char** argv)
   }
   TIME(ts_end);
   printf("Dilation took %f ms\n", 1000*diff_time(&ts_end, &ts_start));
-
   //-----------------------------------------------
 
 #ifdef VISUAL
@@ -282,6 +282,11 @@ int main(int argc, char** argv)
   CloseWindow();
 #else
   if (masks != NULL) {
+    struct bitmap_t* bitmap = uint16_to_bitmap(masks, width, height);
+    if (bitmap != NULL) {
+      save_png(bitmap, "../out.png");
+      free(bitmap);
+    }
     write_array("../out.bin", masks, width*height*sizeof(uint16_t));
     free(masks);
   }
-- 
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