1 files changed, 76 insertions, 0 deletions
diff --git a/wr/write-png.c b/wr/write-png.c
new file mode 100644
index 0000000..ee4fc09
--- /dev/null
+++ b/wr/write-png.c
@@ -0,0 +1,76 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <png.h>
+
+#include "readers.h"
+#include "writers.h"
+#include "viewer.h"
+
+/* ---------------------------------------------------------------------- */
+/* save                                                                   */
+
+static int
+png_write(FILE *fp, struct ida_image *img)
+{
+    png_structp png_ptr = NULL;
+    png_infop info_ptr  = NULL;
+    png_bytep row;
+    unsigned int y;
+    
+   /* Create and initialize the png_struct with the desired error handler
+    * functions.  If you want to use the default stderr and longjump method,
+    * you can supply NULL for the last three parameters.  We also check that
+    * the library version is compatible with the one used at compile time,
+    * in case we are using dynamically linked libraries.  REQUIRED.
+    */
+    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,NULL,NULL,NULL);
+    if (png_ptr == NULL)
+	goto oops;
+
+   /* Allocate/initialize the image information data.  REQUIRED */
+   info_ptr = png_create_info_struct(png_ptr);
+   if (info_ptr == NULL)
+       goto oops;
+   if (setjmp(png_jmpbuf(png_ptr)))
+       goto oops;
+
+   png_init_io(png_ptr, fp);
+   png_set_IHDR(png_ptr, info_ptr, img->i.width, img->i.height, 8,
+		PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
+		PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+   if (img->i.dpi) {
+       png_set_pHYs(png_ptr, info_ptr,
+		    res_inch_to_m(img->i.dpi),
+		    res_inch_to_m(img->i.dpi),
+		    PNG_RESOLUTION_METER);
+   }
+   png_write_info(png_ptr, info_ptr);
+   png_set_packing(png_ptr);
+
+   for (y = 0; y < img->i.height; y++) {
+       row = img->data + y * 3 * img->i.width;
+       png_write_rows(png_ptr, &row, 1);
+   }
+   png_write_end(png_ptr, info_ptr);
+   png_destroy_write_struct(&png_ptr, &info_ptr);
+   return 0;
+
+ oops:
+   fprintf(stderr,"can't save image: libpng error\n");
+   if (png_ptr)
+       png_destroy_write_struct(&png_ptr,  (png_infopp)NULL);
+   return -1;
+}
+
+static struct ida_writer png_writer = {
+    label:  "PNG",
+    ext:    { "png", NULL},
+    write:  png_write,
+};
+
+static void __init init_wr(void)
+{
+    write_register(&png_writer);
+}