Module: Axon::PNGNativeWriter

Included in:
PNGWriter
Defined in:
ext/axon/png_native_writer.c

Instance Method Summary collapse

Instance Method Details

#write(io) ⇒ nil

Compress image and write the png to io.

Returns:

  • (nil) 


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# File 'ext/axon/png_native_writer.c', line 118

static VALUE
pngwrite(VALUE self, VALUE io)
{
    VALUE ensure_args[3];

    png_structp png_ptr;
    png_infop info_ptr;

    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, (png_voidp)NULL,
				      (png_error_ptr)png_error_fn,
				      (png_error_ptr)png_warning_fn);

    if (png_ptr == NULL)
	rb_raise(rb_eRuntimeError, "unable to allocate a png object");

    info_ptr = png_create_info_struct(png_ptr);
    if (info_ptr == NULL) {
	png_destroy_write_struct(&png_ptr, png_infopp_NULL);
	rb_raise(rb_eRuntimeError, "unable to allocate a png info object");
    }

    png_set_write_fn(png_ptr, (void *)io, write_data, flush_data);

    ensure_args[0] = self;
    ensure_args[1] = (VALUE)png_ptr;
    ensure_args[2] = (VALUE)info_ptr;

    return rb_ensure(write2, (VALUE)ensure_args, write2_ensure,
                     (VALUE)ensure_args);
}