C-interface: return images as base64.

I couldn't figure out how to return them as MagickWand, maybe I can't
mix Magick++ with MagickWand.

src/c_interface.cpp

@@ -23,7 +23,8 @@
 #include "debug.hpp"
 #include "identiconpp_c.h"
 
-std::unique_ptr<Identiconpp> identicon;
+static std::unique_ptr<Identiconpp> identicon;
+static string base64;
 
 bool identiconpp_setup(const uint8_t columns, const uint8_t rows,
                        identiconpp_algorithm type,
@@ -72,11 +73,19 @@ bool identiconpp_setup(const uint8_t columns, const uint8_t rows,
     return true;
 }
 
-bool identiconpp_generate(MagickWand *wand,
-                          const char digest[], const uint16_t width)
+uint64_t identiconpp_generate(const char magick[],
+                              const char digest[], const uint16_t width)
 {
     Magick::Image img = identicon->generate(digest, width);
     Magick::Blob blob;
+    img.magick(magick);
     img.write(&blob);
-    MagickReadImageBlob(wand, blob.data(), blob.length());
+    base64 = blob.base64();
+
+    return blob.base64().length();
+}
+
+const char *identiconpp_base64()
+{
+    return base64.c_str();
 }

src/identiconpp_c.h

@@ -25,8 +25,18 @@ extern "C"
     #include <stdbool.h>
     #include <stdint.h>
     #include <stddef.h>
-    #include <MagickWand/MagickWand.h>
 
+    /*!
+     * @example example.c
+     */
+
+    /*!
+     *  @brief  C interface for identiconpp.
+     */
+
+    /*!
+     * @brief  List of identicon algorithms
+     */
     typedef enum
     {
         identiconpp_ltr_symmetric,
@@ -34,14 +44,38 @@ extern "C"
         identiconpp_sigil
     } identiconpp_algorithm;
 
+    /*!
+     *  @brief  Setup identicon parameters.
+     *
+     *  @param  columns         Number of columns
+     *  @param  rows            Number of rows
+     *  @param  type            The algorithm to use
+     *  @param  background      Background color, hexadecimal, rrggbbaa
+     *  @param  foreground      Array of foreground colors
+     *  @param  foreground_len  Length of the array of foreground colors
+     *  @param  padding         Padding in pixels { left & right, top & down }
+     *
+     *  @return { description_of_the_return_value }
+     */
     bool identiconpp_setup(const uint8_t columns, const uint8_t rows,
                            identiconpp_algorithm type,
                            const char background[9],
                            const char foreground[][9],
                            const uint8_t foreground_len,
                            const uint8_t padding[2]);
-    bool identiconpp_generate(MagickWand *wand,
-                              const char digest[], const uint16_t width);
+
+    /*!
+     *  @brief  Generates identicon from digest.
+     *
+     *  @param  magick  See http://imagemagick.org/script/formats.php
+     *  @param  digest  The pre-computed digest
+     *  @param  width   The width of the identicon
+     *
+     *  @return Length of the generated base64-string
+     */
+    uint64_t identiconpp_generate(const char magick[],
+                                  const char digest[], const uint16_t width);
+    const char *identiconpp_base64();
 
 #ifdef __cplusplus
 }