Merge pull request #124 from saxbophone/josh/113-refactor-render-backends

Re-organise and refactor the rendering units

Author: saxbophone

saxbospiral/render.c

@@ -83,7 +83,9 @@ static void get_bounds(sxbp_spiral_t spiral, sxbp_co_ord_t* bounds) {
  * - That image->pixels is NULL
  * - That spiral.lines is not NULL
  */
-sxbp_status_t sxbp_render_spiral(sxbp_spiral_t spiral, sxbp_bitmap_t* image) {
+sxbp_status_t sxbp_render_spiral_raw(
+    sxbp_spiral_t spiral, sxbp_bitmap_t* image
+) {
     // preconditional assertions
     assert(image->pixels == NULL);
     assert(spiral.lines != NULL);
@@ -159,6 +161,40 @@ sxbp_status_t sxbp_render_spiral(sxbp_spiral_t spiral, sxbp_bitmap_t* image) {
     return result;
 }
 
+/*
+ * given a spiral struct, a pointer to a blank buffer and a pointer to a
+ * function with the appropriate signature, render the spiral as a bitmap and
+ * then call the pointed-to function to render the image to the buffer (in
+ * whatever format the function pointer is written for)
+ * returns a status struct with error information (if any)
+ *
+ * Asserts:
+ * - That spiral.lines is not NULL
+ * - That buffer->bytes is NULL
+ * - That the function pointer is not NULL
+ */
+sxbp_status_t sxbp_render_spiral_image(
+    sxbp_spiral_t spiral, sxbp_buffer_t* buffer,
+    sxbp_status_t(* image_writer_callback)(
+        sxbp_bitmap_t image, sxbp_buffer_t* buffer
+    )
+) {
+    // preconditional assertions
+    assert(spiral.lines != NULL);
+    assert(buffer->bytes == NULL);
+    assert(image_writer_callback != NULL);
+    // create bitmap to render raw image to
+    sxbp_bitmap_t raw_image = {0, 0, NULL};
+    // render spiral to raw image (and store success/failure)
+    sxbp_status_t result = sxbp_render_spiral_raw(spiral, &raw_image);
+    // check return status
+    if(result != SXBP_OPERATION_OK) {
+        return result;
+    }
+    // render to buffer using callback (and return its status code)
+    return image_writer_callback(raw_image, buffer);
+}
+
 #ifdef __cplusplus
 } // extern "C"
 #endif

saxbospiral/render.h

@@ -48,7 +48,28 @@ typedef struct sxbp_bitmap_t {
  * - That image->pixels is NULL
  * - That spiral.lines is not NULL
  */
-sxbp_status_t sxbp_render_spiral(sxbp_spiral_t spiral, sxbp_bitmap_t* image);
+sxbp_status_t sxbp_render_spiral_raw(
+    sxbp_spiral_t spiral, sxbp_bitmap_t* image
+);
+
+/*
+ * given a spiral struct, a pointer to a blank buffer and a pointer to a
+ * function with the appropriate signature, render the spiral as a bitmap and
+ * then call the pointed-to function to render the image to the buffer (in
+ * whatever format the function pointer is written for)
+ * returns a status struct with error information (if any)
+ *
+ * Asserts:
+ * - That spiral.lines is not NULL
+ * - That buffer->bytes is NULL
+ * - That the function pointer is not NULL
+ */
+sxbp_status_t sxbp_render_spiral_image(
+    sxbp_spiral_t spiral, sxbp_buffer_t* buffer,
+    sxbp_status_t(* image_writer_callback)(
+        sxbp_bitmap_t image, sxbp_buffer_t* buffer
+    )
+);
 
 #ifdef __cplusplus
 } // extern "C"

saxbospiral/render_backends/png_backend.c renamed to saxbospiral/render_backends/backend_png.c

@@ -2,7 +2,8 @@
  * This source file forms part of libsaxbospiral, a library which generates
  * experimental 2D spiral-like shapes based on input binary data.
  *
- * This compilation unit provides functionality to render a bitmap struct to PNG
+ * This compilation unit provides functionality to render a bitmap struct to a
+ * PNG image (stored in a buffer).
  *
  *
  *
@@ -28,7 +29,7 @@
 
 #include "../saxbospiral.h"
 #include "../render.h"
-#include "png_backend.h"
+#include "backend_png.h"
 
 
 #ifdef __cplusplus
@@ -89,7 +90,7 @@ static void cleanup_png_lib(
  * - That bitmap.pixels is not NULL
  * - That buffer->bytes is NULL
  */
-sxbp_status_t sxbp_write_png_image(
+sxbp_status_t sxbp_render_backend_png(
     sxbp_bitmap_t bitmap, sxbp_buffer_t* buffer
 ) {
     // preconditional assertsions

saxbospiral/render_backends/png_backend.h renamed to saxbospiral/render_backends/backend_png.h

@@ -2,7 +2,8 @@
  * This source file forms part of libsaxbospiral, a library which generates
  * experimental 2D spiral-like shapes based on input binary data.
  *
- * This compilation unit provides functionality to render a bitmap struct to PNG
+ * This compilation unit provides functionality to render a bitmap struct to a
+ * PNG image (stored in a buffer).
  *
  *
  *
@@ -20,8 +21,8 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-#ifndef SAXBOPHONE_SAXBOSPIRAL_PNG_BACKEND_H
-#define SAXBOPHONE_SAXBOSPIRAL_PNG_BACKEND_H
+#ifndef SAXBOPHONE_SAXBOSPIRAL_BACKEND_PNG_H
+#define SAXBOPHONE_SAXBOSPIRAL_BACKEND_PNG_H
 
 #include "../saxbospiral.h"
 #include "../render.h"
@@ -40,7 +41,9 @@ extern "C"{
  * - That bitmap.pixels is not NULL
  * - That buffer->bytes is NULL
  */
-sxbp_status_t sxbp_write_png_image(sxbp_bitmap_t bitmap, sxbp_buffer_t* buffer);
+sxbp_status_t sxbp_render_backend_png(
+    sxbp_bitmap_t bitmap, sxbp_buffer_t* buffer
+);
 
 #ifdef __cplusplus
 } // extern "C"