Add fbg_loadImageFromMemory() to allow loading images from data buffers

Fixes #13

src/fbgraphics.c

@@ -27,6 +27,7 @@
 
 #include <string.h>
 #include <stdlib.h>
+// TODO: Allow implementation of our own error reporting through WITHOUT_STDIO
 #include <stdio.h>
 
 #ifndef WITHOUT_PNG
@@ -1268,6 +1269,7 @@ struct _fbg_img *fbg_createImage(struct _fbg *fbg, unsigned int width, unsigned
     return img;
 }
 
+#ifndef WITHOUT_STDIO
 #ifndef WITHOUT_JPEG
 struct _fbg_img *fbg_loadJPEG(struct _fbg *fbg, const char *filename) {
     unsigned char *data;
@@ -1441,6 +1443,7 @@ struct _fbg_img *fbg_loadSTBImage(struct _fbg *fbg, const char *filename) {
         return NULL;
     }
 
+    free(img->data);
     img->data = data;
 
     return img;
@@ -1468,6 +1471,51 @@ struct _fbg_img *fbg_loadImage(struct _fbg *fbg, const char *filename) {
 
     return img;
 }
+#endif // WITHOUT_STDIO
+
+#ifndef WITHOUT_STB_IMAGE
+struct _fbg_img *fbg_loadSTBImageFromMemory(struct _fbg *fbg, const unsigned char *buffer, int size) {
+    unsigned char *output;
+    int width;
+    int height;
+    int components;
+    output = stbi_load_from_memory(buffer, size, &width, &height, &components, fbg->components);
+    if (!output) {
+        fprintf(stderr, "fbg_loadSTBImage: %s\n", stbi_failure_reason());
+
+        return NULL;
+    }
+
+    struct _fbg_img *img = fbg_createImage(fbg, width, height);
+    if (!img) {
+        fprintf(stderr, "fbg_loadSTBImageFromMemory: Image of %ix%i data allocation failed\n", width, height);
+
+        stbi_image_free(output);
+
+        return NULL;
+    }
+
+    free(img->data);
+    img->data = output;
+
+    return img;
+}
+#endif
+
+struct _fbg_img *fbg_loadImageFromMemory(struct _fbg *fbg, const unsigned char *data, int size) {
+    struct _fbg_img *img = NULL;
+
+    // TODO: Implement fbg_loadPNGFromMemory()
+    // TODO: Implement fbg_loadJPEGFromMemory()
+
+#ifndef WITHOUT_STB_IMAGE
+    if (img == NULL) {
+        img = fbg_loadSTBImageFromMemory(fbg, data, size);
+    }
+#endif
+
+    return img;
+}
 
 void fbg_image(struct _fbg *fbg, struct _fbg_img *img, int x, int y) {
     unsigned char *pix_pointer = (unsigned char *)(fbg->back_buffer + (y * fbg->line_length) + x * fbg->components);

src/fbgraphics.h

@@ -589,6 +589,7 @@
     */
     extern struct _fbg_img *fbg_createImage(struct _fbg *fbg, unsigned int width, unsigned int height);
 
+#ifndef WITHOUT_STDIO
     //! load a PNG image from a file (lodePNG library)
     /*!
       \param fbg pointer to a FBG context / data structure
@@ -611,15 +612,14 @@
     extern struct _fbg_img *fbg_loadJPEG(struct _fbg *fbg, const char *filename);
 #endif
 
-#ifndef WITHOUT_STB_IMAGE
-
     //! load an image from a file (STB Image library)
     /*!
       \param fbg pointer to a FBG context / data structure
       \param filename image filename
       \return _fbg_img data structure pointer
       \sa fbg_freeImage(), fbg_image(), fbg_imageFlip(), fbg_createFont(), fbg_imageClip(), fbg_loadImage(), fbg_imageEx(), fbg_imageScale(), fbg_imageColorkey()
     */
+#ifndef WITHOUT_STB_IMAGE
     extern struct _fbg_img *fbg_loadSTBImage(struct _fbg *fbg, const char *filename);
 #endif
 
@@ -631,6 +631,29 @@
       \sa fbg_freeImage(), fbg_image(), fbg_imageFlip(), fbg_createFont(), fbg_imageClip(), fbg_loadPNG(), fbg_loadJPEG(), fbg_imageEx(), fbg_imageScale(), fbg_imageColorkey()
     */
     extern struct _fbg_img *fbg_loadImage(struct _fbg *fbg, const char *filename);
+#endif // WITHOUT_STDIO
+
+    //! load an image from memory (STB Image library)
+    /*!
+      \param fbg pointer to a FBG context / data structure
+      \param data The image data from memory.
+      \param size The size of the image in bytes.
+      \return _fbg_img data structure pointer
+      \sa fbg_freeImage(), fbg_image(), fbg_imageFlip(), fbg_createFont(), fbg_imageClip(), fbg_loadPNG(), fbg_loadJPEG(), fbg_imageEx(), fbg_imageScale(), fbg_imageColorkey()
+    */
+#ifndef WITHOUT_STB_IMAGE
+    extern struct _fbg_img *fbg_loadSTBImageFromMemory(struct _fbg *fbg, const unsigned char *data, int size);
+#endif
+
+    //! load an image from memory
+    /*!
+      \param fbg pointer to a FBG context / data structure
+      \param data The image data from memory.
+      \param size The size of the image in bytes.
+      \return _fbg_img data structure pointer
+      \sa fbg_freeImage(), fbg_image(), fbg_imageFlip(), fbg_createFont(), fbg_imageClip(), fbg_loadPNG(), fbg_loadJPEG(), fbg_imageEx(), fbg_imageScale(), fbg_imageColorkey()
+    */
+    extern struct _fbg_img *fbg_loadImageFromMemory(struct _fbg *fbg, const unsigned char *data, int size);
 
     //! draw an image
     /*!