PicoGraphics: Fix set_framebuffer.

libraries/pico_graphics/pico_graphics.cpp

@@ -11,10 +11,11 @@ namespace pimoroni {
   void PicoGraphics::palette_lookup(void *frame_buffer, void *result, uint offset, uint length) {};
 
   void PicoGraphics::set_dimensions(int width, int height) {
-    bounds.w = width;
-    bounds.h = height;
-    clip.w = width;
-    clip.h = height;
+    bounds = clip = {0, 0, width, height};
+  }
+
+  void PicoGraphics::set_framebuffer(void *frame_buffer) {
+    this->frame_buffer = frame_buffer;
   }
 
   void *PicoGraphics::get_data() {

libraries/pico_graphics/pico_graphics.hpp

@@ -110,6 +110,7 @@ namespace pimoroni {
     void set_font(std::string font);
 
     void set_dimensions(int width, int height);
+    void set_framebuffer(void *frame_buffer);
 
     void *get_data();
     void get_data(uint y, void *row_buf);

micropython/modules/picographics/picographics.cpp

@@ -181,9 +181,6 @@ mp_obj_t ModPicoGraphics_set_font(mp_obj_t self_in, mp_obj_t font) {
 }
 
 mp_obj_t ModPicoGraphics_set_framebuffer(mp_obj_t self_in, mp_obj_t framebuffer) {
-    (void)self_in;
-    (void)framebuffer;
-    /*
     ModPicoGraphics_obj_t *self = MP_OBJ_TO_PTR2(self_in, ModPicoGraphics_obj_t);
 
     if (framebuffer == mp_const_none) {
@@ -193,10 +190,16 @@ mp_obj_t ModPicoGraphics_set_framebuffer(mp_obj_t self_in, mp_obj_t framebuffer)
     } else {
         mp_buffer_info_t bufinfo;
         mp_get_buffer_raise(framebuffer, &bufinfo, MP_BUFFER_RW);
+
+        // This should have no effect if you try to replace the framebuffer with itself
+        // but it will free up a buffer that has no other references
+        if(self->buffer != nullptr) {
+            m_del(uint8_t, self->buffer, self->graphics->bounds.w * self->graphics->bounds.h);
+        }
+
         self->buffer = bufinfo.buf;
         self->graphics->set_framebuffer(self->buffer);
     }
-    */
     return mp_const_none;
 }