WIP but nearly there: need to resolve string vs. buffer protocol

micropython/modules/pico_scroll/micropython.cmake

@@ -2,6 +2,7 @@ add_library(usermod_pico_scroll INTERFACE)
 
 target_sources(usermod_pico_scroll INTERFACE
     ${CMAKE_CURRENT_LIST_DIR}/pico_scroll.c
+    ${CMAKE_CURRENT_LIST_DIR}/pico_scroll_font.c
     ${CMAKE_CURRENT_LIST_DIR}/pico_scroll.cpp
     ${CMAKE_CURRENT_LIST_DIR}/../../../libraries/pico_scroll/pico_scroll.cpp
 )

micropython/modules/pico_scroll/pico_scroll.c

@@ -21,6 +21,7 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_0(picoscroll_get_height_obj, picoscroll_get_heigh
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(picoscroll_update_obj, picoscroll_update);
 STATIC MP_DEFINE_CONST_FUN_OBJ_3(picoscroll_set_pixel_obj, picoscroll_set_pixel);
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(picoscroll_set_pixels_obj, picoscroll_set_pixels);
+STATIC MP_DEFINE_CONST_FUN_OBJ_3(picoscroll_show_text_obj, picoscroll_show_text);
 STATIC MP_DEFINE_CONST_FUN_OBJ_3(picoscroll_show_bitmap_1d_obj, picoscroll_show_bitmap_1d);
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(picoscroll_clear_obj, picoscroll_clear);
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(picoscroll_is_pressed_obj, picoscroll_is_pressed);
@@ -34,6 +35,7 @@ STATIC const mp_map_elem_t picoscroll_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_update), MP_ROM_PTR(&picoscroll_update_obj) },
     { MP_ROM_QSTR(MP_QSTR_set_pixel), MP_ROM_PTR(&picoscroll_set_pixel_obj) },
     { MP_ROM_QSTR(MP_QSTR_set_pixels), MP_ROM_PTR(&picoscroll_set_pixels_obj) },
+    { MP_ROM_QSTR(MP_QSTR_show_text), MP_ROM_PTR(&picoscroll_show_text_obj) },
     { MP_ROM_QSTR(MP_QSTR_show_bitmap_1d), MP_ROM_PTR(&picoscroll_show_bitmap_1d_obj) },
     { MP_ROM_QSTR(MP_QSTR_clear), MP_ROM_PTR(&picoscroll_clear_obj) },
     { MP_ROM_QSTR(MP_QSTR_is_pressed), MP_ROM_PTR(&picoscroll_is_pressed_obj) },        

micropython/modules/pico_scroll/pico_scroll.cpp

@@ -11,6 +11,7 @@ PicoScroll *scroll = nullptr;
 
 extern "C" {
 #include "pico_scroll.h"
+#include "pico_scroll_font.h"
 
 #define NOT_INITIALISED_MSG     "Cannot call this function, as picoscroll is not initialised. Call picoscroll.init() first."
 #define BUFFER_TOO_SMALL_MSG "bytearray too small: len(image) < width * height."
@@ -60,6 +61,57 @@ mp_obj_t picoscroll_set_pixel(mp_obj_t x_obj, mp_obj_t y_obj, mp_obj_t v_obj) {
     return mp_const_none;
 }
 
+
+  mp_obj_t picoscroll_show_text(mp_obj_t text_obj, mp_obj_t brightness_obj, mp_obj_t offset_obj) {
+    if(scroll != nullptr) {
+        mp_buffer_info_t bufinfo;
+	unsigned char * buffer;
+	int text_len, bfr_len;
+	
+	mp_get_buffer_raise(text_obj, &bufinfo, MP_BUFFER_RW);
+	unsigned char * values = (unsigned char *) bufinfo.buf;
+        int brightness = mp_obj_get_int(brightness_obj);
+        int offset = mp_obj_get_int(offset_obj);
+	
+	text_len = bufinfo.len;
+	bfr_len = 6 * text_len;
+	
+	int width = PicoScroll::WIDTH;
+	int height = PicoScroll::HEIGHT;
+
+	// clear the scroll, so only need to write visible bytes
+	scroll->clear();
+
+	if ((offset < -width) || (offset > bfr_len)) {
+	    return mp_const_none;
+	}
+
+	// allocate buffer, render text, free buffer #TODO probably can do
+	// without the buffer here
+	
+	buffer = (unsigned char *) m_malloc (sizeof(unsigned char) * bfr_len);
+	render(values, text_len, buffer, bfr_len);
+	
+	for (int x = 0; x < width; x++) {
+	    int k = offset + x;
+	    if ((k >= 0) && (k < bfr_len)) {
+	        unsigned char col = buffer[k];
+		for (int y = 0; y < height; y++) {
+		    int val = brightness * ((col >> y) & 1);
+		    scroll->set_pixel(x, y, val);
+		}
+	    }
+	}
+	m_free(buffer);
+    } else {
+        mp_raise_msg(&mp_type_RuntimeError, NOT_INITIALISED_MSG);
+    }
+
+    return mp_const_none;
+}
+	
+  
+  
 mp_obj_t picoscroll_set_pixels(mp_obj_t image_obj) {
     if(scroll != nullptr) {
         mp_buffer_info_t bufinfo;

micropython/modules/pico_scroll/pico_scroll.h

@@ -8,6 +8,7 @@ extern mp_obj_t picoscroll_get_height();
 extern mp_obj_t picoscroll_update();
 extern mp_obj_t picoscroll_set_pixel(mp_obj_t x_obj, mp_obj_t y_obj, mp_obj_t v_obj);
 extern mp_obj_t picoscroll_set_pixels(mp_obj_t image_obj);
+extern mp_obj_t picoscroll_show_text(mp_obj_t text_obj, mp_obj_t brightness, mp_obj_t offset);
 extern mp_obj_t picoscroll_show_bitmap_1d(mp_obj_t bitmap_obj, mp_obj_t brightness, mp_obj_t offset);
 extern mp_obj_t picoscroll_clear();
 extern mp_obj_t picoscroll_is_pressed(mp_obj_t button_obj);

micropython/modules/pico_scroll/pico_scroll_font.c

@@ -143,4 +143,5 @@ int render(unsigned char *text, int nchr, unsigned char *buffer, int nbfr) {
 	}
 	buffer[i * 6 + 6] = 0x0;
     }
+    return 0;
 }