pybricks.hubs.PrimeHub: Use new awaitable for text animation.

Now that we can have protothreads as the iterable function, we can trivially do these in C instead of importing Python code from C.

Now they can correctly be cancelled, too. A new text animation will take over and stop any ongoing ones.

Author: laurensvalk

bricks/primehub/manifest.py

@@ -2,4 +2,3 @@
 include("../_common/manifest.py")
 
 freeze_as_mpy("../primehub/modules", "_imu_calibrate.py")
-freeze_as_mpy("../primehub/modules", "_light_matrix.py")

bricks/primehub/modules/_light_matrix.py

@@ -12,6 +12,7 @@
 #include "py/objstr.h"
 
 #include <pybricks/common.h>
+#include <pybricks/tools/pb_type_async.h>
 #include <pybricks/tools/pb_type_matrix.h>
 #include <pybricks/parameters.h>
 
@@ -20,15 +21,22 @@
 #include <pybricks/util_mp/pb_kwarg_helper.h>
 #include <pybricks/util_mp/pb_type_enum.h>
 
+typedef struct {
+    mp_obj_t string_obj;
+    pbio_os_timer_t timer;
+    uint32_t idx;
+    uint32_t on_time;
+    uint32_t off_time;
+} text_animation_state_t;
 
 // pybricks._common.LightMatrix class object
 typedef struct _common_LightMatrix_obj_t {
     mp_obj_base_t base;
     pbio_light_matrix_t *light_matrix;
     uint8_t *data;
     uint8_t frames;
-    // Frozen Python implementation of the async text() method.
-    mp_obj_t async_text_method;
+    pb_type_async_t *text_iter;
+    text_animation_state_t text;
 } common_LightMatrix_obj_t;
 
 // Renews memory for a given number of frames
@@ -273,53 +281,66 @@ static mp_obj_t common_LightMatrix_pixel(size_t n_args, const mp_obj_t *pos_args
 }
 static MP_DEFINE_CONST_FUN_OBJ_KW(common_LightMatrix_pixel_obj, 1, common_LightMatrix_pixel);
 
-// pybricks._common.LightMatrix.text
-static mp_obj_t common_LightMatrix_text(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    PB_PARSE_ARGS_METHOD(n_args, pos_args, kw_args,
-        common_LightMatrix_obj_t, self,
-        PB_ARG_REQUIRED(text),
-        PB_ARG_DEFAULT_INT(on, 500),
-        PB_ARG_DEFAULT_INT(off, 50));
+static pbio_error_t pb_type_lightmatrix_text_iterate_once(pbio_os_state_t *state, mp_obj_t parent_obj) {
 
-    if (pb_module_tools_run_loop_is_active()) {
-        if (self->async_text_method == MP_OBJ_NULL) {
-            self->async_text_method = pb_function_import_helper(MP_QSTR__light_matrix, MP_QSTR_light_matrix_text_async);
+    common_LightMatrix_obj_t *self = MP_OBJ_TO_PTR(parent_obj);
+    text_animation_state_t *text = &self->text;
+    pbio_error_t err;
+
+    size_t len;
+    const char *data = mp_obj_str_get_data(text->string_obj, &len);
+
+    PBIO_OS_ASYNC_BEGIN(state);
+
+    for (text->idx = 0; text->idx < len; text->idx++) {
+
+        // Raise on invalid character.
+        if (text->idx >= len || data[text->idx] < 32 || data[text->idx] > 126) {
+            return PBIO_ERROR_INVALID_ARG;
         }
-        mp_obj_t args[] = {
-            MP_OBJ_FROM_PTR(self),
-            text_in,
-            on_in,
-            off_in,
-        };
-        return mp_call_function_n_kw(self->async_text_method, MP_ARRAY_SIZE(args), 0, args);
-    }
 
-    // Assert that the input is a single text
-    GET_STR_DATA_LEN(text_in, text, text_len);
+        // On time.
+        err = pbio_light_matrix_set_rows(self->light_matrix, pb_font_5x5[data[text->idx] - 32]);
+        if (err != PBIO_SUCCESS) {
+            return err;
+        }
+        PBIO_OS_AWAIT_MS(state, &text->timer, text->on_time);
 
-    // Make sure all characters are valid
-    for (size_t i = 0; i < text_len; i++) {
-        if (text[0] < 32 || text[0] > 126) {
-            pb_assert(PBIO_ERROR_INVALID_ARG);
+        // Off time so we can see multiple of the same characters.
+        if (text->off_time > 0 || text->idx == len - 1) {
+            err = pbio_light_matrix_clear(self->light_matrix);
+            if (err != PBIO_SUCCESS) {
+                return err;
+            }
+            PBIO_OS_AWAIT_MS(state, &text->timer, text->off_time);
         }
     }
 
-    mp_int_t on = pb_obj_get_int(on_in);
-    mp_int_t off = pb_obj_get_int(off_in);
+    PBIO_OS_ASYNC_END(PBIO_SUCCESS);
+}
 
-    // Display all characters one by one
-    for (size_t i = 0; i < text_len; i++) {
-        pb_assert(pbio_light_matrix_set_rows(self->light_matrix, pb_font_5x5[text[i] - 32]));
-        mp_hal_delay_ms(on);
+// pybricks._common.LightMatrix.text
+static mp_obj_t common_LightMatrix_text(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    PB_PARSE_ARGS_METHOD(n_args, pos_args, kw_args,
+        common_LightMatrix_obj_t, self,
+        PB_ARG_REQUIRED(text),
+        PB_ARG_DEFAULT_INT(on, 500),
+        PB_ARG_DEFAULT_INT(off, 50));
 
-        // Some off time so we can see multiple of the same characters
-        if (off > 0 || i == text_len - 1) {
-            pb_assert(pbio_light_matrix_clear(self->light_matrix));
-            mp_hal_delay_ms(off);
-        }
-    }
+    text_animation_state_t *text = &self->text;
 
-    return mp_const_none;
+    text->on_time = pb_obj_get_int(on_in);
+    text->off_time = pb_obj_get_int(off_in);
+    text->idx = 0;
+    text->string_obj = text_in;
+
+    pb_type_async_t config = {
+        .parent_obj = MP_OBJ_FROM_PTR(self),
+        .iter_once = pb_type_lightmatrix_text_iterate_once,
+    };
+    // New operation always wins; ongoing animation is cancelled.
+    pb_type_async_schedule_cancel(self->text_iter);
+    return pb_type_async_wait_or_await(&config, &self->text_iter);
 }
 static MP_DEFINE_CONST_FUN_OBJ_KW(common_LightMatrix_text_obj, 1, common_LightMatrix_text);
 
@@ -348,7 +369,7 @@ mp_obj_t pb_type_LightMatrix_obj_new(pbio_light_matrix_t *light_matrix) {
     common_LightMatrix_obj_t *self = mp_obj_malloc(common_LightMatrix_obj_t, &pb_type_LightMatrix);
     self->light_matrix = light_matrix;
     pbio_light_matrix_set_orientation(light_matrix, PBIO_GEOMETRY_SIDE_TOP);
-    self->async_text_method = MP_OBJ_NULL;
+    self->text_iter = NULL;
     return MP_OBJ_FROM_PTR(self);
 }