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dunkmann00dunkmann00
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Implement negative step for pixelbuf slices
1 parent eea01c3 commit 16ffc73

3 files changed

Lines changed: 25 additions & 19 deletions

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‎shared-bindings/_pixelbuf/PixelBuf.c‎

Lines changed: 13 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -300,17 +300,20 @@ STATIC mp_obj_t pixelbuf_pixelbuf_subscr(mp_obj_t self_in, mp_obj_t index_in, mp
300300
size_t length = common_hal__pixelbuf_pixelbuf_get_len(self_in);
301301
mp_seq_get_fast_slice_indexes(length, index_in, &slice);
302302

303-
if (slice.step < 0) {
304-
mp_raise_IndexError(translate("Negative step not supported"));
303+
size_t slice_len;
304+
if (slice.step > 0) {
305+
slice_len = slice.stop - slice.start;
306+
}else{
307+
slice_len = 1 + slice.start - slice.stop;
308+
}
309+
if (slice.step > 1 || slice.step < -1) {
310+
size_t step = slice.step > 0 ? slice.step : slice.step * -1;
311+
slice_len = (slice_len / step) + (slice_len % step ? 1 : 0);
305312
}
306313

307314
if (value == MP_OBJ_SENTINEL) { // Get
308-
size_t len = slice.stop - slice.start;
309-
if (slice.step > 1) {
310-
len = (len / slice.step) + (len % slice.step ? 1 : 0);
311-
}
312-
mp_obj_tuple_t* t = MP_OBJ_TO_PTR(mp_obj_new_tuple(len, NULL));
313-
for (uint i = 0; i < len; i++) {
315+
mp_obj_tuple_t* t = MP_OBJ_TO_PTR(mp_obj_new_tuple(slice_len, NULL));
316+
for (uint i = 0; i < slice_len; i++) {
314317
t->items[i] = common_hal__pixelbuf_pixelbuf_get_pixel(self_in, i * slice.step + slice.start);
315318
}
316319
return MP_OBJ_FROM_PTR(t);
@@ -321,10 +324,6 @@ STATIC mp_obj_t pixelbuf_pixelbuf_subscr(mp_obj_t self_in, mp_obj_t index_in, mp
321324
mp_raise_ValueError(translate("tuple/list required on RHS"));
322325
}
323326

324-
size_t dst_len = (slice.stop - slice.start);
325-
if (slice.step > 1) {
326-
dst_len = (dst_len / slice.step) + (dst_len % slice.step ? 1 : 0);
327-
}
328327
mp_obj_t *src_objs;
329328
size_t num_items;
330329
if (MP_OBJ_IS_TYPE(value, &mp_type_list)) {
@@ -336,9 +335,9 @@ STATIC mp_obj_t pixelbuf_pixelbuf_subscr(mp_obj_t self_in, mp_obj_t index_in, mp
336335
num_items = l->len;
337336
src_objs = l->items;
338337
}
339-
if (num_items != dst_len) {
338+
if (num_items != slice_len) {
340339
mp_raise_ValueError_varg(translate("Unmatched number of items on RHS (expected %d, got %d)."),
341-
dst_len, num_items);
340+
slice_len, num_items);
342341
}
343342

344343
common_hal__pixelbuf_pixelbuf_set_pixels(self_in, slice.start, slice.stop, slice.step, src_objs);

‎shared-bindings/_pixelbuf/PixelBuf.h‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -47,6 +47,6 @@ void common_hal__pixelbuf_pixelbuf_fill(mp_obj_t self, mp_obj_t item);
4747
void common_hal__pixelbuf_pixelbuf_show(mp_obj_t self);
4848
mp_obj_t common_hal__pixelbuf_pixelbuf_get_pixel(mp_obj_t self, size_t index);
4949
void common_hal__pixelbuf_pixelbuf_set_pixel(mp_obj_t self, size_t index, mp_obj_t item);
50-
void common_hal__pixelbuf_pixelbuf_set_pixels(mp_obj_t self_in, size_t start, size_t stop, size_t step, mp_obj_t* values);
50+
void common_hal__pixelbuf_pixelbuf_set_pixels(mp_obj_t self_in, size_t start, size_t stop, mp_int_t step, mp_obj_t* values);
5151

5252
#endif // CP_SHARED_BINDINGS_PIXELBUF_PIXELBUF_H

‎shared-module/_pixelbuf/PixelBuf.c‎

Lines changed: 11 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -216,12 +216,19 @@ void _pixelbuf_set_pixel(pixelbuf_pixelbuf_obj_t* self, size_t index, mp_obj_t v
216216
_pixelbuf_set_pixel_color(self, index, r, g, b, w);
217217
}
218218

219-
void common_hal__pixelbuf_pixelbuf_set_pixels(mp_obj_t self_in, size_t start, size_t stop, size_t step, mp_obj_t* values) {
219+
void common_hal__pixelbuf_pixelbuf_set_pixels(mp_obj_t self_in, size_t start, size_t stop, mp_int_t step, mp_obj_t* values) {
220220
pixelbuf_pixelbuf_obj_t* self = native_pixelbuf(self_in);
221221
size_t source_i = 0;
222-
for (size_t target_i = start; target_i < stop; target_i += step) {
223-
_pixelbuf_set_pixel(self, target_i, values[source_i]);
224-
source_i++;
222+
if (step > 0) {
223+
for (size_t target_i = start; target_i < stop; target_i += step) {
224+
_pixelbuf_set_pixel(self, target_i, values[source_i]);
225+
source_i++;
226+
}
227+
}else{
228+
for (size_t target_i = start; target_i >= stop; target_i += step) {
229+
_pixelbuf_set_pixel(self, target_i, values[source_i]);
230+
source_i++;
231+
}
225232
}
226233
if (self->auto_write) {
227234
common_hal__pixelbuf_pixelbuf_show(self_in);

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