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extmod/framebuf: Add polygon drawing methods. #8987

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15 changes: 13 additions & 2 deletions docs/library/framebuf.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -11,8 +11,8 @@ class FrameBuffer
-----------------

The FrameBuffer class provides a pixel buffer which can be drawn upon with
pixels, lines, rectangles, text and even other FrameBuffer's. It is useful
when generating output for displays.
pixels, lines, rectangles, polygons, text and even other FrameBuffers. It is
useful when generating output for displays.

For example::

Expand Down Expand Up @@ -84,6 +84,17 @@ The following methods draw shapes onto the FrameBuffer.
method draws only a 1 pixel outline whereas the `fill_rect` method
draws both the outline and interior.

.. method:: FrameBuffer.poly(x, y, coords, c)
.. method:: FrameBuffer.fill_poly(x, y, coords, c)

Given a list of coordinates, draw an arbitrary (convex or concave) closed
polygon at the given x, y location using the given color. The `poly`
method draws polygon edges as 1 pixel lines whereas the `fill_poly` method
draws filled polygons. For both methods, *coords* may be specified as a
list of x, y tuples, e.g. ``[(x0, y0), (x1, y1), ... (xn, yn)]`` or as an
:mod:`array`, e.g. ``array('h', [x0, y0, x1, y1, ... xn, yn])``.


Drawing text
------------

Expand Down
202 changes: 186 additions & 16 deletions extmod/modframebuf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,7 @@
#include <string.h>

#include "py/runtime.h"
#include "py/binary.h"

#if MICROPY_PY_FRAMEBUF

Expand Down Expand Up @@ -404,16 +405,7 @@ STATIC mp_obj_t framebuf_rect(size_t n_args, const mp_obj_t *args) {
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(framebuf_rect_obj, 6, 6, framebuf_rect);

STATIC mp_obj_t framebuf_line(size_t n_args, const mp_obj_t *args) {
(void)n_args;

mp_obj_framebuf_t *self = MP_OBJ_TO_PTR(args[0]);
mp_int_t x1 = mp_obj_get_int(args[1]);
mp_int_t y1 = mp_obj_get_int(args[2]);
mp_int_t x2 = mp_obj_get_int(args[3]);
mp_int_t y2 = mp_obj_get_int(args[4]);
mp_int_t col = mp_obj_get_int(args[5]);

STATIC void line(const mp_obj_framebuf_t *fb, mp_int_t x1, mp_int_t y1, mp_int_t x2, mp_int_t y2, mp_int_t col) {
mp_int_t dx = x2 - x1;
mp_int_t sx;
if (dx > 0) {
Expand Down Expand Up @@ -452,12 +444,12 @@ STATIC mp_obj_t framebuf_line(size_t n_args, const mp_obj_t *args) {
mp_int_t e = 2 * dy - dx;
for (mp_int_t i = 0; i < dx; ++i) {
if (steep) {
if (0 <= y1 && y1 < self->width && 0 <= x1 && x1 < self->height) {
setpixel(self, y1, x1, col);
if (0 <= y1 && y1 < fb->width && 0 <= x1 && x1 < fb->height) {
setpixel(fb, y1, x1, col);
}
} else {
if (0 <= x1 && x1 < self->width && 0 <= y1 && y1 < self->height) {
setpixel(self, x1, y1, col);
if (0 <= x1 && x1 < fb->width && 0 <= y1 && y1 < fb->height) {
setpixel(fb, x1, y1, col);
}
}
while (e >= 0) {
Expand All @@ -468,14 +460,190 @@ STATIC mp_obj_t framebuf_line(size_t n_args, const mp_obj_t *args) {
e += 2 * dy;
}

if (0 <= x2 && x2 < self->width && 0 <= y2 && y2 < self->height) {
setpixel(self, x2, y2, col);
if (0 <= x2 && x2 < fb->width && 0 <= y2 && y2 < fb->height) {
setpixel(fb, x2, y2, col);
}
}

STATIC mp_obj_t framebuf_line(size_t n_args, const mp_obj_t *args) {
(void)n_args;

mp_obj_framebuf_t *self = MP_OBJ_TO_PTR(args[0]);
mp_int_t x1 = mp_obj_get_int(args[1]);
mp_int_t y1 = mp_obj_get_int(args[2]);
mp_int_t x2 = mp_obj_get_int(args[3]);
mp_int_t y2 = mp_obj_get_int(args[4]);
mp_int_t col = mp_obj_get_int(args[5]);

line(self, x1, y1, x2, y2, col);

return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(framebuf_line_obj, 6, 6, framebuf_line);

STATIC mp_obj_t framebuf_poly(size_t n_args, const mp_obj_t *args) {
(void)n_args;

mp_obj_framebuf_t *self = MP_OBJ_TO_PTR(args[0]);

mp_int_t x = mp_obj_get_int(args[1]);
mp_int_t y = mp_obj_get_int(args[2]);

size_t poly_len;
mp_buffer_info_t bufinfo;
mp_obj_t *polygon;

bool is_buffer = mp_get_buffer(args[3], &bufinfo, MP_BUFFER_READ);
if (is_buffer) {
poly_len = bufinfo.len / (mp_binary_get_size('@', bufinfo.typecode, NULL) * 2);
} else {
mp_obj_get_array(args[3], &poly_len, &polygon);
}

if (poly_len == 0) {
return mp_const_none;
}

mp_int_t col = mp_obj_get_int(args[4]);

mp_int_t px1, py1, px2, py2;

if (is_buffer) {
px1 = x + mp_obj_get_int(mp_binary_get_val_array(bufinfo.typecode, bufinfo.buf, (poly_len - 1) * 2));
py1 = y + mp_obj_get_int(mp_binary_get_val_array(bufinfo.typecode, bufinfo.buf, (poly_len - 1) * 2 + 1));
} else {
mp_obj_t *point;
mp_obj_get_array_fixed_n(polygon[poly_len - 1], 2, &point);
px1 = x + mp_obj_get_int(point[0]);
py1 = y + mp_obj_get_int(point[1]);
}

for (size_t i = 0; i < poly_len; i++) {
if (is_buffer) {
px2 = x + mp_obj_get_int(mp_binary_get_val_array(bufinfo.typecode, bufinfo.buf, i * 2));
py2 = y + mp_obj_get_int(mp_binary_get_val_array(bufinfo.typecode, bufinfo.buf, i * 2 + 1));
} else {
mp_obj_t *point;
mp_obj_get_array_fixed_n(polygon[i], 2, &point);
px2 = x + mp_obj_get_int(point[0]);
py2 = y + mp_obj_get_int(point[1]);
}

line(self, px1, py1, px2, py2, col);
px1 = px2;
py1 = py2;
}
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(framebuf_poly_obj, 5, 5, framebuf_poly);

STATIC mp_obj_t framebuf_fill_poly(size_t n_args, const mp_obj_t *args) {
(void)n_args;

mp_obj_framebuf_t *self = MP_OBJ_TO_PTR(args[0]);

mp_int_t x = mp_obj_get_int(args[1]);
mp_int_t y = mp_obj_get_int(args[2]);

size_t poly_len;
mp_buffer_info_t bufinfo;
mp_obj_t *polygon;

bool is_buffer = mp_get_buffer(args[3], &bufinfo, MP_BUFFER_READ);
if (is_buffer) {
poly_len = bufinfo.len / (mp_binary_get_size('@', bufinfo.typecode, NULL) * 2);
} else {
mp_obj_get_array(args[3], &poly_len, &polygon);
}

if (poly_len == 0) {
return mp_const_none;
}

mp_int_t col = mp_obj_get_int(args[4]);

mp_int_t px, py;
mp_int_t y_min = INT_MAX, y_max = INT_MIN;

mp_int_t *points = m_malloc(poly_len * 2 * sizeof(mp_int_t));
for (size_t i = 0; i < poly_len; i++) {
if (is_buffer) {
px = x + mp_obj_get_int(mp_binary_get_val_array(bufinfo.typecode, bufinfo.buf, i * 2));
py = y + mp_obj_get_int(mp_binary_get_val_array(bufinfo.typecode, bufinfo.buf, i * 2 + 1));
} else {
mp_obj_t *point;
mp_obj_get_array_fixed_n(polygon[i], 2, &point);
px = x + mp_obj_get_int(point[0]);
py = y + mp_obj_get_int(point[1]);
}

points[i * 2] = px;
points[i * 2 + 1] = py;
if (py < y_min) {
y_min = py;
}
if (py > y_max) {
y_max = py;
}
}

mp_int_t nodes[poly_len];
for (mp_int_t row = y_min; row <= y_max; row++) {
size_t node_count = 0;
mp_int_t px1 = points[(poly_len - 1) * 2];
mp_int_t py1 = points[(poly_len - 1) * 2 + 1];
for (size_t i = 0; i < poly_len; i++) {
mp_int_t px2 = points[i * 2];
mp_int_t py2 = points[i * 2 + 1];

// Find the x-coord of where the polygon side intersects the current row
if (py1 != py2
&& ((py1 > row && py2 <= row) || (py1 <= row && py2 > row))) {
float node = px1
+ (float)(row - py1) / (float)(py2 - py1)
* (px2 - px1);
if (node - (mp_int_t)node <= 0.5f) {
nodes[node_count++] = (mp_int_t)(node);
} else {
nodes[node_count++] = (mp_int_t)(node + 1);
}
}

px1 = px2;
py1 = py2;
}

size_t idx = 0;
if (node_count > 0) {
while (idx < node_count - 1) {
if (nodes[idx] > nodes[idx + 1]) {
mp_int_t swap = nodes[idx];
nodes[idx] = nodes[idx + 1];
nodes[idx + 1] = swap;
if (idx) {
idx--;
}
} else {
idx++;
}
}
}

for (size_t i = 0; i < node_count; i += 2) {
fill_rect(self, nodes[i], row, (nodes[i + 1] - nodes[i]) + 1, 1, col);
}
}

m_free(points
#if MICROPY_MALLOC_USES_ALLOCATED_SIZE
, poly_len * 2 * sizeof(mp_int_t)
#endif
);

return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(framebuf_fill_poly_obj, 5, 5, framebuf_fill_poly);

STATIC mp_obj_t framebuf_blit(size_t n_args, const mp_obj_t *args) {
mp_obj_framebuf_t *self = MP_OBJ_TO_PTR(args[0]);
mp_obj_t source_in = mp_obj_cast_to_native_base(args[1], MP_OBJ_FROM_PTR(&mp_type_framebuf));
Expand Down Expand Up @@ -610,6 +778,8 @@ STATIC const mp_rom_map_elem_t framebuf_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_vline), MP_ROM_PTR(&framebuf_vline_obj) },
{ MP_ROM_QSTR(MP_QSTR_rect), MP_ROM_PTR(&framebuf_rect_obj) },
{ MP_ROM_QSTR(MP_QSTR_line), MP_ROM_PTR(&framebuf_line_obj) },
{ MP_ROM_QSTR(MP_QSTR_poly), MP_ROM_PTR(&framebuf_poly_obj) },
{ MP_ROM_QSTR(MP_QSTR_fill_poly), MP_ROM_PTR(&framebuf_fill_poly_obj) },
{ MP_ROM_QSTR(MP_QSTR_blit), MP_ROM_PTR(&framebuf_blit_obj) },
{ MP_ROM_QSTR(MP_QSTR_scroll), MP_ROM_PTR(&framebuf_scroll_obj) },
{ MP_ROM_QSTR(MP_QSTR_text), MP_ROM_PTR(&framebuf_text_obj) },
Expand Down
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