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@louisswarren
Last active June 12, 2023 08:39
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ctypes example
from ctypes import *
import sys
class Colour(Structure):
_fields_ = [(c, c_uint8) for c in "rgb"]
foo = cdll.LoadLibrary('./image.so')
# foo.setup_image
foo.add_point.argtypes = (c_int, c_int, Colour)
foo.colour.argtypes = (c_uint8, c_uint8, c_uint8)
foo.colour.restype = Colour
# foo.write_image
foo.setup_image()
# We can define colours either using the C function or the above class
red = foo.colour(255, 0, 0)
blue = Colour(0, 0, 255)
for i in range(10, 50):
for j in range(10, 50):
if foo.add_point(i, j, red):
print("Failed add point", file=sys.stderr)
for i in range(30, 70):
for j in range(30, 70):
if foo.add_point(i, j, blue):
print("Failed add point", file=sys.stderr)
if foo.write_image():
print("Failed to write image", file=sys.stderr)
#include <stdint.h>
#include <stdio.h>
struct colour {
uint8_t r, g, b;
} image[80][80];
void
setup_image(void)
{
for (int y = 0; y < 80; y++) {
for (int x = 0; x < 80; x++) {
image[x][y].r = 0;
image[x][y].g = 0;
image[x][y].b = 0;
}
}
}
int
add_point(int x, int y, struct colour p)
{
if (x < 0 || x >= 80 || y < 0 || y >= 80)
return 1;
image[x][y] = p;
return 0;
}
struct colour
colour(int r, int g, int b)
{
return (struct colour){(uint8_t)r, (uint8_t)g, (uint8_t)b};
}
int
write_image(void)
{
int r = 0 > printf("P3\n%d %d\n%d\n", 80, 80, 255);
for (int y = 0; y < 80; y++) {
for (int x = 0; x < 80; x++) {
r |= 0 > printf("%d %d %d ",
image[x][y].r,
image[x][y].g,
image[x][y].b);
}
printf("\n");
}
return r;
}
void
say_hello(int x)
{
printf("Hello: %d\n", x);
}
.PHONY: default
default: out.png
%.png: %.ppm
convert $< $@
out.ppm: draw.py image.so
python3 $< > $@
image.so: image.c
$(CC) $(CFLAGS) $(LDFLAGS) -fPIC -shared -o $@ $<
.PHONY: clean
clean:
rm -f image.so out.png out.ppm
@louisswarren
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