I am trying to draw the vertical dotted line. If i try to draw horizontal line and rotate it, it rotates the whole image. So how can i rotate only line or text without rotating the whole image.
how do you draw the dotted line?
i dont think its a nice way but i am trying something like this
dotline = x * “.”
and use cvputtext
in C++ you could have used OpenCV’s LineIterator. that thing implements bresenham.
in python, that’s not accessible.
if you just want vertical/horizontal lines, not angled, you don’t even need bresenham.
just set the pixels yourself.
use numba's @njit decorator to compile the python code. or leave it off. the code is simple enough, won’t take long.
a single such draw call takes maybe 20-50 microseconds on my system.
from numba import njit
@njit
def dashed_vertical_line(img, x, y0, y1, color, stroke=5, gap=5):
stride = stroke + gap
for y in range(y0, y1):
if (y % stride) < stroke:
img[y,x] = color
im = cv.imread(cv.samples.findFile("lena.jpg"))
dashed_vertical_line(im, x=256, y0=64, y1=384, color=(255,0,0))
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