如何计算具有起点 (x,y) 、像素长度和角度的像素坐标？

Question

I have an image 640 x 640 and I'd like to draw the line on it. Common task where package like PIL allows me to write a line using

line(x1,y1,x2,y2)

where x1,y1 is start the and x2,y2 is end line coordinates. I have a different task where I have x1,y1 and line length in pixels with angle of direction. How to calculate x2,y2 having those data only?
Thanks Erick

As per stackoverflow.com Admins advice I'm modifying this comment instead of posting answer separately below to provide code to my question plus one doubt that this code works with 0 (zero) angle drawing straight line towards right hand site as it should however 90 degree angle looks like more 110 or something as per picture. What am I doing wrong ? Thanks again in advance.

 import math from PIL import Image, ImageDraw def calc_x2y2(length, angle, x1,y1): x2 = x1 + math.cos(angle)*length y2 = y1 + math.sin(angle)*length return (x2,y2) w, h = 640, 640 x1,y1 = w/2, h/2 shape = [(x1,y1), calc_x2y2(300,90,x1,y1)] # creating new Image object img = Image.new("RGB", (w, h),(225,225,225)) # create line on the image img1 = ImageDraw.Draw(img) img1.line(shape, fill="#401eba", width=5) img.show()

Straight line that should be 90 degree except it's not

Answer 1

sin(θ) is perpendicular/hypotenuse and cos(θ) is base/hypotenuse . So, this becomes a simple math's problem, where y2 = y1 + L.sin(θ) and x2 = x1 + L.cos(θ). Hence, the new co-ordinates are:

(y2 = y1 + L.sin(θ), x2 = x1 + L.cos(θ))

where L = length of line θ = angle between line and X - axis

Answer 2

You can make a right angle triangle with given information. from there we can see that

sin(A) = p/h cos(A) = b/h --- (1)

Where h is length of line and A is angle h makes with b(base) and p is perpendicular .

We also know that

X2 = X1+b and Y2 = Y1+p --- (2)

Replacing p and b in (2) with (1) you will get

X2 = X1+cos(A)*h
Y2 = Y1+sin(A)*h