`stroke()` does not handle float values correctly

stroke() appears to mis-handle float inputs. When using floats (e.g. 150.0), the rendered color is incorrect

Expected behavior

Float values in the same range as integers should produce identical results, as in Processing.

Actual behavior

• stroke(150) → correct grayscale
• stroke(150.0) → renders as white

Reproduction (mewnala)

from mewnala import *

def setup():
    size(640, 360)
    background(255)

def draw():
    stroke(150.0)
    line(0, 0, width, height)
    line(width, 0, 0, height)

    stroke(155.0, 100.0, 0.0)
    line(0, height // 2, width, height // 2)
    line(width // 2, 0, width // 2, height)

run()

Equivalent Processing sketch (works as expected)

void setup() {
  size(640, 360);
  background(255);
}

void draw() {
  stroke(150.0);
  line(0, 0, width, height);
  line(width, 0, 0, height);

  stroke(155.0, 100.0, 0.0);
  line(0, height/2, width, height/2);
  line(width/2, 0, width/2, height);
}

首先定位 stroke() 的 Rust 實作，並執行提供的 mewnala 重現。以 Processing sketch 作為預期參考，比較整數和浮點灰階輸入及 RGB 輸入的處理方式。當等效的浮點值和整數值渲染出相同顏色，且在相關測試存在時包含相應的測試覆蓋，即視為完成。