使用RGB將畫布分成多個條紋

Question

我想將畫布分成8個垂直的黑色和白色條紋。我寫了一個方法changeValue，每次循環執行時都改變顏色的值，但畫布完全是白色的。我認爲我的changeValue方法沒有按照假設做，但我無法解釋原因。

到目前爲止，我得到這個：

public class Stripe { 

    public boolean switch = false; 

    private void stripes(int[] pixels, int width, int height) { 
     // TODO set some values here 
     int counter = 1; 
     for (int y = 0; y < height; y++) { 
      for (int x = 0; x < width; x++) { 
       int pos = y * width + x; 
       int r, g, b; 
       // TODO code for the flag. 
       r = 255; 
       g = 255; 
       b = 255; 

       for (int i = 0; i < 8; i++) { 
        if (x < (counter * (width - 1))/8) { 
         r = changeValue(); 
         g = changeValue(); 
         b = changeValue(); 
        } 
        counter++; 
        switch ^= true; 

       } 

       pixels[pos] = 0xFF000000 | (r << 16) | (g << 8) | b; 
      } 
     } 
    } 

    public int changeValue() { 
     if (switch) { 
      return 255; 
     } else { 
      return 0; 
     } 
    } 
} 

我應該不要寫8如果語句爲8條，但本作例子是意大利國旗的3個豎條紋但實際工作的代碼：

private void flagItalian(int[] pixels, int width, int height) { 
    // TODO set some values here 
    for (int y = 0; y < height; y++) { 
     for (int x = 0; x < width; x++) { 
      int pos = y * width + x; 
      int r, g, b; 
      // TODO code for the flag. 
      r = 255; 
      g = 0; 
      b = 0; 
      if (x < 2 * (width - 1)/3) { 
       r = 255; 
       g = 255; 
       b = 255; 
      } 
      if (x < (width - 1)/3) { 
       r = 0; 
       g = 255; 
       b = 0; 
      } 
      pixels[pos] = 0xFF000000 | (r << 16) | (g << 8) | b; 
     } 
    } 
} 

Answer 1

如果你需要交替顏色條紋，那麼你可以去經典的奇數/偶數檢查。相反的，你下面的代碼塊

for (int i = 0; i < 8; i++) { 
    if (x < (counter * (width - 1))/8) { 
    r = changeValue(); 
    g = changeValue(); 
    b = changeValue(); 
    } 
counter++; 
switch ^= true; 

} 

嘗試用這一個

if (x%2) { 
    r = 255; 
    g = 255; 
    b = 255 
} else { 
    r = 0; 
    g = 0; 
    b = 0; 
}