Question

我想将画布分成8个垂直的黑白条纹。我写了一个方法changeValue来在每次执行循环时更改颜色的值，但画布是完全白色的。我认为我的changeValue方法没有按照假设做，但我无法解释原因。

到目前为止，我得到了这个：

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;
        }
    }
}

我不应该为8条纹编写8 If语句，但这例如是意大利国旗的代码，它是3条垂直条纹但实际上有效：

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

如果您需要交替颜色条纹，那么您可以选择经典的奇数/偶数检查。而不是你下面的代码块

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

}

尝试替换这个

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

使用RGB将画布划分为多个条纹

1 个答案: