java - Java初学者协调超出范围

我一直在学习如何旋转图片，并且必须将图片旋转180度和270度。我尚未开始使用270，而且似乎无法弄清楚如何解决越界错误。

public Picture rotate180()
{
    Picture rotated = new Picture ();

    for (int x = 0, roty = 0; x < getWidth(); x++, roty++)
    {
      for (int y = 0, rotx = getWidth()-1; y<getHeight(); y++, rotx--)
      {
        Pixel oldPixel = getPixel(x,y);
        Pixel newPixel = getPixel(rotx,roty);
        newPixel.setColor(oldPixel.getColor());
      }
    }
return rotated;
}

最佳答案

private enum Degree {
    _90_ {
        public Picture rotate(Picture picture) {
            Picture res = swapRowCol(new Picture(picture.height, picture.width), picture);

            // mirror each column
            for (int col = 0; col < res.width; col++)
                for (int row1 = 0, row2 = res.height - 1; row1 < row2; row1++, row2--)
                    swapColor(res, col, row1, col, row2);

            return res;
        }
    },
    _180_ {
        public Picture rotate(Picture picture) {
            Picture res = new Picture(picture.width, picture.height);

            // desc rows and mirror each one
            for (int row1 = 0, row2 = res.height - 1; row1 < res.height; row1++, row2--)
                for (int col1 = 0, col2 = picture.width - 1; col1 < picture.width; col1++, col2--)
                    res.getPixel(col2, row2).setColor(picture.getPixel(col1, row1).getColor());

            return res;
        }
    },
    _270_ {
        public Picture rotate(Picture picture) {
            Picture res = swapRowCol(new Picture(picture.height, picture.width), picture);

            // mirror each row
            for (int row = 0; row < res.height; row++)
                for (int col1 = 0, col2 = res.width - 1; col1 < col2; col1++, col2--)
                    swapColor(res, col1, row, col2, row);

            return res;
        }
    };

    public abstract Picture rotate(Picture picture);

    protected static Picture swapRowCol(Picture dst, Picture src) {
        // (x;y) -> (y;x)
        for (int row = 0; row < src.height; row++)
            for (int col = 0; col < src.width; col++)
                dst.getPixel(row, col).setColor(src.getPixel(col, row).getColor());

        return dst;
    }

    protected static void swapColor(Picture res, int srcCol, int srcRow, int dstCol, int dstRow) {
        Pixel pixel1 = res.getPixel(srcCol, srcRow);
        Pixel pixel2 = res.getPixel(dstCol, dstRow);
        int color = pixel1.getColor();
        pixel1.setColor(pixel2.getColor());
        pixel2.setColor(color);
    }
}