public static int[][] Rotate(int[][] mat, double alpha, DoublePoint c, int bg)
{
int width = mat.Length;
int height = mat[0].Length;
int[][] newImg = Util.BuildMatInt(width, height);
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
double[] input = new double[] { y - c.Y, x - c.X, 1 };
double[] output = NcvMatrix.RotateInvert(input, alpha);
int oldY = (int)Math.Round(output[0] + c.Y);
int oldX = (int)Math.Round(output[1] + c.X);
if (Util.InRect(oldX, oldY, width, height))
{
newImg[x][y] = mat[oldX][oldY];
}
else
{
newImg[x][y] = bg;
}
}
}
return(newImg);
}
/// <summary>
/// foamliu, 2009/02/02, 彩色图片旋转.
/// </summary>
/// <param name="bmp"></param>
/// <param name="alpha">旋转角度(弧度)</param>
/// <param name="bi">bilinear interpolation (双线性插值)</param>
/// <returns></returns>
public static Bitmap Rotate(Bitmap bmp, double alpha, bool bi)
{
int width, height;
int[][][] img, newImg;
Bitmap newBmp;
ImageConvert.Bitmap2MatColor(bmp, out img, out width, out height);
newImg = Util.BuildMatIntColor(width, height);
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
if (!bi)
{
double[] input = new double[] { y, x, 1 };
double[] output = NcvMatrix.RotateInvert(input, alpha);
int oldY = (int)Math.Round(output[0]);
int oldX = (int)Math.Round(output[1]);
if (Util.InRect(oldX, oldY, width, height))
{
// RGB
newImg[0][x][y] = img[0][oldX][oldY];
newImg[1][x][y] = img[1][oldX][oldY];
newImg[2][x][y] = img[2][oldX][oldY];
}
}
else
{
// p00 ------------- p01
// | |
// p10 ------------- p11
//
// 双线性插值需要更长的计算时间 (原来的5倍以上)
//
double[] input = new double[] { y, x, 1 };
double[] output = NcvMatrix.RotateInvert(input, alpha);
double newY = output[0];
double newX = output[1];
int p00Y = (int)Math.Floor(newY);
int p00X = (int)Math.Floor(newX);
int p01Y = (int)Math.Floor(newY);
int p01X = (int)Math.Ceiling(newX);
int p10Y = (int)Math.Ceiling(newY);
int p10X = (int)Math.Floor(newX);
int p11Y = (int)Math.Ceiling(newY);
int p11X = (int)Math.Ceiling(newX);
if (Util.InRect(p00X, p00Y, width, height)
&& Util.InRect(p01X, p01Y, width, height)
&& Util.InRect(p10X, p10Y, width, height)
&& Util.InRect(p11X, p11Y, width, height))
{
double a = newY - p00Y;
double b = newX - p00X;
for (int c = 0; c < 3; c++)
{
int g00 = img[c][p00X][p00Y];
int g01 = img[c][p01X][p01Y];
int g10 = img[c][p10X][p10Y];
int g11 = img[c][p11X][p11Y];
double g = b * (a * g11 + (1 - a) * g01) + (1 - b) * (a * g01 + (1 - a) * g00);
newImg[c][x][y] = (byte)Math.Round(g);
}
}
}
}
}
ImageConvert.Mat2BitmapColor(newImg, width, height, out newBmp);
return newBmp;
}