/// <summary>
/// 比率 s,t を求める
/// </summary>
/// <param name="p">形状変形パラメータ</param>
/// <param name="s">[out]比率(横方向)</param>
/// <param name="t">[out]比率(縦方向)</param>
/// <returns>true:範囲内, false:範囲外</returns>
private static bool ResolveEqu(TfParam p, out double s, out double t)
{
s = -1.0;
t = -1.0;
double sa = -1.0;
double ta = -1.0;
double sb = -1.0;
double tb = -1.0;
double p1 = (p.a * p.h - p.f * p.c);
double p2 = (p.d * p.f - p.c * p.g + p.b * p.h - p.a * p.e);
double p3 = (p.d * p.g - p.b * p.e);
double tm;
if (p1 == 0.0)
{
s = (p.d / p.b);
t = (p.b * p.e - p.d * p.g) / (p.b * p.h + p.d * p.f);
//return true;
}
else if (Resolve2Equ(p1, p2, p3, out ta, out tb))
{
tm = (p.a * ta + p.b);
if (tm != 0.0)
{
sa = (p.d - p.c * ta) / tm;
}
tm = (p.a * tb + p.b);
if (tm != 0.0)
{
sb = (p.d - p.c * tb) / tm;
}
if ((0 <= sa && sa <= 1.0) && (0 <= ta && ta <= 1.0))
{
s = sa;
t = ta;
}
else if ((0 <= sb && sb <= 1.0) && (0 <= tb && tb <= 1.0))
{
s = sb;
t = tb;
}
}
return(s != -1.0 && t != -1.0);
}
/// <summary>
/// 変形処理
/// </summary>
/// <param name="srcImg">元画像</param>
/// <param name="destImg">[out] 変形後画像</param>
/// <param name="pt">変形後画像の頂点情報</param>
/// <returns>true:成功, false:失敗</returns>
public static bool Transform(Bitmap srcImg, out Bitmap destImg, List <Point> pt)
{
System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();
sw.Reset();
sw.Start();
destImg = null;
BitmapByte srcByte = new BitmapByte();
BitmapByte destByte = new BitmapByte();
Color pxCol = Color.FromArgb(0, 0, 0, 0);
Color bgCol = Color.FromArgb(0, 0, 0, 0);
TfParam p = new TfParam();
int calcWidth, calcHeight;
int destWidth, destHeight;
double xa, ya, xb, yb, xc, yc, xd, yd;
double s, t; // 対象画素の元画像に対する比率 (0 <= s,t <=1)
double tx, ty; // 変形後の座標
try
{
destWidth = pt[0].X;
destHeight = pt[0].Y;;
for (int i = 1; i < pt.Count; i++)
{
if (destWidth < pt[i].X)
{
destWidth = pt[i].X;
}
if (destHeight < pt[i].Y)
{
destHeight = pt[i].Y;
}
}
destWidth++;
destHeight++;
destImg = new Bitmap(destWidth, destHeight);
destByte.LockBitmap(destImg, ImageLockMode.WriteOnly);
srcByte.LockBitmap(srcImg, ImageLockMode.ReadOnly);
calcWidth = srcByte.Width - 1;
calcHeight = srcByte.Height - 1;
// 頂点データは反時計回りだが、パラメータには時計回りでセットする
xa = pt[0].X; ya = pt[0].Y;
xb = pt[3].X; yb = pt[3].Y;
xc = pt[2].X; yc = pt[2].Y;
xd = pt[1].X; yd = pt[1].Y;
p.a = (xc - xd - xb + xa);
p.b = (xb - xa);
p.c = (xd - xa);
p.f = (yc - yd - yb + ya);
p.g = (yb - ya);
p.h = (yd - ya);
for (int y = 0; y < destHeight; y++)
{
for (int x = 0; x < destWidth; x++)
{
p.d = (x - xa);
p.e = (y - ya);
if (ResolveEqu(p, out s, out t) == false)
{
SetPixelByte(destByte, x, y, bgCol);
continue;
}
//if ((0 <= s && s <= 1.0) && (0 <= t && t <= 1.0))
//{
tx = s * calcWidth;
ty = t * calcHeight;
//}
if (Interpolate(srcByte, tx, ty, ref pxCol))
{
SetPixelByte(destByte, x, y, pxCol);
}
else
{
SetPixelByte(destByte, x, y, bgCol);
}
}
}
destByte.MarshalCopy();
}
catch (Exception ex)
{
return(false);
}
finally
{
try
{
if (srcByte != null)
{
srcByte.UnlockBitmap();
}
}
finally
{
if (destByte != null)
{
destByte.UnlockBitmap();
}
}
sw.Stop();
Console.WriteLine("Transform time: {0}", sw.ElapsedMilliseconds);
}
return(true);
}