/// <summary>
/// draw overlay(has transparent background ) on bg
/// </summary>
/// <param name="bg"></param>
/// <param name="overlay"></param>
public unsafe static void DrawOverlay(Mat bg, Mat overlay)
{
if (bg.Size() != overlay.Size())
{
throw new System.ArgumentException("bg.Size()!=overlay.Size()");
}
if (overlay.Channels() < 4)
{
throw new System.ArgumentException("overlay.Channels()<4");
}
int colsOverlay = overlay.Cols;
int rowsOverlay = overlay.Rows;
//https://stackoverflow.com/questions/54069766/overlaying-an-image-over-another-image-both-with-transparent-background-using-op
for (int i = 0; i < rowsOverlay; i++)
{
Vec3b *pBg = (Vec3b *)bg.Ptr(i);
Vec4b *pOverlay = (Vec4b *)overlay.Ptr(i);
for (int j = 0; j < colsOverlay; j++)
{
Vec3b *pointBg = pBg + j;
Vec4b *pointOverlay = pOverlay + j;
if (pointOverlay->Item3 != 0)
{
pointBg->Item0 = pointOverlay->Item0;
pointBg->Item1 = pointOverlay->Item1;
pointBg->Item2 = pointOverlay->Item2;
}
}
}
}
unsafe void OpVec3b(Vec3b *bt, int *pos)
{
byte r, g, b;
r = (*bt).Item2;
g = (*bt).Item1;
b = (*bt).Item0;
//if ( r> 80 && g > 80 && b > 80)
{
itemcnt++;
item0 += r;
item1 += g;
item2 += b;
}
}
/// <summary>
/// Render matMask by src, every green pixel on src will cause a black pixel rendered on the same position on matMask,
/// otherwise, a white pixel will be rendered on matMask
/// </summary>
/// <param name="src"></param>
/// <param name="matMask"></param>
private unsafe void RenderGreenScreenMask(Mat src, Mat matMask)
{
if (src.Channels() < 3)
{
throw new ArgumentException("src.Channels() should >=3");
}
if (matMask.Channels() != 1)
{
throw new ArgumentException("matMask.Channels() should == 1");
}
if (src.Size() != matMask.Size())
{
throw new System.ArgumentException("src.Size()!=matMask.Size()");
}
//https://codereview.stackexchange.com/questions/184044/processing-an-image-to-extract-green-screen-mask
int rows = src.Rows;
int cols = src.Cols;
for (int x = 0; x < rows; x++)
{
Vec3b *srcRow = (Vec3b *)src.Ptr(x);
byte * maskRow = (byte *)matMask.Ptr(x);
for (int y = 0; y < cols; y++)
{
var pData = srcRow + y;
byte blue = pData->Item0;
byte green = pData->Item1;
byte red = pData->Item2;
byte max1 = blue > green ? blue : green;
byte max = max1 > red?max1:red;
//if this pixel is some green, render the pixel with the same position on matMask as black
if (green == max && green > this._greenScale)
{
*(maskRow + y) = 0;
}
else
{
*(maskRow + y) = 255;//render as white
}
}
}
}
public static extern unsafe int core_Mat_nGetVec3b(IntPtr obj, int row, int col,
Vec3b *vals, int valsLength);
private static unsafe void ReverseHue(Vec3b *value, int *position)
{
var bgr = (value->Item0 / 255f, value->Item1 / 255f, value->Item2 / 255f);
var max = Math.Max(bgr.Item1, Math.Max(bgr.Item2, bgr.Item3));
var min = Math.Min(bgr.Item1, Math.Min(bgr.Item2, bgr.Item3));
var hsv = (double.NaN, double.NaN, double.NaN);
hsv.Item2 = max - (double)min;
hsv.Item3 = max;
if (max == min)
{
hsv.Item1 = 0f;
}
else if (min == bgr.Item1)
{
hsv.Item1 = 60d * (bgr.Item2 - bgr.Item3) / hsv.Item2 + 60d;
}
else if (min == bgr.Item3)
{
hsv.Item1 = 60 * (bgr.Item1 - bgr.Item2) / hsv.Item2 + 180;
}
else if (min == bgr.Item2)
{
hsv.Item1 = 60 * (bgr.Item3 - bgr.Item1) / hsv.Item2 + 300;
}
hsv.Item1 = (hsv.Item1 + 180) % 360;
var Hd = hsv.Item1 / 60d;
var C = hsv.Item2;
var X = C * (1 - Math.Abs((Hd % 2) - 1));
var rgb = (hsv.Item3 - C, hsv.Item3 - C, hsv.Item3 - C);
if (Hd < 1)
{
rgb.Item1 += C;
rgb.Item2 += X;
}
else if (Hd < 2)
{
rgb.Item1 += X;
rgb.Item2 += C;
}
else if (Hd < 3)
{
rgb.Item2 += C;
rgb.Item3 += X;
}
else if (Hd < 4)
{
rgb.Item2 += X;
rgb.Item3 += C;
}
else if (Hd < 5)
{
rgb.Item1 += X;
rgb.Item3 += C;
}
else if (Hd < 6)
{
rgb.Item1 += C;
rgb.Item3 += X;
}
value->Item0 = (byte)(rgb.Item3 * 255);
value->Item1 = (byte)(rgb.Item2 * 255);
value->Item2 = (byte)(rgb.Item1 * 255);
}
private static unsafe void DecreaseColor(Vec3b *value, int *position)
{
