// average,Brightness or maximum over area of bitmap
public static Tuple <float, float, float, float> Function(this Bitmap bmp, BitmapFunction mode, int x, int y, int width, int height)
{
System.Drawing.Imaging.BitmapData bmpdata = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height),
System.Drawing.Imaging.ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb); // 32 bit words, ARGB format
IntPtr baseptr = bmpdata.Scan0; // its a byte ptr
int linestride = bmp.Width * 4;
uint red = 0;
uint green = 0;
uint blue = 0;
uint alpha = 0;
for (int gy = y; gy < y + height; gy++)
{
IntPtr ptr = baseptr + x * 4 + gy * linestride;
for (int gx = x; gx < x + width; gx++)
{
uint v = (uint)System.Runtime.InteropServices.Marshal.ReadInt32(ptr); // ARBG
if (mode != BitmapFunction.Maximum)
{
alpha += ((v >> 24) & 0xff);
red += ((v >> 16) & 0xff);
green += ((v >> 8) & 0xff);
blue += ((v >> 0) & 0xff);
ptr += 4;
}
else
{
alpha = Math.Max(alpha, ((v >> 24) & 0xff));
red += Math.Max(red, ((v >> 16) & 0xff));
green += Math.Max(green, ((v >> 8) & 0xff));
blue += Math.Max(blue, ((v >> 0) & 0xff));
}
}
}
bmp.UnlockBits(bmpdata);
int pixels = width * height;
float ac = (float)alpha / pixels;
float rc = (float)red / pixels;
float gc = (float)green / pixels;
float bc = (float)blue / pixels;
if (mode == BitmapFunction.Average)
{
return(new Tuple <float, float, float, float>(ac, rc, gc, bc));
}
else if (mode == BitmapFunction.Brightness)
{
double v = (float)rc * (float)rc + (float)gc * (float)gc + (float)bc * (float)bc;
v = Math.Sqrt(v);
return(new Tuple <float, float, float, float>(ac, (float)v / 441.67296f, 0, 0)); // that Math.Sqrt(255^2+255^2+255^2)
}
else
{
return(new Tuple <float, float, float, float>(alpha, red, green, blue));
}
}
public static Bitmap Function(this Bitmap bmp, int granularityx, int granularityy, int avggranulatityx = 0, int avggranulatityy = 0, BitmapFunction mode = BitmapFunction.Average,
bool enablered = true, bool enablegreen = true, bool enableblue = true,
bool flipx = false, bool flipy = false)
{
System.Drawing.Imaging.BitmapData bmpdata = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height),
System.Drawing.Imaging.ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb); // 32 bit words, ARGB format
IntPtr baseptr = bmpdata.Scan0; // its a byte ptr
Bitmap newbmp = new Bitmap(granularityx, granularityy); // bitmap to match
if (avggranulatityx == 0)
{
avggranulatityx = granularityx;
}
if (avggranulatityy == 0)
{
avggranulatityy = granularityy;
}
int bmpcellsizex = bmp.Width / granularityx; // no of avg points
int bmpcellsizey = bmp.Height / granularityx;
int avgwidth = bmp.Width / avggranulatityx;
int avgheight = bmp.Height / avggranulatityx;
int linestride = bmp.Width * 4;
for (int gy = 0; gy < granularityy; gy++)
{
for (int gx = 0; gx < granularityx; gx++)
{
int x = bmpcellsizex / 2 + bmpcellsizex * gx - avgwidth / 2;
int mx = x + avgwidth;
x = x.Range(0, bmp.Width - 1);
mx = mx.Range(0, bmp.Width);
int y = bmpcellsizey / 2 + bmpcellsizey * gy - avgheight / 2;
int my = y + avgheight;
y = y.Range(0, bmp.Height - 1);
my = my.Range(0, bmp.Height); // yes, let it go to height, its the stop value
// System.Diagnostics.Debug.WriteLine("Avg " + x + "->" + mx + ", " + y +"->" + my);
uint red = 0, green = 0, blue = 0, points = 0;
for (int ay = y; ay < my; ay++)
{
IntPtr ptr = baseptr + x * 4 + ay * linestride;
for (int ax = x; ax < mx; ax++)
{
int v = System.Runtime.InteropServices.Marshal.ReadInt32(ptr); // ARBG
red += enablered ? (uint)((v >> 16) & 0xff) : 0;
green += enablegreen ? (uint)((v >> 8) & 0xff) : 0;
blue += enableblue ? (uint)((v >> 0) & 0xff) : 0;
ptr += 4;
points++;
//System.Diagnostics.Debug.WriteLine("Avg " + ax + "," + ay);
}
}
Color res;
if (mode == BitmapFunction.HeatMap)
{
double ir = (double)red * (double)red + (double)green * (double)green + (double)blue * (double)blue;
ir = Math.Sqrt(ir) * 255 / 442; // scaling is for sqrt(255*255+255*255+255*255) to bring it back to 255 nom
ir /= points;
res = Color.FromArgb(255, (int)ir, (int)ir, (int)ir);
}
else
{
res = Color.FromArgb(255, (int)(red / points), (int)(blue / points), (int)(green / points));
}
newbmp.SetPixel(flipx ? (newbmp.Width - 1 - gx) : gx, flipy ? (newbmp.Height - 1 - gy) : gy, res);
}
}
bmp.UnlockBits(bmpdata);
return(newbmp);
}
