private static bool IsPartOfTheLetter(Bitmap downscaled, int x, int y)
{
const int marginsBlackThreshold = 200;
const int marginsTransparentThreshold = 240;
int suit = 0;
for (int i = x - 1; i <= x + 1; i++)
{
for (int j = y - 1; j <= y + 1; j++)
{
if (i < 0 || j < 0 || i >= downscaled.Width || j >= downscaled.Height)
{
continue;
}
Color pixel = downscaled.GetPixel(i, j);
if (pixel.A > marginsBlackThreshold && BitmapUtils.GetGrayscale(pixel) < marginsBlackThreshold)
{
suit++;
}
}
}
return(suit > 2);
}
private int GetFormType(Bitmap prepForm)
{
const double markerDist = 10.0 / 165.0;
const double xOff = 10.0 / 165.0;
const double yOff = 2.5 / 255.0;
for (int i = 0; i < formCount; i++)
{
double x = (xOff + i * markerDist) * prepForm.Width;
double y = yOff * prepForm.Height;
if (BitmapUtils.GetGrayscale(prepForm.GetPixel((int)x, (int)y)) < 128)
{
return(i);
}
}
throw new MarkersNotFoundException("Couldn't determine form type");
}
private Bitmap PrepareLetterImage(Bitmap image, int formType)
{
Bitmap standartImage = new Bitmap(Font.imagePixelW, Font.imagePixelH, PixelFormat.Format32bppArgb);
//remove black borders
using (Graphics gr = Graphics.FromImage(image))
{
int pixelThicknessH = (int)(borderCutThickness * image.Width);
int pixelThicknessV = (int)(borderCutThickness * image.Height);
gr.FillRectangle(Brushes.White, new Rectangle(0, 0, pixelThicknessH, image.Height)); //left
gr.FillRectangle(Brushes.White, new Rectangle(0, 0, image.Width, pixelThicknessV)); //top
gr.FillRectangle(Brushes.White, new Rectangle(image.Width - pixelThicknessH, 0, pixelThicknessH, image.Height)); //right
gr.FillRectangle(Brushes.White, new Rectangle(0, image.Height - pixelThicknessV, image.Width, image.Height)); //bottom
}
//copy over the image
using (Graphics gr = Graphics.FromImage(standartImage))
{
int topOffset = (int)(Font.imagePixelH / 2 - Font.imagePixelW * lineHeights[formType]);
gr.Clear(Color.Transparent);
gr.DrawImage(image, new Rectangle(0, topOffset, Font.imagePixelW, Font.imagePixelW));
}
//make white transparent
BitmapData data = standartImage.LockBits(new Rectangle(0, 0, standartImage.Width, standartImage.Height), ImageLockMode.ReadWrite, standartImage.PixelFormat);
unsafe
{
byte *arr = (byte *)data.Scan0;
int channelCount = Image.GetPixelFormatSize(standartImage.PixelFormat) / 8;
for (int i = 0; i < standartImage.Width * standartImage.Height * channelCount; i += channelCount)
{
int grayscale = BitmapUtils.GetGrayscale(arr[i], arr[i + 1], arr[i + 2]);
if (grayscale > 200)
{
arr[i + 3] = (byte)(255 - grayscale);
}
}
}
standartImage.UnlockBits(data);
return(standartImage);
}
private void FindCoreRegion()
{
int[] histogram = new int[Font.imagePixelH];
foreach (FChar letter in smallLetters)
{
for (int i = 0; i < font.images[letter].Count; i++)
{
Bitmap image = font.images[letter][i];
BitmapData data = image.LockBits(new Rectangle(0, 0, image.Width, image.Height), ImageLockMode.ReadOnly, image.PixelFormat);
unsafe
{
byte *arr = (byte *)data.Scan0;
int channelCount = Bitmap.GetPixelFormatSize(image.PixelFormat) / 8;
for (int j = 0; j < image.Width * image.Height * channelCount; j += channelCount)
{
if (BitmapUtils.GetGrayscale(arr[j], arr[j + 1], arr[j + 2]) < 128 && arr[j + 3] > 240)
{
histogram[j / channelCount / image.Width]++;
}
}
}
image.UnlockBits(data);
}
}
int[] cumulativeHistogram = new int[Font.imagePixelH];
cumulativeHistogram[0] = histogram[0];
for (int i = 1; i < cumulativeHistogram.Length; i++)
{
cumulativeHistogram[i] = cumulativeHistogram[i - 1] + histogram[i];
}
double cutoffRatio = 0.05;
int total = cumulativeHistogram.Last();
int leftBorder = 0;
for (int i = 0; i < cumulativeHistogram.Length; i++)
{
if ((double)cumulativeHistogram[i] / total > cutoffRatio)
{
leftBorder = i;
break;
}
}
int rightBorder = cumulativeHistogram.Length;
for (int i = cumulativeHistogram.Length - 1; i >= 0; i--)
{
if ((double)cumulativeHistogram[i] / total < (1.0 - cutoffRatio))
{
rightBorder = i;
break;
}
}
coreRegionTop = leftBorder * Font.cmPerPixelV;
coreRegionBottom = rightBorder * Font.cmPerPixelV;
}
