I have a Hex string that's coming from postscript file.
This Hex string is for the image - for which I need to modify RGB color values.
After modifying color values, I need to write the image back as Hex string in postscript file.
Below are the methods that I am using. All these methods are working fine including `UpdateColour(bitmapImage)`. I have confirmed it through debugging.
public static void ProcessImageColourMapping()
{
string imageDataSource = "803fe0503824160d0784426150b864361d0f8844625138a4562d178c466351b8e4763d1f904864523924964d27944a6552b964b65d2f984c665339a4d66d379c4e6753b9e4f67d3fa05068543a25168d47a4526954ba648202";
string imageDataSourceUpdated = GetUpdatedImage(imageDataSource);
}
public static string GetUpdatedImage(string strImageDataSource)
{
string imageDataSourceUpdated = "";
byte[] imageBytes = StringToByteArray(strImageDataSource);
Bitmap bitmapImage = ByteArrayToBitmap(imageBytes);
UpdateColour(bitmapImage); //I have confirmed by debugging that color values for pixel are actually updated for bitmapImage
byte[] imageBytesUpdated = BitmapToByteArray(bitmapImage);
imageDataSourceUpdated = ByteArrayToString(imageBytes);
return imageDataSourceUpdated;
}
public static byte[] StringToByteArray(String imageHexString)
{
int numberOfChars = imageHexString.Length / 2;
byte[] byteArray = new byte[numberOfChars];
using (var sr = new StringReader(imageHexString))
{
for (int i = 0; i < numberOfChars; i++)
byteArray[i] = Convert.ToByte(new string(new char[2] { (char)sr.Read(), (char)sr.Read() }), 16);
}
return byteArray;
}
public static Bitmap ByteArrayToBitmap(byte[] byteArray)
{
int width = 2144; //width and height are taken from postscript file for testing a single hex string.
int height = 3;
Bitmap bitmapImage = new Bitmap(width, height, PixelFormat.Format32bppPArgb);
BitmapData bmpData = bitmapImage.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format32bppPArgb);
try
{
Marshal.Copy(byteArray, 0, bmpData.Scan0, byteArray.Length);
}
finally
{
bitmapImage.UnlockBits(bmpData);
}
return bitmapImage;
}
public static byte[] BitmapToByteArray(Bitmap bitmap)
{
BitmapData bmpdata = bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), ImageLockMode.ReadOnly, bitmap.PixelFormat);
int numbytes = bmpdata.Stride * bitmap.Height;
byte[] bytedata = new byte[numbytes];
try
{
Marshal.Copy(bmpdata.Scan0, bytedata, 0, numbytes);
}
finally
{
bitmap.UnlockBits(bmpdata);
}
return bytedata;
}
public static string ByteArrayToString(byte[] byteArray)
{
StringBuilder hex = new StringBuilder(byteArray.Length * 2);
foreach (byte b in byteArray)
{
hex.AppendFormat("{0:x2}", b);
}
return hex.ToString();
}
public static void UpdateColour(Bitmap bitmapImage)
{
for (int x = 0; x < bitmapImage.Width; x++)
{
for (int y = 0; y < bitmapImage.Height; y++)
{
Color color = Color.FromKnownColor(KnownColor.Aqua); //For Testing, change all pixels color to Color.Aqua
bitmapImage.SetPixel(x, y, color);
}
}
}
**Issue:**
Even though the color for all image pixels are changed:
bitmapImage.GetPixel(0,0) "{Name=50ffc8ff, ARGB=(80, 255, 200, 255)}" - BEFORE UpdateColor()
bitmapImage.GetPixel(0,0) "{Name=ff00ffff, ARGB=(255, 0, 255, 255)}" - AFTER UpdateColor()
If I compare the two hex strings:
`imageDataSource` and `imageDataSourceUpdated`, they are same :-(
Shouldn't they be different after I have modified underlying bitmap color values?
Can please guide what I am missing here.
