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conamx  
#1 Posted : Tuesday, April 10, 2018 6:46:33 AM(UTC)
conamx

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Hi…

I was able to read 8-bit JPG (24bpp RGB) pixels using C# and the pixel values are in the range of 0-255 which is normal as 2^8=256.
Following is the code I used to access 8 bit image pixel values in C#:

Code:

       for (int x = 0; x < image.width; x++)  
         {       
            for (int y = 0; y < image.height; y++)    
            {           
                     int redValue     = image.GetPixel(x, y).R;      
                     int greenValue = image.GetPixel(x, y).G;  
                     int blueValue   = image.GetPixel(x, y).B;  
                    //Do something with redValue, greenValue, blueValue here
             } 
        }


Please let me know if I can read 16-bit TIFF (48bpp RGB) pixel values using GM and what would be the range of those pixel values.

Thanks.
Fedor  
#2 Posted : Tuesday, April 10, 2018 7:44:53 AM(UTC)
Fedor

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Could you attach an example of 48bpp TIFF image?

Edited by user Tuesday, April 10, 2018 9:08:24 AM(UTC)  | Reason: Not specified

Best regards,
Fedor Skvortsov
conamx  
#3 Posted : Tuesday, April 10, 2018 10:25:40 AM(UTC)
conamx

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Sure, here it is
Gradient16.png
Eugene Kosmin  
#4 Posted : Tuesday, April 10, 2018 4:25:02 PM(UTC)
Eugene Kosmin

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Hi,

Please try the following code.

Code:
using (var bitmap = new Bitmap("48bppRgb.tif"))
{
    var pixel = (Rgb16Color)bitmap.GetPixel(x, y);
    Console.WriteLine(pixel.R);
    Console.WriteLine(pixel.G);
    Console.WriteLine(pixel.B);
}


The range will be [0..65535].
Best regards,
Eugene Kosmin.
Aurigma Development Team
thanks 1 user thanked Eugene Kosmin for this useful post.
conamx on 4/14/2018(UTC)
conamx  
#5 Posted : Tuesday, April 10, 2018 11:35:04 PM(UTC)
conamx

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That's good. But the code takes very long time to execute. Is it possible to make code execution faster?
Eugene Kosmin  
#6 Posted : Thursday, April 12, 2018 4:18:44 PM(UTC)
Eugene Kosmin

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Only with unsafe code. It's faster but requires dealing with data pointer.
Please check this topic about Scan0 property.
Best regards,
Eugene Kosmin.
Aurigma Development Team
thanks 1 user thanked Eugene Kosmin for this useful post.
conamx on 4/14/2018(UTC)
conamx  
#7 Posted : Friday, April 13, 2018 9:44:04 AM(UTC)
conamx

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Thank you for the link. The example on the page states that the code is for 8 bit images where each byte is incremented to get next color.
But, I'm not sure how to implement the same example for 48bpp images where two bytes are incremented to get next color.
conamx  
#8 Posted : Saturday, April 14, 2018 11:00:48 AM(UTC)
conamx

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Okay, I finally figured it out. Here is the code:

Code:
 using (var bitmap = new Aurigma.GraphicsMill.Bitmap(@"48bpp.tif"))
            {
               unsafe
                {
                      //A pointer to the beginning of the pixel data region
                      byte* pointer = (byte*)(bitmap.Scan0.ToPointer());

                      //Number of bytes in a row
                      ushort stride =(ushort) bitmap.Stride;

                      //Number of rows
                      int height = bitmap.Height;

                      //bytesperpixel
                      int bytesperpixel = bitmap.PixelFormat.Size/8;

                        for (int i = 0; i < height; i++)
                        {
                            ushort* position = (ushort*)(pointer + stride * i);

                            for (int j = 0; j < stride; j = j + bytesperpixel)
                            {
                                double red = position[j + 2];
                                double green = position[j + 1];
                                double blue = position[j];

                                //do something with red green blue

                            }
                        }

                }
            }
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