copy data from bitmap array into new array store data of bmp

zozo ahmed

12y3k

I work on bitmap i read header of bmp 24 bit per pixel ,width 320 height 240,offset start of image data in location 54,use c#

in location 54 in bmp array i access to data ,i store data in new array :

struct pix //structure for pixel in bmp image

{

public byte r;//Red

public byte g;//Green

public byte b;//Blue

};

Bitmap img = new Bitmap(opendialog1.FileName);

string filename = opendialog1.FileName;

byte[] bmp = File.ReadAllBytes(filename);

int i=54;

pix[ , ] bmpdata = new pix[img.Height, img.Width]; //create array of structure

for (int row = 0; row < img.Height; row++)

{

for (int col = 0; col < img.Width; col++)

{

bmpdata[row, col].r = bmp[i];

bmpdata[row, col].g = bmp[i + 1];

bmpdata[row, col].b = bmp[i + 2];

i += 3;

}

is this correct method for copy data from bmp array into new array for data only ,i use c# window form ?

1 Reply

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Vulpes12y ago
If you're doing this with a view to making large scale changes to the bitmap, then the usual method would be to use the Bitmap.LockBits method to lock the bitmap in memory and then Marshal.Copy to copy the bytes to an array.

You can then make changes to the array, copy the bytes back to the Bitmap and then unlock it.

For large scale changes, this is quicker than making individual changes to the pixels using the Bitmap.SetPixel method.

There's some sample code for doing all this here:

http://msdn.microsoft.com/en-us/library/system.drawing.imaging.bitmapdata.scan0(v=vs.110).aspx

Of course, there's nothing to stop you copying your array of bytes to an array of your pix struct (and back again) if you find that easier to work with.
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