UnmanagedImage stride, multiple of four

[halachkin]

Hello,

I noticed, that UnmanagedImage.Create method adjusts stride to make it multiple of four. It is the stride that System.Drawing.Bitmap needs.

framework/Sources/Accord.Imaging/AForge.Imaging/UnmanagedImage.cs

Lines 394 to 407 in 1b27ff9

	public static UnmanagedImage Create(int width, int height, PixelFormat pixelFormat)
	{
	int bytesPerPixel = GetBytesPerPixel(pixelFormat);
	// calculate stride
	int stride = width * bytesPerPixel;
	if (stride % 4 != 0)
	{
	stride += (4 - (stride % 4));
	}
	return Create(width, height, stride, pixelFormat);
	}

Hovewer there is another method UnmanagedImage.Create

framework/Sources/Accord.Imaging/AForge.Imaging/UnmanagedImage.cs

Line 441 in 1b27ff9

public static UnmanagedImage Create(int width, int height, int stride, PixelFormat pixelFormat)

that accepts stride and does not check it.

Than following code ends with exception, img.ToManagedImage is creating Bitmap image from invalid stride value.

using Accord.Imaging;
using System.Drawing.Imaging;
using System;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                var img = UnmanagedImage.FromByteArray(new byte[16], 3, 3, PixelFormat.Format8bppIndexed);
                img.ToManagedImage(false);
            }
            catch(Exception e)
            {
                Console.WriteLine(e);
            }
        }
    }
}

Here System.Drawing.Bitmap constructor will have invalid stride value (not mulitple of four)

framework/Sources/Accord.Imaging/AForge.Imaging/UnmanagedImage.cs

Lines 521 to 533 in 1b27ff9

	public Bitmap ToManagedImage(bool makeCopy)
	{
	Bitmap dstImage = null;
	try
	{
	if (!makeCopy)
	{
	dstImage = new Bitmap(width, height, stride, pixelFormat, imageData);
	if (pixelFormat == PixelFormat.Format8bppIndexed)
	{
	Image.SetGrayscalePalette(dstImage);
	}