So XNA will let you load the color[] data from a texture2D object with Texture2D.GetData(), and through the Width and Height properties of the object, you have the dimensions handy. It's not the most efficient algorithm, but you could loop through rows first, then columns, determining at what index in the row/column the color shifts over the "culling" threshold (i.e. coming form the left, which index is the first to switch from white to black, and then what's the index from black back to white). Store the biggest index ranges across all rows and columns (which will give you the smallest dimensions that still contain your 'good' pixels), and then copy in the relevant data to a new, smaller color[] with the dimensions you just calculated. (System.Array has handy methods for copying select ranges of data).

You can use Texture2D.GetData to get a Color[] representation of the texture. Are you generating these images on the GPU? Because if the images are created on the CPU, you don't have to get the data in the first place.


Texture2D Crop(Color[] data, int width, int height, Color excess)
{
int x1 = width, x2 = 0, y1 = height, y2 = 0;
for (int i = 0; i < width * height; i++)
{
if (data != excess)
{
int y = i / width;
int x = i % width;
x1 = Math.Min(x, x1);
x2 = Math.Max(x, x2);
y1 = Math.Min(y, y1);
y2 = Math.Max(y, y2);
}
}
Rectangle cropped = new Rectangle(x1, y1, x2 - x1 + 1, y2 - y1 + 1);
Color[] newData = new Color[cropped.Width * cropped.Height];
for (int y = 0; y < cropped.Height; y++)
{
for (int x = 0; x < cropped.Width; x++)
{
int newIndex = y * cropped.Width + x;
int oldIndex = (y + cropped.Y) * width + (x + cropped.X);
newData[newIndex] = data[oldIndex];
}
}
Texture2D texture = new Texture2D(this.GraphicsDevice, cropped.Width, cropped.Height);
texture.SetData(newData);
return texture;
}


You can use Texture2D.GetData to get a Color[] representation of the texture. Are you generating these images on the GPU? Because if the images are created on the CPU, you don't have to get the data in the first place.


//some slick stuff here


Yes, like that! What I meant, only much cleaner and more efficient Describing algorithms is much easier if you just show someone the actual code...

Ha, I knew I shouldn't have used the Rectangle. I fixed the code in my previous post.