/// <summary>
/// Detects the widest and tallest pixels to determine the image padding based on the optional background color.
/// </summary>
/// <param name="image">The original image</param>
/// <param name="backgroundColor">Specifies a background color for this image or transparent by default.</param>
/// <returns>A rectangle containing the borders of this image's content.</returns>
public static Rectangle DetectPadding(this Image image, Color backgroundColor = default(Color))
{
if (backgroundColor.IsEmpty)
{
backgroundColor = Color.Transparent;
}
var top = image.Height;
var bottom = 0;
var left = image.Width;
var right = 0;
var width = image.Width - 1;
var height = image.Height - 1;
using (var context = new UnsafeBitmapContext(image))
{
for (int y = 0; y < context.Height; y++)
{
for (int x = 0; x < context.Width; x++)
{
if (width - right <= x && left <= x && height - bottom <= y)
{
break;
}
if (x < left && !context.GetRawPixel(x, y).EqualsColor(backgroundColor))
{
if (y < top)
{
top = y;
}
left = x;
}
if (x < width - right && !context.GetRawPixel(width - x, y).EqualsColor(backgroundColor))
{
if (y < top)
{
top = y;
}
right = width - x;
}
if (y < height - bottom && !context.GetRawPixel(x, height - y).EqualsColor(backgroundColor))
{
bottom = height - y;
}
}
}
}
width = Math.Max(0, right - left);
height = Math.Max(0, bottom - top);
return(new Rectangle(left, top, width, height));
}
/// <summary>
/// Compares a pixel and color and determines equality.
/// </summary>
public static bool EqualsPixel(this Color color, UnsafeBitmapContext.Pixel pixel)
{
return pixel.EqualsColor(color);
}
