/// <summary>
/// Resizes an image in accordance with the given <see cref="ResizeOptions"/>.
/// </summary>
/// <typeparam name="TPixel">The pixel format.</typeparam>
/// <param name="source">The image to resize.</param>
/// <param name="options">The resize options.</param>
/// <returns>The <see cref="Image{TPixel}"/></returns>
/// <remarks>Passing zero for one of height or width within the resize options will automatically preserve the aspect ratio of the original image</remarks>
public static IImageProcessingContext <TPixel> Resize <TPixel>(this IImageProcessingContext <TPixel> source, ResizeOptions options)
where TPixel : struct, IPixel <TPixel>
=> source.ApplyProcessor(new ResizeProcessor <TPixel>(options, source.GetCurrentSize()));
private static (Size, Rectangle) CalculateCropRectangle(Size source, ResizeOptions options, int width, int height)
{
if (width <= 0 || height <= 0)
{
return(new Size(source.Width, source.Height), new Rectangle(0, 0, source.Width, source.Height));
}
float ratio;
int sourceWidth = source.Width;
int sourceHeight = source.Height;
int destinationX = 0;
int destinationY = 0;
int destinationWidth = width;
int destinationHeight = height;
// Fractional variants for preserving aspect ratio.
float percentHeight = MathF.Abs(height / (float)sourceHeight);
float percentWidth = MathF.Abs(width / (float)sourceWidth);
if (percentHeight < percentWidth)
{
ratio = percentWidth;
if (options.CenterCoordinates.Any())
{
float center = -(ratio * sourceHeight) * options.CenterCoordinates.ToArray()[1];
destinationY = (int)MathF.Round(center + (height / 2F));
if (destinationY > 0)
{
destinationY = 0;
}
if (destinationY < (int)MathF.Round(height - (sourceHeight * ratio)))
{
destinationY = (int)MathF.Round(height - (sourceHeight * ratio));
}
}
else
{
switch (options.Position)
{
case AnchorPosition.Top:
case AnchorPosition.TopLeft:
case AnchorPosition.TopRight:
destinationY = 0;
break;
case AnchorPosition.Bottom:
case AnchorPosition.BottomLeft:
case AnchorPosition.BottomRight:
destinationY = (int)MathF.Round(height - (sourceHeight * ratio));
break;
default:
destinationY = (int)MathF.Round((height - (sourceHeight * ratio)) / 2F);
break;
}
}
destinationHeight = (int)MathF.Ceiling(sourceHeight * percentWidth);
}
else
{
ratio = percentHeight;
if (options.CenterCoordinates.Any())
{
float center = -(ratio * sourceWidth) * options.CenterCoordinates.First();
destinationX = (int)MathF.Round(center + (width / 2F));
if (destinationX > 0)
{
destinationX = 0;
}
if (destinationX < (int)MathF.Round(width - (sourceWidth * ratio)))
{
destinationX = (int)MathF.Round(width - (sourceWidth * ratio));
}
}
else
{
switch (options.Position)
{
case AnchorPosition.Left:
case AnchorPosition.TopLeft:
case AnchorPosition.BottomLeft:
destinationX = 0;
break;
case AnchorPosition.Right:
case AnchorPosition.TopRight:
case AnchorPosition.BottomRight:
destinationX = (int)MathF.Round(width - (sourceWidth * ratio));
break;
default:
destinationX = (int)MathF.Round((width - (sourceWidth * ratio)) / 2F);
break;
}
}
destinationWidth = (int)MathF.Ceiling(sourceWidth * percentHeight);
}
return(new Size(width, height), new Rectangle(destinationX, destinationY, destinationWidth, destinationHeight));
}
private static (Size, Rectangle) CalculateBoxPadRectangle(Size source, ResizeOptions options, int width, int height)
{
if (width <= 0 || height <= 0)
{
return(new Size(source.Width, source.Height), new Rectangle(0, 0, source.Width, source.Height));
}
int sourceWidth = source.Width;
int sourceHeight = source.Height;
// Fractional variants for preserving aspect ratio.
float percentHeight = MathF.Abs(height / (float)sourceHeight);
float percentWidth = MathF.Abs(width / (float)sourceWidth);
int boxPadHeight = height > 0 ? height : (int)MathF.Round(sourceHeight * percentWidth);
int boxPadWidth = width > 0 ? width : (int)MathF.Round(sourceWidth * percentHeight);
// Only calculate if upscaling.
if (sourceWidth < boxPadWidth && sourceHeight < boxPadHeight)
{
int destinationX;
int destinationY;
int destinationWidth = sourceWidth;
int destinationHeight = sourceHeight;
width = boxPadWidth;
height = boxPadHeight;
switch (options.Position)
{
case AnchorPosition.Left:
destinationY = (height - sourceHeight) / 2;
destinationX = 0;
break;
case AnchorPosition.Right:
destinationY = (height - sourceHeight) / 2;
destinationX = width - sourceWidth;
break;
case AnchorPosition.TopRight:
destinationY = 0;
destinationX = width - sourceWidth;
break;
case AnchorPosition.Top:
destinationY = 0;
destinationX = (width - sourceWidth) / 2;
break;
case AnchorPosition.TopLeft:
destinationY = 0;
destinationX = 0;
break;
case AnchorPosition.BottomRight:
destinationY = height - sourceHeight;
destinationX = width - sourceWidth;
break;
case AnchorPosition.Bottom:
destinationY = height - sourceHeight;
destinationX = (width - sourceWidth) / 2;
break;
case AnchorPosition.BottomLeft:
destinationY = height - sourceHeight;
destinationX = 0;
break;
default:
destinationY = (height - sourceHeight) / 2;
destinationX = (width - sourceWidth) / 2;
break;
}
return(new Size(width, height), new Rectangle(destinationX, destinationY, destinationWidth, destinationHeight));
}
// Switch to pad mode to downscale and calculate from there.
return(CalculatePadRectangle(source, options, width, height));
}
/// <summary>
/// Calculates the target location and bounds to perform the resize operation against.
/// </summary>
/// <param name="sourceSize">The source image size.</param>
/// <param name="options">The resize options.</param>
/// <param name="width">The target width</param>
/// <param name="height">The target height</param>
/// <returns>
/// The <see cref="ValueTuple{Size,Rectangle}"/>.
/// </returns>
public static (Size, Rectangle) CalculateTargetLocationAndBounds(Size sourceSize, ResizeOptions options, int width, int height)
{
switch (options.Mode)
{
case ResizeMode.Crop:
return(CalculateCropRectangle(sourceSize, options, width, height));
case ResizeMode.Pad:
return(CalculatePadRectangle(sourceSize, options, width, height));
case ResizeMode.BoxPad:
return(CalculateBoxPadRectangle(sourceSize, options, width, height));
case ResizeMode.Max:
return(CalculateMaxRectangle(sourceSize, options, width, height));
case ResizeMode.Min:
return(CalculateMinRectangle(sourceSize, options, width, height));
// Last case ResizeMode.Stretch:
default:
return(new Size(width, height), new Rectangle(0, 0, width, height));
}
}
private static (Size, Rectangle) CalculatePadRectangle(Size source, ResizeOptions options, int width, int height)
{
if (width <= 0 || height <= 0)
{
return(new Size(source.Width, source.Height), new Rectangle(0, 0, source.Width, source.Height));
}
float ratio;
int sourceWidth = source.Width;
int sourceHeight = source.Height;
int destinationX = 0;
int destinationY = 0;
int destinationWidth = width;
int destinationHeight = height;
// Fractional variants for preserving aspect ratio.
float percentHeight = MathF.Abs(height / (float)sourceHeight);
float percentWidth = MathF.Abs(width / (float)sourceWidth);
if (percentHeight < percentWidth)
{
ratio = percentHeight;
destinationWidth = (int)MathF.Round(sourceWidth * percentHeight);
switch (options.Position)
{
case AnchorPosition.Left:
case AnchorPosition.TopLeft:
case AnchorPosition.BottomLeft:
destinationX = 0;
break;
case AnchorPosition.Right:
case AnchorPosition.TopRight:
case AnchorPosition.BottomRight:
destinationX = (int)MathF.Round(width - (sourceWidth * ratio));
break;
default:
destinationX = (int)MathF.Round((width - (sourceWidth * ratio)) / 2F);
break;
}
}
else
{
ratio = percentWidth;
destinationHeight = (int)MathF.Round(sourceHeight * percentWidth);
switch (options.Position)
{
case AnchorPosition.Top:
case AnchorPosition.TopLeft:
case AnchorPosition.TopRight:
destinationY = 0;
break;
case AnchorPosition.Bottom:
case AnchorPosition.BottomLeft:
case AnchorPosition.BottomRight:
destinationY = (int)MathF.Round(height - (sourceHeight * ratio));
break;
default:
destinationY = (int)MathF.Round((height - (sourceHeight * ratio)) / 2F);
break;
}
}
return(new Size(width, height), new Rectangle(destinationX, destinationY, destinationWidth, destinationHeight));
}
