/// <summary>
/// Scale image by width and keep same aspect ratio of target image same as the original image.
/// Height will be adjusted automatically
/// </summary>
/// <param name="img"></param>
/// <param name="newWidth"></param>
/// <param name="ops">Graphic options <see cref="GraphicOptions"/></param>
/// <returns></returns>
public static Image ScaleByWidth(this Image img, int newWidth, GraphicOptions ops)
{
var resize = new Scale(img.Size, new Size(newWidth, 0));
return(Resize(img, resize.SourceRect, resize.TargetRect, ops));
}
/// <summary>
/// Specify custom resize options
/// </summary>
/// <param name="img">the image to resize</param>
/// <param name="source">The coordinates to read as source from the image,
/// can be the whole image or part of it</param>
/// <param name="target">The coordinates of the target image size</param>
/// <param name="ops">Graphic options <see cref="GraphicOptions"/></param>
/// <returns></returns>
public static Image Resize(this Image img, Rectangle source, Rectangle target, GraphicOptions ops)
{
var pixF = ImageColorFormats.GetColorFormat((Bitmap)img) == ImageColorFormat.Cmyk
? PixelFormat.Format32bppArgb
: img.PixelFormat;
using (Bitmap outputImage = new Bitmap(target.Width, target.Height, pixF))
{
outputImage.SetResolution(img.HorizontalResolution, img.VerticalResolution);
using (var graphics = Graphics.FromImage(outputImage))
{
graphics.SmoothingMode = ops.SmoothingMode;
graphics.InterpolationMode = ops.InterpolationMode;
graphics.PixelOffsetMode = ops.PixelOffsetMode;
graphics.CompositingQuality = ops.CompositingQuality;
graphics.CompositingMode = ops.CompositingMode;
graphics.PageUnit = ops.PageUnit;
graphics.DrawImage(
img,
target,
source,
ops.PageUnit);
}
return(Image.FromHbitmap(outputImage.GetHbitmap()));
}
}
/// <summary>
/// Scale image by height and keep same aspect ratio of target image same as the original image.
/// Width will be adjusted automatically
/// </summary>
/// <param name="img"></param>
/// <param name="newHeight"></param>
/// <param name="ops">Graphic options <see cref="GraphicOptions"/></param>
/// <returns></returns>
public static Image ScaleByHeight(this Image img, int newHeight, GraphicOptions ops)
{
var resize = new Scale(img.Size, new Size(0, newHeight));
return(Resize(img, resize.SourceRect, resize.TargetRect, ops));
}
/// <summary>
/// Directly crop original image without scaling it.
/// Final image aspect ratio is equal to given new width/height
/// </summary>
/// <param name="img"></param>
/// <param name="newWidth"></param>
/// <param name="newHeight"></param>
/// <param name="spot">target spot to crop and save</param>
/// <param name="ops">Graphic options <see cref="GraphicOptions"/></param>
/// <returns></returns>
public static Image Crop(this Image img, int newWidth, int newHeight, GraphicOptions ops, TargetSpot spot = TargetSpot.Center)
{
var resize = new Crop(img.Size, new Size(newWidth, newHeight), spot);
return(Resize(img, resize.SourceRect, resize.TargetRect, ops));
}
/// <summary>
/// Specify custom resize options
/// </summary>
/// <param name="img">the image to resize</param>
/// <param name="source">The coordinates to read as source from the image,
/// can be the whole image or part of it</param>
/// <param name="target">The coordinates of the target image size</param>
/// <param name="ops">Graphic options <see cref="GraphicOptions"/></param>
/// <returns></returns>
public static Image Resize(this Image img, Rectangle source, Rectangle target, GraphicOptions ops)
{
// check for CMYK pixel format to use Format32bppArgb
// or use the image pixel format
var pixF = ImageColorFormats.GetColorFormat((Bitmap)img) == ImageColorFormat.Cmyk
? PixelFormat.Format32bppArgb
: img.PixelFormat;
using (Bitmap outputImage = new Bitmap(target.Width, target.Height, pixF))
{
outputImage.SetResolution(img.HorizontalResolution, img.VerticalResolution);
using (var graphics = Graphics.FromImage(outputImage))
{
graphics.SmoothingMode = ops.SmoothingMode;
graphics.InterpolationMode = ops.InterpolationMode;
graphics.PixelOffsetMode = ops.PixelOffsetMode;
graphics.CompositingQuality = ops.CompositingQuality;
graphics.CompositingMode = ops.CompositingMode;
graphics.PageUnit = ops.PageUnit;
graphics.DrawImage(
img,
target,
source,
ops.PageUnit);
}
// If the image has alpha channel (png) return image memory stream
if (img.PixelFormat == PixelFormat.Format32bppArgb)
{
using (var ms = new MemoryStream())
{
outputImage.Save(ms, img.RawFormat);
return(Image.FromStream(ms));
}
}
return(Image.FromHbitmap(outputImage.GetHbitmap()));
}
}
