private static MvcHtmlString GeneratePictureElement(PictureProfile profile, string imgUrl, string[] sourceSets, string alternateText = "", string cssClass = "")
{
var picture = new TagBuilder("picture");
var source = new TagBuilder("source");
if (profile.SrcSetSizes != null && profile.SrcSetSizes.Length > 0)
{
source.Attributes.Add("sizes", string.Join(", ", profile.SrcSetSizes));
}
source.Attributes.Add("srcset", string.Join(", ", sourceSets));
var img = new TagBuilder("img");
img.Attributes.Add("src", imgUrl);
img.Attributes.Add("alt", alternateText);
if (!string.IsNullOrEmpty(cssClass))
{
img.Attributes.Add("class", cssClass);
}
picture.InnerHtml = source.ToString(TagRenderMode.SelfClosing) + img.ToString(TagRenderMode.SelfClosing);
return(new MvcHtmlString(picture.ToString()));
}
public static MvcHtmlString ResizePicture(this HtmlHelper helper, UrlBuilder url, PictureProfile profile, string alternateText = "", string cssClass = "")
{
var imgUrl = url.Clone();
imgUrl.QueryCollection["w"] = profile.DefaultWidth.ToString();
var sourceSets = profile.SrcSetWidths.Select(w =>
{
var sourceUrl = url.Clone();
sourceUrl.QueryCollection["w"] = w.ToString();
return($"{sourceUrl} {w}w");
}).ToArray();
return(GeneratePictureElement(profile, imgUrl.ToString(), sourceSets, alternateText, cssClass));
}
public static MvcHtmlString ResizePictureWithFallback(this HtmlHelper helper, ContentReference image, PictureProfile profile, string fallbackImage, string alternateText = "", string cssClass = "")
{
return(image == null || image == ContentReference.EmptyReference
? ResizePicture(helper, new UrlBuilder(fallbackImage), profile, alternateText, cssClass)
: ResizePicture(helper, image, profile, alternateText, cssClass));
}
public static MvcHtmlString ResizePictures(this HtmlHelper helper, ContentReference[] images, PictureProfile profile, string alternateText = "", string cssClass = "")
{
if (images == null)
{
throw new ArgumentNullException(nameof(images));
}
return(helper.ResizePictures(images.Select((c, i) => helper.ResizeImage(c, profile.SrcSetWidths[i])).ToArray(), profile, alternateText, cssClass));
}
public static MvcHtmlString ResizePictures(this HtmlHelper helper, UrlBuilder[] urls, PictureProfile profile, string alternateText = "", string cssClass = "")
{
if (urls == null)
{
throw new ArgumentNullException(nameof(urls));
}
if (urls.Length == 0)
{
throw new ArgumentException($"{nameof(urls)} contains no elements");
}
if (profile == null)
{
throw new ArgumentNullException(nameof(profile));
}
if (profile.SrcMedias == null)
{
throw new ArgumentNullException(nameof(profile.SrcMedias));
}
if (profile.SrcMedias.Length == 0)
{
throw new ArgumentException($"{nameof(profile.SrcMedias)} contains no elements");
}
if (urls.Length != profile.SrcMedias?.Length)
{
throw new ArgumentException($"Length for `{nameof(urls)}` ({urls.Length}) and `{nameof(profile.SrcMedias)}` ({profile.SrcMedias.Length}) does not match.");
}
var picture = new TagBuilder("picture");
var sources = new StringBuilder();
for (var i = 0; i < urls.Length; i++)
{
var source = new TagBuilder("source");
var media = profile.SrcMedias[i];
var width = profile.SrcSetWidths[i];
var url = urls[i].Clone();
url.QueryCollection["w"] = width.ToString();
source.Attributes.Add("srcset", url.ToString());
source.Attributes.Add("media", media);
sources.Append(source.ToString(TagRenderMode.SelfClosing));
}
var img = new TagBuilder("img");
var defaultUrl = urls.First().Clone();
defaultUrl.QueryCollection["w"] = profile.DefaultWidth.ToString();
img.Attributes.Add("src", defaultUrl.ToString());
img.Attributes.Add("alt", alternateText);
if (!string.IsNullOrEmpty(cssClass))
{
img.Attributes.Add("class", cssClass);
}
picture.InnerHtml = sources + img.ToString(TagRenderMode.SelfClosing);
return(new MvcHtmlString(picture.ToString()));
}
public static MvcHtmlString ResizePicture(this HtmlHelper helper, ContentReference image, PictureProfile profile, string alternateText = "", string cssClass = "")
{
var imgUrl = helper.ResizeImage(image, profile.DefaultWidth);
var sourceSets = profile.SrcSetWidths.Select(w => $"{helper.ResizeImage(image, w)} {w}w").ToArray();
return(GeneratePictureElement(profile, imgUrl.ToString(), sourceSets, alternateText, cssClass));
}