public static UrlBuilder Format(this UrlBuilder target, ResizedImageFormat format)
{
if (format == ResizedImageFormat.Preserve)
target.QueryCollection.Remove("format");
else
target.Add("format", format.ToString().ToLowerInvariant());
return target;
}
public static UrlBuilder ResizedImageUrl(this HtmlHelper helper, ContentReference image, int width,
ResizedImageFormat format = ResizedImageFormat.Preserve)
{
var baseUrl = ResolveImageUrl(image);
return(new UrlBuilder(baseUrl)
.Width(width)
.Format(format));
}
private static string BuildSize(string imageUrl, int width, ScaleMode sourceMode,
AspectRatio sourceTargetAspectRatio, int?sourceQuality, IResponsiveImage focalPoint, int maxImageDimension,
ResizedImageFormat format)
{
var url = BuildResizedImageUrl(imageUrl, width, sourceMode, sourceTargetAspectRatio, sourceQuality,
focalPoint,
maxImageDimension,
format);
return($"{url} {width}w");
}
public string TestResizedImageUrl(ResizedImageFormat format)
{
HtmlHelper html = null;
return(html.ResizedImageUrl(new ContentReference(123), 500, format).ToString());
}
private static void RenderBackgroundCssClass(HtmlHelper helper, ContentReference image,
StringBuilder stringBuilder,
string className, int imageWidth, ResizedImageFormat format)
{
stringBuilder.Append($".{className} {{ ");
stringBuilder.Append(
$"background-image: url('{helper.ResizedImageUrl(image, imageWidth, format)}');");
stringBuilder.Append("}"); // css class close
}
private static void RenderNonRetinaCss(HtmlHelper helper, ContentReference image, string mediaQuery,
StringBuilder stringBuilder, string className, PictureSize allowedSize, ResizedImageFormat format)
{
if (!string.IsNullOrEmpty(mediaQuery))
{
stringBuilder.Append($"@media ({mediaQuery}) {{");
}
RenderBackgroundCssClass(helper, image, stringBuilder, className, Math.Min(allowedSize.ImageWidth,
MaxResizedImageWidth), format);
if (!string.IsNullOrEmpty(mediaQuery))
{
stringBuilder.Append("}"); // media query close
}
}
private static void RenderRetinaCss(HtmlHelper helper, ContentReference image, string mediaQuery,
StringBuilder stringBuilder, string className, PictureSize allowedSize, ResizedImageFormat format)
{
var mediaQuerySelector = string.IsNullOrEmpty(mediaQuery)
? ""
: $"and ({mediaQuery})";
stringBuilder.Append($@"@media (-webkit-min-device-pixel-ratio: 2) {mediaQuerySelector},
(min--moz-device-pixel-ratio: 2) {mediaQuerySelector},
(-o-min-device-pixel-ratio: 2/1) {mediaQuerySelector},
( min-device-pixel-ratio: 2) {mediaQuerySelector} {{");
RenderBackgroundCssClass(helper, image, stringBuilder, className,
Math.Min(allowedSize.ImageWidth * 2, MaxResizedImageWidth), format);
stringBuilder.Append("}");
}
private static TagBuilder CreateSourceElement(string imageUrl, PictureSource source,
IResponsiveImage focalPoint, int maxImageDimension, ResizedImageFormat format)
{
var srcSets = source.AllowedWidths
.Select(width => BuildSize(imageUrl, width, source.Mode, source.TargetAspectRatio, source.Quality,
focalPoint, maxImageDimension, format));
var tagBuilder = new TagBuilder("source")
{
Attributes =
{
{ "media", $"{source.MediaCondition}" },
{ "srcset", string.Join(", ", srcSets) },
{ "sizes", string.Join(", ", source.Sizes)}
}
};
return(tagBuilder);
}
private static UrlBuilder BuildResizedImageUrl(string imageUrl, int width,
ScaleMode scaleMode, AspectRatio targetAspectRatio, int?quality,
IResponsiveImage image, int?maxImageDimension, ResizedImageFormat format)
{
width = Math.Min(width, maxImageDimension ?? int.MaxValue);
var target = new UrlBuilder(imageUrl);
if (scaleMode != ScaleMode.Default)
{
target.Mode(scaleMode);
}
if (quality.HasValue)
{
target.Quality(quality.Value);
}
target.Format(format);
if (scaleMode != ScaleMode.Default && scaleMode != ScaleMode.Max &&
image != null)
{
if (targetAspectRatio == null || !targetAspectRatio.HasValue)
{
throw new ArgumentException("Aspect ratio is required when ScaleMode is other than Max");
}
var height = (int)(width / targetAspectRatio.Ratio);
if (height > maxImageDimension)
{
height = maxImageDimension.Value;
width = (int)(height * targetAspectRatio.Ratio);
}
target.Width(width);
target.Height(height);
var cropSettings = ImageCropper.GetCropSettings(targetAspectRatio, image);
if (cropSettings != null)
{
target.Crop(cropSettings);
}
}
else
{
target.Width(width);
}
return(target);
}
