/// <summary>
/// Creates the proper CSS link reference within the target CSHTML page's head section
/// </summary>
/// <param name="virtualPath">The relative path of the image to be displayed, or its directory</param>
/// <returns>Link tag if the file is found.</returns>
public static IHtmlString ImportStylesheet(string virtualPath)
{
ImageOptimizations.EnsureInitialized();
if (Path.HasExtension(virtualPath))
{
virtualPath = Path.GetDirectoryName(virtualPath);
}
HttpContextBase httpContext = new HttpContextWrapper(HttpContext.Current);
string cssFileName = ImageOptimizations.LinkCompatibleCssFile(httpContext.Request.Browser) ?? ImageOptimizations.LowCompatibilityCssFileName;
virtualPath = Path.Combine(virtualPath, cssFileName);
string physicalPath = HttpContext.Current.Server.MapPath(virtualPath);
if (File.Exists(physicalPath))
{
TagBuilder htmlTag = new TagBuilder("link");
htmlTag.MergeAttribute("href", ResolveUrl(virtualPath));
htmlTag.MergeAttribute("rel", "stylesheet");
htmlTag.MergeAttribute("type", "text/css");
htmlTag.MergeAttribute("media", "all");
return(new HtmlString(htmlTag.ToString(TagRenderMode.SelfClosing)));
}
return(null);
}
/// <summary>
/// Prepares some field variables and check them if they are correct for sprite rendering.
/// </summary>
/// <returns>true if ready for sprite rendering</returns>
private bool PrepareSpriteRendering()
{
ImageOptimizations.EnsureInitialized();
if (!EnableSprites)
{
return(false);
}
_cssFileName = ImageOptimizations.LinkCompatibleCssFile(new HttpContextWrapper(Context).Request.Browser);
if (String.IsNullOrEmpty(_cssFileName))
{
return(false);
}
string spriteDirectoryPath = Path.GetDirectoryName(ImageUrl);
// Check that CSS file is accessible
if (!File.Exists(Path.Combine(Context.Server.MapPath(spriteDirectoryPath), _cssFileName)))
{
return(false);
}
return(true);
}
protected override void Render(HtmlTextWriter writer)
{
if (_usingSprites)
{
// Need to output the src element but without using the ImageUrl (ViewState)
string imageUrl = ImageOptimizations.GetBlankImageSource(new HttpContextWrapper(Context).Request.Browser);
ImageHtmlTextWriter imageHtmlTextWriter = new ImageHtmlTextWriter(writer, ResolveClientUrl(imageUrl));
base.Render(imageHtmlTextWriter);
}
else
{
base.Render(writer);
}
}
public void Init(HttpApplication context)
{
lock (_lockObj) {
if (_hasAlreadyRun)
{
return;
}
else
{
_hasAlreadyRun = true;
}
}
var spriteDirectoryPhysicalPath = context.Context.Server.MapPath(ImageOptimizations.SpriteDirectoryRelativePath);
if (Directory.Exists(spriteDirectoryPhysicalPath))
{
ImageOptimizations.SaveBlankFile(spriteDirectoryPhysicalPath);
ImageOptimizations.AddCacheDependencies(spriteDirectoryPhysicalPath, rebuildImages: true);
ImageOptimizations.Initialized = true;
}
}
/// <summary>
/// Creates a reference to the sprite / inlined version of the desired image including special attributes.
/// </summary>
/// <param name="virtualPath">The relative path of the image to be displayed</param>
/// <param name="htmlAttributes">Html Attributes of IDictionary form</param>
/// <returns>Image tag.</returns>
public static IHtmlString Image(string virtualPath, IDictionary <string, object> htmlAttributes)
{
ImageOptimizations.EnsureInitialized();
TagBuilder htmlTag = new TagBuilder("img");
htmlTag.MergeAttributes(htmlAttributes);
HttpContextBase httpContext = new HttpContextWrapper(HttpContext.Current);
if (ImageOptimizations.LinkCompatibleCssFile(httpContext.Request.Browser) == null)
{
htmlTag.MergeAttribute("src", ResolveUrl(virtualPath));
return(new HtmlString(htmlTag.ToString(TagRenderMode.SelfClosing)));
}
else
{
htmlTag.AddCssClass(ImageOptimizations.MakeCssClassName(virtualPath));
htmlTag.MergeAttribute("src", ResolveUrl(ImageOptimizations.GetBlankImageSource(httpContext.Request.Browser)));
return(new HtmlString(htmlTag.ToString(TagRenderMode.SelfClosing)));
}
}
protected override void OnPreRender(EventArgs e)
{
ImageOptimizations.EnsureInitialized();
if (Path.HasExtension(ImageUrl) || ImageUrl.EndsWith(Path.AltDirectorySeparatorChar.ToString(), StringComparison.OrdinalIgnoreCase) || ImageUrl.EndsWith(Path.DirectorySeparatorChar.ToString(), StringComparison.OrdinalIgnoreCase))
{
ImageUrl = Path.GetDirectoryName(ImageUrl);
}
string cssFileName = ImageOptimizations.LinkCompatibleCssFile(new HttpContextWrapper(Context).Request.Browser) ?? ImageOptimizations.LowCompatibilityCssFileName;
// Set up fileName and path variables
string localPath = Context.Server.MapPath(ImageUrl);
// Check that CSS file is accessible
if (!File.Exists(Path.Combine(localPath, cssFileName)))
{
return;
}
AddCssToPage(Page, Path.Combine(ImageUrl, cssFileName));
}
internal static void AddCssToPage(Page page, string href)
{
string keyDirectory = href;
if (Path.HasExtension(keyDirectory))
{
keyDirectory = Path.GetDirectoryName(keyDirectory);
}
SpriteDirectoryPathKey key = new SpriteDirectoryPathKey(keyDirectory);
if (!page.Items.Contains(key))
{
page.Items.Add(key, null);
HtmlLink css = new HtmlLink();
css.Href = ImageOptimizations.FixVirtualPathSlashes(href);
css.Attributes["rel"] = "stylesheet";
css.Attributes["type"] = "text/css";
css.Attributes["media"] = "all";
page.Header.Controls.Add(css);
}
}
protected override void OnPreRender(EventArgs e)
{
if (PrepareSpriteRendering())
{
string spriteDirectoryPath = Path.GetDirectoryName(ImageUrl);
string spriteCssClassName = ImageOptimizations.MakeCssClassName(ImageUrl);
if (CssClass.Length != 0)
{
CssClass = spriteCssClassName + " " + CssClass;
}
else
{
CssClass = spriteCssClassName;
}
ImageSpriteCssLink.AddCssToPage(Page, Path.Combine(spriteDirectoryPath, _cssFileName));
_usingSprites = true;
}
base.OnPreRender(e);
}
