internal static bool TryGetBackgroundDeclaration(this IEnumerable <DeclarationNode> declarationAstNodes, AstNode parentAstNode, out Background backgroundNode, out BackgroundImage backgroundImageNode, out BackgroundPosition backgroundPositionNode, out DeclarationNode backgroundSize, List <string> imageReferencesInInvalidDeclarations, HashSet <string> imageReferencesToIgnore, ImageAssemblyAnalysisLog imageAssemblyAnalysisLog, string outputUnit, double outputUnitFactor, bool ignoreImagesWithNonDefaultBackgroundSize = false)
{
// Initialize the nodes to null
backgroundNode = null;
backgroundImageNode = null;
backgroundPositionNode = null;
backgroundSize = null;
// With CSS3 multiple urls can be present in a single rule, this is not yet supported
// background: url(flower.png), url(ball.png), url(grass.png) no-repeat;
if (BackgroundImage.HasMultipleUrls(parentAstNode.MinifyPrint()))
{
imageAssemblyAnalysisLog.SafeAdd(parentAstNode, null, FailureReason.MultipleUrls);
return(false);
}
// This will check if the selector hash -wg-spriting: ignore. If it does we will ignore the sprite.
var webGreaseSpritingProperty = declarationAstNodes.FirstOrDefault(d => d.Property == "-wg-spriting");
if (webGreaseSpritingProperty != null && webGreaseSpritingProperty.ExprNode.TermNode.StringBasedValue == "ignore")
{
imageAssemblyAnalysisLog.SafeAdd(parentAstNode, null, FailureReason.SpritingIgnore);
return(false);
}
// The list of declarations should not have the duplicate declaration
// properties. Validate and get the dictionary of declarations.
var declarationProperties = declarationAstNodes.LoadDeclarationPropertiesDictionary();
// The selector design is inefficient if the shorthand notation and long name is defined
// in a scope of ruleset declaration, media ruleset declaration or page declaration. This
// would be a great feature to add to Optimization visitor but would require a full table
// scanning which is not yet implemented.
// Per MSN CSS standards, the practice of defining the shorthand notation and long name
// in scope of same selector is not allowed.
DeclarationNode declarationAstNode;
if (declarationProperties.TryGetValue(ImageAssembleConstants.Background, out declarationAstNode))
{
// There should not be any short and long notation simultaneosuly used in these set of declarations.
// For example: Such a list of declarations end up in inefficient CSS.
// #selector
// {
// background:url(foo.gif);
// background-image:url(../../i/D5/DF5D9B4EFD5CFF9122942A67A1EEC5.gif);
// background-position:500px 500px;
// background-repeat:no-repeat
// }
// By design, we are not computing cascade here.
// TODO: RTUIT: Add support to override some of these with extra values depending on the order, or use optimization to do this when merging styles.
if (declarationProperties.ContainsKey(ImageAssembleConstants.BackgroundRepeat) ||
declarationProperties.ContainsKey(ImageAssembleConstants.BackgroundImage) ||
declarationProperties.ContainsKey(ImageAssembleConstants.BackgroundPosition))
{
throw new ImageAssembleException(CssStrings.DuplicateBackgroundFormatError);
}
// Load the model for the "background" declaration
var parsedBackground = new Background(declarationAstNode, outputUnit, outputUnitFactor);
////
//// The url should be present
////
bool shouldIgnore;
if (!parsedBackground.BackgroundImage.VerifyBackgroundUrl(parentAstNode, imageReferencesToIgnore, imageAssemblyAnalysisLog, out shouldIgnore) ||
shouldIgnore)
{
return(false);
}
////
//// The "no-repeat" term should be explicitly configured on the "background" declaration
////
if (!parsedBackground.BackgroundRepeat.VerifyBackgroundNoRepeat())
{
imageAssemblyAnalysisLog.SafeAdd(parentAstNode, parsedBackground.Url, FailureReason.BackgroundRepeatInvalid);
UpdateFailedUrlsList(parsedBackground.Url, imageReferencesInInvalidDeclarations);
return(false);
}
////
//// The background position should only be empty, x = any value and y = 0, top or px
////
if (!parsedBackground.BackgroundPosition.IsVerticalSpriteCandidate())
{
imageAssemblyAnalysisLog.SafeAdd(parentAstNode, parsedBackground.Url, FailureReason.IncorrectPosition);
UpdateFailedUrlsList(parsedBackground.Url, imageReferencesInInvalidDeclarations);
return(false);
}
//// Try to get the background size, returns false if we want to ignore images with background sizes and the background size is set to a non-default value.
if (!TryGetBackgroundSize(ignoreImagesWithNonDefaultBackgroundSize, declarationProperties, out backgroundSize))
{
imageAssemblyAnalysisLog.SafeAdd(parentAstNode, parsedBackground.Url, FailureReason.BackgroundSizeIsSetToNonDefaultValue);
UpdateFailedUrlsList(parsedBackground.Url, imageReferencesInInvalidDeclarations);
return(false);
}
backgroundNode = parsedBackground;
imageAssemblyAnalysisLog.SafeAdd(parentAstNode, parsedBackground.Url);
//// SUCCESS - This is the candidate!
return(true);
}
// Now there should be declaration for "background-image" or "background-repeat" or both
if (declarationProperties.TryGetValue(ImageAssembleConstants.BackgroundImage, out declarationAstNode))
{
// Load the property model for the "background-image" declaration
var parsedBackgroundImage = new BackgroundImage(declarationAstNode);
////
//// The url should be present
////
bool shouldIgnore;
if (!parsedBackgroundImage.VerifyBackgroundUrl(parentAstNode, imageReferencesToIgnore, imageAssemblyAnalysisLog, out shouldIgnore) ||
shouldIgnore)
{
return(false);
}
////
//// There is a "background-repeat" declaration found
////
DeclarationNode backgroundRepeat;
if (!declarationProperties.TryGetValue(ImageAssembleConstants.BackgroundRepeat, out backgroundRepeat))
{
imageAssemblyAnalysisLog.SafeAdd(parentAstNode, parsedBackgroundImage.Url, FailureReason.NoRepeat);
UpdateFailedUrlsList(parsedBackgroundImage.Url, imageReferencesInInvalidDeclarations);
return(false);
}
////
//// Now make sure that "background-repeat" is "no-repeat"
////
if (!new BackgroundRepeat(backgroundRepeat).VerifyBackgroundNoRepeat())
{
imageAssemblyAnalysisLog.SafeAdd(parentAstNode, parsedBackgroundImage.Url, FailureReason.BackgroundRepeatInvalid);
UpdateFailedUrlsList(parsedBackgroundImage.Url, imageReferencesInInvalidDeclarations);
return(false);
}
//// Try to get the background size, returns false if we want to ignore images with background sizes and the background size is set to a non-default value.
if (!TryGetBackgroundSize(ignoreImagesWithNonDefaultBackgroundSize, declarationProperties, out backgroundSize))
{
imageAssemblyAnalysisLog.SafeAdd(parentAstNode, parsedBackgroundImage.Url, FailureReason.BackgroundSizeIsSetToNonDefaultValue);
UpdateFailedUrlsList(parsedBackgroundImage.Url, imageReferencesInInvalidDeclarations);
return(false);
}
////
//// The background position should only be empty, x = any value and y = 0, top or px
////
DeclarationNode backgroundPosition;
if (declarationProperties.TryGetValue(ImageAssembleConstants.BackgroundPosition, out backgroundPosition))
{
// Now if there is a "background-position" declaration (optional), lets make
// it should only be empty, px or left/top or right/px
var parsedBackgroundPosition = new BackgroundPosition(backgroundPosition, outputUnit, outputUnitFactor);
if (!parsedBackgroundPosition.IsVerticalSpriteCandidate())
{
imageAssemblyAnalysisLog.SafeAdd(parentAstNode, parsedBackgroundImage.Url, FailureReason.IncorrectPosition);
UpdateFailedUrlsList(parsedBackgroundImage.Url, imageReferencesInInvalidDeclarations);
return(false);
}
backgroundImageNode = parsedBackgroundImage;
backgroundPositionNode = parsedBackgroundPosition;
imageAssemblyAnalysisLog.SafeAdd(parentAstNode, parsedBackgroundImage.Url);
//// SUCCESS - This is the candidate!
return(true);
}
backgroundImageNode = parsedBackgroundImage;
imageAssemblyAnalysisLog.SafeAdd(parentAstNode, backgroundImageNode.Url);
//// SUCCESS - This is the candidate!
return(true);
}
return(false);
}
