/// <summary>
/// Currently used by the image server
/// to get thumbnails that are used in the add page dialog. Since this dialog can show
/// an enlarged version of the page, we generate these at a higher resolution than usual.
/// Also, to make more realistic views of template pages we insert fake text wherever
/// there is an empty edit block.
///
/// The result is cached for possible future use so the caller should not dispose of it.
/// </summary>
/// <param name="book"></param>
/// <param name="page"></param>
/// <param name="isLandscape"></param>
/// <param name="mustRegenerate"></param>
/// <returns></returns>
public Image GetThumbnailForPage(Book.Book book, IPage page, bool isLandscape, bool mustRegenerate = false)
{
var pageDom = book.GetThumbnailXmlDocumentForPage(page);
var thumbnailOptions = new HtmlThumbNailer.ThumbnailOptions()
{
BackgroundColor = Color.White, // matches the hand-made previews.
BorderStyle = HtmlThumbNailer.ThumbnailOptions.BorderStyles.None, // allows the HTML to add its preferred border in the larger preview
CenterImageUsingTransparentPadding = true,
MustRegenerate = mustRegenerate
};
var pageDiv = pageDom.RawDom.SafeSelectNodes("descendant-or-self::div[contains(@class,'bloom-page')]").Cast <XmlElement>().FirstOrDefault();
// The actual page size is rather arbitrary, but we want the right ratio for A4.
// Using the actual A4 sizes in mm makes a big enough image to look good in the larger
// preview box on the right as well as giving exactly the ratio we want.
// We need to make the image the right shape to avoid some sort of shadow/box effects
// that I can't otherwise find a way to get rid of.
if (isLandscape)
{
thumbnailOptions.Width = 297;
thumbnailOptions.Height = 210;
pageDiv.SetAttribute("class", pageDiv.Attributes["class"].Value.Replace("Portrait", "Landscape"));
}
else
{
thumbnailOptions.Width = 210;
thumbnailOptions.Height = 297;
// On the offchance someone makes a template with by-default-landscape pages...
pageDiv.SetAttribute("class", pageDiv.Attributes["class"].Value.Replace("Landscape", "Portrait"));
}
// In different books (or even the same one) in the same session we may have portrait and landscape
// versions of the same template page. So we must use different IDs.
return(_thumbnailProvider.GetThumbnail(page.Id + (isLandscape ? "L" : ""), pageDom, thumbnailOptions));
}
/// <summary>
/// Will call either 'callback' or 'errorCallback' UNLESS the thumbnail is readonly, in which case it will do neither.
/// </summary>
/// <param name="book"></param>
/// <param name="thumbnailOptions"></param>
/// <param name="callback"></param>
/// <param name="errorCallback"></param>
private void RebuildThumbNail(Book.Book book, HtmlThumbNailer.ThumbnailOptions thumbnailOptions,
Action <BookInfo, Image> callback, Action <BookInfo, Exception> errorCallback, bool async)
{
try
{
if (!book.Storage.RemoveBookThumbnail(thumbnailOptions.FileName))
{
// thumbnail is marked readonly, so just use it
Image thumb;
book.Storage.TryGetPremadeThumbnail(thumbnailOptions.FileName, out thumb);
callback(book.BookInfo, thumb);
return;
}
_thumbnailProvider.RemoveFromCache(book.Storage.Key);
thumbnailOptions.BorderStyle = GetThumbnailBorderStyle(book);
GetThumbNailOfBookCover(book, thumbnailOptions, image => callback(book.BookInfo, image),
error =>
{
//Enhance; this isn't a very satisfying time to find out, because it's only going to happen if we happen to be rebuilding the thumbnail.
//It does help in the case where things are bad, so no thumbnail was created, but by then probably the user has already had some big error.
//On the other hand, given that they have this bad book in their collection now, it's good to just remind them that it's broken and not
//keep showing green error boxes.
book.CheckForErrors();
errorCallback(book.BookInfo, error);
}, async);
}
catch (Exception error)
{
NonFatalProblem.Report(ModalIf.Alpha, PassiveIf.All, "Problem creating book thumbnail ", exception: error);
}
}
/// <summary>
/// Check if the cover image is valid
/// </summary>
/// <returns>True if it's valid. It may be invalid if imageSrc is missing. In certain scenarios, if the imageSrc is "placeHolder.png", that's not valid either.</returns>
internal static bool IsCoverImageSrcValid(string imageSrc, HtmlThumbNailer.ThumbnailOptions options)
{
if (string.IsNullOrEmpty(imageSrc))
{
return(false);
}
else if (Path.GetFileName(imageSrc) == "placeHolder.png")
{
// Valid examples:
// thumbnail.png
// thumbnail-256.png
// thumbnail-300x300.png
if (Regex.IsMatch(options.FileName, "thumbnail(-[0-9]+(x[0-9]+)?)?\\.png"))
{
return(true);
}
else
{
return(false);
}
}
else
{
return(true);
}
}
/// <summary>
/// Currently used by the image server
/// to get thumbnails that are used in the add page dialog. Since this dialog can show
/// an enlarged version of the page, we generate these at a higher resolution than usual.
/// Also, to make more realistic views of template pages we insert fake text wherever
/// there is an empty edit block.
///
/// The result is cached for possible future use so the caller should not dispose of it.
/// </summary>
/// <param name="book"></param>
/// <param name="page"></param>
/// <param name="isLandscape"></param>
/// <returns></returns>
public Image GetThumbnailForPage(Book.Book book, IPage page, bool isLandscape)
{
var pageDom = book.GetThumbnailXmlDocumentForPage(page);
var thumbnailOptions = new HtmlThumbNailer.ThumbnailOptions()
{
BackgroundColor = Color.White,// matches the hand-made previews.
BorderStyle = HtmlThumbNailer.ThumbnailOptions.BorderStyles.None, // allows the HTML to add its preferred border in the larger preview
CenterImageUsingTransparentPadding = true
};
var pageDiv = pageDom.RawDom.SafeSelectNodes("descendant-or-self::div[contains(@class,'bloom-page')]").Cast<XmlElement>().FirstOrDefault();
// The actual page size is rather arbitrary, but we want the right ratio for A4.
// Using the actual A4 sizes in mm makes a big enough image to look good in the larger
// preview box on the right as well as giving exactly the ratio we want.
// We need to make the image the right shape to avoid some sort of shadow/box effects
// that I can't otherwise find a way to get rid of.
if (isLandscape)
{
thumbnailOptions.Width = 297;
thumbnailOptions.Height = 210;
pageDiv.SetAttribute("class", pageDiv.Attributes["class"].Value.Replace("Portrait", "Landscape"));
}
else
{
thumbnailOptions.Width = 210;
thumbnailOptions.Height = 297;
// On the offchance someone makes a template with by-default-landscape pages...
pageDiv.SetAttribute("class", pageDiv.Attributes["class"].Value.Replace("Landscape", "Portrait"));
}
// In different books (or even the same one) in the same session we may have portrait and landscape
// versions of the same template page. So we must use different IDs.
return _thumbnailProvider.GetThumbnail(page.Id + (isLandscape ? "L" : ""), pageDom, thumbnailOptions);
}
/// <summary>
/// Will make a new thumbnail (or throw) UNLESS the thumbnail is readonly, in which case it will do nothing.
/// </summary>
/// <param name="book"></param>
/// <param name="thumbnailOptions"></param>
private void RebuildThumbNailNow(Book.Book book, HtmlThumbNailer.ThumbnailOptions thumbnailOptions)
{
RebuildThumbNail(book, thumbnailOptions, (info, image) => { },
(info, ex) =>
{
throw ex;
}, false);
}
/// <summary>
/// Creates a thumbnail of just the cover image (no title, language name, etc.)
/// </summary>
/// <returns>Returns true if successful; false otherwise. </returns>
internal static bool CreateThumbnailOfCoverImage(Book.Book book, HtmlThumbNailer.ThumbnailOptions options, Action <Image> callback = null)
{
var imageSrc = book.GetCoverImagePath();
if (!IsCoverImageSrcValid(imageSrc, options))
{
Debug.WriteLine(book.StoragePageFolder + " does not have a cover image.");
return(false);
}
var size = Math.Max(options.Width, options.Height);
var destFilePath = Path.Combine(book.StoragePageFolder, options.FileName);
// Writing a transparent image to a file, then reading it in again appears to be the only
// way to get the thumbnail image to draw with the book's cover color background reliably.
var transparentImageFile = Path.Combine(Path.GetTempPath(), "Bloom", "Transparent", Path.GetFileName(imageSrc));
Directory.CreateDirectory(Path.GetDirectoryName(transparentImageFile));
try
{
if (RuntimeImageProcessor.MakePngBackgroundTransparent(imageSrc, transparentImageFile))
{
imageSrc = transparentImageFile;
}
using (var coverImage = PalasoImage.FromFile(imageSrc))
{
if (imageSrc == transparentImageFile)
{
coverImage.Image = MakeImageOpaque(coverImage.Image, book.GetCoverColor());
}
var shouldAddDashedBorder = options.BorderStyle == HtmlThumbNailer.ThumbnailOptions.BorderStyles.Dashed;
coverImage.Image = options.CenterImageUsingTransparentPadding ?
ImageUtils.CenterImageIfNecessary(new Size(size, size), coverImage.Image, shouldAddDashedBorder) :
ImageUtils.ResizeImageIfNecessary(new Size(size, size), coverImage.Image, shouldAddDashedBorder);
switch (Path.GetExtension(destFilePath).ToLowerInvariant())
{
case ".jpg":
case ".jpeg":
ImageUtils.SaveAsTopQualityJpeg(coverImage.Image, destFilePath);
break;
default:
PalasoImage.SaveImageRobustly(coverImage, destFilePath);
break;
}
if (callback != null)
{
callback(coverImage.Image.Clone() as Image); // don't leave GC to chance
}
}
}
finally
{
if (File.Exists(transparentImageFile))
{
SIL.IO.RobustFile.Delete(transparentImageFile);
}
}
return(true);
}
/// <summary>
/// Generates the cover image for a book, e.g. the thumbnail used on Bloom Library
/// </summary>
/// <param name="book"></param>
/// <param name="requestedSize">The maximum size of either dimension</param>
public static string GenerateCoverImageOfRequestedMaxSize(Book.Book book, int requestedSize)
{
HtmlThumbNailer.ThumbnailOptions thumbnailOptions = BookThumbNailer.GetCoverThumbnailOptions(requestedSize, new Guid());
BookThumbNailer.CreateThumbnailOfCoverImage(book, thumbnailOptions, null);
string thumbnailDestination = Path.Combine(book.FolderPath, thumbnailOptions.FileName);
return(thumbnailDestination);
}
/// <summary>
/// Generates a web thumbnail image from the book's front cover image.
/// The resulting image will fit into a 200px x 200px box with no loss of aspect ratio.
/// This means that either the height or the width will be 200px.
/// </summary>
/// <param name="book"></param>
public static void GenerateImageForWeb(Book.Book book)
{
HtmlThumbNailer.ThumbnailOptions options = new HtmlThumbNailer.ThumbnailOptions
{
Height = 200,
Width = 200,
CenterImageUsingTransparentPadding = false,
FileName = "coverImage200.jpg"
};
CreateThumbnailOfCoverImage(book, options);
}
private void GetThumbNailOfBookCover(Book.Book book, HtmlThumbNailer.ThumbnailOptions thumbnailOptions, Action <Image> callback, Action <Exception> errorCallback, bool async)
{
if (book is ErrorBook)
{
callback(Resources.Error70x70);
return;
}
try
{
if (book.HasFatalError) //NB: we might not know yet... we don't fully load every book just to show its thumbnail
{
callback(Resources.Error70x70);
return;
}
GenerateImageForWeb(book);
Image thumb;
if (book.Storage.TryGetPremadeThumbnail(thumbnailOptions.FileName, out thumb))
{
callback(thumb);
return;
}
#if USE_HTMLTHUMBNAILER_FOR_COVER
var dom = book.GetPreviewXmlDocumentForFirstPage();
if (dom == null)
{
callback(Resources.Error70x70);
return;
}
string folderForCachingThumbnail;
folderForCachingThumbnail = book.StoragePageFolder;
_thumbnailProvider.GetThumbnail(folderForCachingThumbnail, book.Storage.Key, dom, thumbnailOptions, callback, errorCallback, async);
#else
if (!CreateThumbnailOfCoverImage(book, thumbnailOptions, callback))
{
callback(Resources.Error70x70);
}
#endif
}
catch (Exception err)
{
callback(Resources.Error70x70);
errorCallback(err);
Debug.Fail(err.Message);
}
}
/// <summary>
/// Make a thumbnail image of a book's front cover.
/// </summary>
/// <param name="book"></param>
/// <param name="height">Optional parameter. If unspecified, use defaults</param>
public void MakeThumbnailOfCover(Book.Book book, int height = -1)
{
HtmlThumbNailer.ThumbnailOptions options = new HtmlThumbNailer.ThumbnailOptions
{
//since this is destined for HTML, it's much easier to handle if there is no pre-padding
CenterImageUsingTransparentPadding = false
};
if (height != -1)
{
options.Height = height;
options.Width = -1;
options.FileName = "thumbnail-" + height + ".png";
}
// else use the defaults
RebuildThumbNailNow(book, options);
}
/// <summary>
/// Gets the default thumbnail options to use when creating a thumbnail of a book's cover
/// </summary>
public static HtmlThumbNailer.ThumbnailOptions GetCoverThumbnailOptions(int height, Guid requestId)
{
var options = new HtmlThumbNailer.ThumbnailOptions
{
//since this is destined for HTML, it's much easier to handle if there is no pre-padding
CenterImageUsingTransparentPadding = false,
RequestId = requestId
};
if (height != -1)
{
options.Height = height;
options.Width = -1;
options.FileName = "thumbnail-" + height + ".png";
}
// else use the defaults
return(options);
}
public void GetThumbNailOfBookCover(Book.Book book, HtmlThumbNailer.ThumbnailOptions thumbnailOptions, Action <Image> callback, Action <Exception> errorCallback, bool async)
{
if (book is ErrorBook)
{
callback(Resources.Error70x70);
return;
}
try
{
if (book.HasFatalError) //NB: we might not know yet... we don't fully load every book just to show its thumbnail
{
callback(Resources.Error70x70);
return;
}
Image thumb;
if (book.Storage.TryGetPremadeThumbnail(thumbnailOptions.FileName, out thumb))
{
callback(thumb);
return;
}
var dom = book.GetPreviewXmlDocumentForFirstPage();
if (dom == null)
{
callback(Resources.Error70x70);
return;
}
string folderForCachingThumbnail;
folderForCachingThumbnail = book.Storage.FolderPath;
_thumbnailProvider.GetThumbnail(folderForCachingThumbnail, book.Storage.Key, dom, thumbnailOptions, callback, errorCallback, async);
}
catch (Exception err)
{
callback(Resources.Error70x70);
Debug.Fail(err.Message);
}
}
/// <summary>
/// Generates a thumbnail suitable for sharing on Facebook
/// </summary>
/// <param name="book"></param>
/// <returns></returns>
public static string GenerateSocialMediaSharingThumbnail(Book.Book book)
{
// 300 x 300 is picked so that FB will consistently generate a thumbnail that is:
// * to the left of the link
// * a fixed aspect ratio (happens to be square)
// * has enough pixels to work with high res screens with devicePixelRatio up to 4. (FB Mobile App was showing it as 75 CSS pixels)
// See BL-8406
int size = 300;
var options = new HtmlThumbNailer.ThumbnailOptions
{
CenterImageUsingTransparentPadding = true,
RequestId = new Guid(),
Height = size,
Width = size,
};
options.FileName = $"thumbnail-{options.Width}x{options.Height}.png";
CreateThumbnailOfCoverImage(book, options);
var thumbnailDestination = Path.Combine(book.FolderPath, options.FileName);
return(thumbnailDestination);
}
/// <summary>
/// Will call either 'callback' or 'errorCallback' UNLESS the thumbnail is readonly, in which case it will do neither.
/// </summary>
/// <param name="book"></param>
/// <param name="thumbnailOptions"></param>
/// <param name="callback"></param>
/// <param name="errorCallback"></param>
public void RebuildThumbNailAsync(Book.Book book, HtmlThumbNailer.ThumbnailOptions thumbnailOptions,
Action <BookInfo, Image> callback, Action <BookInfo, Exception> errorCallback)
{
RebuildThumbNail(book, thumbnailOptions, callback, errorCallback, true);
}
/// <summary>
/// Make a thumbnail image of a book's front cover.
/// </summary>
/// <param name="book"></param>
/// <param name="height">Optional parameter. If unspecified, use defaults</param>
public void MakeThumbnailOfCover(Book.Book book, int height = -1, Guid requestId = new Guid())
{
HtmlThumbNailer.ThumbnailOptions options = GetCoverThumbnailOptions(height, requestId);
RebuildThumbNailNow(book, options);
}
public void MakeThumbnailOfCover(Book.Book book, int height, Control invokeTarget)
{
HtmlThumbNailer.ThumbnailOptions options = new HtmlThumbNailer.ThumbnailOptions
{
//since this is destined for HTML, it's much easier to handle if there is no pre-padding
CenterImageUsingTransparentPadding = false
};
if (height != -1)
{
options.Height = height;
options.Width = -1;
options.FileName = "thumbnail-" + height + ".png";
}
// else use the defaults
RebuildThumbNailNow(book, options);
}
