added cache preview generator and queue (tested but not yet hooked into the UI/logic)...

Signed-off-by: Alex A. Naanou <alex.nanou@gmail.com>

ui/compatibility.js

@@ -125,6 +125,139 @@ if(window.CEF_dumpJSON != null){
 		$('.title-bar .title').text(title)
 	}
 
+	// vips preview generation...
+	// XXX make this queuable...
+	window.makeImagePreviews = function(gid){
+
+		var img = IMAGES[gid]
+		var source = normalizePath(img.path)
+		var name = gid +' - '+ source.split('/').pop()
+		var compression = 90
+
+		var previews = []
+
+		// XXX get real sizes from config...
+		var sizes = [
+				150,
+				350,
+				900
+			]
+
+		// XXX take this from config...
+		var path = normalizePath(CACHE_DIR)
+		path = path.replace(fp, '')
+
+		// XXX get cur image size...
+		var size_getter = $.Deferred()
+		var _i = new Image()
+		_i.onload = function(){
+			size_getter.resolve(Math.max(parseInt(this.width), parseInt(this.height)))
+		} 
+		_i.src = source
+		
+		for(var i=0; i < sizes.length; i++){
+			var size = sizes[i]
+			var target_path = [ path, size+'px' ].join('/')
+
+			var deferred = $.Deferred()
+			previews.push(deferred)
+
+			// NOTE: for some magical reason writing this like this:
+			// 		(function(...){
+			// 			...
+			// 		}(...))
+			// 		produces a "undefined is not a function" in except the 
+			// 		first invocation...
+			var _f = function(size, target_path, deferred){
+				size_getter.done(function(source_size){
+
+					// skip previews larger than cur image...
+					if(fs.existsSync(target_path +'/'+ name) || source_size <= size){
+						console.log('>>> Preview:', name, '('+size+'): Skipped.')
+						return deferred.resolve()
+					}
+
+					// XXX check for errors...
+					fse.mkdirRecursive(target_path, function(err){
+
+						var preview_path = [target_path, name].join('/')
+						var factor = source_size / size
+
+						var cmd = 'vips im_shrink "$IN" "$OUT:$COMPRESSION" $FACTOR $FACTOR'
+							.replace(/\$IN/g, source.replace(fp, ''))
+							.replace(/\$OUT/g, preview_path)
+							.replace(/\$COMPRESSION/g, compression)
+							.replace(/\$FACTOR/g, factor)
+
+						proc.exec(cmd, function(error, stdout, stderr){
+							if(error != null){
+								console.error('>>> Error: preview:', stderr)
+								deferred.reject()
+
+							} else {
+
+								console.log('>>> Preview:', name, '('+size+'): Done.')
+
+								if(!('preview' in img)){
+									img.preview = {}
+								}
+
+								img.preview[size+'px'] = './' + CACHE_DIR +'/'+ preview_path.split(CACHE_DIR).pop()
+
+								// mark image dirty...
+								if(IMAGES_UPDATED.indexOf(gid) < 0){
+									IMAGES_UPDATED.push(gid)
+								}
+
+								deferred.resolve()
+							}
+						})
+					})
+				})
+			}
+			// NOTE: wrapping this in a closure saves the specific data that would
+			// 		otherwise be overwritten by the next loop iteration...
+			_f(size, target_path, deferred)
+		}
+
+		return $.when.apply(null, previews)
+	}
+
+	// XXX is this robust enough???
+	window._PREVIW_CREATE_QUEUE = null
+	window.makeImagesPreviewsQ = function(gids){
+		var previews = []
+
+		$.each(gids, function(i, e){
+			var deferred = $.Deferred()
+
+			var last = previews[previews.length-1]
+
+			// first in this set...
+			if(last == null){
+				if(_PREVIW_CREATE_QUEUE == null){
+					// if nothing in queue, start at once...
+					last = $.Deferred().resolve()
+				} else {
+					last = _PREVIW_CREATE_QUEUE
+				}
+			}
+
+			// append to deffered queue...
+			last.always(function(){
+				makeImagePreviews(e)
+					.always(function(){
+						deferred.resolve()
+					})
+			})
+
+			previews.push(deferred)
+		})
+
+		_PREVIW_CREATE_QUEUE = $.when.apply(null, previews)
+		return _PREVIW_CREATE_QUEUE
+	}
+
 	// load UI stuff...
 	$(function(){
 		$('<div class="title-bar"/>')