Index: third_party/flot/jquery.flot.canvas.js |
diff --git a/third_party/flot/jquery.flot.canvas.js b/third_party/flot/jquery.flot.canvas.js |
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+/* Flot plugin for drawing all elements of a plot on the canvas. |
+ |
+Copyright (c) 2007-2014 IOLA and Ole Laursen. |
+Licensed under the MIT license. |
+ |
+Flot normally produces certain elements, like axis labels and the legend, using |
+HTML elements. This permits greater interactivity and customization, and often |
+looks better, due to cross-browser canvas text inconsistencies and limitations. |
+ |
+It can also be desirable to render the plot entirely in canvas, particularly |
+if the goal is to save it as an image, or if Flot is being used in a context |
+where the HTML DOM does not exist, as is the case within Node.js. This plugin |
+switches out Flot's standard drawing operations for canvas-only replacements. |
+ |
+Currently the plugin supports only axis labels, but it will eventually allow |
+every element of the plot to be rendered directly to canvas. |
+ |
+The plugin supports these options: |
+ |
+{ |
+ canvas: boolean |
+} |
+ |
+The "canvas" option controls whether full canvas drawing is enabled, making it |
+possible to toggle on and off. This is useful when a plot uses HTML text in the |
+browser, but needs to redraw with canvas text when exporting as an image. |
+ |
+*/ |
+ |
+(function($) { |
+ |
+ var options = { |
+ canvas: true |
+ }; |
+ |
+ var render, getTextInfo, addText; |
+ |
+ // Cache the prototype hasOwnProperty for faster access |
+ |
+ var hasOwnProperty = Object.prototype.hasOwnProperty; |
+ |
+ function init(plot, classes) { |
+ |
+ var Canvas = classes.Canvas; |
+ |
+ // We only want to replace the functions once; the second time around |
+ // we would just get our new function back. This whole replacing of |
+ // prototype functions is a disaster, and needs to be changed ASAP. |
+ |
+ if (render == null) { |
+ getTextInfo = Canvas.prototype.getTextInfo, |
+ addText = Canvas.prototype.addText, |
+ render = Canvas.prototype.render; |
+ } |
+ |
+ // Finishes rendering the canvas, including overlaid text |
+ |
+ Canvas.prototype.render = function() { |
+ |
+ if (!plot.getOptions().canvas) { |
+ return render.call(this); |
+ } |
+ |
+ var context = this.context, |
+ cache = this._textCache; |
+ |
+ // For each text layer, render elements marked as active |
+ |
+ context.save(); |
+ context.textBaseline = "middle"; |
+ |
+ for (var layerKey in cache) { |
+ if (hasOwnProperty.call(cache, layerKey)) { |
+ var layerCache = cache[layerKey]; |
+ for (var styleKey in layerCache) { |
+ if (hasOwnProperty.call(layerCache, styleKey)) { |
+ var styleCache = layerCache[styleKey], |
+ updateStyles = true; |
+ for (var key in styleCache) { |
+ if (hasOwnProperty.call(styleCache, key)) { |
+ |
+ var info = styleCache[key], |
+ positions = info.positions, |
+ lines = info.lines; |
+ |
+ // Since every element at this level of the cache have the |
+ // same font and fill styles, we can just change them once |
+ // using the values from the first element. |
+ |
+ if (updateStyles) { |
+ context.fillStyle = info.font.color; |
+ context.font = info.font.definition; |
+ updateStyles = false; |
+ } |
+ |
+ for (var i = 0, position; position = positions[i]; i++) { |
+ if (position.active) { |
+ for (var j = 0, line; line = position.lines[j]; j++) { |
+ context.fillText(lines[j].text, line[0], line[1]); |
+ } |
+ } else { |
+ positions.splice(i--, 1); |
+ } |
+ } |
+ |
+ if (positions.length == 0) { |
+ delete styleCache[key]; |
+ } |
+ } |
+ } |
+ } |
+ } |
+ } |
+ } |
+ |
+ context.restore(); |
+ }; |
+ |
+ // Creates (if necessary) and returns a text info object. |
+ // |
+ // When the canvas option is set, the object looks like this: |
+ // |
+ // { |
+ // width: Width of the text's bounding box. |
+ // height: Height of the text's bounding box. |
+ // positions: Array of positions at which this text is drawn. |
+ // lines: [{ |
+ // height: Height of this line. |
+ // widths: Width of this line. |
+ // text: Text on this line. |
+ // }], |
+ // font: { |
+ // definition: Canvas font property string. |
+ // color: Color of the text. |
+ // }, |
+ // } |
+ // |
+ // The positions array contains objects that look like this: |
+ // |
+ // { |
+ // active: Flag indicating whether the text should be visible. |
+ // lines: Array of [x, y] coordinates at which to draw the line. |
+ // x: X coordinate at which to draw the text. |
+ // y: Y coordinate at which to draw the text. |
+ // } |
+ |
+ Canvas.prototype.getTextInfo = function(layer, text, font, angle, width) { |
+ |
+ if (!plot.getOptions().canvas) { |
+ return getTextInfo.call(this, layer, text, font, angle, width); |
+ } |
+ |
+ var textStyle, layerCache, styleCache, info; |
+ |
+ // Cast the value to a string, in case we were given a number |
+ |
+ text = "" + text; |
+ |
+ // If the font is a font-spec object, generate a CSS definition |
+ |
+ if (typeof font === "object") { |
+ textStyle = font.style + " " + font.variant + " " + font.weight + " " + font.size + "px " + font.family; |
+ } else { |
+ textStyle = font; |
+ } |
+ |
+ // Retrieve (or create) the cache for the text's layer and styles |
+ |
+ layerCache = this._textCache[layer]; |
+ |
+ if (layerCache == null) { |
+ layerCache = this._textCache[layer] = {}; |
+ } |
+ |
+ styleCache = layerCache[textStyle]; |
+ |
+ if (styleCache == null) { |
+ styleCache = layerCache[textStyle] = {}; |
+ } |
+ |
+ info = styleCache[text]; |
+ |
+ if (info == null) { |
+ |
+ var context = this.context; |
+ |
+ // If the font was provided as CSS, create a div with those |
+ // classes and examine it to generate a canvas font spec. |
+ |
+ if (typeof font !== "object") { |
+ |
+ var element = $("<div> </div>") |
+ .css("position", "absolute") |
+ .addClass(typeof font === "string" ? font : null) |
+ .appendTo(this.getTextLayer(layer)); |
+ |
+ font = { |
+ lineHeight: element.height(), |
+ style: element.css("font-style"), |
+ variant: element.css("font-variant"), |
+ weight: element.css("font-weight"), |
+ family: element.css("font-family"), |
+ color: element.css("color") |
+ }; |
+ |
+ // Setting line-height to 1, without units, sets it equal |
+ // to the font-size, even if the font-size is abstract, |
+ // like 'smaller'. This enables us to read the real size |
+ // via the element's height, working around browsers that |
+ // return the literal 'smaller' value. |
+ |
+ font.size = element.css("line-height", 1).height(); |
+ |
+ element.remove(); |
+ } |
+ |
+ textStyle = font.style + " " + font.variant + " " + font.weight + " " + font.size + "px " + font.family; |
+ |
+ // Create a new info object, initializing the dimensions to |
+ // zero so we can count them up line-by-line. |
+ |
+ info = styleCache[text] = { |
+ width: 0, |
+ height: 0, |
+ positions: [], |
+ lines: [], |
+ font: { |
+ definition: textStyle, |
+ color: font.color |
+ } |
+ }; |
+ |
+ context.save(); |
+ context.font = textStyle; |
+ |
+ // Canvas can't handle multi-line strings; break on various |
+ // newlines, including HTML brs, to build a list of lines. |
+ // Note that we could split directly on regexps, but IE < 9 is |
+ // broken; revisit when we drop IE 7/8 support. |
+ |
+ var lines = (text + "").replace(/<br ?\/?>|\r\n|\r/g, "\n").split("\n"); |
+ |
+ for (var i = 0; i < lines.length; ++i) { |
+ |
+ var lineText = lines[i], |
+ measured = context.measureText(lineText); |
+ |
+ info.width = Math.max(measured.width, info.width); |
+ info.height += font.lineHeight; |
+ |
+ info.lines.push({ |
+ text: lineText, |
+ width: measured.width, |
+ height: font.lineHeight |
+ }); |
+ } |
+ |
+ context.restore(); |
+ } |
+ |
+ return info; |
+ }; |
+ |
+ // Adds a text string to the canvas text overlay. |
+ |
+ Canvas.prototype.addText = function(layer, x, y, text, font, angle, width, halign, valign) { |
+ |
+ if (!plot.getOptions().canvas) { |
+ return addText.call(this, layer, x, y, text, font, angle, width, halign, valign); |
+ } |
+ |
+ var info = this.getTextInfo(layer, text, font, angle, width), |
+ positions = info.positions, |
+ lines = info.lines; |
+ |
+ // Text is drawn with baseline 'middle', which we need to account |
+ // for by adding half a line's height to the y position. |
+ |
+ y += info.height / lines.length / 2; |
+ |
+ // Tweak the initial y-position to match vertical alignment |
+ |
+ if (valign == "middle") { |
+ y = Math.round(y - info.height / 2); |
+ } else if (valign == "bottom") { |
+ y = Math.round(y - info.height); |
+ } else { |
+ y = Math.round(y); |
+ } |
+ |
+ // FIXME: LEGACY BROWSER FIX |
+ // AFFECTS: Opera < 12.00 |
+ |
+ // Offset the y coordinate, since Opera is off pretty |
+ // consistently compared to the other browsers. |
+ |
+ if (!!(window.opera && window.opera.version().split(".")[0] < 12)) { |
+ y -= 2; |
+ } |
+ |
+ // Determine whether this text already exists at this position. |
+ // If so, mark it for inclusion in the next render pass. |
+ |
+ for (var i = 0, position; position = positions[i]; i++) { |
+ if (position.x == x && position.y == y) { |
+ position.active = true; |
+ return; |
+ } |
+ } |
+ |
+ // If the text doesn't exist at this position, create a new entry |
+ |
+ position = { |
+ active: true, |
+ lines: [], |
+ x: x, |
+ y: y |
+ }; |
+ |
+ positions.push(position); |
+ |
+ // Fill in the x & y positions of each line, adjusting them |
+ // individually for horizontal alignment. |
+ |
+ for (var i = 0, line; line = lines[i]; i++) { |
+ if (halign == "center") { |
+ position.lines.push([Math.round(x - line.width / 2), y]); |
+ } else if (halign == "right") { |
+ position.lines.push([Math.round(x - line.width), y]); |
+ } else { |
+ position.lines.push([Math.round(x), y]); |
+ } |
+ y += line.height; |
+ } |
+ }; |
+ } |
+ |
+ $.plot.plugins.push({ |
+ init: init, |
+ options: options, |
+ name: "canvas", |
+ version: "1.0" |
+ }); |
+ |
+})(jQuery); |