242 lines
7.2 KiB
JavaScript
242 lines
7.2 KiB
JavaScript
/* Flot plugin for plotting images.
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Copyright (c) 2007-2014 IOLA and Ole Laursen.
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Licensed under the MIT license.
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The data syntax is [ [ image, x1, y1, x2, y2 ], ... ] where (x1, y1) and
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(x2, y2) are where you intend the two opposite corners of the image to end up
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in the plot. Image must be a fully loaded Javascript image (you can make one
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with new Image()). If the image is not complete, it's skipped when plotting.
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There are two helpers included for retrieving images. The easiest work the way
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that you put in URLs instead of images in the data, like this:
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[ "myimage.png", 0, 0, 10, 10 ]
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Then call $.plot.image.loadData( data, options, callback ) where data and
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options are the same as you pass in to $.plot. This loads the images, replaces
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the URLs in the data with the corresponding images and calls "callback" when
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all images are loaded (or failed loading). In the callback, you can then call
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$.plot with the data set. See the included example.
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A more low-level helper, $.plot.image.load(urls, callback) is also included.
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Given a list of URLs, it calls callback with an object mapping from URL to
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Image object when all images are loaded or have failed loading.
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The plugin supports these options:
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series: {
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images: {
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show: boolean
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anchor: "corner" or "center"
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alpha: [ 0, 1 ]
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}
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}
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They can be specified for a specific series:
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$.plot( $("#placeholder"), [{
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data: [ ... ],
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images: { ... }
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])
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Note that because the data format is different from usual data points, you
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can't use images with anything else in a specific data series.
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Setting "anchor" to "center" causes the pixels in the image to be anchored at
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the corner pixel centers inside of at the pixel corners, effectively letting
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half a pixel stick out to each side in the plot.
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A possible future direction could be support for tiling for large images (like
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Google Maps).
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*/
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(function ($) {
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var options = {
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series: {
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images: {
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show: false,
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alpha: 1,
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anchor: "corner" // or "center"
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}
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}
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};
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$.plot.image = {};
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$.plot.image.loadDataImages = function (series, options, callback) {
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var urls = [], points = [];
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var defaultShow = options.series.images.show;
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$.each(series, function (i, s) {
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if (!(defaultShow || s.images.show))
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return;
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if (s.data)
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s = s.data;
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$.each(s, function (i, p) {
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if (typeof p[0] == "string") {
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urls.push(p[0]);
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points.push(p);
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}
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});
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});
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$.plot.image.load(urls, function (loadedImages) {
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$.each(points, function (i, p) {
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var url = p[0];
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if (loadedImages[url])
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p[0] = loadedImages[url];
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});
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callback();
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});
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}
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$.plot.image.load = function (urls, callback) {
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var missing = urls.length, loaded = {};
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if (missing == 0)
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callback({});
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$.each(urls, function (i, url) {
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var handler = function () {
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--missing;
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loaded[url] = this;
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if (missing == 0)
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callback(loaded);
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};
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$('<img />').load(handler).error(handler).attr('src', url);
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});
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};
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function drawSeries(plot, ctx, series) {
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var plotOffset = plot.getPlotOffset();
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if (!series.images || !series.images.show)
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return;
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var points = series.datapoints.points,
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ps = series.datapoints.pointsize;
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for (var i = 0; i < points.length; i += ps) {
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var img = points[i],
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x1 = points[i + 1], y1 = points[i + 2],
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x2 = points[i + 3], y2 = points[i + 4],
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xaxis = series.xaxis, yaxis = series.yaxis,
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tmp;
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// actually we should check img.complete, but it
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// appears to be a somewhat unreliable indicator in
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// IE6 (false even after load event)
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if (!img || img.width <= 0 || img.height <= 0)
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continue;
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if (x1 > x2) {
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tmp = x2;
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x2 = x1;
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x1 = tmp;
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}
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if (y1 > y2) {
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tmp = y2;
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y2 = y1;
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y1 = tmp;
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}
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// if the anchor is at the center of the pixel, expand the
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// image by 1/2 pixel in each direction
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if (series.images.anchor == "center") {
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tmp = 0.5 * (x2-x1) / (img.width - 1);
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x1 -= tmp;
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x2 += tmp;
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tmp = 0.5 * (y2-y1) / (img.height - 1);
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y1 -= tmp;
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y2 += tmp;
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}
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// clip
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if (x1 == x2 || y1 == y2 ||
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x1 >= xaxis.max || x2 <= xaxis.min ||
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y1 >= yaxis.max || y2 <= yaxis.min)
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continue;
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var sx1 = 0, sy1 = 0, sx2 = img.width, sy2 = img.height;
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if (x1 < xaxis.min) {
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sx1 += (sx2 - sx1) * (xaxis.min - x1) / (x2 - x1);
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x1 = xaxis.min;
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}
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if (x2 > xaxis.max) {
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sx2 += (sx2 - sx1) * (xaxis.max - x2) / (x2 - x1);
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x2 = xaxis.max;
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}
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if (y1 < yaxis.min) {
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sy2 += (sy1 - sy2) * (yaxis.min - y1) / (y2 - y1);
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y1 = yaxis.min;
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}
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if (y2 > yaxis.max) {
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sy1 += (sy1 - sy2) * (yaxis.max - y2) / (y2 - y1);
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y2 = yaxis.max;
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}
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x1 = xaxis.p2c(x1);
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x2 = xaxis.p2c(x2);
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y1 = yaxis.p2c(y1);
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y2 = yaxis.p2c(y2);
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// the transformation may have swapped us
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if (x1 > x2) {
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tmp = x2;
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x2 = x1;
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x1 = tmp;
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}
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if (y1 > y2) {
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tmp = y2;
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y2 = y1;
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y1 = tmp;
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}
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tmp = ctx.globalAlpha;
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ctx.globalAlpha *= series.images.alpha;
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ctx.drawImage(img,
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sx1, sy1, sx2 - sx1, sy2 - sy1,
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x1 + plotOffset.left, y1 + plotOffset.top,
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x2 - x1, y2 - y1);
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ctx.globalAlpha = tmp;
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}
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}
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function processRawData(plot, series, data, datapoints) {
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if (!series.images.show)
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return;
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// format is Image, x1, y1, x2, y2 (opposite corners)
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datapoints.format = [
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{ required: true },
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{ x: true, number: true, required: true },
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{ y: true, number: true, required: true },
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{ x: true, number: true, required: true },
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{ y: true, number: true, required: true }
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];
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}
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function init(plot) {
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plot.hooks.processRawData.push(processRawData);
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plot.hooks.drawSeries.push(drawSeries);
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}
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$.plot.plugins.push({
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init: init,
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options: options,
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name: 'image',
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version: '1.1'
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});
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})(jQuery);
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