+/**
+ * Transition function to use in animations. Returns values between 0.0
+ * (totally old values) and 1.0 (totally new values) for each frame.
+ * @private
+ */
+Dygraph.zoomAnimationFunction = function(frame, numFrames) {
+ var k = 1.5;
+ return (1.0 - Math.pow(k, -frame)) / (1.0 - Math.pow(k, -numFrames));
+};
+
+/**
+ * Zoom to something containing [minDate, maxDate] values. Don't confuse this
+ * method with doZoomX which accepts pixel coordinates. This function redraws
+ * the graph.
+ *
+ * @param {Number} minDate The minimum date that should be visible.
+ * @param {Number} maxDate The maximum date that should be visible.
+ * @private
+ */
+Dygraph.prototype.doZoomXDates_ = function(minDate, maxDate) {
+ // TODO(danvk): when yAxisRange is null (i.e. "fit to data", the animation
+ // can produce strange effects. Rather than the y-axis transitioning slowly
+ // between values, it can jerk around.)
+ var old_window = this.xAxisRange();
+ var new_window = [minDate, maxDate];
+ this.zoomed_x_ = true;
+ var that = this;
+ this.doAnimatedZoom(old_window, new_window, null, null, function() {
+ if (that.attr_("zoomCallback")) {
+ that.attr_("zoomCallback")(minDate, maxDate, that.yAxisRanges());
+ }
+ });
+};
+
+/**
+ * Zoom to something containing [lowY, highY]. These are pixel coordinates in
+ * the canvas. This function redraws the graph.
+ *
+ * @param {Number} lowY The topmost pixel value that should be visible.
+ * @param {Number} highY The lowest pixel value that should be visible.
+ * @private
+ */
+Dygraph.prototype.doZoomY_ = function(lowY, highY) {
+ this.currentZoomRectArgs_ = null;
+ // Find the highest and lowest values in pixel range for each axis.
+ // Note that lowY (in pixels) corresponds to the max Value (in data coords).
+ // This is because pixels increase as you go down on the screen, whereas data
+ // coordinates increase as you go up the screen.
+ var oldValueRanges = this.yAxisRanges();
+ var newValueRanges = [];
+ for (var i = 0; i < this.axes_.length; i++) {
+ var hi = this.toDataYCoord(lowY, i);
+ var low = this.toDataYCoord(highY, i);
+ newValueRanges.push([low, hi]);
+ }
+
+ this.zoomed_y_ = true;
+ var that = this;
+ this.doAnimatedZoom(null, null, oldValueRanges, newValueRanges, function() {
+ if (that.attr_("zoomCallback")) {
+ var xRange = that.xAxisRange();
+ that.attr_("zoomCallback")(xRange[0], xRange[1], that.yAxisRanges());
+ }
+ });
+};
+
+/**
+ * Reset the zoom to the original view coordinates. This is the same as
+ * double-clicking on the graph.
+ *
+ * @private
+ */
+Dygraph.prototype.doUnzoom_ = function() {
+ var dirty = false, dirtyX = false, dirtyY = false;
+ if (this.dateWindow_ !== null) {
+ dirty = true;
+ dirtyX = true;
+ }
+
+ for (var i = 0; i < this.axes_.length; i++) {
+ if (typeof(this.axes_[i].valueWindow) !== 'undefined' && this.axes_[i].valueWindow !== null) {
+ dirty = true;
+ dirtyY = true;
+ }
+ }
+
+ // Clear any selection, since it's likely to be drawn in the wrong place.
+ this.clearSelection();
+
+ if (dirty) {
+ this.zoomed_x_ = false;
+ this.zoomed_y_ = false;
+
+ var minDate = this.rawData_[0][0];
+ var maxDate = this.rawData_[this.rawData_.length - 1][0];
+
+ // With only one frame, don't bother calculating extreme ranges.
+ // TODO(danvk): merge this block w/ the code below.
+ if (!this.attr_("animatedZooms")) {
+ this.dateWindow_ = null;
+ for (i = 0; i < this.axes_.length; i++) {
+ if (this.axes_[i].valueWindow !== null) {
+ delete this.axes_[i].valueWindow;
+ }
+ }
+ this.drawGraph_();
+ if (this.attr_("zoomCallback")) {
+ this.attr_("zoomCallback")(minDate, maxDate, this.yAxisRanges());
+ }
+ return;
+ }
+
+ var oldWindow=null, newWindow=null, oldValueRanges=null, newValueRanges=null;
+ if (dirtyX) {
+ oldWindow = this.xAxisRange();
+ newWindow = [minDate, maxDate];
+ }
+
+ if (dirtyY) {
+ oldValueRanges = this.yAxisRanges();
+ // TODO(danvk): this is pretty inefficient
+ var packed = this.gatherDatasets_(this.rolledSeries_, null);
+ var extremes = packed[1];
+
+ // this has the side-effect of modifying this.axes_.
+ // this doesn't make much sense in this context, but it's convenient (we
+ // need this.axes_[*].extremeValues) and not harmful since we'll be
+ // calling drawGraph_ shortly, which clobbers these values.
+ this.computeYAxisRanges_(extremes);
+
+ newValueRanges = [];
+ for (i = 0; i < this.axes_.length; i++) {
+ var axis = this.axes_[i];
+ newValueRanges.push(axis.valueRange != null ? axis.valueRange : axis.extremeRange);
+ }
+ }
+
+ var that = this;
+ this.doAnimatedZoom(oldWindow, newWindow, oldValueRanges, newValueRanges,
+ function() {
+ that.dateWindow_ = null;
+ for (var i = 0; i < that.axes_.length; i++) {
+ if (that.axes_[i].valueWindow !== null) {
+ delete that.axes_[i].valueWindow;
+ }
+ }
+ if (that.attr_("zoomCallback")) {
+ that.attr_("zoomCallback")(minDate, maxDate, that.yAxisRanges());
+ }
+ });