+/**
+ * Returns the currently-visible x-range. This can be affected by zooming,
+ * panning or a call to updateOptions.
+ * Returns a two-element array: [left, right].
+ * If the Dygraph has dates on the x-axis, these will be millis since epoch.
+ */
+Dygraph.prototype.xAxisRange = function() {
+ if (this.dateWindow_) return this.dateWindow_;
+
+ // The entire chart is visible.
+ var left = this.rawData_[0][0];
+ var right = this.rawData_[this.rawData_.length - 1][0];
+ return [left, right];
+};
+
+/**
+ * Returns the currently-visible y-range for an axis. This can be affected by
+ * zooming, panning or a call to updateOptions. Axis indices are zero-based. If
+ * called with no arguments, returns the range of the first axis.
+ * Returns a two-element array: [bottom, top].
+ */
+Dygraph.prototype.yAxisRange = function(idx) {
+ if (typeof(idx) == "undefined") idx = 0;
+ if (idx < 0 || idx >= this.axes_.length) return null;
+ return [ this.axes_[idx].computedValueRange[0],
+ this.axes_[idx].computedValueRange[1] ];
+};
+
+/**
+ * Returns the currently-visible y-ranges for each axis. This can be affected by
+ * zooming, panning, calls to updateOptions, etc.
+ * Returns an array of [bottom, top] pairs, one for each y-axis.
+ */
+Dygraph.prototype.yAxisRanges = function() {
+ var ret = [];
+ for (var i = 0; i < this.axes_.length; i++) {
+ ret.push(this.yAxisRange(i));
+ }
+ return ret;
+};
+
+// TODO(danvk): use these functions throughout dygraphs.
+/**
+ * Convert from data coordinates to canvas/div X/Y coordinates.
+ * If specified, do this conversion for the coordinate system of a particular
+ * axis. Uses the first axis by default.
+ * Returns a two-element array: [X, Y]
+ *
+ * Note: use toDomXCoord instead of toDomCoords(x, null) and use toDomYCoord
+ * instead of toDomCoords(null, y, axis).
+ */
+Dygraph.prototype.toDomCoords = function(x, y, axis) {
+ return [ this.toDomXCoord(x), this.toDomYCoord(y, axis) ];
+};
+
+/**
+ * Convert from data x coordinates to canvas/div X coordinate.
+ * If specified, do this conversion for the coordinate system of a particular
+ * axis.
+ * Returns a single value or null if x is null.
+ */
+Dygraph.prototype.toDomXCoord = function(x) {
+ if (x == null) {
+ return null;
+ };
+
+ var area = this.plotter_.area;
+ var xRange = this.xAxisRange();
+ return area.x + (x - xRange[0]) / (xRange[1] - xRange[0]) * area.w;
+}
+
+/**
+ * Convert from data x coordinates to canvas/div Y coordinate and optional
+ * axis. Uses the first axis by default.
+ *
+ * returns a single value or null if y is null.
+ */
+Dygraph.prototype.toDomYCoord = function(y, axis) {
+ var pct = this.toPercentYCoord(y, axis);
+
+ if (pct == null) {
+ return null;
+ }
+ var area = this.plotter_.area;
+ return area.y + pct * area.h;
+}
+
+/**
+ * Convert from canvas/div coords to data coordinates.
+ * If specified, do this conversion for the coordinate system of a particular
+ * axis. Uses the first axis by default.
+ * Returns a two-element array: [X, Y].
+ *
+ * Note: use toDataXCoord instead of toDataCoords(x, null) and use toDataYCoord
+ * instead of toDataCoords(null, y, axis).
+ */
+Dygraph.prototype.toDataCoords = function(x, y, axis) {
+ return [ this.toDataXCoord(x), this.toDataYCoord(y, axis) ];
+};
+
+/**
+ * Convert from canvas/div x coordinate to data coordinate.
+ *
+ * If x is null, this returns null.
+ */
+Dygraph.prototype.toDataXCoord = function(x) {
+ if (x == null) {
+ return null;
+ }
+
+ var area = this.plotter_.area;
+ var xRange = this.xAxisRange();
+ return xRange[0] + (x - area.x) / area.w * (xRange[1] - xRange[0]);
+};
+
+/**
+ * Convert from canvas/div y coord to value.
+ *
+ * If y is null, this returns null.
+ * if axis is null, this uses the first axis.
+ */
+Dygraph.prototype.toDataYCoord = function(y, axis) {
+ if (y == null) {
+ return null;
+ }
+
+ var area = this.plotter_.area;
+ var yRange = this.yAxisRange(axis);
+
+ if (typeof(axis) == "undefined") axis = 0;
+ if (!this.axes_[axis].logscale) {
+ return yRange[0] + (area.h - y) / area.h * (yRange[1] - yRange[0]);
+ } else {
+ // Computing the inverse of toDomCoord.
+ var pct = (y - area.y) / area.h
+
+ // Computing the inverse of toPercentYCoord. The function was arrived at with
+ // the following steps:
+ //
+ // Original calcuation:
+ // pct = (logr1 - Dygraph.log10(y)) / (logr1 - Dygraph.log10(yRange[0]));
+ //
+ // Move denominator to both sides:
+ // pct * (logr1 - Dygraph.log10(yRange[0])) = logr1 - Dygraph.log10(y);
+ //
+ // subtract logr1, and take the negative value.
+ // logr1 - (pct * (logr1 - Dygraph.log10(yRange[0]))) = Dygraph.log10(y);
+ //
+ // Swap both sides of the equation, and we can compute the log of the
+ // return value. Which means we just need to use that as the exponent in
+ // e^exponent.
+ // Dygraph.log10(y) = logr1 - (pct * (logr1 - Dygraph.log10(yRange[0])));
+
+ var logr1 = Dygraph.log10(yRange[1]);
+ var exponent = logr1 - (pct * (logr1 - Dygraph.log10(yRange[0])));
+ var value = Math.pow(Dygraph.LOG_SCALE, exponent);
+ return value;
+ }
+};
+
+/**
+ * Converts a y for an axis to a percentage from the top to the
+ * bottom of the div.
+ *
+ * If the coordinate represents a value visible on the canvas, then
+ * the value will be between 0 and 1, where 0 is the top of the canvas.
+ * However, this method will return values outside the range, as
+ * values can fall outside the canvas.
+ *
+ * If y is null, this returns null.
+ * if axis is null, this uses the first axis.
+ */
+Dygraph.prototype.toPercentYCoord = function(y, axis) {
+ if (y == null) {
+ return null;
+ }
+ if (typeof(axis) == "undefined") axis = 0;
+
+ var area = this.plotter_.area;
+ var yRange = this.yAxisRange(axis);
+
+ var pct;
+ if (!this.axes_[axis].logscale) {
+ // yrange[1] - y is unit distance from the bottom.
+ // yrange[1] - yrange[0] is the scale of the range.
+ // (yRange[1] - y) / (yRange[1] - yRange[0]) is the % from the bottom.
+ pct = (yRange[1] - y) / (yRange[1] - yRange[0]);
+ } else {
+ var logr1 = Dygraph.log10(yRange[1]);
+ pct = (logr1 - Dygraph.log10(y)) / (logr1 - Dygraph.log10(yRange[0]));
+ }
+ return pct;
+}
+
+/**
+ * Returns the number of columns (including the independent variable).
+ */
+Dygraph.prototype.numColumns = function() {
+ return this.rawData_[0].length;
+};
+
+/**
+ * Returns the number of rows (excluding any header/label row).
+ */
+Dygraph.prototype.numRows = function() {
+ return this.rawData_.length;
+};
+
+/**
+ * Returns the value in the given row and column. If the row and column exceed
+ * the bounds on the data, returns null. Also returns null if the value is
+ * missing.
+ */
+Dygraph.prototype.getValue = function(row, col) {
+ if (row < 0 || row > this.rawData_.length) return null;
+ if (col < 0 || col > this.rawData_[row].length) return null;
+
+ return this.rawData_[row][col];
+};
+
projects / dygraphs.git / blobdiff