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- /*
- Flot plugin for showing a crosshair, thin lines, when the mouse hovers
- over the plot.
-
- crosshair: {
- mode: null or "x" or "y" or "xy"
- color: color
- lineWidth: number
- }
-
- Set the mode to one of "x", "y" or "xy". The "x" mode enables a
- vertical crosshair that lets you trace the values on the x axis, "y"
- enables a horizontal crosshair and "xy" enables them both. "color" is
- the color of the crosshair (default is "rgba(170, 0, 0, 0.80)"),
- "lineWidth" is the width of the drawn lines (default is 1).
-
- The plugin also adds four public methods:
-
- - setCrosshair(pos)
-
- Set the position of the crosshair. Note that this is cleared if
- the user moves the mouse. "pos" should be on the form { x: xpos,
- y: ypos } (or x2 and y2 if you're using the secondary axes), which
- is coincidentally the same format as what you get from a "plothover"
- event. If "pos" is null, the crosshair is cleared.
-
- - clearCrosshair()
-
- Clear the crosshair.
-
- - lockCrosshair(pos)
-
- Cause the crosshair to lock to the current location, no longer
- updating if the user moves the mouse. Optionally supply a position
- (passed on to setCrosshair()) to move it to.
-
- Example usage:
- var myFlot = $.plot( $("#graph"), ..., { crosshair: { mode: "x" } } };
- $("#graph").bind("plothover", function (evt, position, item) {
- if (item) {
- // Lock the crosshair to the data point being hovered
- myFlot.lockCrosshair({ x: item.datapoint[0], y: item.datapoint[1] });
- }
- else {
- // Return normal crosshair operation
- myFlot.unlockCrosshair();
- }
- });
-
- - unlockCrosshair()
-
- Free the crosshair to move again after locking it.
- */
-
- (function ($) {
- var options = {
- crosshair: {
- mode: null, // one of null, "x", "y" or "xy",
- color: "rgba(170, 0, 0, 0.80)",
- lineWidth: 1
- }
- };
-
- function init(plot) {
- // position of crosshair in pixels
- var crosshair = { x: -1, y: -1, locked: false };
-
- plot.setCrosshair = function setCrosshair(pos) {
- if (!pos)
- crosshair.x = -1;
- else {
- var axes = plot.getAxes();
-
- crosshair.x = Math.max(0, Math.min(pos.x != null ? axes.xaxis.p2c(pos.x) : axes.x2axis.p2c(pos.x2), plot.width()));
- crosshair.y = Math.max(0, Math.min(pos.y != null ? axes.yaxis.p2c(pos.y) : axes.y2axis.p2c(pos.y2), plot.height()));
- }
-
- plot.triggerRedrawOverlay();
- };
-
- plot.clearCrosshair = plot.setCrosshair; // passes null for pos
-
- plot.lockCrosshair = function lockCrosshair(pos) {
- if (pos)
- plot.setCrosshair(pos);
- crosshair.locked = true;
- }
-
- plot.unlockCrosshair = function unlockCrosshair() {
- crosshair.locked = false;
- }
-
- plot.hooks.bindEvents.push(function (plot, eventHolder) {
- if (!plot.getOptions().crosshair.mode)
- return;
-
- eventHolder.mouseout(function () {
- if (crosshair.x != -1) {
- crosshair.x = -1;
- plot.triggerRedrawOverlay();
- }
- });
-
- eventHolder.mousemove(function (e) {
- if (plot.getSelection && plot.getSelection()) {
- crosshair.x = -1; // hide the crosshair while selecting
- return;
- }
-
- if (crosshair.locked)
- return;
-
- var offset = plot.offset();
- crosshair.x = Math.max(0, Math.min(e.pageX - offset.left, plot.width()));
- crosshair.y = Math.max(0, Math.min(e.pageY - offset.top, plot.height()));
- plot.triggerRedrawOverlay();
- });
- });
-
- plot.hooks.drawOverlay.push(function (plot, ctx) {
- var c = plot.getOptions().crosshair;
- if (!c.mode)
- return;
-
- var plotOffset = plot.getPlotOffset();
-
- ctx.save();
- ctx.translate(plotOffset.left, plotOffset.top);
-
- if (crosshair.x != -1) {
- ctx.strokeStyle = c.color;
- ctx.lineWidth = c.lineWidth;
- ctx.lineJoin = "round";
-
- ctx.beginPath();
- if (c.mode.indexOf("x") != -1) {
- ctx.moveTo(crosshair.x, 0);
- ctx.lineTo(crosshair.x, plot.height());
- }
- if (c.mode.indexOf("y") != -1) {
- ctx.moveTo(0, crosshair.y);
- ctx.lineTo(plot.width(), crosshair.y);
- }
- ctx.stroke();
- }
- ctx.restore();
- });
- }
-
- $.plot.plugins.push({
- init: init,
- options: options,
- name: 'crosshair',
- version: '1.0'
- });
- })(jQuery);
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