旋转jQuery Flot值标签90度

Question

我正在使用Value Label plugin进行基于jQuery的Flot（生成图形）。

我想将值旋转到90度，以便标签值不会相互重叠。请注意，我使用的是Canvas而不是HTML模式。

在此处查看问题： https://github.com/leonardoeloy/flot-valuelabels/issues/8

Answer 1

此选项未包含在您链接的插件中。我t was pretty easy to modify and hack it in（这是修改过的插件源代码）：

/**
* Value Labels Plugin for flot.
* http://leonardoeloy.github.com/flot-valuelabels
* http://wiki.github.com/leonardoeloy/flot-valuelabels/
*
* Using canvas.fillText instead of divs, which is better for printing - by Leonardo Eloy, March 2010.
* Tested with Flot 0.6 and JQuery 1.3.2.
*
* Original homepage: http://sites.google.com/site/petrsstuff/projects/flotvallab
* Released under the MIT license by Petr Blahos, December 2009.
*/
(function ($) {
    var options = {
        valueLabels: {
        show: false,
            showAsHtml: false, // Set to true if you wanna switch back to DIV usage (you need plot.css for this)
            showLastValue: false, // Use this to show the label only for the last value in the series
            verticalText: false // should text be written vertically
        }
    };

    function init(plot) {
        plot.hooks.draw.push(function (plot, ctx) {
        if (!plot.getOptions().valueLabels.show) return;

            var showLastValue = plot.getOptions().valueLabels.showLastValue;
            var showAsHtml = plot.getOptions().valueLabels.showAsHtml;
            var verticalText = plot.getOptions().valueLabels.verticalText;
            var ctx = plot.getCanvas().getContext("2d");
        $.each(plot.getData(), function(ii, series) {
                    // Workaround, since Flot doesn't set this value anymore
                    series.seriesIndex = ii;
            if (showAsHtml) plot.getPlaceholder().find("#valueLabels"+ii).remove();
            var html = '<div id="valueLabels' + series.seriesIndex + '" class="valueLabels">';

            var last_val = null;
            var last_x = -1000;
            var last_y = -1000;
            for (var i = 0; i < series.data.length; ++i) {
            if (series.data[i] == null || (showLastValue && i != series.data.length-1))  continue;

            var x = series.data[i][0], y = series.data[i][2];
            if (x < series.xaxis.min || x > series.xaxis.max || y < series.yaxis.min || y > series.yaxis.max)  continue;
            var val = y;

            if (series.valueLabelFunc) val = series.valueLabelFunc({ series: series, seriesIndex: ii, index: i });
            val = ""+val;

            if (val!=last_val || i==series.data.length-1) {
                var xx = series.xaxis.p2c(x)+plot.getPlotOffset().left;
                var yy = series.yaxis.p2c(y)-12+plot.getPlotOffset().top;
                if (Math.abs(yy-last_y)>20 || last_x<xx) {
                    last_val = val;
                    last_x = xx + val.length*8;
                    last_y = yy;

                                        if (!showAsHtml) {
                                            // Little 5 px padding here helps the number to get
                                            // closer to points
                                            x_pos = xx;
                                            y_pos = yy+6;

                                            // If the value is on the top of the canvas, we need
                                            // to push it down a little
                                            if (yy <= 0) y_pos = 18;
                                            // The same happens with the x axis
                                            if (xx >= plot.width()) x_pos = plot.width();
                                            // Translate to near the center to rotate about the center
                                            if (verticalText){
                                                ctx.save();
                                                ctx.translate(x_pos,y_pos);
                                                ctx.rotate(Math.PI / 2);
                                                ctx.translate(-x_pos,-y_pos);
                                            }
                                            ctx.fillText(val, x_pos, y_pos);
                                            if (verticalText) ctx.restore();
                                        } else {
                                            var head = '<div style="left:' + xx + 'px;top:' + yy + 'px;" class="valueLabel';
                                            var tail = '">' + val + '</div>';
                                            html+= head + "Light" + tail + head + tail;
                                        }
                }
            }
            }

                    if (showAsHtml) {
                        html+= "</div>";
                        plot.getPlaceholder().append(html);
                    }
        });
        });
    }

    $.plot.plugins.push({
        init: init,
        options: options,
        name: 'valueLabels',
        version: '1.1'
    });
})(jQuery);

如何称呼它：

        var data_a = {
            label: "Series A",
            data: [[1, 10], [2, 20], [3, 30]]
        };
        var data_b = {
            label: "Series B",
            data: [[1, 30], [2, 20], [3, 10]]
        };
        var options = {
            valueLabels: {
                show: true,
                verticalText: true
            }
        };
        var plot = $.plot($('#placeholder'), [data_a, data_b], options);

结果图：