1# Drawing a scatter best fit chart 2 3[Reference](http://wiki.pchart.net/doc.scatter.drawscatterbestfit.html) 4 5```php 6require '/path/to/your/vendor/autoload.php'; 7 8use CpChart\Chart\Scatter; 9use CpChart\Data; 10use CpChart\Image; 11 12/* Create the Data object */ 13$data = new Data(); 14 15/* Create the X axis and the binded series */ 16for ($i = 0; $i <= 360; $i = $i + 10) { 17 $data->addPoints(rand(1, 20) * 10 + rand(0, $i), "Probe 1"); 18} 19for ($i = 0; $i <= 360; $i = $i + 10) { 20 $data->addPoints(rand(1, 2) * 10 + rand(0, $i), "Probe 2"); 21} 22$data->setAxisName(0, "X-Index"); 23$data->setAxisXY(0, AXIS_X); 24$data->setAxisPosition(0, AXIS_POSITION_TOP); 25 26/* Create the Y axis and the binded series */ 27for ($i = 0; $i <= 360; $i = $i + 10) { 28 $data->addPoints($i, "Probe 3"); 29} 30$data->setSerieOnAxis("Probe 3", 1); 31$data->setAxisName(1, "Y-Index"); 32$data->setAxisXY(1, AXIS_Y); 33$data->setAxisPosition(1, AXIS_POSITION_LEFT); 34 35/* Create the 1st scatter chart binding */ 36$data->setScatterSerie("Probe 1", "Probe 3", 0); 37$data->setScatterSerieDescription(0, "This year"); 38$data->setScatterSerieColor(0, ["R" => 0, "G" => 0, "B" => 0]); 39 40/* Create the 2nd scatter chart binding */ 41$data->setScatterSerie("Probe 2", "Probe 3", 1); 42$data->setScatterSerieDescription(1, "Last Year"); 43 44/* Create the Image object */ 45$image = new Image(400, 400, $data); 46 47/* Draw the background */ 48$settings = ["R" => 170, "G" => 183, "B" => 87, "Dash" => 1, "DashR" => 190, "DashG" => 203, "DashB" => 107]; 49$image->drawFilledRectangle(0, 0, 400, 400, $settings); 50 51/* Overlay with a gradient */ 52$image->drawGradientArea(0, 0, 400, 400, DIRECTION_VERTICAL, [ 53 "StartR" => 219, 54 "StartG" => 231, 55 "StartB" => 139, 56 "EndR" => 1, 57 "EndG" => 138, 58 "EndB" => 68, 59 "Alpha" => 50 60]); 61$image->drawGradientArea(0, 0, 400, 20, DIRECTION_VERTICAL, [ 62 "StartR" => 0, 63 "StartG" => 0, 64 "StartB" => 0, 65 "EndR" => 50, 66 "EndG" => 50, 67 "EndB" => 50, 68 "Alpha" => 80 69]); 70 71/* Write the picture title */ 72$image->setFontProperties(["FontName" => "Silkscreen.ttf", "FontSize" => 6]); 73$image->drawText(10, 13, "drawScatterBestFit() - Linear regression", [ 74 "R" => 255, 75 "G" => 255, 76 "B" => 255 77]); 78 79/* Add a border to the picture */ 80$image->drawRectangle(0, 0, 399, 399, ["R" => 0, "G" => 0, "B" => 0]); 81 82/* Set the default font */ 83$image->setFontProperties(["FontName" => "pf_arma_five.ttf", "FontSize" => 6]); 84 85/* Set the graph area */ 86$image->setGraphArea(50, 60, 350, 360); 87 88/* Create the Scatter chart object */ 89$myScatter = new Scatter($image, $data); 90 91/* Draw the scale */ 92$myScatter->drawScatterScale(); 93 94/* Turn on shadow computing */ 95$image->setShadow(true, ["X" => 1, "Y" => 1, "R" => 0, "G" => 0, "B" => 0, "Alpha" => 10]); 96 97/* Draw a scatter plot chart */ 98$myScatter->drawScatterPlotChart(); 99 100/* Draw the legend */ 101$myScatter->drawScatterLegend(280, 380, ["Mode" => LEGEND_HORIZONTAL, "Style" => LEGEND_NOBORDER]); 102 103/* Draw the line of best fit */ 104$myScatter->drawScatterBestFit(); 105 106/* Render the picture (choose the best way) */ 107$image->autoOutput("example.drawScatterBestFit.png"); 108``` 109
