Google Charts display options - charts

Question

My questions (short style)
Can you customize a y-axis labeling interval ?
Can you display the extreme values of a series as an horizontal line ?
The detailed explanations
I have a combo chart made with Google Charts : the first set of data uses an area style, and the second a line style. The second one is the one that matters here :
it represents a percentage
i don't want it from 0 to 1 (or 0 to 100 in percentage), but from its min to its max (or something near)
and i want to display those min and max values
If i modify the scale so :
PHP
$min_reject_percentage = 5 * floor($min_reject_percentage / 5);
$max_reject_percentage = 5 * ceil($max_reject_percentage / 5);
JS
var options = {
...
vAxes: {
...
1: {
format:"##%",
viewWindow: {
min: <?php echo ($min_taux_rejet / 100); ?>,
max: <?php echo ($max_taux_rejet / 100); ?>,
},
},
},
series: {
0: {
targetAxisIndex: 0,
type: 'area',
},
1: {
targetAxisIndex: 1,
type: 'line',
},
}
}
The vertical axis is limited to the nearest multiple of 5 for min and max values, but :
the interval shown on the axis is from 10 to 10, which is too big. Since i have a real max of 31.5 and a real min of 17.1, axis min is 15 is 15 and axis max is 35, but the only graduation labeled are 20 and 30.
i can't see the real min and max on the graph

Answer 1

you can use config option ticks, which is an array of values to be used for the labels...
see following working snippet...
google.charts.load('current', {
packages: ['corechart']
}).then(function () {
var data = google.visualization.arrayToDataTable([
['x', 'y0', 'y1'],
[0, 18, 0.171],
[1, 28, 0.315],
]);
var chart = new google.visualization.LineChart(document.getElementById('chart_div'));
var axisMin = 0.15;
var axisMax = 0.35;
var ticks = [];
for (var i = axisMin; i <= axisMax; i = i + 0.05) {
ticks.push(i);
}
var options = {
vAxes: {
1: {
format: '##%',
ticks: ticks,
viewWindow: {
min: axisMin,
max: axisMax,
},
},
},
series: {
0: {
targetAxisIndex: 0,
type: 'area',
},
1: {
targetAxisIndex: 1,
type: 'line',
},
}
};
chart.draw(data, options);
});
<script src="https://www.gstatic.com/charts/loader.js"></script>
<div id="chart_div"></div>