private static float calculateMin(Number[] yValues) {
float min = yValues[0].floatValue();
for (Number d : yValues) {
min = Math.min(min, d.floatValue());
}
return min;
}
private static float calculateMax(Number[] yValues) {
float max = yValues[0].floatValue();
for (Number d : yValues) {
max = Math.max(max, d.floatValue());
}
return max;
}
/**
* Draw a sparkline with x axis and y axis values, and pre-calculated min and max of the y axis
* values. Use this when you already have min/max values calculated and want to avoid extra
* calculations by <code>SparklineGraph</code> X values <b>must</b> be ordered and not repeated.
*
* @param xValues X axis values
* @param yValues Y axis values
* @param yMinValue Minimum value of the Y axis, should be correct
* @param yMaxValue Maximum value of the Y axis, should be correct
* @param parameters Rendering parameters
* @return Image of the sparkline
*/
public static BufferedImage draw(
Number[] xValues,
Number[] yValues,
Number yMinValue,
Number yMaxValue,
SparklineParameters parameters) {
if (parameters == null) {
throw new IllegalArgumentException("parameters can't be null");
}
if (yValues == null || yValues.length < 2) {
throw new IllegalArgumentException("Y values can't be null and have a length of at least 2");
}
if (xValues != null && xValues.length != yValues.length) {
throw new IllegalArgumentException("X values should have the same length as Y values");
}
final BufferedImage image =
new BufferedImage(
parameters.getWidth(), parameters.getHeight(), BufferedImage.TYPE_INT_ARGB);
final Color backgroundColor =
parameters.getBackgroundColor() != null
? parameters.getBackgroundColor()
: SparklineParameters.DEFAULT_BACKGROUND_COLOR;
final Color lineColor =
parameters.getLineColor() != null
? parameters.getLineColor()
: SparklineParameters.DEFAULT_LINE_COLOR;
final Color areaColor =
parameters.getAreaColor() != null
? parameters.getAreaColor()
: SparklineParameters.DEFAULT_AREA_COLOR;
Color highlightMinColor = parameters.getHighlightMinColor();
Color highlightMaxColor = parameters.getHighlightMaxColor();
int width = parameters.getWidth();
int height = parameters.getHeight();
ArrayList<HighlightParameters> highlightsList = new ArrayList<>();
Color highlightValueColor =
parameters.getHighligtValueColor() != null
? parameters.getHighligtValueColor()
: SparklineParameters.DEFAULT_HIGHLIGHT_VALUE_COLOR;
Integer highlightedValueXPosition = parameters.getHighlightedValueXPosition();
String highlightedValueText = null;
// Calculate y min if not provided:
float yMin;
if (yMinValue != null) {
yMin = yMinValue.floatValue();
} else {
yMin = calculateMin(yValues);
}
// Calculate y max if not provided:
float yMax;
if (yMaxValue != null) {
yMax = yMaxValue.floatValue();
} else {
yMax = calculateMax(yValues);
}
// Begin drawing:
final Graphics2D g = image.createGraphics();
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
// Background:
if (backgroundColor != null && !parameters.isTransparentBackground()) {
g.setBackground(backgroundColor);
g.clearRect(0, 0, width, height);
}
// Sparklines:
g.setPaint(lineColor);
// For special case, all the Y values are equal:
if (yMin == yMax) {
// Disable min/max highlight since all Y values are equal
highlightMaxColor = null;
highlightMinColor = null;
}
if (highlightMaxColor != null || highlightMinColor != null || highlightValueColor != null) {
height -=
HIGHLIGHT_RADIUS; // Highlight circle radius pixels less in order not to draw outside
// bounds
width -= HIGHLIGHT_RADIUS; // Highlight circle radius pixels less in order not to draw outside
// bounds
g.translate(HIGHLIGHT_RADIUS / 2, HIGHLIGHT_RADIUS / 2);
}
// Poly for area:
Path2D.Float path = new Path2D.Float();
path.moveTo(0, height);
// Calculate x tick width and x min value:
float xMin;
float xTickWidth;
if (xValues == null) {
xMin = 0;
xTickWidth = (float) width / (yValues.length - 1);
} else {
xMin = xValues[0].floatValue(); // X values have to be ordered
xTickWidth = (float) width / (xValues[xValues.length - 1].floatValue() - xMin);
}
// Calculate yTickWidth:
float yTickWidth = height / (yMax - yMin);
float bottom = height;
float x0, y0, x1, y1;
for (int i = 0; i < yValues.length - 1; i++) {
if (xValues == null) {
x0 = i * xTickWidth;
x1 = (i + 1) * xTickWidth;
} else {
x0 = (xValues[i].floatValue() - xMin) * xTickWidth;
x1 = (xValues[i + 1].floatValue() - xMin) * xTickWidth;
}
if (yMin == yMax) {
// For special case, all the Y values are equal:
y0 = y1 = bottom - height / 2.0f;
} else {
y0 = bottom - (yValues[i].floatValue() - yMin) * yTickWidth;
y1 = bottom - (yValues[i + 1].floatValue() - yMin) * yTickWidth;
}
// Draw line:
g.draw(new Line2D.Double(x0, y0, x1, y1));
// Add to path for area:
if (parameters.isDrawArea()) {
if (i == 0) {
path.lineTo(x0, y0);
}
path.lineTo(x1, y1);
}
// Save min/max values highlihgting if enabled:
if (yValues[i + 1].floatValue() == yMin && highlightMinColor != null) {
highlightsList.add(new HighlightParameters(x1, y1, highlightMinColor));
highlightMinColor = null; // Only highlight first min
}
if (yValues[i + 1].floatValue() == yMax && highlightMaxColor != null) {
highlightsList.add(new HighlightParameters(x1, y1, highlightMaxColor));
highlightMaxColor = null; // Only highlight first max
}
// Save first point special case min/max values highlihgting if enabled:
if (i == 0) {
if (yValues[0].floatValue() == yMin && highlightMinColor != null) {
highlightsList.add(new HighlightParameters(x0, y0, highlightMinColor));
highlightMinColor = null; // Only highlight first min
}
if (yValues[0].floatValue() == yMax && highlightMaxColor != null) {
highlightsList.add(new HighlightParameters(x0, y0, highlightMaxColor));
highlightMaxColor = null; // Only highlight first max
}
}
// Save x position value highlighting if enabled:
if (highlightedValueXPosition != null && x1 >= highlightedValueXPosition) {
// Highlight closest point:
if ((highlightedValueXPosition - x0) < (x1 - x0) / 2f) { // Highlight left point
highlightsList.add(new HighlightParameters(x0, y0, highlightValueColor));
if (parameters.getHighlightTextColor() != null) {
highlightedValueText =
buildHighlightText(
parameters.getHighlightTextMode(),
xValues != null ? xValues[i] : i,
yValues[i]);
}
} else { // Highlight right point
highlightsList.add(new HighlightParameters(x1, y1, highlightValueColor));
if (parameters.getHighlightTextColor() != null) {
highlightedValueText =
buildHighlightText(
parameters.getHighlightTextMode(),
xValues != null ? xValues[i + 1] : i + 1,
yValues[i + 1]);
}
}
highlightedValueXPosition = null;
}
}
// Draw area
if (parameters.isDrawArea()) {
// End Path
path.lineTo(width, height);
path.lineTo(0, height);
g.setColor(areaColor);
g.fill(path);
}
// Draw list of highlights at the end in order to always draw them on top of lines:
for (HighlightParameters p : highlightsList) {
drawHighlight(g, p.x, p.y, p.color);
}
// Finally draw value text (x,y) if enabled:
if (highlightedValueText != null) {
g.setFont(g.getFont().deriveFont(Font.BOLD));
int textWidth = g.getFontMetrics().stringWidth(highlightedValueText);
int textHeight = g.getFontMetrics().getHeight();
g.translate((width - textWidth) / 2f, (height + textHeight / 2f) / 2f);
// Draw bounding box if enabled:
if (parameters.getHighlightTextBoxColor() != null) {
g.setPaint(parameters.getHighlightTextBoxColor());
g.fill(g.getFontMetrics().getStringBounds(highlightedValueText, g));
}
g.setPaint(parameters.getHighlightTextColor());
g.drawString(highlightedValueText, 0, 0);
}
return image;
}