Class HeatmapRenderer

java.lang.Object

com.arbergashi.charts.render.BaseRenderer

com.arbergashi.charts.render.specialized.HeatmapRenderer

All Implemented Interfaces:

ChartRenderer

public class HeatmapRenderer
extends BaseRenderer
implements ChartRenderer

Renderer for 2D heatmaps.

Unified renderer for density and grid visualizations. Supports two modes: 1. Grid mode: Direct rendering of a double[][] matrix (via setGridData(double[][], double, double, double, double)). 2. Density mode: Automatic binning of ChartModel points into a grid.

Optimized for performance via direct pixel operations and a color LUT.

Since:

2025-06-01

Version:

1.0.0

Author:

Arber Gashi

Field Summary

Fields inherited from class BaseRenderer

PIXEL_BUF, PIXEL_BUF4

Constructor Summary

Constructors

Constructor	Description
HeatmapRenderer()

Method Summary

Modifier and Type	Method	Description
protected void	drawData(Graphics2D g2, ChartModel model, PlotContext context)	Implementation-specific drawing logic.
String	getName()	Returns the renderer name used by legends and UI labels.
Optional<Integer>	getPointAt(Point2D pixel, ChartModel model, PlotContext context)	Returns the data index nearest to the given pixel coordinate, if supported.
String	getTooltipText(int index, ChartModel model)	Returns tooltip text for the given data index, or null when not supported.
void	setGridData(double[][] data, double minX, double maxX, double minY, double maxY)	Sets the grid data.

Methods inherited from class BaseRenderer

drawHighlightPoint, drawI18nLabel, drawLabel, getArc, getCachedFont, getCachedGradient, getCachedStroke, getCachedStroke, getCachedStroke, getCubicCurve, getEllipse, getId, getLayerIndex, getLegendColor, getLine, getPathCache, getRect, getRoundRectangle, getSeriesColor, getSeriesStroke, getTheme, isLegendRequired, isMultiColor, pBuffer, pBuffer4, render, resolveTheme, seriesOrBase, setLayerIndex, setMultiColor, setTheme, setupQualityHints, themeAccent, themeAxisLabel, themeBackground, themeBearish, themeBullish, themeForeground, themeGrid, themeSeries

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface ChartRenderer

clearHover, createContext, getFocusValues, getPreferredYRange, isLegendRequired, render, renderEmptyState, supportsEmptyState

Constructor Details

HeatmapRenderer

public HeatmapRenderer()

Method Details

getName

public String getName()

Description copied from class: BaseRenderer

Returns the renderer name used by legends and UI labels.

Specified by:

getName in interface ChartRenderer

Overrides:

getName in class BaseRenderer

Returns:

renderer name

getTooltipText

public String getTooltipText(int index,
 ChartModel model)

Description copied from class: BaseRenderer

Returns tooltip text for the given data index, or null when not supported.

Specified by:

getTooltipText in interface ChartRenderer

Overrides:

getTooltipText in class BaseRenderer

Parameters:

index - The index of the data point.

model - The data model.

Returns:

A formatted string for the tooltip, or null if no tooltip should be shown.

getPointAt

public Optional<Integer> getPointAt(Point2D pixel,
 ChartModel model,
 PlotContext context)

Description copied from class: BaseRenderer

Returns the data index nearest to the given pixel coordinate, if supported.

Specified by:

getPointAt in interface ChartRenderer

Overrides:

getPointAt in class BaseRenderer

Parameters:

pixel - mouse/crosshair position in component coordinates

model - data model for this layer

context - current plot context

Returns:

optional point index

setGridData

public void setGridData(double[][] data,
 double minX,
 double maxX,
 double minY,
 double maxY)

Sets the grid data.

Parameters:

data - [rows][cols] array (row = y, col = x).

minX - Start X.

maxX - End X.

minY - Start Y.

maxY - End Y.

drawData

protected void drawData(Graphics2D g2,
 ChartModel model,
 PlotContext context)

Description copied from class: BaseRenderer

Implementation-specific drawing logic. Must follow Zero-Allocation rules.

Specified by:

drawData in class BaseRenderer