Class QAccelPlot::SpatialGrid¶

ClassList > QAccelPlot > SpatialGrid

Uniform-grid spatial index with bounded per-rectangle storage. More...

#include <SpatialGrid.hpp>

Public Functions¶

Type	Name
void	build (const double * data, int itemCount, int valuesPerItem=4) Rebuilds the spatial index from data containing__itemCount axis-aligned rectangles.
void	buildF (const float * data, int itemCount, int valuesPerItem=4) Rebuilds the spatial index from single-precision data , like`build()` .
int	query (double x, double y) const Returns the index of the topmost rectangle that contains point ( x _,_y ), or -1 if none.
int	queryTopmost (double minX, double minY, double maxX, double maxY, const std::function< bool(int)> & accept) const Returns the highest index among rectangles overlapping the box for which accept returns true, or -1.

Public Static Functions¶

Type	Name
int	scanTopmost (const double * data, int itemCount, double minX, double minY, double maxX, double maxY, const std::function< bool(int)> & accept, int valuesPerItem=4) Returns what `queryTopmost()` returns on a grid built from the same rectangles, without building one.
int	scanTopmostF (const float * data, int itemCount, double minX, double minY, double maxX, double maxY, const std::function< bool(int)> & accept, int valuesPerItem=4) Scans single-precision data , like`scanTopmost()` .

Detailed Description¶

Each item is stored as four consecutive doubles (x1, y1, x2, y2) in a flat array with a configurable valuesPerItem stride. Intended for use by RectangleSeries and similar shape types. Rectangles spanning more than 64 cells are stored once and checked separately during queries. An infinite edge leaves a rectangle unbounded in that direction; a rectangle with a NaN edge is never hit.

Public Functions Documentation¶

function build¶

Rebuilds the spatial index from data containing__itemCount axis-aligned rectangles.

void QAccelPlot::SpatialGrid::build (
    const double * data,
    int itemCount,
    int valuesPerItem=4
)

Parameters:

data Pointer to the flat double array (x1, y1, x2, y2 per item, with valuesPerItem stride).
itemCount Number of rectangles in data.
valuesPerItem Number of doubles per rectangle entry (default 4).

function buildF¶

Rebuilds the spatial index from single-precision data , likebuild() .

void QAccelPlot::SpatialGrid::buildF (
    const float * data,
    int itemCount,
    int valuesPerItem=4
)

function query¶

Returns the index of the topmost rectangle that contains point ( x _,_y ), or -1 if none.

int QAccelPlot::SpatialGrid::query (
    double x,
    double y
) const

function queryTopmost¶

Returns the highest index among rectangles overlapping the box for which accept returns true, or -1.

int QAccelPlot::SpatialGrid::queryTopmost (
    double minX,
    double minY,
    double maxX,
    double maxY,
    const std::function< bool(int)> & accept
) const

Lets callers apply a precise hit test, e.g. in pixel space, to the few candidates near a point.

Public Static Functions Documentation¶

function scanTopmost¶

Returns what queryTopmost() returns on a grid built from the same rectangles, without building one.

static int QAccelPlot::SpatialGrid::scanTopmost (
    const double * data,
    int itemCount,
    double minX,
    double minY,
    double maxX,
    double maxY,
    const std::function< bool(int)> & accept,
    int valuesPerItem=4
)

Tests rectangles from the last to the first, so a call costs up to one pass over data. That is cheaper than a rebuild while the data is replaced after only a few queries.

function scanTopmostF¶

Scans single-precision data , likescanTopmost() .

static int QAccelPlot::SpatialGrid::scanTopmostF (
    const float * data,
    int itemCount,
    double minX,
    double minY,
    double maxX,
    double maxY,
    const std::function< bool(int)> & accept,
    int valuesPerItem=4
)

The documentation for this class was generated from the following file QAccelPlot/src/QAccelPlot/series/SpatialGrid.hpp