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Add the geopoly_group_bbox() aggregate function to the Geopoly module.

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FossilOrigin-Name: 2d4debccbc027405a33aeb10f9d65f6fe4bfb5eb1be5a4d8b82158caba04643f
This commit is contained in:
drh
2018-08-29 15:50:47 +00:00
parent 8ab114c6a9
commit c0d2117f1c
4 changed files with 117 additions and 16 deletions
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95
ext/rtree/geopoly.c
View File

@ -477,9 +477,14 @@ static void geopolyAreaFunc(
}
/*
** Compute a bound-box on a polygon. Return a new GeoPoly object
** that describes the bounding box. Or, if aCoord is not a NULL pointer
** fill it in with the bounding box instead.
** If pPoly is a polygon, compute its bounding box. Then:
**
** (1) if aCoord!=0 store the bounding box in aCoord, returning NULL
** (2) otherwise, compute a GeoPoly for the bounding box and return the
** new GeoPoly
**
** If pPoly is NULL but aCoord is not NULL, then compute a new GeoPoly from
** the bounding box in aCoord and return a pointer to that GeoPoly.
*/
static GeoPoly *geopolyBBox(
sqlite3_context *context, /* For recording the error */
@ -487,11 +492,21 @@ static GeoPoly *geopolyBBox(
RtreeCoord *aCoord, /* Results here */
int *pRc /* Error code here */
){
GeoPoly *p = geopolyFuncParam(context, pPoly, pRc);
GeoPoly *pOut = 0;
GeoPoly *p;
float mnX, mxX, mnY, mxY;
if( pPoly==0 && aCoord!=0 ){
p = 0;
mnX = aCoord[0].f;
mxX = aCoord[1].f;
mnY = aCoord[2].f;
mxY = aCoord[3].f;
goto geopolyBboxFill;
}else{
p = geopolyFuncParam(context, pPoly, pRc);
}
if( p ){
int ii;
float mnX, mxX, mnY, mxY;
mnX = mxX = p->a[0];
mnY = mxY = p->a[1];
for(ii=1; ii<p->nVertex; ii++){
@ -504,6 +519,7 @@ static GeoPoly *geopolyBBox(
}
if( pRc ) *pRc = SQLITE_OK;
if( aCoord==0 ){
geopolyBboxFill:
pOut = sqlite3_realloc(p, sizeof(GeoPoly)+sizeof(GeoCoord)*6);
if( pOut==0 ){
sqlite3_free(p);
@ -512,6 +528,8 @@ static GeoPoly *geopolyBBox(
return 0;
}
pOut->nVertex = 4;
ii = 1;
pOut->hdr[0] = *(unsigned char*)&ii;
pOut->hdr[1] = 0;
pOut->hdr[2] = 0;
pOut->hdr[3] = 4;
@ -550,6 +568,58 @@ static void geopolyBBoxFunc(
}
}
/*
** State vector for the geopoly_group_bbox() aggregate function.
*/
typedef struct GeoBBox GeoBBox;
struct GeoBBox {
int isInit;
RtreeCoord a[4];
};
/*
** Implementation of the geopoly_group_bbox(X) aggregate SQL function.
*/
static void geopolyBBoxStep(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
RtreeCoord a[4];
int rc = SQLITE_OK;
(void)geopolyBBox(context, argv[0], a, &rc);
if( rc==SQLITE_OK ){
GeoBBox *pBBox;
pBBox = (GeoBBox*)sqlite3_aggregate_context(context, sizeof(*pBBox));
if( pBBox==0 ) return;
if( pBBox->isInit==0 ){
pBBox->isInit = 1;
memcpy(pBBox->a, a, sizeof(RtreeCoord)*4);
}else{
if( a[0].f < pBBox->a[0].f ) pBBox->a[0] = a[0];
if( a[1].f > pBBox->a[1].f ) pBBox->a[1] = a[1];
if( a[2].f < pBBox->a[2].f ) pBBox->a[2] = a[2];
if( a[3].f > pBBox->a[3].f ) pBBox->a[3] = a[3];
}
}
}
static void geopolyBBoxFinal(
sqlite3_context *context
){
GeoPoly *p;
GeoBBox *pBBox;
pBBox = (GeoBBox*)sqlite3_aggregate_context(context, 0);
if( pBBox==0 ) return;
p = geopolyBBox(context, 0, pBBox->a, 0);
if( p ){
sqlite3_result_blob(context, p->hdr,
4+8*p->nVertex, SQLITE_TRANSIENT);
sqlite3_free(p);
}
}
/*
** Determine if point (x0,y0) is beneath line segment (x1,y1)->(x2,y2).
** Returns:
@ -1057,7 +1127,7 @@ static int geopolyInit(
pRtree->nAux++;
sqlite3_str_appendf(pSql, ",%s", argv[ii]);
}
sqlite3_str_appendf(pSql, ",_bbox HIDDEN);");
sqlite3_str_appendf(pSql, ");");
zSql = sqlite3_str_finish(pSql);
if( !zSql ){
rc = SQLITE_NOMEM;
@ -1345,8 +1415,6 @@ static int geopolyColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
}
}
sqlite3_result_value(ctx, sqlite3_column_value(pCsr->pReadAux, i+2));
}else{
/* Must be the _bbox column */
}
return SQLITE_OK;
}
@ -1559,12 +1627,23 @@ static int sqlite3_geopoly_init(sqlite3 *db){
{ geopolyBBoxFunc, 1, "geopoly_bbox" },
{ geopolyXformFunc, 7, "geopoly_xform" },
};
static const struct {
void (*xStep)(sqlite3_context*,int,sqlite3_value**);
void (*xFinal)(sqlite3_context*);
const char *zName;
} aAgg[] = {
{ geopolyBBoxStep, geopolyBBoxFinal, "geopoly_group_bbox" },
};
int i;
for(i=0; i<sizeof(aFunc)/sizeof(aFunc[0]) && rc==SQLITE_OK; i++){
rc = sqlite3_create_function(db, aFunc[i].zName, aFunc[i].nArg,
SQLITE_UTF8, 0,
aFunc[i].xFunc, 0, 0);
}
for(i=0; i<sizeof(aAgg)/sizeof(aAgg[0]) && rc==SQLITE_OK; i++){
rc = sqlite3_create_function(db, aAgg[i].zName, 1, SQLITE_UTF8, 0,
0, aAgg[i].xStep, aAgg[i].xFinal);
}
if( rc==SQLITE_OK ){
rc = sqlite3_create_module_v2(db, "geopoly", &geopolyModule, 0, 0);
}

22
ext/rtree/visual01.txt
View File

@ -400,6 +400,28 @@ SELECT geopoly_svg(poly,
FROM querypoly;
.print '</svg>'
.print '<h1>Overlap Query And Result Bounding Box</h1>'
.print '<svg width="1000" height="800" style="border:1px solid black">'
SELECT geopoly_svg(_shape,
printf('style="fill:none;stroke:%s;stroke-width:1"',geo1.clr)
)
FROM geo1, querypoly
WHERE geopoly_overlap(_shape, poly);
SELECT geopoly_svg(geopoly_bbox(poly),
'style="fill:none;stroke:black;stroke-width:3"'
)
FROM querypoly;
SELECT geopoly_svg(poly,
printf('style="fill:%s;fill-opacity:0.5;"',clr)
)
FROM querypoly;
SELECT geopoly_svg(geopoly_group_bbox(_shape),
'style="fill:none;stroke:red;stroke-width:3"'
)
FROM geo1, querypoly
WHERE geopoly_overlap(_shape, poly);
.print '</svg>'
.print '<h1>Bounding-Box Overlap Query</h1>'
.print '<svg width="1000" height="800" style="border:1px solid black">'
SELECT geopoly_svg(_shape,