/****************************************************************************** * * Purpose: Oracle curve to linestring stroking (approximation). * Author: Frank Warmerdam, warmerdam@pobox.com * ****************************************************************************** * Copyright (c) 2008, Frank Warmerdam * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. ****************************************************************************/ #include #include "ogr_oci.h" #include "cpl_conv.h" #include "cpl_string.h" CPL_CVSID("$Id: ogrocistroke.cpp ff8146d84de7cba8e09d212d5481ea7d2ede3e98 2017-06-27 20:47:31Z Even Rouault $") /************************************************************************/ /* OGROCIArcCenterFromEdgePoints() */ /* */ /* Compute the center of an arc/circle from three edge points. */ /************************************************************************/ static int OGROCIArcCenterFromEdgePoints( double x_c0, double y_c0, double x_c1, double y_c1, double x_c2, double y_c2, double *x_center, double *y_center ) { /* -------------------------------------------------------------------- */ /* Handle a degenerate case that occurs in OSNI products by */ /* making some assumptions. If the first and third points are */ /* the same assume they are intended to define a full circle, */ /* and that the second point is on the opposite side of the */ /* circle. */ /* -------------------------------------------------------------------- */ if( x_c0 == x_c2 && y_c0 == y_c2 ) { *x_center = (x_c0 + x_c1) * 0.5; *y_center = (y_c0 + y_c1) * 0.5; return TRUE; } /* -------------------------------------------------------------------- */ /* Compute the inverse of the slopes connecting the first and */ /* second points. Also compute the center point of the two */ /* lines ... the point our crossing line will go through. */ /* -------------------------------------------------------------------- */ double m1, x1, y1; if( (y_c1 - y_c0) != 0.0 ) m1 = (x_c0 - x_c1) / (y_c1 - y_c0); else m1 = 1e+10; x1 = (x_c0 + x_c1) * 0.5; y1 = (y_c0 + y_c1) * 0.5; /* -------------------------------------------------------------------- */ /* Compute the same for the second point compared to the third */ /* point. */ /* -------------------------------------------------------------------- */ double m2, x2, y2; if( (y_c2 - y_c1) != 0.0 ) m2 = (x_c1 - x_c2) / (y_c2 - y_c1); else m2 = 1e+10; x2 = (x_c1 + x_c2) * 0.5; y2 = (y_c1 + y_c2) * 0.5; /* -------------------------------------------------------------------- */ /* Turn these into the Ax+By+C = 0 form of the lines. */ /* -------------------------------------------------------------------- */ double a1, a2, l_b1, l_b2, c1, c2; a1 = m1; a2 = m2; l_b1 = -1.0; l_b2 = -1.0; c1 = (y1 - m1*x1); c2 = (y2 - m2*x2); /* -------------------------------------------------------------------- */ /* Compute the intersection of the two lines through the center */ /* of the circle, using Kramers rule. */ /* -------------------------------------------------------------------- */ double det_inv; if( a1*l_b2 - a2*l_b1 == 0.0 ) return FALSE; det_inv = 1 / (a1*l_b2 - a2*l_b1); *x_center = (l_b1*c2 - l_b2*c1) * det_inv; *y_center = (a2*c1 - a1*c2) * det_inv; return TRUE; } /************************************************************************/ /* OGROCIStrokeArcToOGRGeometry_Angles() */ /************************************************************************/ static int OGROCIStrokeArcToOGRGeometry_Angles( double dfCenterX, double dfCenterY, double dfRadius, double dfStartAngle, double dfEndAngle, double dfMaxAngleStepSizeDegrees, OGRLineString *poLine ) { double dfArcX, dfArcY, dfSlice; int iPoint, iAppendLocation, nVertexCount; double dfEps = dfRadius / 100000.0; nVertexCount = (int) ceil(fabs(dfEndAngle - dfStartAngle)/dfMaxAngleStepSizeDegrees) + 1; nVertexCount = MAX(2,nVertexCount); dfSlice = (dfEndAngle-dfStartAngle)/(nVertexCount-1); iAppendLocation = poLine->getNumPoints(); for( iPoint=0; iPoint < nVertexCount; iPoint++ ) { double dfAngle; dfAngle = (dfStartAngle + iPoint * dfSlice) * M_PI / 180.0; dfArcX = dfCenterX + cos(dfAngle) * dfRadius; dfArcY = dfCenterY + sin(dfAngle) * dfRadius; if( iPoint == 0 ) { if( poLine->getNumPoints() > 0 && fabs(poLine->getX(poLine->getNumPoints()-1)-dfArcX) < dfEps && fabs(poLine->getY(poLine->getNumPoints()-1)-dfArcY) < dfEps) { poLine->setNumPoints( poLine->getNumPoints() + nVertexCount - 1 ); } else { poLine->setNumPoints( poLine->getNumPoints() + nVertexCount - 1 ); poLine->setPoint( iAppendLocation++, dfArcX, dfArcY ); } } else poLine->setPoint( iAppendLocation++, dfArcX, dfArcY ); } return TRUE; } /************************************************************************/ /* OGROCIStrokeArcToOGRGeometry_Points() */ /************************************************************************/ int OGROCIStrokeArcToOGRGeometry_Points( double dfStartX, double dfStartY, double dfAlongX, double dfAlongY, double dfEndX, double dfEndY, double dfMaxAngleStepSizeDegrees, int bForceWholeCircle, OGRLineString *poLine ) { double dfStartAngle, dfEndAngle, dfAlongAngle; double dfCenterX, dfCenterY, dfRadius; if( !OGROCIArcCenterFromEdgePoints( dfStartX, dfStartY, dfAlongX, dfAlongY, dfEndX, dfEndY, &dfCenterX, &dfCenterY ) ) return FALSE; if( bForceWholeCircle || (dfStartX == dfEndX && dfStartY == dfEndY) ) { dfStartAngle = 0.0; dfEndAngle = 360.0; } else { double dfDeltaX, dfDeltaY; dfDeltaX = dfStartX - dfCenterX; dfDeltaY = dfStartY - dfCenterY; dfStartAngle = atan2(dfDeltaY,dfDeltaX) * 180.0 / M_PI; dfDeltaX = dfAlongX - dfCenterX; dfDeltaY = dfAlongY - dfCenterY; dfAlongAngle = atan2(dfDeltaY,dfDeltaX) * 180.0 / M_PI; dfDeltaX = dfEndX - dfCenterX; dfDeltaY = dfEndY - dfCenterY; dfEndAngle = atan2(dfDeltaY,dfDeltaX) * 180.0 / M_PI; // Try positive (clockwise?) winding. while( dfAlongAngle < dfStartAngle ) dfAlongAngle += 360.0; while( dfEndAngle < dfAlongAngle ) dfEndAngle += 360.0; // If that doesn't work out, then go anticlockwise. if( dfEndAngle - dfStartAngle > 360.0 ) { while( dfAlongAngle > dfStartAngle ) dfAlongAngle -= 360.0; while( dfEndAngle > dfAlongAngle ) dfEndAngle -= 360.0; } } dfRadius = sqrt( (dfCenterX - dfStartX) * (dfCenterX - dfStartX) + (dfCenterY - dfStartY) * (dfCenterY - dfStartY) ); int bResult; bResult = OGROCIStrokeArcToOGRGeometry_Angles( dfCenterX, dfCenterY, dfRadius, dfStartAngle, dfEndAngle, dfMaxAngleStepSizeDegrees, poLine ); /* -------------------------------------------------------------------- */ /* Force the points for arcs, to avoid odd rounding/math */ /* issues. Perhaps we should do this for the start too, but */ /* this is a bit tricky since it isn't obvious which point is */ /* the start. */ /* -------------------------------------------------------------------- */ if( bResult && !bForceWholeCircle ) { poLine->setPoint( poLine->getNumPoints() - 1, dfEndX, dfEndY ); } return bResult; }