tdf#130655 added callback interface to ::applyLineDashing

This version of the tooling method allows to avoid collecting line
snippets in a return value PolyPolygon. Instead, offer lambda
functions to get callbacks for created snippets. The original
method using a B2DPolyPolygon return value is adapted to already
use this, so serves as example of usage and ensures that only
one identical algorithm is used.

Change-Id: Ie306968a895ad280fc2425fb40b3244769216ba0

1 files changed, 23 insertions, 1 deletions

diff --git a/include/basegfx/polygon/b2dpolygontools.hxx b/include/basegfx/polygon/b2dpolygontools.hxx
index 57b9130b4399..9defd76ef548 100644
--- a/include/basegfx/polygon/b2dpolygontools.hxx
+++ b/include/basegfx/polygon/b2dpolygontools.hxx
@@ -20,6 +20,9 @@
 #ifndef INCLUDED_BASEGFX_POLYGON_B2DPOLYGONTOOLS_HXX
 #define INCLUDED_BASEGFX_POLYGON_B2DPOLYGONTOOLS_HXX
 
+#include <vector>
+#include <functional>
+
 #include <basegfx/point/b2dpoint.hxx>
 #include <basegfx/vector/b2dvector.hxx>
 #include <basegfx/range/b2drectangle.hxx>
@@ -27,7 +30,6 @@
 #include <basegfx/polygon/b2dpolygontriangulator.hxx>
 #include <com/sun/star/drawing/PointSequence.hpp>
 #include <com/sun/star/drawing/FlagSequence.hpp>
-#include <vector>
 #include <basegfx/basegfxdllapi.h>
 #include <o3tl/typed_flags_set.hxx>
 
@@ -188,9 +190,29 @@ namespace basegfx
             @param fFullDashDotLen
             The summed-up length of the rDotDashArray. If zero, it will
             be calculated internally.
+
+            There is now a 2nd version that allows to provide callback
+            functions that get called when a snippet of a line/gap is
+            produced and needs to be added. This allows to use it like
+            a 'pipeline'. When using this (e.g. the 1st version uses
+            this internally to guarantee the same algorithm is used)
+            it is not needed to accumulate a potentially huge number
+            of polygons in the result-polyPolygons, but e.g. consume
+            them directly in the caller. Example is renderinmg a
+            dashed line but without creating the potentially huge amount
+            of polygons.
+            The 2nd version will also merge first/last line/gap snippets
+            if the input polygon is closed and the start/end-points match
+            accordingly - at the cost that this will be delivered last.
         */
         BASEGFX_DLLPUBLIC void applyLineDashing(
             const B2DPolygon& rCandidate,
+            const std::vector<double>& rDotDashArray,
+            std::function<void(const basegfx::B2DPolygon& rSnippet)> aLineTargetCallback,
+            std::function<void(const basegfx::B2DPolygon& rSnippet)> aGapTargetCallback = std::function<void(const basegfx::B2DPolygon&)>(),
+            double fDotDashLength = 0.0);
+        BASEGFX_DLLPUBLIC void applyLineDashing(
+            const B2DPolygon& rCandidate,
             const ::std::vector<double>& rDotDashArray,
             B2DPolyPolygon* pLineTarget,
             B2DPolyPolygon* pGapTarget = nullptr,