7d06e2642b
Add AsWinding to convert SkPath with even odd fill to winding fill. This basic implementation works for simple non-intersecting paths. It may fail if contours in paths touch, specifically when the leftmost point in a contour is shared with another contour. The incomplete parts are marked with TODO in the code. If this interface and implementation look promising, I will continue to tackle the more difficult cases. R=reed@google.com,bungeman@google.com Bug: skia:7682 Change-Id: I479fba60072eb1391b451fcb819504245da2e2a9 Reviewed-on: https://skia-review.googlesource.com/147044 Commit-Queue: Cary Clark <caryclark@google.com> Reviewed-by: Mike Reed <reed@google.com>
114 lines
4.0 KiB
C++
114 lines
4.0 KiB
C++
/*
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* Copyright 2012 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkPathOps_DEFINED
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#define SkPathOps_DEFINED
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#include "../private/SkTArray.h"
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#include "../private/SkTDArray.h"
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#include "SkPreConfig.h"
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class SkPath;
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struct SkRect;
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// FIXME: move everything below into the SkPath class
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/**
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* The logical operations that can be performed when combining two paths.
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*/
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enum SkPathOp {
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kDifference_SkPathOp, //!< subtract the op path from the first path
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kIntersect_SkPathOp, //!< intersect the two paths
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kUnion_SkPathOp, //!< union (inclusive-or) the two paths
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kXOR_SkPathOp, //!< exclusive-or the two paths
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kReverseDifference_SkPathOp, //!< subtract the first path from the op path
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};
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/** Set this path to the result of applying the Op to this path and the
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specified path: this = (this op operand).
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The resulting path will be constructed from non-overlapping contours.
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The curve order is reduced where possible so that cubics may be turned
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into quadratics, and quadratics maybe turned into lines.
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Returns true if operation was able to produce a result;
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otherwise, result is unmodified.
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@param one The first operand (for difference, the minuend)
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@param two The second operand (for difference, the subtrahend)
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@param op The operator to apply.
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@param result The product of the operands. The result may be one of the
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inputs.
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@return True if the operation succeeded.
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*/
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bool SK_API Op(const SkPath& one, const SkPath& two, SkPathOp op, SkPath* result);
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/** Set this path to a set of non-overlapping contours that describe the
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same area as the original path.
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The curve order is reduced where possible so that cubics may
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be turned into quadratics, and quadratics maybe turned into lines.
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Returns true if operation was able to produce a result;
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otherwise, result is unmodified.
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@param path The path to simplify.
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@param result The simplified path. The result may be the input.
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@return True if simplification succeeded.
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*/
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bool SK_API Simplify(const SkPath& path, SkPath* result);
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/** Set the resulting rectangle to the tight bounds of the path.
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@param path The path measured.
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@param result The tight bounds of the path.
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@return True if the bounds could be computed.
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*/
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bool SK_API TightBounds(const SkPath& path, SkRect* result);
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/** Set the result with fill type winding to area equivalent to path.
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Returns true if successful. Does not detect if path contains contours which
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contain self-crossings or cross other contours; in these cases, may return
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true even though result does not fill same area as path.
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Returns true if operation was able to produce a result;
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otherwise, result is unmodified. The result may be the input.
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@param path The path typically with fill type set to even odd.
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@param result The equivalent path with fill type set to winding.
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@return True if winding path was set.
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*/
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bool SK_API AsWinding(const SkPath& path, SkPath* result);
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/** Perform a series of path operations, optimized for unioning many paths together.
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*/
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class SK_API SkOpBuilder {
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public:
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/** Add one or more paths and their operand. The builder is empty before the first
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path is added, so the result of a single add is (emptyPath OP path).
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@param path The second operand.
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@param _operator The operator to apply to the existing and supplied paths.
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*/
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void add(const SkPath& path, SkPathOp _operator);
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/** Computes the sum of all paths and operands, and resets the builder to its
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initial state.
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@param result The product of the operands.
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@return True if the operation succeeded.
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*/
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bool resolve(SkPath* result);
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private:
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SkTArray<SkPath> fPathRefs;
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SkTDArray<SkPathOp> fOps;
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static bool FixWinding(SkPath* path);
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static void ReversePath(SkPath* path);
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void reset();
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};
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#endif
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