/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* vim: set ts=8 sts=2 et sw=2 tw=80: */ /* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #ifndef DOM_SVG_SVGPATHSEGUTILS_H_ #define DOM_SVG_SVGPATHSEGUTILS_H_ #include "mozilla/ArrayUtils.h" #include "mozilla/dom/SVGPathSegBinding.h" #include "mozilla/gfx/Point.h" #include "nsDebug.h" namespace mozilla { #define NS_SVG_PATH_SEG_MAX_ARGS 7 #define NS_SVG_PATH_SEG_FIRST_VALID_TYPE \ dom::SVGPathSeg_Binding::PATHSEG_CLOSEPATH #define NS_SVG_PATH_SEG_LAST_VALID_TYPE \ dom::SVGPathSeg_Binding::PATHSEG_CURVETO_QUADRATIC_SMOOTH_REL #define NS_SVG_PATH_SEG_TYPE_COUNT (NS_SVG_PATH_SEG_LAST_VALID_TYPE + 1) /** * Code that works with path segments can use an instance of this class to * store/provide information about the start of the current subpath and the * last path segment (if any). */ struct SVGPathTraversalState { using Point = gfx::Point; enum TraversalMode { eUpdateAll, eUpdateOnlyStartAndCurrentPos }; SVGPathTraversalState() : start(0.0, 0.0), pos(0.0, 0.0), cp1(0.0, 0.0), cp2(0.0, 0.0), length(0.0), mode(eUpdateAll) {} bool ShouldUpdateLengthAndControlPoints() { return mode == eUpdateAll; } Point start; // start point of current sub path (reset each moveto) Point pos; // current position (end point of previous segment) Point cp1; // quadratic control point - if the previous segment was a // quadratic bezier curve then this is set to the absolute // position of its control point, otherwise its set to pos Point cp2; // cubic control point - if the previous segment was a cubic // bezier curve then this is set to the absolute position of // its second control point, otherwise it's set to pos float length; // accumulated path length TraversalMode mode; // indicates what to track while traversing a path }; /** * This class is just a collection of static methods - it doesn't have any data * members, and it's not possible to create instances of this class. This class * exists purely as a convenient place to gather together a bunch of methods * related to manipulating and answering questions about path segments. * Internally we represent path segments purely as an array of floats. See the * comment documenting SVGPathData for more info on that. * * The DOM wrapper classes for encoded path segments (data contained in * instances of SVGPathData) is DOMSVGPathSeg and its sub-classes. Note that * there are multiple different DOM classes for path segs - one for each of the * 19 SVG 1.1 segment types. */ class SVGPathSegUtils { private: SVGPathSegUtils() = default; // private to prevent instances public: static void GetValueAsString(const float* aSeg, nsAString& aValue); /** * Encode a segment type enum to a float. * * At some point in the future we will likely want to encode other * information into the float, such as whether the command was explicit or * not. For now all this method does is save on int to float runtime * conversion by requiring uint32_t and float to be of the same size so we * can simply do a bitwise uint32_t<->float copy. */ static float EncodeType(uint32_t aType) { static_assert(sizeof(uint32_t) == sizeof(float), "sizeof uint32_t and float must be the same"); MOZ_ASSERT(IsValidType(aType), "Seg type not recognized"); return *(reinterpret_cast(&aType)); } static uint32_t DecodeType(float aType) { static_assert(sizeof(uint32_t) == sizeof(float), "sizeof uint32_t and float must be the same"); uint32_t type = *(reinterpret_cast(&aType)); MOZ_ASSERT(IsValidType(type), "Seg type not recognized"); return type; } static char16_t GetPathSegTypeAsLetter(uint32_t aType) { MOZ_ASSERT(IsValidType(aType), "Seg type not recognized"); static const char16_t table[] = { char16_t('x'), // 0 == PATHSEG_UNKNOWN char16_t('z'), // 1 == PATHSEG_CLOSEPATH char16_t('M'), // 2 == PATHSEG_MOVETO_ABS char16_t('m'), // 3 == PATHSEG_MOVETO_REL char16_t('L'), // 4 == PATHSEG_LINETO_ABS char16_t('l'), // 5 == PATHSEG_LINETO_REL char16_t('C'), // 6 == PATHSEG_CURVETO_CUBIC_ABS char16_t('c'), // 7 == PATHSEG_CURVETO_CUBIC_REL char16_t('Q'), // 8 == PATHSEG_CURVETO_QUADRATIC_ABS char16_t('q'), // 9 == PATHSEG_CURVETO_QUADRATIC_REL char16_t('A'), // 10 == PATHSEG_ARC_ABS char16_t('a'), // 11 == PATHSEG_ARC_REL char16_t('H'), // 12 == PATHSEG_LINETO_HORIZONTAL_ABS char16_t('h'), // 13 == PATHSEG_LINETO_HORIZONTAL_REL char16_t('V'), // 14 == PATHSEG_LINETO_VERTICAL_ABS char16_t('v'), // 15 == PATHSEG_LINETO_VERTICAL_REL char16_t('S'), // 16 == PATHSEG_CURVETO_CUBIC_SMOOTH_ABS char16_t('s'), // 17 == PATHSEG_CURVETO_CUBIC_SMOOTH_REL char16_t('T'), // 18 == PATHSEG_CURVETO_QUADRATIC_SMOOTH_ABS char16_t('t') // 19 == PATHSEG_CURVETO_QUADRATIC_SMOOTH_REL }; static_assert(MOZ_ARRAY_LENGTH(table) == NS_SVG_PATH_SEG_TYPE_COUNT, "Unexpected table size"); return table[aType]; } static uint32_t ArgCountForType(uint32_t aType) { MOZ_ASSERT(IsValidType(aType), "Seg type not recognized"); static const uint8_t table[] = { 0, // 0 == PATHSEG_UNKNOWN 0, // 1 == PATHSEG_CLOSEPATH 2, // 2 == PATHSEG_MOVETO_ABS 2, // 3 == PATHSEG_MOVETO_REL 2, // 4 == PATHSEG_LINETO_ABS 2, // 5 == PATHSEG_LINETO_REL 6, // 6 == PATHSEG_CURVETO_CUBIC_ABS 6, // 7 == PATHSEG_CURVETO_CUBIC_REL 4, // 8 == PATHSEG_CURVETO_QUADRATIC_ABS 4, // 9 == PATHSEG_CURVETO_QUADRATIC_REL 7, // 10 == PATHSEG_ARC_ABS 7, // 11 == PATHSEG_ARC_REL 1, // 12 == PATHSEG_LINETO_HORIZONTAL_ABS 1, // 13 == PATHSEG_LINETO_HORIZONTAL_REL 1, // 14 == PATHSEG_LINETO_VERTICAL_ABS 1, // 15 == PATHSEG_LINETO_VERTICAL_REL 4, // 16 == PATHSEG_CURVETO_CUBIC_SMOOTH_ABS 4, // 17 == PATHSEG_CURVETO_CUBIC_SMOOTH_REL 2, // 18 == PATHSEG_CURVETO_QUADRATIC_SMOOTH_ABS 2 // 19 == PATHSEG_CURVETO_QUADRATIC_SMOOTH_REL }; static_assert(MOZ_ARRAY_LENGTH(table) == NS_SVG_PATH_SEG_TYPE_COUNT, "Unexpected table size"); return table[aType]; } /** * Convenience so that callers can pass a float containing an encoded type * and have it decoded implicitly. */ static uint32_t ArgCountForType(float aType) { return ArgCountForType(DecodeType(aType)); } static bool IsValidType(uint32_t aType) { return aType >= NS_SVG_PATH_SEG_FIRST_VALID_TYPE && aType <= NS_SVG_PATH_SEG_LAST_VALID_TYPE; } static bool IsCubicType(uint32_t aType) { return aType == dom::SVGPathSeg_Binding::PATHSEG_CURVETO_CUBIC_REL || aType == dom::SVGPathSeg_Binding::PATHSEG_CURVETO_CUBIC_ABS || aType == dom::SVGPathSeg_Binding::PATHSEG_CURVETO_CUBIC_SMOOTH_REL || aType == dom::SVGPathSeg_Binding::PATHSEG_CURVETO_CUBIC_SMOOTH_ABS; } static bool IsQuadraticType(uint32_t aType) { return aType == dom::SVGPathSeg_Binding::PATHSEG_CURVETO_QUADRATIC_REL || aType == dom::SVGPathSeg_Binding::PATHSEG_CURVETO_QUADRATIC_ABS || aType == dom::SVGPathSeg_Binding::PATHSEG_CURVETO_QUADRATIC_SMOOTH_REL || aType == dom::SVGPathSeg_Binding::PATHSEG_CURVETO_QUADRATIC_SMOOTH_ABS; } static bool IsArcType(uint32_t aType) { return aType == dom::SVGPathSeg_Binding::PATHSEG_ARC_ABS || aType == dom::SVGPathSeg_Binding::PATHSEG_ARC_REL; } static bool IsRelativeOrAbsoluteType(uint32_t aType) { MOZ_ASSERT(IsValidType(aType), "Seg type not recognized"); // When adding a new path segment type, ensure that the returned condition // below is still correct. static_assert( NS_SVG_PATH_SEG_LAST_VALID_TYPE == dom::SVGPathSeg_Binding::PATHSEG_CURVETO_QUADRATIC_SMOOTH_REL, "Unexpected type"); return aType >= dom::SVGPathSeg_Binding::PATHSEG_MOVETO_ABS; } static bool IsRelativeType(uint32_t aType) { MOZ_ASSERT(IsRelativeOrAbsoluteType(aType), "IsRelativeType called with segment type that does not come in " "relative and absolute forms"); // When adding a new path segment type, ensure that the returned condition // below is still correct. static_assert( NS_SVG_PATH_SEG_LAST_VALID_TYPE == dom::SVGPathSeg_Binding::PATHSEG_CURVETO_QUADRATIC_SMOOTH_REL, "Unexpected type"); return aType & 1; } static uint32_t RelativeVersionOfType(uint32_t aType) { MOZ_ASSERT(IsRelativeOrAbsoluteType(aType), "RelativeVersionOfType called with segment type that does not " "come in relative and absolute forms"); // When adding a new path segment type, ensure that the returned condition // below is still correct. static_assert( NS_SVG_PATH_SEG_LAST_VALID_TYPE == dom::SVGPathSeg_Binding::PATHSEG_CURVETO_QUADRATIC_SMOOTH_REL, "Unexpected type"); return aType | 1; } static uint32_t SameTypeModuloRelativeness(uint32_t aType1, uint32_t aType2) { if (!IsRelativeOrAbsoluteType(aType1)) { return aType1 == aType2; } return RelativeVersionOfType(aType1) == RelativeVersionOfType(aType2); } /** * Traverse the given path segment and update the SVGPathTraversalState * object. */ static void TraversePathSegment(const float* aData, SVGPathTraversalState& aState); }; } // namespace mozilla #endif // DOM_SVG_SVGPATHSEGUTILS_H_