Initial working Kanimaji implementation
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4e87a67296
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8 changed files with 588 additions and 83 deletions
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@ -1,14 +1,29 @@
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#include "SVG.hpp"
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#include <algorithm>
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#include <cctype>
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#include <charconv>
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#include <cmath>
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#include <format>
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#include <memory>
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namespace Kanimaji::SVG
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{
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ParseError::ParseError(std::size_t current, std::string_view message)
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: Error(std::format("[At: {}] {}", current, message))
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, mPosition(current)
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{}
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struct Vec2
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{
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double x;
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double y;
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double Length() const
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{
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return std::sqrt(x * x + y * y);
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}
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friend Vec2 operator+(const Vec2& u, const Vec2& v)
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{
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return Vec2 {
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@ -16,43 +31,187 @@ namespace Kanimaji::SVG
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.y = u.y + v.y,
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};
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}
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friend Vec2 operator-(const Vec2& u, const Vec2& v)
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{
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return Vec2 {
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.x = u.x - v.x,
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.y = u.y - v.y,
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};
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}
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friend Vec2 operator-(const Vec2& u)
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{
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return Vec2 {
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.x = -u.x,
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.y = -u.y,
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};
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}
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friend Vec2 operator*(const Vec2& u, double s)
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{
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return Vec2 {
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.x = u.x * s,
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.y = u.y * s,
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};
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}
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friend Vec2 operator*(double s, const Vec2& u)
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{
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return Vec2 {
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.x = s * u.x,
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.y = s * u.y,
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};
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}
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};
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template <typename T>
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T Squared(T val)
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{
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return val * val;
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}
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template <typename T>
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T Cubed(T val)
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{
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return val * val * val;
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}
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class Path::Element
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{
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public:
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enum class Type
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{
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Move,
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CubicBezier,
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};
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Element(Type type)
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: mType(type)
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{}
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virtual ~Element() = default;
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Type GetType() const { return mType; }
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virtual double Length(Vec2 origin) const = 0;
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virtual Vec2 Endpoint(Vec2 origin) const = 0;
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virtual void Serialize(std::string& out) const = 0;
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protected:
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Type mType;
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};
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namespace
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{
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class ParseError : public Error
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void SkipWhitespace(std::string_view source, std::size_t& current)
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{
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public:
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ParseError(std::size_t current, std::string_view message)
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: Error(std::format("[At: {}] {}", current, message))
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{}
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};
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while (current < source.size() && std::isspace(source[current])) {
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current++;
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}
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}
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void SkipCommaWhitespace(std::string_view source, std::size_t& current)
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{
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SkipWhitespace(source, current);
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if (current < source.size() && source[current] == ',') {
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current++;
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}
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SkipWhitespace(source, current);
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}
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double ConvertNumber(std::size_t position, std::string_view raw)
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{
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double result = 0;
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auto [ptr, ec] = std::from_chars(raw.data(), raw.data() + raw.size(), result);
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if (ec == std::errc::invalid_argument) {
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throw ParseError(position, "This is not a number");
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} else if (ec == std::errc::result_out_of_range) {
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throw ParseError(position, "This number cannot fit in a double");
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} else if (ec != std::errc{}) {
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throw ParseError(position, "Unknown error");
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} else if (ptr != raw.data() + raw.size()) {
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throw ParseError(position, "The number does not reach the end of the range");
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}
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return result;
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}
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double ParseNumber(std::string_view source, std::size_t& current)
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{
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constexpr auto isNumeric = [] (char ch) {
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return std::isdigit(ch) || ch == '.';
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};
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std::size_t begin = current;
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if (current < source.size() && source[current] == '-') {
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current++;
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}
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while (current < source.size() && isNumeric(source[current])) {
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current++;
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}
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if (current - begin == 0) {
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throw ParseError(current, "Numbers cannot be zero width");
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}
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return ConvertNumber(begin, { source.data() + begin, current - begin });
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}
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Vec2 ParseVector(std::string_view source, std::size_t& current)
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{
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double x = ParseNumber(source, current);
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SkipCommaWhitespace(source, current);
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if (current >= source.size()) {
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throw ParseError(current, "Unexpected input end, a 2D vector needs two numbers");
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}
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double y = ParseNumber(source, current);
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SkipCommaWhitespace(source, current);
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return {
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.x = x,
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.y = y,
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};
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}
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using ElementPtr = std::unique_ptr<Path::Element>;
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class Move : public Path::Element
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{
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public:
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Move(bool relative, Vec2 move)
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: mRelative(relative), mMove(move)
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: Element(Type::Move), mRelative(relative), mMove(move)
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{}
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double Length(Vec2 origin) const override
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{
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return 0;
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return 0.0;
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}
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Vec2 Endpoint(Vec2 origin) const override
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{
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return mRelative ? origin + mMove : mMove;
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}
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static ElementPtr Parse(std::string_view source, std::size_t& current)
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{
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constexpr auto verify = [] (char ch) {
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return ch == 'M' || ch == 'm';
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};
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if (current >= source.size() || !verify(source[current])) {
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throw ParseError(current, "Invalid move start");
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}
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bool relative = std::islower(source[current]);
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current++;
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SkipWhitespace(source, current);
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return std::make_unique<Move>(relative, ParseVector(source, current));
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}
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void Serialize(std::string& out) const override
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{
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out.append(std::format("{}{:.3},{:.3}", mRelative ? 'm' : 'M', mMove.x, mMove.y));
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}
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private:
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bool mRelative; // 7B padding, oof
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Vec2 mMove;
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@ -62,17 +221,107 @@ namespace Kanimaji::SVG
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{
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public:
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CubicBezier(bool relative, Vec2 control1, Vec2 control2, Vec2 end)
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: mRelative(relative), mControl1(control1), mControl2(control2), mEnd(end)
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: Element(Type::CubicBezier)
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, mRelative(relative)
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, mControl1(control1)
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, mControl2(control2)
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, mEnd(end)
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{}
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Vec2 Interpolate(Vec2 origin, double t) const
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{
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t = std::clamp(t, 0.0, 1.0);
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Vec2 control1 = mRelative ? origin + mControl1 : mControl1;
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Vec2 control2 = mRelative ? origin + mControl2 : mControl2;
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Vec2 end = mRelative ? origin + mEnd : mEnd;
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return origin * Cubed(1.0 - t)
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+ 3.0 * control1 * Squared(1.0 - t) * t
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+ 3.0 * control2 * (1.0 - t) * Squared(t)
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+ end * Cubed(t);
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}
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double Length(Vec2 origin) const override
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{
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throw Error("not implemented");
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constexpr std::int32_t precision = 128;
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double length = 0.0;
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Vec2 previous = origin;
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Vec2 current = origin;
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for (std::int32_t i = 1; i <= precision; ++i) {
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double t = static_cast<double>(i) / static_cast<double>(precision);
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current = Interpolate(origin, t);
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length += (previous - current).Length();
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previous = current;
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}
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return length;
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}
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Vec2 Endpoint(Vec2 origin) const override
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{
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return mEnd;
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return mRelative ? origin + mEnd : mEnd;
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}
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Vec2 ReflectControl2(const Vec2& origin, bool relative) const
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{
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Vec2 control2 = mRelative ? origin + mControl2 : mControl2;
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Vec2 end = mRelative ? origin + mEnd : mEnd;
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Vec2 reflected = relative ? end - control2 : 2.0 * end - control2;
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return reflected;
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}
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static ElementPtr Parse(std::string_view source, std::size_t& current)
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{
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constexpr auto verify = [] (char ch) {
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return ch == 'C' || ch == 'c';
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};
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if (current >= source.size() || !verify(source[current])) {
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throw ParseError(current, "Invalid Cubic Bezier start");
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}
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bool relative = std::islower(source[current]);
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current++;
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SkipWhitespace(source, current);
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Vec2 control1 = ParseVector(source, current);
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SkipCommaWhitespace(source, current);
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Vec2 control2 = ParseVector(source, current);
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SkipCommaWhitespace(source, current);
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Vec2 end = ParseVector(source, current);
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SkipWhitespace(source, current);
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return std::make_unique<CubicBezier>(relative, control1, control2, end);
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}
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static ElementPtr ParseExtension(std::string_view source, std::size_t& current,
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const Vec2& previousEnd, const CubicBezier& previous)
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{
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constexpr auto verify = [] (char ch) {
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return ch == 'S' || ch == 's';
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};
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if (current >= source.size() || !verify(source[current])) {
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throw ParseError(current, "Invalid Cubic Bezier Extension start");
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}
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bool relative = std::islower(source[current]);
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current++;
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SkipWhitespace(source, current);
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Vec2 control1 = previous.ReflectControl2(previousEnd, relative);
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Vec2 control2 = ParseVector(source, current);
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SkipCommaWhitespace(source, current);
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Vec2 end = ParseVector(source, current);
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SkipWhitespace(source, current);
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return std::make_unique<CubicBezier>(relative, control1, control2, end);
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}
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void Serialize(std::string& out) const override
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{
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out.append(std::format("{}{:.3},{:.3},{:.3},{:.3},{:.3},{:.3}",
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mRelative ? 'c' : 'C',
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mControl1.x, mControl1.y,
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mControl2.x, mControl2.y,
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mEnd.x, mEnd.y));
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}
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private:
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bool mRelative; // 7B padding, oof
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@ -81,24 +330,47 @@ namespace Kanimaji::SVG
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Vec2 mEnd;
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};
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using ElementPtr = std::unique_ptr<Path::Element>;
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void Parse(std::string_view definition, std::vector<ElementPtr>& elements)
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{
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std::size_t current = 0;
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Vec2 previousEnd = { .x = 0.0, .y = 0.0, };
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Vec2 currentEnd = { .x = 0.0, .y = 0.0, };
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while (current < definition.size()) {
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SkipWhitespace(definition, current);
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switch (definition[current]) {
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case 'M': [[fallthrough]];
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case 'm':
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// ParseMove
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elements.push_back(Move::Parse(definition, current));
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break;
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case 'C': [[fallthrough]];
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case 'c':
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// ParseCubicBezier
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elements.push_back(CubicBezier::Parse(definition, current));
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break;
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case 'S': [[fallthrough]];
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case 's': {
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if (elements.empty()) {
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throw ParseError(current, "Cubic Bezier Extensions without predecessors "
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"are unsupported");
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}
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if (elements.back()->GetType() != Path::Element::Type::CubicBezier) {
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throw ParseError(current, "The predecessor of this Cubic Bezier Extension "
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"is not a Cubic Bezier itself");
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}
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CubicBezier *previous = dynamic_cast<CubicBezier *>(elements.back().get());
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if (!previous) {
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throw ParseError(current, "The previous element could not be cast to a "
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"Cubic Bezier for some reason");
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}
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elements.push_back(CubicBezier::ParseExtension(definition, current, previousEnd,
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*previous));
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break;
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}
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default:
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throw ParseError(current, "Unrecognized character");
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}
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previousEnd = currentEnd;
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currentEnd = elements.back()->Endpoint(currentEnd);
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}
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}
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}
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@ -112,6 +384,19 @@ namespace Kanimaji::SVG
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double Path::Length() const
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{
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return 0;
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Vec2 origin { .x = 0.0, .y = 0.0, };
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double length = 0.0;
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for (const auto& segment : mSegments) {
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length += segment->Length(origin);
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origin = segment->Endpoint(origin);
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}
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return length;
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}
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void Path::Serialize(std::string& out) const
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{
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for (const auto& segment : mSegments) {
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segment->Serialize(out);
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}
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}
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}
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