Contour.cpp

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// Copyright 2023 Google LLC
// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
 
#include "modules/bentleyottmann/include/Contour.h"
 
#include "include/core/SkPath.h"
#include "include/core/SkScalar.h"
#include "include/private/base/SkPoint_impl.h"
#include "include/private/base/SkTo.h"
#include "modules/bentleyottmann/include/Myers.h"
 
#include <algorithm>
#include <vector>
 
namespace contour {
Contours Contours::Make(SkPath path) {
    SkPoint pts[4];
    SkPath::Iter iter(path, false);
    SkPath::Verb verb;
    Contours contours;
    while ((verb = iter.next(pts)) != SkPath::kDone_Verb) {
        switch (verb) {
            case SkPath::kConic_Verb: {
                SK_ABORT("Not implemented");
                break;
            }
            case SkPath::kMove_Verb:
                contours.closeContourIfNeeded();
                contours.moveToStartOfContour(pts[0]);
                break;
            case SkPath::kLine_Verb: {
                contours.addPointToCurrentContour(pts[1]);
                break;
            }
            case SkPath::kQuad_Verb: {
                SK_ABORT("Not implemented");
                break;
            }
            case SkPath::kCubic_Verb: {
                SK_ABORT("Not implemented");
                break;
            }
            case SkPath::kClose_Verb: {
                contours.closeContourIfNeeded();
                break;
            }
            case SkPath::kDone_Verb:
                SK_ABORT("The while loop above failed.");
        }
    }
 
    // Close the remaining contour.
    contours.closeContourIfNeeded();
 
    return contours;
}
 
std::vector<myers::Segment> Contours::segments() const {
    SK_ABORT("Not implemented");
}
 
static SkIRect extend_rect(SkIRect r, Point p) {
    int32_t left   = std::min(p.x, r.fLeft),
            top    = std::min(p.y, r.fTop),
            right  = std::max(p.x, r.fRight),
            bottom = std::max(p.y, r.fBottom);
    return {left, top, right, bottom};
}
 
Point Contours::RoundSkPoint(SkPoint p) {
    return {SkScalarRoundToInt(p.x() * kScaleFactor), SkScalarRoundToInt(p.y() * kScaleFactor)};
}
 
bool Contours::currentContourIsEmpty() const {
    int32_t lastEnd = fContours.empty() ? 0 : fContours.back().end;
    return lastEnd == SkToS32(fPoints.size());
}
 
void Contours::addPointToCurrentContour(SkPoint p) {
    if (this->currentContourIsEmpty()) {
        fPoints.push_back(fContourStart);
        fContourBounds = extend_rect(fContourBounds, fContourStart);
    }
    Point point = RoundSkPoint(p);
    fPoints.push_back(point);
    fContourBounds = extend_rect(fContourBounds, point);
}
 
void Contours::moveToStartOfContour(SkPoint p) {
    fContourStart = RoundSkPoint(p);
}
 
void Contours::closeContourIfNeeded() {
    if (this->currentContourIsEmpty()) {
        // The current contour is empty. Don't record it.
        return;
    }
    fContours.push_back({fContourBounds, SkToS32(fPoints.size())});
    fContourBounds = kEmptyRect;
}
}  // namespace contour