src/pathops/SkPathOpsTightBounds.cpp

/*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
#include "SkOpEdgeBuilder.h"
#include "SkPathOpsCommon.h"

bool TightBounds(const SkPath& path, SkRect* result) {
    SkChunkAlloc allocator(4096);  // FIXME: constant-ize, tune
    SkOpContour contour;
    SkOpContourHead* contourList = static_cast<SkOpContourHead*>(&contour);
    SkOpGlobalState globalState(contourList, &allocator  SkDEBUGPARAMS(false)
            SkDEBUGPARAMS(nullptr));
    // turn path into list of segments
    SkScalar scaleFactor = ScaleFactor(path);
    SkPath scaledPath;
    const SkPath* workingPath;
    if (scaleFactor > SK_Scalar1) {
        ScalePath(path, 1.f / scaleFactor, &scaledPath);
        workingPath = &scaledPath;
    } else {
        workingPath = &path;
    }
    SkOpEdgeBuilder builder(*workingPath, contourList, &globalState);
    if (!builder.finish()) {
        return false;
    }
    if (!SortContourList(&contourList, false, false)) {
        result->setEmpty();
        return true;
    }
    SkOpContour* current = contourList;
    SkPathOpsBounds bounds = current->bounds();
    while ((current = current->next())) {
        bounds.add(current->bounds());
    }
    *result = bounds;
    return true;
}