src/core/SkFontPriv.cpp

/*
 * Copyright 2018 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "SkFontPriv.h"
#include "SkGraphics.h"
#include "SkMatrix.h"

static SkScalar mag2(SkScalar x, SkScalar y) {
    return x * x + y * y;
}

static bool tooBig(const SkMatrix& m, SkScalar ma2max) {
    return  mag2(m[SkMatrix::kMScaleX], m[SkMatrix::kMSkewY]) > ma2max
            ||
            mag2(m[SkMatrix::kMSkewX], m[SkMatrix::kMScaleY]) > ma2max;
}

bool SkFontPriv::TooBigToUseCache(const SkMatrix& ctm, const SkMatrix& textM, SkScalar maxLimit) {
    SkASSERT(!ctm.hasPerspective());
    SkASSERT(!textM.hasPerspective());

    SkMatrix matrix;
    matrix.setConcat(ctm, textM);
    return tooBig(matrix, MaxCacheSize2(maxLimit));
}

SkScalar SkFontPriv::MaxCacheSize2(SkScalar maxLimit) {
    // we have a self-imposed maximum, just for memory-usage sanity
    const int limit = SkMin32(SkGraphics::GetFontCachePointSizeLimit(), maxLimit);
    const SkScalar maxSize = SkIntToScalar(limit);
    return maxSize * maxSize;
}