src/effects/SkLumaColorFilter.cpp

/*
 * Copyright 2013 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "include/core/SkString.h"
#include "include/effects/SkLumaColorFilter.h"
#include "include/effects/SkRuntimeEffect.h"

sk_sp<SkColorFilter> SkLumaColorFilter::Make() {
    static SkColorFilter* filter = []{
        const char* code =
            "uniform shader input;"
            "half4 main() {"
                "return saturate(dot(half3(0.2126, 0.7152, 0.0722), sample(input).rgb)).000r;"
            "}";
        auto [effect, err] = SkRuntimeEffect::Make(SkString{code}, SkRuntimeEffect::Options{});
        SkASSERT(effect && err.isEmpty());

        sk_sp<SkColorFilter> input = nullptr;
        return effect->makeColorFilter(SkData::MakeEmpty(), &input, 1).release();
    }();
    return sk_ref_sp(filter);
}