blob: ebd43d05b8f8393f8870e27cd9f1ad8807cc3135 [file] [log] [blame]
/*
* Copyright 2021 Google LLC
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "include/core/SkBlender.h"
#include "include/core/SkRefCnt.h"
#include "include/core/SkTypes.h"
#include "include/effects/SkBlenders.h"
#ifdef SK_ENABLE_SKSL
#include "include/core/SkBlendMode.h"
#include "include/core/SkData.h"
#include "include/core/SkScalar.h"
#include "include/core/SkString.h"
#include "include/effects/SkRuntimeEffect.h"
sk_sp<SkBlender> SkBlenders::Arithmetic(float k1, float k2, float k3, float k4,
bool enforcePremul) {
if (!SkScalarIsFinite(k1) ||
!SkScalarIsFinite(k2) ||
!SkScalarIsFinite(k3) ||
!SkScalarIsFinite(k4)) {
return nullptr;
}
// Are we nearly a SkBlendMode?
const struct {
float k1, k2, k3, k4;
SkBlendMode mode;
} table[] = {
{ 0, 1, 0, 0, SkBlendMode::kSrc },
{ 0, 0, 1, 0, SkBlendMode::kDst },
{ 0, 0, 0, 0, SkBlendMode::kClear },
};
for (const auto& t : table) {
if (SkScalarNearlyEqual(k1, t.k1) &&
SkScalarNearlyEqual(k2, t.k2) &&
SkScalarNearlyEqual(k3, t.k3) &&
SkScalarNearlyEqual(k4, t.k4)) {
return SkBlender::Mode(t.mode);
}
}
// If we get here, we need the actual blender effect.
static SkRuntimeEffect* gArithmeticEffect = []{
const char prog[] =
"uniform half4 k;"
"uniform half pmClamp;"
"half4 main(half4 src, half4 dst) {"
"half4 c = k.x * src * dst + k.y * src + k.z * dst + k.w;"
"c.rgb = min(c.rgb, max(c.a, pmClamp));"
// rely on skia to saturate our alpha
"return c;"
"}"
;
auto result = SkRuntimeEffect::MakeForBlender(SkString(prog));
SkASSERTF(result.effect, "SkBlenders::Arithmetic: %s", result.errorText.c_str());
return result.effect.release();
}();
const float array[] = {
k1, k2, k3, k4,
enforcePremul ? 0.0f : 1.0f,
};
return gArithmeticEffect->makeBlender(SkData::MakeWithCopy(array, sizeof(array)));
}
#else // SK_ENABLE_SKSL
sk_sp<SkBlender> SkBlenders::Arithmetic(float k1, float k2, float k3, float k4,
bool enforcePremul) {
// TODO(skia:12197)
return nullptr;
}
#endif