Draw gainmaps in HDR

Test: manual
Bug: 266628247
Change-Id: Iad0234089913637f9cddcb39d8fc32badabf3865
diff --git a/libs/hwui/effects/GainmapRenderer.cpp b/libs/hwui/effects/GainmapRenderer.cpp
new file mode 100644
index 0000000..a544ae8
--- /dev/null
+++ b/libs/hwui/effects/GainmapRenderer.cpp
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "GainmapRenderer.h"
+
+#include <SkGainmapShader.h>
+
+#include "Gainmap.h"
+#include "Rect.h"
+#include "utils/Trace.h"
+
+#ifdef __ANDROID__
+#include "renderthread/CanvasContext.h"
+#endif
+
+namespace android::uirenderer {
+
+using namespace renderthread;
+
+void DrawGainmapBitmap(SkCanvas* c, const sk_sp<const SkImage>& image, const SkRect& src,
+                       const SkRect& dst, const SkSamplingOptions& sampling, const SkPaint* paint,
+                       SkCanvas::SrcRectConstraint constraint,
+                       const sk_sp<const SkImage>& gainmapImage, const SkGainmapInfo& gainmapInfo) {
+    ATRACE_CALL();
+#ifdef __ANDROID__
+    CanvasContext* context = CanvasContext::getActiveContext();
+    float targetSdrHdrRatio = context ? context->targetSdrHdrRatio() : 1.f;
+    if (targetSdrHdrRatio > 1.f && gainmapImage) {
+        SkPaint gainmapPaint = *paint;
+        float sX = gainmapImage->width() / (float)image->width();
+        float sY = gainmapImage->height() / (float)image->height();
+        SkRect gainmapSrc = src;
+        // TODO: Tweak rounding?
+        gainmapSrc.fLeft *= sX;
+        gainmapSrc.fRight *= sX;
+        gainmapSrc.fTop *= sY;
+        gainmapSrc.fBottom *= sY;
+        // TODO: Temporary workaround for SkGainmapShader::Make not having a const variant
+        sk_sp<SkImage> mutImage = sk_ref_sp(const_cast<SkImage*>(image.get()));
+        sk_sp<SkImage> mutGainmap = sk_ref_sp(const_cast<SkImage*>(gainmapImage.get()));
+        auto shader = SkGainmapShader::Make(mutImage, src, sampling, mutGainmap, gainmapSrc,
+                                            sampling, gainmapInfo, dst, targetSdrHdrRatio,
+                                            c->imageInfo().refColorSpace());
+        gainmapPaint.setShader(shader);
+        c->drawRect(dst, gainmapPaint);
+    } else
+#endif
+        c->drawImageRect(image.get(), src, dst, sampling, paint, constraint);
+}
+
+}  // namespace android::uirenderer
\ No newline at end of file
diff --git a/libs/hwui/effects/GainmapRenderer.h b/libs/hwui/effects/GainmapRenderer.h
new file mode 100644
index 0000000..7c56d94
--- /dev/null
+++ b/libs/hwui/effects/GainmapRenderer.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <SkCanvas.h>
+#include <SkGainmapInfo.h>
+#include <SkImage.h>
+#include <SkPaint.h>
+
+#include "hwui/Bitmap.h"
+
+namespace android::uirenderer {
+
+void DrawGainmapBitmap(SkCanvas* c, const sk_sp<const SkImage>& image, const SkRect& src,
+                       const SkRect& dst, const SkSamplingOptions& sampling, const SkPaint* paint,
+                       SkCanvas::SrcRectConstraint constraint,
+                       const sk_sp<const SkImage>& gainmapImage, const SkGainmapInfo& gainmapInfo);
+
+}  // namespace android::uirenderer