SF: Introduce LayerSnapshot and LayerSnapshotBuilder
Create a builder that walks through the layer hierarchy
to build an ordered list of LayerSnapshots that can be
passed on to CompositionEngine.
This builder does a minimum amount of work to update
an existing set of snapshots based on hierarchy changes
and RequestedLayerState changes.
The builder also introduces a fast path to update
snapshots when there are only buffer updates.
Additionally, pull out LayerSnapshot class from LayerFE
and move it to frontend package.
Bug: 238781169
Test: presubmit
Change-Id: I3fbd6d60968950df2ee97d975c72f9e0aa31b007
diff --git a/services/surfaceflinger/FrontEnd/LayerSnapshot.cpp b/services/surfaceflinger/FrontEnd/LayerSnapshot.cpp
new file mode 100644
index 0000000..d483a99
--- /dev/null
+++ b/services/surfaceflinger/FrontEnd/LayerSnapshot.cpp
@@ -0,0 +1,162 @@
+/*
+ * Copyright 2022 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.
+ */
+
+#define ATRACE_TAG ATRACE_TAG_GRAPHICS
+#undef LOG_TAG
+#define LOG_TAG "LayerSnapshot"
+
+#include "LayerSnapshot.h"
+
+namespace android::surfaceflinger::frontend {
+
+using namespace ftl::flag_operators;
+
+LayerSnapshot::LayerSnapshot(const RequestedLayerState& state,
+ const LayerHierarchy::TraversalPath& path)
+ : path(path) {
+ sequence = static_cast<int32_t>(state.id);
+ name = state.name;
+ textureName = state.textureName;
+ premultipliedAlpha = state.premultipliedAlpha;
+ inputInfo.name = state.name;
+ inputInfo.id = static_cast<int32_t>(state.id);
+ inputInfo.ownerUid = static_cast<int32_t>(state.ownerUid);
+ inputInfo.ownerPid = state.ownerPid;
+}
+
+// As documented in libhardware header, formats in the range
+// 0x100 - 0x1FF are specific to the HAL implementation, and
+// are known to have no alpha channel
+// TODO: move definition for device-specific range into
+// hardware.h, instead of using hard-coded values here.
+#define HARDWARE_IS_DEVICE_FORMAT(f) ((f) >= 0x100 && (f) <= 0x1FF)
+
+bool LayerSnapshot::isOpaqueFormat(PixelFormat format) {
+ if (HARDWARE_IS_DEVICE_FORMAT(format)) {
+ return true;
+ }
+ switch (format) {
+ case PIXEL_FORMAT_RGBA_8888:
+ case PIXEL_FORMAT_BGRA_8888:
+ case PIXEL_FORMAT_RGBA_FP16:
+ case PIXEL_FORMAT_RGBA_1010102:
+ case PIXEL_FORMAT_R_8:
+ return false;
+ }
+ // in all other case, we have no blending (also for unknown formats)
+ return true;
+}
+
+bool LayerSnapshot::hasBufferOrSidebandStream() const {
+ return ((sidebandStream != nullptr) || (buffer != nullptr));
+}
+
+bool LayerSnapshot::drawShadows() const {
+ return shadowSettings.length > 0.f;
+}
+
+bool LayerSnapshot::fillsColor() const {
+ return !hasBufferOrSidebandStream() && color.r >= 0.0_hf && color.g >= 0.0_hf &&
+ color.b >= 0.0_hf;
+}
+
+bool LayerSnapshot::hasBlur() const {
+ return backgroundBlurRadius > 0 || blurRegions.size() > 0;
+}
+
+bool LayerSnapshot::hasEffect() const {
+ return fillsColor() || drawShadows() || hasBlur();
+}
+
+bool LayerSnapshot::hasSomethingToDraw() const {
+ return hasEffect() || hasBufferOrSidebandStream();
+}
+
+bool LayerSnapshot::isContentOpaque() const {
+ // if we don't have a buffer or sidebandStream yet, we're translucent regardless of the
+ // layer's opaque flag.
+ if (!hasSomethingToDraw()) {
+ return false;
+ }
+
+ // if the layer has the opaque flag, then we're always opaque
+ if (layerOpaqueFlagSet) {
+ return true;
+ }
+
+ // If the buffer has no alpha channel, then we are opaque
+ if (hasBufferOrSidebandStream() &&
+ isOpaqueFormat(buffer ? buffer->getPixelFormat() : PIXEL_FORMAT_NONE)) {
+ return true;
+ }
+
+ // Lastly consider the layer opaque if drawing a color with alpha == 1.0
+ return fillsColor() && color.a == 1.0_hf;
+}
+
+bool LayerSnapshot::isHiddenByPolicy() const {
+ if (CC_UNLIKELY(invalidTransform)) {
+ ALOGW("Hide layer %s because it has invalid transformation.", name.c_str());
+ return true;
+ }
+ return isHiddenByPolicyFromParent || isHiddenByPolicyFromRelativeParent;
+}
+
+bool LayerSnapshot::getIsVisible() const {
+ if (!hasSomethingToDraw()) {
+ return false;
+ }
+
+ if (isHiddenByPolicy()) {
+ return false;
+ }
+
+ return color.a > 0.0f || hasBlur();
+}
+
+std::string LayerSnapshot::getIsVisibleReason() const {
+ if (!hasSomethingToDraw()) {
+ return "!hasSomethingToDraw";
+ }
+
+ if (isHiddenByPolicy()) {
+ return "isHiddenByPolicy";
+ }
+
+ if (color.a > 0.0f || hasBlur()) {
+ return "";
+ }
+
+ return "alpha = 0 and !hasBlur";
+}
+
+bool LayerSnapshot::canReceiveInput() const {
+ return !isHiddenByPolicy() && (!hasBufferOrSidebandStream() || color.a > 0.0f);
+}
+
+bool LayerSnapshot::isTransformValid(const ui::Transform& t) {
+ float transformDet = t.det();
+ return transformDet != 0 && !isinf(transformDet) && !isnan(transformDet);
+}
+
+std::string LayerSnapshot::getDebugString() const {
+ return "Snapshot(" + base::StringPrintf("%p", this) + "){" + path.toString() + name +
+ " isHidden=" + std::to_string(isHiddenByPolicyFromParent) +
+ " isHiddenRelative=" + std::to_string(isHiddenByPolicyFromRelativeParent) +
+ " isVisible=" + std::to_string(isVisible) + " " + getIsVisibleReason() + "}";
+}
+
+} // namespace android::surfaceflinger::frontend