1 files changed, 87 insertions, 0 deletions
diff --git a/libs/hwui/shader/Shader.cpp b/libs/hwui/shader/Shader.cpp
new file mode 100644
index 000000000000..45123dd55002
--- /dev/null
+++ b/libs/hwui/shader/Shader.cpp
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2020 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 "Shader.h"
+
+#include "SkImageFilters.h"
+#include "SkPaint.h"
+#include "SkRefCnt.h"
+
+namespace android::uirenderer {
+
+Shader::Shader(const SkMatrix* matrix)
+        : localMatrix(matrix ? *matrix : SkMatrix::I())
+        , skShader(nullptr)
+        , skImageFilter(nullptr) {}
+
+Shader::~Shader() {}
+
+sk_sp<SkShader> Shader::asSkShader() {
+    // If we already have created a shader with these parameters just return the existing
+    // shader we have already created
+    if (!this->skShader.get()) {
+        this->skShader = makeSkShader();
+        if (this->skShader.get()) {
+            if (!localMatrix.isIdentity()) {
+                this->skShader = this->skShader->makeWithLocalMatrix(localMatrix);
+            }
+        }
+    }
+    return this->skShader;
+}
+
+/**
+ * By default return null as we cannot convert all visual effects to SkShader instances
+ */
+sk_sp<SkShader> Shader::makeSkShader() {
+    return nullptr;
+}
+
+sk_sp<SkImageFilter> Shader::asSkImageFilter() {
+    // If we already have created an ImageFilter with these parameters just return the existing
+    // ImageFilter we have already created
+    if (!this->skImageFilter.get()) {
+        // Attempt to create an SkImageFilter from the current Shader implementation
+        this->skImageFilter = makeSkImageFilter();
+        if (this->skImageFilter) {
+            if (!localMatrix.isIdentity()) {
+                // If we have created an SkImageFilter and we have a transformation, wrap
+                // the created SkImageFilter to apply the given matrix
+                this->skImageFilter = SkImageFilters::MatrixTransform(
+                    localMatrix, kMedium_SkFilterQuality, this->skImageFilter);
+            }
+        } else {
+            // Otherwise if no SkImageFilter implementation is provided, create one from
+            // the result of asSkShader. Note the matrix is already applied to the shader in
+            // this case so just convert it to an SkImageFilter using SkImageFilters::Paint
+            SkPaint paint;
+            paint.setShader(asSkShader());
+            sk_sp<SkImageFilter> paintFilter = SkImageFilters::Paint(paint);
+            this->skImageFilter = SkImageFilters::Xfermode(SkBlendMode::kDstIn,
+                    std::move(paintFilter));
+        }
+    }
+    return this->skImageFilter;
+}
+
+/**
+ * By default return null for subclasses to implement. If there is not a direct SkImageFilter
+ * conversion
+ */
+sk_sp<SkImageFilter> Shader::makeSkImageFilter() {
+    return nullptr;
+}
+}  // namespace android::uirenderer
+\ No newline at end of file