Add drop shadows.

Change-Id: Ic6a72409d4785968d1fbdff229f17ee5c00b240b
diff --git a/libs/hwui/TextDropShadowCache.cpp b/libs/hwui/TextDropShadowCache.cpp
new file mode 100644
index 0000000..aab5bd4
--- /dev/null
+++ b/libs/hwui/TextDropShadowCache.cpp
@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 2010 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 LOG_TAG "OpenGLRenderer"
+
+#include "TextDropShadowCache.h"
+
+namespace android {
+namespace uirenderer {
+
+///////////////////////////////////////////////////////////////////////////////
+// Constructors/destructor
+///////////////////////////////////////////////////////////////////////////////
+
+TextDropShadowCache::TextDropShadowCache(uint32_t maxByteSize):
+        mCache(GenerationCache<ShadowText, ShadowTexture*>::kUnlimitedCapacity),
+        mSize(0), mMaxSize(maxByteSize) {
+    mCache.setOnEntryRemovedListener(this);
+}
+
+TextDropShadowCache::~TextDropShadowCache() {
+    mCache.clear();
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// Size management
+///////////////////////////////////////////////////////////////////////////////
+
+uint32_t TextDropShadowCache::getSize() {
+    return mSize;
+}
+
+uint32_t TextDropShadowCache::getMaxSize() {
+    return mMaxSize;
+}
+
+void TextDropShadowCache::setMaxSize(uint32_t maxSize) {
+    mMaxSize = maxSize;
+    while (mSize > mMaxSize) {
+        mCache.removeOldest();
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// Callbacks
+///////////////////////////////////////////////////////////////////////////////
+
+void TextDropShadowCache::operator()(ShadowText& text, ShadowTexture*& texture) {
+    const uint32_t size = texture->width * texture->height;
+    mSize -= size;
+
+    if (texture) {
+        glDeleteTextures(1, &texture->id);
+        delete texture;
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// Caching
+///////////////////////////////////////////////////////////////////////////////
+
+void TextDropShadowCache::clear() {
+    mCache.clear();
+}
+
+ShadowTexture* TextDropShadowCache::get(SkPaint* paint, const char* text, uint32_t len,
+        int numGlyphs, uint32_t radius) {
+    ShadowText entry(paint, radius, len, text);
+    ShadowTexture* texture = mCache.get(entry);
+
+    if (!texture) {
+        FontRenderer::DropShadow shadow = mRenderer->renderDropShadow(paint, text, 0,
+                len, numGlyphs, radius);
+
+        texture = new ShadowTexture;
+        texture->left = shadow.penX;
+        texture->top = shadow.penY;
+        texture->width = shadow.width;
+        texture->height = shadow.height;
+        texture->generation = 0;
+        texture->blend = true;
+
+        const uint32_t size = shadow.width * shadow.height;
+        // Don't even try to cache a bitmap that's bigger than the cache
+        if (size < mMaxSize) {
+            while (mSize + size > mMaxSize) {
+                mCache.removeOldest();
+            }
+        }
+
+        glGenTextures(1, &texture->id);
+
+        glBindTexture(GL_TEXTURE_2D, texture->id);
+        // Textures are Alpha8
+        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, texture->width, texture->height, 0,
+                GL_ALPHA, GL_UNSIGNED_BYTE, shadow.image);
+
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+        if (size < mMaxSize) {
+            mSize += size;
+            mCache.put(entry, texture);
+        } else {
+            texture->cleanup = true;
+        }
+
+        // Cleanup shadow
+        delete[] shadow.image;
+    }
+
+    return texture;
+}
+
+}; // namespace uirenderer
+}; // namespace android