libs/hwui/TextDropShadowCache.h

/*
 * 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.
 */

#ifndef ANDROID_HWUI_TEXT_DROP_SHADOW_CACHE_H
#define ANDROID_HWUI_TEXT_DROP_SHADOW_CACHE_H

#include <GLES2/gl2.h>

#include <SkPaint.h>

#include <utils/String8.h>

#include "utils/Compare.h"
#include "utils/GenerationCache.h"
#include "FontRenderer.h"
#include "Texture.h"

namespace android {
namespace uirenderer {

struct ShadowText {
    ShadowText(): radius(0), len(0), hash(0), textSize(0.0f), typeface(NULL) {
    }

    ShadowText(SkPaint* paint, uint32_t radius, uint32_t len, const char* srcText):
            radius(radius), len(len) {
        // The source text we receive is in UTF-16, convert to UTF-8
        str.setTo((const char16_t*) srcText, len >> 1);

        textSize = paint->getTextSize();
        typeface = paint->getTypeface();

        hash = 0;
        uint32_t multiplier = 1;
        const char* text = str.string();
        for (uint32_t i = 0; i < len; i++) {
            hash += text[i] * multiplier;
            uint32_t shifted = multiplier << 5;
            multiplier = shifted - multiplier;
        }
    }

    ShadowText(const ShadowText& shadow):
            radius(shadow.radius), len(shadow.len), hash(shadow.hash),
            textSize(shadow.textSize), typeface(shadow.typeface), str(shadow.str) {
    }

    ~ShadowText() {
    }

    uint32_t radius;
    uint32_t len;
    uint32_t hash;
    float textSize;
    SkTypeface* typeface;
    String8 str;

    bool operator<(const ShadowText& rhs) const {
        LTE_INT(hash) {
            LTE_INT(len) {
                LTE_INT(radius) {
                    LTE_FLOAT(textSize) {
                        if (typeface < rhs.typeface) return true;
                        else if (typeface == rhs.typeface) {
                            return str.compare(rhs.str) < 0;
                        }
                    }
                }
            }
        }
        return false;
    }
}; // struct ShadowText

/**
 * Alpha texture used to represent a shadow.
 */
struct ShadowTexture: public Texture {
    ShadowTexture(): Texture() {
    }

    float left;
    float top;
}; // struct ShadowTexture

class TextDropShadowCache: public OnEntryRemoved<ShadowText, ShadowTexture*> {
public:
    TextDropShadowCache();
    TextDropShadowCache(uint32_t maxByteSize);
    ~TextDropShadowCache();

    /**
     * Used as a callback when an entry is removed from the cache.
     * Do not invoke directly.
     */
    void operator()(ShadowText& text, ShadowTexture*& texture);

    ShadowTexture* get(SkPaint* paint, const char* text, uint32_t len,
            int numGlyphs, uint32_t radius);

    /**
     * Clears the cache. This causes all textures to be deleted.
     */
    void clear();

    void setFontRenderer(FontRenderer& fontRenderer) {
        mRenderer = &fontRenderer;
    }

    /**
     * Sets the maximum size of the cache in bytes.
     */
    void setMaxSize(uint32_t maxSize);
    /**
     * Returns the maximum size of the cache in bytes.
     */
    uint32_t getMaxSize();
    /**
     * Returns the current size of the cache in bytes.
     */
    uint32_t getSize();

private:
    void init();

    GenerationCache<ShadowText, ShadowTexture*> mCache;

    uint32_t mSize;
    uint32_t mMaxSize;
    FontRenderer* mRenderer;
    bool mDebugEnabled;
}; // class TextDropShadowCache

}; // namespace uirenderer
}; // namespace android

#endif // ANDROID_HWUI_TEXT_DROP_SHADOW_CACHE_H