CacheTexture.h revision 9b1204baf4740b4d443e72157dea98571cf84e1f 
1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ANDROID_HWUI_CACHE_TEXTURE_H
18#define ANDROID_HWUI_CACHE_TEXTURE_H
19
20#include <GLES2/gl2.h>
21
22#include <SkScalerContext.h>
23
24#include <utils/Log.h>
25
26#include "FontUtil.h"
27
28namespace android {
29namespace uirenderer {
30
31/**
32 * CacheBlock is a node in a linked list of current free space areas in a CacheTexture.
33 * Using CacheBlocks enables us to pack the cache from top to bottom as well as left to right.
34 * When we add a glyph to the cache, we see if it fits within one of the existing columns that
35 * have already been started (this is the case if the glyph fits vertically as well as
36 * horizontally, and if its width is sufficiently close to the column width to avoid
37 * sub-optimal packing of small glyphs into wide columns). If there is no column in which the
38 * glyph fits, we check the final node, which is the remaining space in the cache, creating
39 * a new column as appropriate.
40 *
41 * As columns fill up, we remove their CacheBlock from the list to avoid having to check
42 * small blocks in the future.
43 */
44struct CacheBlock {
45    uint16_t mX;
46    uint16_t mY;
47    uint16_t mWidth;
48    uint16_t mHeight;
49    CacheBlock* mNext;
50    CacheBlock* mPrev;
51
52    CacheBlock(uint16_t x, uint16_t y, uint16_t width, uint16_t height, bool empty = false):
53            mX(x), mY(y), mWidth(width), mHeight(height), mNext(NULL), mPrev(NULL) {
54    }
55
56    static CacheBlock* insertBlock(CacheBlock* head, CacheBlock *newBlock);
57
58    static CacheBlock* removeBlock(CacheBlock* head, CacheBlock *blockToRemove);
59
60    void output() {
61        CacheBlock *currBlock = this;
62        while (currBlock) {
63            ALOGD("Block: this, x, y, w, h = %p, %d, %d, %d, %d",
64                    currBlock, currBlock->mX, currBlock->mY, currBlock->mWidth, currBlock->mHeight);
65            currBlock = currBlock->mNext;
66        }
67    }
68};
69
70class CacheTexture {
71public:
72    CacheTexture(uint16_t width, uint16_t height) :
73            mTexture(NULL), mTextureId(0), mWidth(width), mHeight(height),
74            mLinearFiltering(false), mDirty(false), mNumGlyphs(0) {
75        mCacheBlocks = new CacheBlock(TEXTURE_BORDER_SIZE, TEXTURE_BORDER_SIZE,
76                mWidth - TEXTURE_BORDER_SIZE, mHeight - TEXTURE_BORDER_SIZE, true);
77    }
78
79    ~CacheTexture() {
80        if (mTexture) {
81            delete[] mTexture;
82        }
83        if (mTextureId) {
84            glDeleteTextures(1, &mTextureId);
85        }
86        reset();
87    }
88
89    void reset() {
90        // Delete existing cache blocks
91        while (mCacheBlocks != NULL) {
92            CacheBlock* tmpBlock = mCacheBlocks;
93            mCacheBlocks = mCacheBlocks->mNext;
94            delete tmpBlock;
95        }
96        mNumGlyphs = 0;
97    }
98
99    void init() {
100        // reset, then create a new remainder space to start again
101        reset();
102        mCacheBlocks = new CacheBlock(TEXTURE_BORDER_SIZE, TEXTURE_BORDER_SIZE,
103                mWidth - TEXTURE_BORDER_SIZE, mHeight - TEXTURE_BORDER_SIZE, true);
104    }
105
106    bool fitBitmap(const SkGlyph& glyph, uint32_t *retOriginX, uint32_t *retOriginY);
107
108    uint8_t* mTexture;
109    GLuint mTextureId;
110    uint16_t mWidth;
111    uint16_t mHeight;
112    bool mLinearFiltering;
113    bool mDirty;
114    uint16_t mNumGlyphs;
115    CacheBlock* mCacheBlocks;
116};
117
118}; // namespace uirenderer
119}; // namespace android
120
121#endif // ANDROID_HWUI_CACHE_TEXTURE_H
122