1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/core/SkMipMap.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,256 @@
1.4 +/*
1.5 + * Copyright 2013 Google Inc.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#include "SkMipMap.h"
1.12 +#include "SkBitmap.h"
1.13 +#include "SkColorPriv.h"
1.14 +
1.15 +static void downsampleby2_proc32(SkBitmap* dst, int x, int y,
1.16 + const SkBitmap& src) {
1.17 + x <<= 1;
1.18 + y <<= 1;
1.19 + const SkPMColor* p = src.getAddr32(x, y);
1.20 + const SkPMColor* baseP = p;
1.21 + SkPMColor c, ag, rb;
1.22 +
1.23 + c = *p; ag = (c >> 8) & 0xFF00FF; rb = c & 0xFF00FF;
1.24 + if (x < src.width() - 1) {
1.25 + p += 1;
1.26 + }
1.27 + c = *p; ag += (c >> 8) & 0xFF00FF; rb += c & 0xFF00FF;
1.28 +
1.29 + p = baseP;
1.30 + if (y < src.height() - 1) {
1.31 + p += src.rowBytes() >> 2;
1.32 + }
1.33 + c = *p; ag += (c >> 8) & 0xFF00FF; rb += c & 0xFF00FF;
1.34 + if (x < src.width() - 1) {
1.35 + p += 1;
1.36 + }
1.37 + c = *p; ag += (c >> 8) & 0xFF00FF; rb += c & 0xFF00FF;
1.38 +
1.39 + *dst->getAddr32(x >> 1, y >> 1) =
1.40 + ((rb >> 2) & 0xFF00FF) | ((ag << 6) & 0xFF00FF00);
1.41 +}
1.42 +
1.43 +static inline uint32_t expand16(U16CPU c) {
1.44 + return (c & ~SK_G16_MASK_IN_PLACE) | ((c & SK_G16_MASK_IN_PLACE) << 16);
1.45 +}
1.46 +
1.47 +// returns dirt in the top 16bits, but we don't care, since we only
1.48 +// store the low 16bits.
1.49 +static inline U16CPU pack16(uint32_t c) {
1.50 + return (c & ~SK_G16_MASK_IN_PLACE) | ((c >> 16) & SK_G16_MASK_IN_PLACE);
1.51 +}
1.52 +
1.53 +static void downsampleby2_proc16(SkBitmap* dst, int x, int y,
1.54 + const SkBitmap& src) {
1.55 + x <<= 1;
1.56 + y <<= 1;
1.57 + const uint16_t* p = src.getAddr16(x, y);
1.58 + const uint16_t* baseP = p;
1.59 + SkPMColor c;
1.60 +
1.61 + c = expand16(*p);
1.62 + if (x < src.width() - 1) {
1.63 + p += 1;
1.64 + }
1.65 + c += expand16(*p);
1.66 +
1.67 + p = baseP;
1.68 + if (y < src.height() - 1) {
1.69 + p += src.rowBytes() >> 1;
1.70 + }
1.71 + c += expand16(*p);
1.72 + if (x < src.width() - 1) {
1.73 + p += 1;
1.74 + }
1.75 + c += expand16(*p);
1.76 +
1.77 + *dst->getAddr16(x >> 1, y >> 1) = (uint16_t)pack16(c >> 2);
1.78 +}
1.79 +
1.80 +static uint32_t expand4444(U16CPU c) {
1.81 + return (c & 0xF0F) | ((c & ~0xF0F) << 12);
1.82 +}
1.83 +
1.84 +static U16CPU collaps4444(uint32_t c) {
1.85 + return (c & 0xF0F) | ((c >> 12) & ~0xF0F);
1.86 +}
1.87 +
1.88 +static void downsampleby2_proc4444(SkBitmap* dst, int x, int y,
1.89 + const SkBitmap& src) {
1.90 + x <<= 1;
1.91 + y <<= 1;
1.92 + const uint16_t* p = src.getAddr16(x, y);
1.93 + const uint16_t* baseP = p;
1.94 + uint32_t c;
1.95 +
1.96 + c = expand4444(*p);
1.97 + if (x < src.width() - 1) {
1.98 + p += 1;
1.99 + }
1.100 + c += expand4444(*p);
1.101 +
1.102 + p = baseP;
1.103 + if (y < src.height() - 1) {
1.104 + p += src.rowBytes() >> 1;
1.105 + }
1.106 + c += expand4444(*p);
1.107 + if (x < src.width() - 1) {
1.108 + p += 1;
1.109 + }
1.110 + c += expand4444(*p);
1.111 +
1.112 + *dst->getAddr16(x >> 1, y >> 1) = (uint16_t)collaps4444(c >> 2);
1.113 +}
1.114 +
1.115 +SkMipMap::Level* SkMipMap::AllocLevels(int levelCount, size_t pixelSize) {
1.116 + if (levelCount < 0) {
1.117 + return NULL;
1.118 + }
1.119 + int64_t size = sk_64_mul(levelCount + 1, sizeof(Level)) + pixelSize;
1.120 + if (!sk_64_isS32(size)) {
1.121 + return NULL;
1.122 + }
1.123 + return (Level*)sk_malloc_throw(sk_64_asS32(size));
1.124 +}
1.125 +
1.126 +SkMipMap* SkMipMap::Build(const SkBitmap& src) {
1.127 + void (*proc)(SkBitmap* dst, int x, int y, const SkBitmap& src);
1.128 +
1.129 + const SkBitmap::Config config = src.config();
1.130 + switch (config) {
1.131 + case SkBitmap::kARGB_8888_Config:
1.132 + proc = downsampleby2_proc32;
1.133 + break;
1.134 + case SkBitmap::kRGB_565_Config:
1.135 + proc = downsampleby2_proc16;
1.136 + break;
1.137 + case SkBitmap::kARGB_4444_Config:
1.138 + proc = downsampleby2_proc4444;
1.139 + break;
1.140 + case SkBitmap::kIndex8_Config:
1.141 + case SkBitmap::kA8_Config:
1.142 + default:
1.143 + return NULL; // don't build mipmaps for these configs
1.144 + }
1.145 +
1.146 + SkAutoLockPixels alp(src);
1.147 + if (!src.readyToDraw()) {
1.148 + return NULL;
1.149 + }
1.150 +
1.151 + // whip through our loop to compute the exact size needed
1.152 + size_t size = 0;
1.153 + int countLevels = 0;
1.154 + {
1.155 + int width = src.width();
1.156 + int height = src.height();
1.157 + for (;;) {
1.158 + width >>= 1;
1.159 + height >>= 1;
1.160 + if (0 == width || 0 == height) {
1.161 + break;
1.162 + }
1.163 + size += SkBitmap::ComputeRowBytes(config, width) * height;
1.164 + countLevels += 1;
1.165 + }
1.166 + }
1.167 + if (0 == countLevels) {
1.168 + return NULL;
1.169 + }
1.170 +
1.171 + Level* levels = SkMipMap::AllocLevels(countLevels, size);
1.172 + if (NULL == levels) {
1.173 + return NULL;
1.174 + }
1.175 +
1.176 + uint8_t* baseAddr = (uint8_t*)&levels[countLevels];
1.177 + uint8_t* addr = baseAddr;
1.178 + int width = src.width();
1.179 + int height = src.height();
1.180 + uint32_t rowBytes;
1.181 + SkBitmap srcBM(src);
1.182 +
1.183 + for (int i = 0; i < countLevels; ++i) {
1.184 + width >>= 1;
1.185 + height >>= 1;
1.186 + rowBytes = SkToU32(SkBitmap::ComputeRowBytes(config, width));
1.187 +
1.188 + levels[i].fPixels = addr;
1.189 + levels[i].fWidth = width;
1.190 + levels[i].fHeight = height;
1.191 + levels[i].fRowBytes = rowBytes;
1.192 + levels[i].fScale = (float)width / src.width();
1.193 +
1.194 + SkBitmap dstBM;
1.195 + dstBM.setConfig(config, width, height, rowBytes);
1.196 + dstBM.setPixels(addr);
1.197 +
1.198 + srcBM.lockPixels();
1.199 + for (int y = 0; y < height; y++) {
1.200 + for (int x = 0; x < width; x++) {
1.201 + proc(&dstBM, x, y, srcBM);
1.202 + }
1.203 + }
1.204 + srcBM.unlockPixels();
1.205 +
1.206 + srcBM = dstBM;
1.207 + addr += height * rowBytes;
1.208 + }
1.209 + SkASSERT(addr == baseAddr + size);
1.210 +
1.211 + return SkNEW_ARGS(SkMipMap, (levels, countLevels, size));
1.212 +}
1.213 +
1.214 +///////////////////////////////////////////////////////////////////////////////
1.215 +
1.216 +//static int gCounter;
1.217 +
1.218 +SkMipMap::SkMipMap(Level* levels, int count, size_t size)
1.219 + : fSize(size), fLevels(levels), fCount(count) {
1.220 + SkASSERT(levels);
1.221 + SkASSERT(count > 0);
1.222 +// SkDebugf("mips %d\n", ++gCounter);
1.223 +}
1.224 +
1.225 +SkMipMap::~SkMipMap() {
1.226 + sk_free(fLevels);
1.227 +// SkDebugf("mips %d\n", --gCounter);
1.228 +}
1.229 +
1.230 +static SkFixed compute_level(SkScalar scale) {
1.231 + SkFixed s = SkAbs32(SkScalarToFixed(SkScalarInvert(scale)));
1.232 +
1.233 + if (s < SK_Fixed1) {
1.234 + return 0;
1.235 + }
1.236 + int clz = SkCLZ(s);
1.237 + SkASSERT(clz >= 1 && clz <= 15);
1.238 + return SkIntToFixed(15 - clz) + ((unsigned)(s << (clz + 1)) >> 16);
1.239 +}
1.240 +
1.241 +bool SkMipMap::extractLevel(SkScalar scale, Level* levelPtr) const {
1.242 + if (scale >= SK_Scalar1) {
1.243 + return false;
1.244 + }
1.245 +
1.246 + int level = compute_level(scale) >> 16;
1.247 + SkASSERT(level >= 0);
1.248 + if (level <= 0) {
1.249 + return false;
1.250 + }
1.251 +
1.252 + if (level > fCount) {
1.253 + level = fCount;
1.254 + }
1.255 + if (levelPtr) {
1.256 + *levelPtr = fLevels[level - 1];
1.257 + }
1.258 + return true;
1.259 +}
