pdf/draw_utils.cc

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "pdf/draw_utils.h"
   6
   7 #include <algorithm>
   8 #include <math.h>
   9 #include <vector>
  10
  11 #include "base/logging.h"
  12 #include "base/numerics/safe_math.h"
  13
  14 namespace chrome_pdf {
  15
  16 inline uint8 GetBlue(const uint32& pixel) {
  17   return static_cast<uint8>(pixel & 0xFF);
  18 }
  19
  20 inline uint8 GetGreen(const uint32& pixel) {
  21   return static_cast<uint8>((pixel >> 8) & 0xFF);
  22 }
  23
  24 inline uint8 GetRed(const uint32& pixel) {
  25   return static_cast<uint8>((pixel >> 16) & 0xFF);
  26 }
  27
  28 inline uint8 GetAlpha(const uint32& pixel) {
  29   return static_cast<uint8>((pixel >> 24) & 0xFF);
  30 }
  31
  32 inline uint32_t MakePixel(uint8 red, uint8 green, uint8 blue, uint8 alpha) {
  33   return (static_cast<uint32_t>(alpha) << 24) |
  34       (static_cast<uint32_t>(red) << 16) |
  35       (static_cast<uint32_t>(green) << 8) |
  36       static_cast<uint32_t>(blue);
  37 }
  38
  39 inline uint8 GradientChannel(uint8 start, uint8 end, double ratio) {
  40   double new_channel = start - (static_cast<double>(start) - end) * ratio;
  41   if (new_channel < 0)
  42     return 0;
  43   if (new_channel > 255)
  44     return 255;
  45   return static_cast<uint8>(new_channel + 0.5);
  46 }
  47
  48 inline uint8 ProcessColor(uint8 src_color, uint8 dest_color, uint8 alpha) {
  49   uint32 processed = static_cast<uint32>(src_color) * alpha +
  50       static_cast<uint32>(dest_color) * (0xFF - alpha);
  51   return static_cast<uint8>((processed / 0xFF) & 0xFF);
  52 }
  53
  54 inline bool ImageDataContainsRect(const pp::ImageData& image_data,
  55                                   const pp::Rect& rect) {
  56   return rect.width() >= 0 && rect.height() >= 0 &&
  57       pp::Rect(image_data.size()).Contains(rect);
  58 }
  59
  60 void AlphaBlend(const pp::ImageData& src, const pp::Rect& src_rc,
  61                 pp::ImageData* dest, const pp::Point& dest_origin,
  62                 uint8 alpha_adjustment) {
  63   if (src_rc.IsEmpty() || !ImageDataContainsRect(src, src_rc))
  64     return;
  65
  66   pp::Rect dest_rc(dest_origin, src_rc.size());
  67   if (dest_rc.IsEmpty() || !ImageDataContainsRect(*dest, dest_rc))
  68     return;
  69
  70   const uint32_t* src_origin_pixel = src.GetAddr32(src_rc.point());
  71   uint32_t* dest_origin_pixel = dest->GetAddr32(dest_origin);
  72
  73   int height = src_rc.height();
  74   int width = src_rc.width();
  75   for (int y = 0; y < height; y++) {
  76     const uint32_t* src_pixel = src_origin_pixel;
  77     uint32_t* dest_pixel = dest_origin_pixel;
  78     for (int x = 0; x < width; x++) {
  79       uint8 alpha = static_cast<uint8>(static_cast<uint32_t>(alpha_adjustment) *
  80           GetAlpha(*src_pixel) / 0xFF);
  81       uint8 red = ProcessColor(GetRed(*src_pixel), GetRed(*dest_pixel), alpha);
  82       uint8 green = ProcessColor(GetGreen(*src_pixel),
  83                                  GetGreen(*dest_pixel), alpha);
  84       uint8 blue = ProcessColor(GetBlue(*src_pixel),
  85                                 GetBlue(*dest_pixel), alpha);
  86       *dest_pixel = MakePixel(red, green, blue, GetAlpha(*dest_pixel));
  87
  88       src_pixel++;
  89       dest_pixel++;
  90     }
  91     src_origin_pixel = reinterpret_cast<const uint32_t*>(
  92         reinterpret_cast<const char*>(src_origin_pixel) + src.stride());
  93     dest_origin_pixel = reinterpret_cast<uint32_t*>(
  94         reinterpret_cast<char*>(dest_origin_pixel) + dest->stride());
  95   }
  96 }
  97
  98 void GradientFill(pp::ImageData* image, const pp::Rect& rc,
  99                   uint32 start_color, uint32 end_color, bool horizontal) {
 100   std::vector<uint32> colors;
 101   colors.resize(horizontal ? rc.width() : rc.height());
 102   for (size_t i = 0; i < colors.size(); ++i) {
 103     double ratio = static_cast<double>(i) / colors.size();
 104     colors[i] = MakePixel(
 105         GradientChannel(GetRed(start_color), GetRed(end_color), ratio),
 106         GradientChannel(GetGreen(start_color), GetGreen(end_color), ratio),
 107         GradientChannel(GetBlue(start_color), GetBlue(end_color), ratio),
 108         GradientChannel(GetAlpha(start_color), GetAlpha(end_color), ratio));
 109   }
 110
 111   if (horizontal) {
 112     const void* data = &(colors[0]);
 113     size_t size = colors.size() * 4;
 114     uint32_t* origin_pixel = image->GetAddr32(rc.point());
 115     for (int y = 0; y < rc.height(); y++) {
 116       memcpy(origin_pixel, data, size);
 117       origin_pixel = reinterpret_cast<uint32_t*>(
 118           reinterpret_cast<char*>(origin_pixel) + image->stride());
 119     }
 120   } else {
 121     uint32_t* origin_pixel = image->GetAddr32(rc.point());
 122     for (int y = 0; y < rc.height(); y++) {
 123       uint32_t* pixel = origin_pixel;
 124       for (int x = 0; x < rc.width(); x++) {
 125         *pixel = colors[y];
 126         pixel++;
 127       }
 128       origin_pixel = reinterpret_cast<uint32_t*>(
 129           reinterpret_cast<char*>(origin_pixel) + image->stride());
 130     }
 131   }
 132 }
 133
 134 void GradientFill(pp::Instance* instance,
 135                   pp::ImageData* image,
 136                   const pp::Rect& dirty_rc,
 137                   const pp::Rect& gradient_rc,
 138                   uint32 start_color,
 139                   uint32 end_color,
 140                   bool horizontal,
 141                   uint8 transparency) {
 142   pp::Rect draw_rc = gradient_rc.Intersect(dirty_rc);
 143   if (draw_rc.IsEmpty())
 144     return;
 145
 146   pp::ImageData gradient(instance, PP_IMAGEDATAFORMAT_BGRA_PREMUL,
 147       gradient_rc.size(), false);
 148
 149   GradientFill(&gradient, pp::Rect(pp::Point(), gradient_rc.size()),
 150                start_color, end_color, horizontal);
 151
 152   pp::Rect copy_rc(draw_rc);
 153   copy_rc.Offset(-gradient_rc.x(), -gradient_rc.y());
 154   AlphaBlend(gradient, copy_rc, image, draw_rc.point(), transparency);
 155 }
 156
 157 void CopyImage(const pp::ImageData& src, const pp::Rect& src_rc,
 158                pp::ImageData* dest, const pp::Rect& dest_rc,
 159                bool stretch) {
 160   if (src_rc.IsEmpty() || !ImageDataContainsRect(src, src_rc))
 161     return;
 162
 163   pp::Rect stretched_rc(dest_rc.point(),
 164                         stretch ? dest_rc.size() : src_rc.size());
 165   if (stretched_rc.IsEmpty() || !ImageDataContainsRect(*dest, stretched_rc))
 166     return;
 167
 168   const uint32_t* src_origin_pixel = src.GetAddr32(src_rc.point());
 169   uint32_t* dest_origin_pixel = dest->GetAddr32(dest_rc.point());
 170   if (stretch) {
 171     double x_ratio = static_cast<double>(src_rc.width()) / dest_rc.width();
 172     double y_ratio = static_cast<double>(src_rc.height()) / dest_rc.height();
 173     int32_t height = dest_rc.height();
 174     int32_t width = dest_rc.width();
 175     for (int32_t y = 0; y < height; ++y) {
 176       uint32_t* dest_pixel = dest_origin_pixel;
 177       for (int32_t x = 0; x < width; ++x) {
 178         uint32 src_x = static_cast<uint32>(x * x_ratio);
 179         uint32 src_y = static_cast<uint32>(y * y_ratio);
 180         const uint32_t* src_pixel = src.GetAddr32(
 181             pp::Point(src_rc.x() + src_x, src_rc.y() + src_y));
 182         *dest_pixel = *src_pixel;
 183         dest_pixel++;
 184       }
 185       dest_origin_pixel = reinterpret_cast<uint32_t*>(
 186           reinterpret_cast<char*>(dest_origin_pixel) + dest->stride());
 187     }
 188   } else {
 189     int32_t height = src_rc.height();
 190     base::CheckedNumeric<int32_t> width_bytes = src_rc.width();
 191     width_bytes *= 4;
 192     for (int32_t y = 0; y < height; ++y) {
 193       memcpy(dest_origin_pixel, src_origin_pixel, width_bytes.ValueOrDie());
 194       src_origin_pixel = reinterpret_cast<const uint32_t*>(
 195           reinterpret_cast<const char*>(src_origin_pixel) + src.stride());
 196       dest_origin_pixel = reinterpret_cast<uint32_t*>(
 197           reinterpret_cast<char*>(dest_origin_pixel) + dest->stride());
 198     }
 199   }
 200 }
 201
 202 void FillRect(pp::ImageData* image, const pp::Rect& rc, uint32 color) {
 203   int height = rc.height();
 204   if (height == 0)
 205     return;
 206
 207   // Fill in first row.
 208   uint32_t* top_line = image->GetAddr32(rc.point());
 209   int width = rc.width();
 210   for (int x = 0; x < width; x++)
 211     top_line[x] = color;
 212
 213   // Fill in the rest of the rectangle.
 214   int byte_width = width * 4;
 215   uint32_t* cur_line = reinterpret_cast<uint32_t*>(
 216           reinterpret_cast<char*>(top_line) + image->stride());
 217   for (int y = 1; y < height; y++) {
 218     memcpy(cur_line, top_line, byte_width);
 219     cur_line = reinterpret_cast<uint32_t*>(
 220             reinterpret_cast<char*>(cur_line) + image->stride());
 221   }
 222 }
 223
 224 ShadowMatrix::ShadowMatrix(uint32 depth, double factor, uint32 background)
 225     : depth_(depth), factor_(factor), background_(background) {
 226   DCHECK(depth_ > 0);
 227   matrix_.resize(depth_ * depth_);
 228
 229   // pv - is a rounding power factor for smoothing corners.
 230   // pv = 2.0 will make corners completely round.
 231   const double pv = 4.0;
 232   // pow_pv - cache to avoid recalculating pow(x, pv) every time.
 233   std::vector<double> pow_pv(depth_, 0.0);
 234
 235   double r = static_cast<double>(depth_);
 236   double coef = 256.0 / pow(r, factor);
 237
 238   for (uint32 y = 0; y < depth_; y++) {
 239     // Since matrix is symmetrical, we can reduce the number of calculations
 240     // by mirroring results.
 241     for (uint32 x = 0; x <= y; x++) {
 242       // Fill cache if needed.
 243       if (pow_pv[x] == 0.0)
 244         pow_pv[x] =  pow(x, pv);
 245       if (pow_pv[y] == 0.0)
 246         pow_pv[y] =  pow(y, pv);
 247
 248       // v - is a value for the smoothing function.
 249       // If x == 0 simplify calculations.
 250       double v = (x == 0) ? y : pow(pow_pv[x] + pow_pv[y], 1 / pv);
 251
 252       // Smoothing function.
 253       // If factor == 1, smoothing will be linear from 0 to the end,
 254       // if 0 < factor < 1, smoothing will drop faster near 0.
 255       // if factor > 1, smoothing will drop faster near the end (depth).
 256       double f = 256.0 - coef * pow(v, factor);
 257
 258       uint8 alpha = 0;
 259       if (f > kOpaqueAlpha)
 260         alpha = kOpaqueAlpha;
 261       else if (f < kTransparentAlpha)
 262         alpha = kTransparentAlpha;
 263       else
 264         alpha = static_cast<uint8>(f);
 265
 266       uint8 red = ProcessColor(0, GetRed(background), alpha);
 267       uint8 green = ProcessColor(0, GetGreen(background), alpha);
 268       uint8 blue = ProcessColor(0, GetBlue(background), alpha);
 269       uint32 pixel = MakePixel(red, green, blue, GetAlpha(background));
 270
 271       // Mirror matrix.
 272       matrix_[y * depth_ + x] = pixel;
 273       matrix_[x * depth_ + y] = pixel;
 274     }
 275   }
 276 }
 277
 278 ShadowMatrix::~ShadowMatrix() {
 279 }
 280
 281 void PaintShadow(pp::ImageData* image,
 282                  const pp::Rect& clip_rc,
 283                  const pp::Rect& shadow_rc,
 284                  const ShadowMatrix& matrix) {
 285   pp::Rect draw_rc = shadow_rc.Intersect(clip_rc);
 286   if (draw_rc.IsEmpty())
 287     return;
 288
 289   int32 depth = static_cast<int32>(matrix.depth());
 290   for (int32_t y = draw_rc.y(); y < draw_rc.bottom(); y++) {
 291     for (int32_t x = draw_rc.x(); x < draw_rc.right(); x++) {
 292       int32_t matrix_x = std::max(depth + shadow_rc.x() - x - 1,
 293                                   depth - shadow_rc.right() + x);
 294       int32_t matrix_y = std::max(depth + shadow_rc.y() - y - 1,
 295                                   depth - shadow_rc.bottom() + y);
 296       uint32_t* pixel = image->GetAddr32(pp::Point(x, y));
 297
 298       if (matrix_x < 0)
 299         matrix_x = 0;
 300       else if (matrix_x >= static_cast<int32>(depth))
 301         matrix_x = depth - 1;
 302
 303       if (matrix_y < 0)
 304         matrix_y = 0;
 305       else if (matrix_y >= static_cast<int32>(depth))
 306         matrix_y = depth - 1;
 307
 308       *pixel = matrix.GetValue(matrix_x, matrix_y);
 309     }
 310   }
 311 }
 312
 313 void DrawShadow(pp::ImageData* image,
 314                 const pp::Rect& shadow_rc,
 315                 const pp::Rect& object_rc,
 316                 const pp::Rect& clip_rc,
 317                 const ShadowMatrix& matrix) {
 318   if (shadow_rc == object_rc)
 319     return;  // Nothing to paint.
 320
 321   // Fill top part.
 322   pp::Rect rc(shadow_rc.point(),
 323               pp::Size(shadow_rc.width(), object_rc.y() - shadow_rc.y()));
 324   PaintShadow(image, rc.Intersect(clip_rc), shadow_rc, matrix);
 325
 326   // Fill bottom part.
 327   rc = pp::Rect(shadow_rc.x(), object_rc.bottom(),
 328                 shadow_rc.width(), shadow_rc.bottom() - object_rc.bottom());
 329   PaintShadow(image, rc.Intersect(clip_rc), shadow_rc, matrix);
 330
 331   // Fill left part.
 332   rc = pp::Rect(shadow_rc.x(), object_rc.y(),
 333                 object_rc.x() - shadow_rc.x(), object_rc.height());
 334   PaintShadow(image, rc.Intersect(clip_rc), shadow_rc, matrix);
 335
 336   // Fill right part.
 337   rc = pp::Rect(object_rc.right(), object_rc.y(),
 338                 shadow_rc.right() - object_rc.right(), object_rc.height());
 339   PaintShadow(image, rc.Intersect(clip_rc), shadow_rc, matrix);
 340 }
 341
 342 }  // namespace chrome_pdf
 343