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