1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/2d/image_operations.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,552 @@
1.4 +// Copyright (c) 2006-2012 The Chromium Authors. All rights reserved.
1.5 +//
1.6 +// Redistribution and use in source and binary forms, with or without
1.7 +// modification, are permitted provided that the following conditions
1.8 +// are met:
1.9 +// * Redistributions of source code must retain the above copyright
1.10 +// notice, this list of conditions and the following disclaimer.
1.11 +// * Redistributions in binary form must reproduce the above copyright
1.12 +// notice, this list of conditions and the following disclaimer in
1.13 +// the documentation and/or other materials provided with the
1.14 +// distribution.
1.15 +// * Neither the name of Google, Inc. nor the names of its contributors
1.16 +// may be used to endorse or promote products derived from this
1.17 +// software without specific prior written permission.
1.18 +//
1.19 +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
1.20 +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
1.21 +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
1.22 +// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
1.23 +// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
1.24 +// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
1.25 +// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
1.26 +// OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
1.27 +// AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
1.28 +// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
1.29 +// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
1.30 +// SUCH DAMAGE.
1.31 +
1.32 +#include "base/basictypes.h"
1.33 +
1.34 +#define _USE_MATH_DEFINES
1.35 +#include <algorithm>
1.36 +#include <cmath>
1.37 +#include <limits>
1.38 +
1.39 +#include "image_operations.h"
1.40 +
1.41 +#include "base/stack_container.h"
1.42 +#include "convolver.h"
1.43 +#include "skia/SkColorPriv.h"
1.44 +#include "skia/SkBitmap.h"
1.45 +#include "skia/SkRect.h"
1.46 +#include "skia/SkFontHost.h"
1.47 +
1.48 +namespace skia {
1.49 +
1.50 +namespace {
1.51 +
1.52 +// Returns the ceiling/floor as an integer.
1.53 +inline int CeilInt(float val) {
1.54 + return static_cast<int>(ceil(val));
1.55 +}
1.56 +inline int FloorInt(float val) {
1.57 + return static_cast<int>(floor(val));
1.58 +}
1.59 +
1.60 +// Filter function computation -------------------------------------------------
1.61 +
1.62 +// Evaluates the box filter, which goes from -0.5 to +0.5.
1.63 +float EvalBox(float x) {
1.64 + return (x >= -0.5f && x < 0.5f) ? 1.0f : 0.0f;
1.65 +}
1.66 +
1.67 +// Evaluates the Lanczos filter of the given filter size window for the given
1.68 +// position.
1.69 +//
1.70 +// |filter_size| is the width of the filter (the "window"), outside of which
1.71 +// the value of the function is 0. Inside of the window, the value is the
1.72 +// normalized sinc function:
1.73 +// lanczos(x) = sinc(x) * sinc(x / filter_size);
1.74 +// where
1.75 +// sinc(x) = sin(pi*x) / (pi*x);
1.76 +float EvalLanczos(int filter_size, float x) {
1.77 + if (x <= -filter_size || x >= filter_size)
1.78 + return 0.0f; // Outside of the window.
1.79 + if (x > -std::numeric_limits<float>::epsilon() &&
1.80 + x < std::numeric_limits<float>::epsilon())
1.81 + return 1.0f; // Special case the discontinuity at the origin.
1.82 + float xpi = x * static_cast<float>(M_PI);
1.83 + return (sin(xpi) / xpi) * // sinc(x)
1.84 + sin(xpi / filter_size) / (xpi / filter_size); // sinc(x/filter_size)
1.85 +}
1.86 +
1.87 +// Evaluates the Hamming filter of the given filter size window for the given
1.88 +// position.
1.89 +//
1.90 +// The filter covers [-filter_size, +filter_size]. Outside of this window
1.91 +// the value of the function is 0. Inside of the window, the value is sinus
1.92 +// cardinal multiplied by a recentered Hamming function. The traditional
1.93 +// Hamming formula for a window of size N and n ranging in [0, N-1] is:
1.94 +// hamming(n) = 0.54 - 0.46 * cos(2 * pi * n / (N-1)))
1.95 +// In our case we want the function centered for x == 0 and at its minimum
1.96 +// on both ends of the window (x == +/- filter_size), hence the adjusted
1.97 +// formula:
1.98 +// hamming(x) = (0.54 -
1.99 +// 0.46 * cos(2 * pi * (x - filter_size)/ (2 * filter_size)))
1.100 +// = 0.54 - 0.46 * cos(pi * x / filter_size - pi)
1.101 +// = 0.54 + 0.46 * cos(pi * x / filter_size)
1.102 +float EvalHamming(int filter_size, float x) {
1.103 + if (x <= -filter_size || x >= filter_size)
1.104 + return 0.0f; // Outside of the window.
1.105 + if (x > -std::numeric_limits<float>::epsilon() &&
1.106 + x < std::numeric_limits<float>::epsilon())
1.107 + return 1.0f; // Special case the sinc discontinuity at the origin.
1.108 + const float xpi = x * static_cast<float>(M_PI);
1.109 +
1.110 + return ((sin(xpi) / xpi) * // sinc(x)
1.111 + (0.54f + 0.46f * cos(xpi / filter_size))); // hamming(x)
1.112 +}
1.113 +
1.114 +// ResizeFilter ----------------------------------------------------------------
1.115 +
1.116 +// Encapsulates computation and storage of the filters required for one complete
1.117 +// resize operation.
1.118 +class ResizeFilter {
1.119 + public:
1.120 + ResizeFilter(ImageOperations::ResizeMethod method,
1.121 + int src_full_width, int src_full_height,
1.122 + int dest_width, int dest_height,
1.123 + const SkIRect& dest_subset);
1.124 +
1.125 + // Returns the filled filter values.
1.126 + const ConvolutionFilter1D& x_filter() { return x_filter_; }
1.127 + const ConvolutionFilter1D& y_filter() { return y_filter_; }
1.128 +
1.129 + private:
1.130 + // Returns the number of pixels that the filer spans, in filter space (the
1.131 + // destination image).
1.132 + float GetFilterSupport(float scale) {
1.133 + switch (method_) {
1.134 + case ImageOperations::RESIZE_BOX:
1.135 + // The box filter just scales with the image scaling.
1.136 + return 0.5f; // Only want one side of the filter = /2.
1.137 + case ImageOperations::RESIZE_HAMMING1:
1.138 + // The Hamming filter takes as much space in the source image in
1.139 + // each direction as the size of the window = 1 for Hamming1.
1.140 + return 1.0f;
1.141 + case ImageOperations::RESIZE_LANCZOS2:
1.142 + // The Lanczos filter takes as much space in the source image in
1.143 + // each direction as the size of the window = 2 for Lanczos2.
1.144 + return 2.0f;
1.145 + case ImageOperations::RESIZE_LANCZOS3:
1.146 + // The Lanczos filter takes as much space in the source image in
1.147 + // each direction as the size of the window = 3 for Lanczos3.
1.148 + return 3.0f;
1.149 + default:
1.150 + return 1.0f;
1.151 + }
1.152 + }
1.153 +
1.154 + // Computes one set of filters either horizontally or vertically. The caller
1.155 + // will specify the "min" and "max" rather than the bottom/top and
1.156 + // right/bottom so that the same code can be re-used in each dimension.
1.157 + //
1.158 + // |src_depend_lo| and |src_depend_size| gives the range for the source
1.159 + // depend rectangle (horizontally or vertically at the caller's discretion
1.160 + // -- see above for what this means).
1.161 + //
1.162 + // Likewise, the range of destination values to compute and the scale factor
1.163 + // for the transform is also specified.
1.164 + void ComputeFilters(int src_size,
1.165 + int dest_subset_lo, int dest_subset_size,
1.166 + float scale, float src_support,
1.167 + ConvolutionFilter1D* output);
1.168 +
1.169 + // Computes the filter value given the coordinate in filter space.
1.170 + inline float ComputeFilter(float pos) {
1.171 + switch (method_) {
1.172 + case ImageOperations::RESIZE_BOX:
1.173 + return EvalBox(pos);
1.174 + case ImageOperations::RESIZE_HAMMING1:
1.175 + return EvalHamming(1, pos);
1.176 + case ImageOperations::RESIZE_LANCZOS2:
1.177 + return EvalLanczos(2, pos);
1.178 + case ImageOperations::RESIZE_LANCZOS3:
1.179 + return EvalLanczos(3, pos);
1.180 + default:
1.181 + return 0;
1.182 + }
1.183 + }
1.184 +
1.185 + ImageOperations::ResizeMethod method_;
1.186 +
1.187 + // Size of the filter support on one side only in the destination space.
1.188 + // See GetFilterSupport.
1.189 + float x_filter_support_;
1.190 + float y_filter_support_;
1.191 +
1.192 + // Subset of scaled destination bitmap to compute.
1.193 + SkIRect out_bounds_;
1.194 +
1.195 + ConvolutionFilter1D x_filter_;
1.196 + ConvolutionFilter1D y_filter_;
1.197 +
1.198 + DISALLOW_COPY_AND_ASSIGN(ResizeFilter);
1.199 +};
1.200 +
1.201 +ResizeFilter::ResizeFilter(ImageOperations::ResizeMethod method,
1.202 + int src_full_width, int src_full_height,
1.203 + int dest_width, int dest_height,
1.204 + const SkIRect& dest_subset)
1.205 + : method_(method),
1.206 + out_bounds_(dest_subset) {
1.207 + // method_ will only ever refer to an "algorithm method".
1.208 + SkASSERT((ImageOperations::RESIZE_FIRST_ALGORITHM_METHOD <= method) &&
1.209 + (method <= ImageOperations::RESIZE_LAST_ALGORITHM_METHOD));
1.210 +
1.211 + float scale_x = static_cast<float>(dest_width) /
1.212 + static_cast<float>(src_full_width);
1.213 + float scale_y = static_cast<float>(dest_height) /
1.214 + static_cast<float>(src_full_height);
1.215 +
1.216 + x_filter_support_ = GetFilterSupport(scale_x);
1.217 + y_filter_support_ = GetFilterSupport(scale_y);
1.218 +
1.219 + // Support of the filter in source space.
1.220 + float src_x_support = x_filter_support_ / scale_x;
1.221 + float src_y_support = y_filter_support_ / scale_y;
1.222 +
1.223 + ComputeFilters(src_full_width, dest_subset.fLeft, dest_subset.width(),
1.224 + scale_x, src_x_support, &x_filter_);
1.225 + ComputeFilters(src_full_height, dest_subset.fTop, dest_subset.height(),
1.226 + scale_y, src_y_support, &y_filter_);
1.227 +}
1.228 +
1.229 +// TODO(egouriou): Take advantage of periods in the convolution.
1.230 +// Practical resizing filters are periodic outside of the border area.
1.231 +// For Lanczos, a scaling by a (reduced) factor of p/q (q pixels in the
1.232 +// source become p pixels in the destination) will have a period of p.
1.233 +// A nice consequence is a period of 1 when downscaling by an integral
1.234 +// factor. Downscaling from typical display resolutions is also bound
1.235 +// to produce interesting periods as those are chosen to have multiple
1.236 +// small factors.
1.237 +// Small periods reduce computational load and improve cache usage if
1.238 +// the coefficients can be shared. For periods of 1 we can consider
1.239 +// loading the factors only once outside the borders.
1.240 +void ResizeFilter::ComputeFilters(int src_size,
1.241 + int dest_subset_lo, int dest_subset_size,
1.242 + float scale, float src_support,
1.243 + ConvolutionFilter1D* output) {
1.244 + int dest_subset_hi = dest_subset_lo + dest_subset_size; // [lo, hi)
1.245 +
1.246 + // When we're doing a magnification, the scale will be larger than one. This
1.247 + // means the destination pixels are much smaller than the source pixels, and
1.248 + // that the range covered by the filter won't necessarily cover any source
1.249 + // pixel boundaries. Therefore, we use these clamped values (max of 1) for
1.250 + // some computations.
1.251 + float clamped_scale = std::min(1.0f, scale);
1.252 +
1.253 + // Speed up the divisions below by turning them into multiplies.
1.254 + float inv_scale = 1.0f / scale;
1.255 +
1.256 + StackVector<float, 64> filter_values;
1.257 + StackVector<int16_t, 64> fixed_filter_values;
1.258 +
1.259 + // Loop over all pixels in the output range. We will generate one set of
1.260 + // filter values for each one. Those values will tell us how to blend the
1.261 + // source pixels to compute the destination pixel.
1.262 + for (int dest_subset_i = dest_subset_lo; dest_subset_i < dest_subset_hi;
1.263 + dest_subset_i++) {
1.264 + // Reset the arrays. We don't declare them inside so they can re-use the
1.265 + // same malloc-ed buffer.
1.266 + filter_values->clear();
1.267 + fixed_filter_values->clear();
1.268 +
1.269 + // This is the pixel in the source directly under the pixel in the dest.
1.270 + // Note that we base computations on the "center" of the pixels. To see
1.271 + // why, observe that the destination pixel at coordinates (0, 0) in a 5.0x
1.272 + // downscale should "cover" the pixels around the pixel with *its center*
1.273 + // at coordinates (2.5, 2.5) in the source, not those around (0, 0).
1.274 + // Hence we need to scale coordinates (0.5, 0.5), not (0, 0).
1.275 + float src_pixel = (static_cast<float>(dest_subset_i) + 0.5f) * inv_scale;
1.276 +
1.277 + // Compute the (inclusive) range of source pixels the filter covers.
1.278 + int src_begin = std::max(0, FloorInt(src_pixel - src_support));
1.279 + int src_end = std::min(src_size - 1, CeilInt(src_pixel + src_support));
1.280 +
1.281 + // Compute the unnormalized filter value at each location of the source
1.282 + // it covers.
1.283 + float filter_sum = 0.0f; // Sub of the filter values for normalizing.
1.284 + for (int cur_filter_pixel = src_begin; cur_filter_pixel <= src_end;
1.285 + cur_filter_pixel++) {
1.286 + // Distance from the center of the filter, this is the filter coordinate
1.287 + // in source space. We also need to consider the center of the pixel
1.288 + // when comparing distance against 'src_pixel'. In the 5x downscale
1.289 + // example used above the distance from the center of the filter to
1.290 + // the pixel with coordinates (2, 2) should be 0, because its center
1.291 + // is at (2.5, 2.5).
1.292 + float src_filter_dist =
1.293 + ((static_cast<float>(cur_filter_pixel) + 0.5f) - src_pixel);
1.294 +
1.295 + // Since the filter really exists in dest space, map it there.
1.296 + float dest_filter_dist = src_filter_dist * clamped_scale;
1.297 +
1.298 + // Compute the filter value at that location.
1.299 + float filter_value = ComputeFilter(dest_filter_dist);
1.300 + filter_values->push_back(filter_value);
1.301 +
1.302 + filter_sum += filter_value;
1.303 + }
1.304 +
1.305 + // The filter must be normalized so that we don't affect the brightness of
1.306 + // the image. Convert to normalized fixed point.
1.307 + int16_t fixed_sum = 0;
1.308 + for (size_t i = 0; i < filter_values->size(); i++) {
1.309 + int16_t cur_fixed = output->FloatToFixed(filter_values[i] / filter_sum);
1.310 + fixed_sum += cur_fixed;
1.311 + fixed_filter_values->push_back(cur_fixed);
1.312 + }
1.313 +
1.314 + // The conversion to fixed point will leave some rounding errors, which
1.315 + // we add back in to avoid affecting the brightness of the image. We
1.316 + // arbitrarily add this to the center of the filter array (this won't always
1.317 + // be the center of the filter function since it could get clipped on the
1.318 + // edges, but it doesn't matter enough to worry about that case).
1.319 + int16_t leftovers = output->FloatToFixed(1.0f) - fixed_sum;
1.320 + fixed_filter_values[fixed_filter_values->size() / 2] += leftovers;
1.321 +
1.322 + // Now it's ready to go.
1.323 + output->AddFilter(src_begin, &fixed_filter_values[0],
1.324 + static_cast<int>(fixed_filter_values->size()));
1.325 + }
1.326 +
1.327 + output->PaddingForSIMD(8);
1.328 +}
1.329 +
1.330 +ImageOperations::ResizeMethod ResizeMethodToAlgorithmMethod(
1.331 + ImageOperations::ResizeMethod method) {
1.332 + // Convert any "Quality Method" into an "Algorithm Method"
1.333 + if (method >= ImageOperations::RESIZE_FIRST_ALGORITHM_METHOD &&
1.334 + method <= ImageOperations::RESIZE_LAST_ALGORITHM_METHOD) {
1.335 + return method;
1.336 + }
1.337 + // The call to ImageOperationsGtv::Resize() above took care of
1.338 + // GPU-acceleration in the cases where it is possible. So now we just
1.339 + // pick the appropriate software method for each resize quality.
1.340 + switch (method) {
1.341 + // Users of RESIZE_GOOD are willing to trade a lot of quality to
1.342 + // get speed, allowing the use of linear resampling to get hardware
1.343 + // acceleration (SRB). Hence any of our "good" software filters
1.344 + // will be acceptable, and we use the fastest one, Hamming-1.
1.345 + case ImageOperations::RESIZE_GOOD:
1.346 + // Users of RESIZE_BETTER are willing to trade some quality in order
1.347 + // to improve performance, but are guaranteed not to devolve to a linear
1.348 + // resampling. In visual tests we see that Hamming-1 is not as good as
1.349 + // Lanczos-2, however it is about 40% faster and Lanczos-2 itself is
1.350 + // about 30% faster than Lanczos-3. The use of Hamming-1 has been deemed
1.351 + // an acceptable trade-off between quality and speed.
1.352 + case ImageOperations::RESIZE_BETTER:
1.353 + return ImageOperations::RESIZE_HAMMING1;
1.354 + default:
1.355 + return ImageOperations::RESIZE_LANCZOS3;
1.356 + }
1.357 +}
1.358 +
1.359 +} // namespace
1.360 +
1.361 +// Resize ----------------------------------------------------------------------
1.362 +
1.363 +// static
1.364 +SkBitmap ImageOperations::Resize(const SkBitmap& source,
1.365 + ResizeMethod method,
1.366 + int dest_width, int dest_height,
1.367 + const SkIRect& dest_subset,
1.368 + void* dest_pixels /* = nullptr */) {
1.369 + if (method == ImageOperations::RESIZE_SUBPIXEL)
1.370 + return ResizeSubpixel(source, dest_width, dest_height, dest_subset);
1.371 + else
1.372 + return ResizeBasic(source, method, dest_width, dest_height, dest_subset,
1.373 + dest_pixels);
1.374 +}
1.375 +
1.376 +// static
1.377 +SkBitmap ImageOperations::ResizeSubpixel(const SkBitmap& source,
1.378 + int dest_width, int dest_height,
1.379 + const SkIRect& dest_subset) {
1.380 + // Currently only works on Linux/BSD because these are the only platforms
1.381 + // where SkFontHost::GetSubpixelOrder is defined.
1.382 +#if defined(XP_UNIX)
1.383 + // Understand the display.
1.384 + const SkFontHost::LCDOrder order = SkFontHost::GetSubpixelOrder();
1.385 + const SkFontHost::LCDOrientation orientation =
1.386 + SkFontHost::GetSubpixelOrientation();
1.387 +
1.388 + // Decide on which dimension, if any, to deploy subpixel rendering.
1.389 + int w = 1;
1.390 + int h = 1;
1.391 + switch (orientation) {
1.392 + case SkFontHost::kHorizontal_LCDOrientation:
1.393 + w = dest_width < source.width() ? 3 : 1;
1.394 + break;
1.395 + case SkFontHost::kVertical_LCDOrientation:
1.396 + h = dest_height < source.height() ? 3 : 1;
1.397 + break;
1.398 + }
1.399 +
1.400 + // Resize the image.
1.401 + const int width = dest_width * w;
1.402 + const int height = dest_height * h;
1.403 + SkIRect subset = { dest_subset.fLeft, dest_subset.fTop,
1.404 + dest_subset.fLeft + dest_subset.width() * w,
1.405 + dest_subset.fTop + dest_subset.height() * h };
1.406 + SkBitmap img = ResizeBasic(source, ImageOperations::RESIZE_LANCZOS3, width,
1.407 + height, subset);
1.408 + const int row_words = img.rowBytes() / 4;
1.409 + if (w == 1 && h == 1)
1.410 + return img;
1.411 +
1.412 + // Render into subpixels.
1.413 + SkBitmap result;
1.414 + result.setConfig(SkBitmap::kARGB_8888_Config, dest_subset.width(),
1.415 + dest_subset.height());
1.416 + result.allocPixels();
1.417 + if (!result.readyToDraw())
1.418 + return img;
1.419 +
1.420 + SkAutoLockPixels locker(img);
1.421 + if (!img.readyToDraw())
1.422 + return img;
1.423 +
1.424 + uint32_t* src_row = img.getAddr32(0, 0);
1.425 + uint32_t* dst_row = result.getAddr32(0, 0);
1.426 + for (int y = 0; y < dest_subset.height(); y++) {
1.427 + uint32_t* src = src_row;
1.428 + uint32_t* dst = dst_row;
1.429 + for (int x = 0; x < dest_subset.width(); x++, src += w, dst++) {
1.430 + uint8_t r = 0, g = 0, b = 0, a = 0;
1.431 + switch (order) {
1.432 + case SkFontHost::kRGB_LCDOrder:
1.433 + switch (orientation) {
1.434 + case SkFontHost::kHorizontal_LCDOrientation:
1.435 + r = SkGetPackedR32(src[0]);
1.436 + g = SkGetPackedG32(src[1]);
1.437 + b = SkGetPackedB32(src[2]);
1.438 + a = SkGetPackedA32(src[1]);
1.439 + break;
1.440 + case SkFontHost::kVertical_LCDOrientation:
1.441 + r = SkGetPackedR32(src[0 * row_words]);
1.442 + g = SkGetPackedG32(src[1 * row_words]);
1.443 + b = SkGetPackedB32(src[2 * row_words]);
1.444 + a = SkGetPackedA32(src[1 * row_words]);
1.445 + break;
1.446 + }
1.447 + break;
1.448 + case SkFontHost::kBGR_LCDOrder:
1.449 + switch (orientation) {
1.450 + case SkFontHost::kHorizontal_LCDOrientation:
1.451 + b = SkGetPackedB32(src[0]);
1.452 + g = SkGetPackedG32(src[1]);
1.453 + r = SkGetPackedR32(src[2]);
1.454 + a = SkGetPackedA32(src[1]);
1.455 + break;
1.456 + case SkFontHost::kVertical_LCDOrientation:
1.457 + b = SkGetPackedB32(src[0 * row_words]);
1.458 + g = SkGetPackedG32(src[1 * row_words]);
1.459 + r = SkGetPackedR32(src[2 * row_words]);
1.460 + a = SkGetPackedA32(src[1 * row_words]);
1.461 + break;
1.462 + }
1.463 + break;
1.464 + case SkFontHost::kNONE_LCDOrder:
1.465 + break;
1.466 + }
1.467 + // Premultiplied alpha is very fragile.
1.468 + a = a > r ? a : r;
1.469 + a = a > g ? a : g;
1.470 + a = a > b ? a : b;
1.471 + *dst = SkPackARGB32(a, r, g, b);
1.472 + }
1.473 + src_row += h * row_words;
1.474 + dst_row += result.rowBytes() / 4;
1.475 + }
1.476 + result.setAlphaType(img.alphaType());
1.477 + return result;
1.478 +#else
1.479 + return SkBitmap();
1.480 +#endif // OS_POSIX && !OS_MACOSX && !defined(OS_ANDROID)
1.481 +}
1.482 +
1.483 +// static
1.484 +SkBitmap ImageOperations::ResizeBasic(const SkBitmap& source,
1.485 + ResizeMethod method,
1.486 + int dest_width, int dest_height,
1.487 + const SkIRect& dest_subset,
1.488 + void* dest_pixels /* = nullptr */) {
1.489 + // Ensure that the ResizeMethod enumeration is sound.
1.490 + SkASSERT(((RESIZE_FIRST_QUALITY_METHOD <= method) &&
1.491 + (method <= RESIZE_LAST_QUALITY_METHOD)) ||
1.492 + ((RESIZE_FIRST_ALGORITHM_METHOD <= method) &&
1.493 + (method <= RESIZE_LAST_ALGORITHM_METHOD)));
1.494 +
1.495 + // If the size of source or destination is 0, i.e. 0x0, 0xN or Nx0, just
1.496 + // return empty.
1.497 + if (source.width() < 1 || source.height() < 1 ||
1.498 + dest_width < 1 || dest_height < 1)
1.499 + return SkBitmap();
1.500 +
1.501 + method = ResizeMethodToAlgorithmMethod(method);
1.502 + // Check that we deal with an "algorithm methods" from this point onward.
1.503 + SkASSERT((ImageOperations::RESIZE_FIRST_ALGORITHM_METHOD <= method) &&
1.504 + (method <= ImageOperations::RESIZE_LAST_ALGORITHM_METHOD));
1.505 +
1.506 + SkAutoLockPixels locker(source);
1.507 + if (!source.readyToDraw())
1.508 + return SkBitmap();
1.509 +
1.510 + ResizeFilter filter(method, source.width(), source.height(),
1.511 + dest_width, dest_height, dest_subset);
1.512 +
1.513 + // Get a source bitmap encompassing this touched area. We construct the
1.514 + // offsets and row strides such that it looks like a new bitmap, while
1.515 + // referring to the old data.
1.516 + const uint8_t* source_subset =
1.517 + reinterpret_cast<const uint8_t*>(source.getPixels());
1.518 +
1.519 + // Convolve into the result.
1.520 + SkBitmap result;
1.521 + result.setConfig(SkBitmap::kARGB_8888_Config,
1.522 + dest_subset.width(), dest_subset.height());
1.523 +
1.524 + if (dest_pixels) {
1.525 + result.setPixels(dest_pixels);
1.526 + } else {
1.527 + result.allocPixels();
1.528 + }
1.529 +
1.530 + if (!result.readyToDraw())
1.531 + return SkBitmap();
1.532 +
1.533 + BGRAConvolve2D(source_subset, static_cast<int>(source.rowBytes()),
1.534 + !source.isOpaque(), filter.x_filter(), filter.y_filter(),
1.535 + static_cast<int>(result.rowBytes()),
1.536 + static_cast<unsigned char*>(result.getPixels()),
1.537 + /* sse = */ false);
1.538 +
1.539 + // Preserve the "opaque" flag for use as an optimization later.
1.540 + result.setAlphaType(source.alphaType());
1.541 +
1.542 + return result;
1.543 +}
1.544 +
1.545 +// static
1.546 +SkBitmap ImageOperations::Resize(const SkBitmap& source,
1.547 + ResizeMethod method,
1.548 + int dest_width, int dest_height,
1.549 + void* dest_pixels /* = nullptr */) {
1.550 + SkIRect dest_subset = { 0, 0, dest_width, dest_height };
1.551 + return Resize(source, method, dest_width, dest_height, dest_subset,
1.552 + dest_pixels);
1.553 +}
1.554 +
1.555 +} // namespace skia
