Convert ui::ScaleFactor -> float in favicon/history code

components/favicon_base/favicon_util.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/favicon_base/favicon_util.h"
 
+#include <cmath>
+
 #include "components/favicon_base/favicon_types.h"
 #include "components/favicon_base/select_favicon_frames.h"
 #include "skia/ext/image_operations.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkCanvas.h"
+#include "ui/base/layout.h"
 #include "ui/gfx/codec/png_codec.h"
 #include "ui/gfx/favicon_size.h"
 #include "ui/gfx/image/image_png_rep.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/size.h"
 
 #if defined(OS_MACOSX) && !defined(OS_IOS)
 #include "base/mac/mac_util.h"
 #endif  // defined(OS_MACOSX) && !defined(OS_IOS)
 
 namespace favicon_base {
 namespace {
 
 // Creates image reps of DIP size |favicon_size| for the subset of
 // |scale_factors| for which the image reps can be created without resizing

[pkotwicz, 2014/06/20 00:35:41]

|scale_factors| -> |favicon_scales|

[oshima, 2014/06/20 04:16:34]

Done.

 // or decoding the bitmap data.
 std::vector<gfx::ImagePNGRep> SelectFaviconFramesFromPNGsWithoutResizing(
     const std::vector<favicon_base::FaviconRawBitmapResult>& png_data,
-    const std::vector<ui::ScaleFactor>& scale_factors,
+    const std::vector<float>& favicon_scales,
     int favicon_size) {
   std::vector<gfx::ImagePNGRep> png_reps;
   if (png_data.empty())
     return png_reps;
 
   // A |favicon_size| of 0 indicates that the largest frame is desired.
   if (favicon_size == 0) {
     int maximum_area = 0;
     scoped_refptr<base::RefCountedMemory> best_candidate;
     for (size_t i = 0; i < png_data.size(); ++i) {
       int area = png_data[i].pixel_size.GetArea();
       if (area > maximum_area) {
         maximum_area = area;
         best_candidate = png_data[i].bitmap_data;
       }
     }
     png_reps.push_back(gfx::ImagePNGRep(best_candidate, 1.0f));
     return png_reps;
   }
 
   // Cache the scale factor for each pixel size as |scale_factors| may contain
   // any of GetFaviconScaleFactors() which may include scale factors not
   // supported by the platform. (ui::GetSupportedScaleFactor() cannot be used.)

[pkotwicz, 2014/06/20 00:35:41]

This comment is no longer valid. We want to keep map to avoid loss of precision.

ceil(favicon_size * scale) / favicon_size != scale

[oshima, 2014/06/20 04:16:34]

Updated the comment.

-  std::map<int, ui::ScaleFactor> desired_pixel_sizes;
-  for (size_t i = 0; i < scale_factors.size(); ++i) {
-    int pixel_size =
-        floor(favicon_size * ui::GetScaleForScaleFactor(scale_factors[i]));
-    desired_pixel_sizes[pixel_size] = scale_factors[i];
+  std::map<int, float> desired_pixel_sizes;
+  for (size_t i = 0; i < favicon_scales.size(); ++i) {
+    int pixel_size = std::ceil(favicon_size * favicon_scales[i]);
+    desired_pixel_sizes[pixel_size] = favicon_scales[i];
   }
 
   for (size_t i = 0; i < png_data.size(); ++i) {
     if (!png_data[i].is_valid())
       continue;
 
     const gfx::Size& pixel_size = png_data[i].pixel_size;
     if (pixel_size.width() != pixel_size.height())
       continue;
 
-    std::map<int, ui::ScaleFactor>::iterator it =
+    std::map<int, float>::iterator it =
         desired_pixel_sizes.find(pixel_size.width());
     if (it == desired_pixel_sizes.end())
       continue;
 
-    png_reps.push_back(gfx::ImagePNGRep(
-        png_data[i].bitmap_data, ui::GetScaleForScaleFactor(it->second)));
+    png_reps.push_back(gfx::ImagePNGRep(png_data[i].bitmap_data, it->second));
   }
 
   return png_reps;
 }
 
 // Returns a resampled bitmap of
 // |desired_size_in_pixel| x |desired_size_in_pixel| by resampling the best
 // bitmap out of |input_bitmaps|. ResizeBitmapByDownsamplingIfPossible() is
 // similar to SelectFaviconFrames() but it operates on bitmaps which have
 // already been resampled via SelectFaviconFrames().
@@ skipping 43 matching lines @@
     return bitmap;
   }
   return skia::ImageOperations::Resize(best_bitmap,
                                        skia::ImageOperations::RESIZE_LANCZOS3,
                                        desired_size_in_pixel,
                                        desired_size_in_pixel);
 }
 
 }  // namespace
 
-std::vector<ui::ScaleFactor> GetFaviconScaleFactors() {
+std::vector<float> GetFaviconScales() {
   const float kScale1x = 1.0f;
-  std::vector<ui::ScaleFactor> favicon_scale_factors =
+  std::vector<ui::ScaleFactor> resource_scale_factors =
       ui::GetSupportedScaleFactors();
 
-  // The scale factors returned from ui::GetSupportedScaleFactors() are sorted.
-  // Insert the 1x scale factor such that GetFaviconScaleFactors() is sorted as
-  // well.
-  size_t insert_index = favicon_scale_factors.size();
-  for (size_t i = 0; i < favicon_scale_factors.size(); ++i) {
-    float scale = ui::GetScaleForScaleFactor(favicon_scale_factors[i]);
-    if (scale == kScale1x) {
-      return favicon_scale_factors;
-    } else if (scale > kScale1x) {
-      insert_index = i;
-      break;
-    }
-  }
-  // TODO(ios): 100p should not be necessary on iOS retina devices. However
+  // TODO(ios): 1.0f should not be necessary on iOS retina devices. However
   // the sync service only supports syncing 100p favicons. Until sync supports
   // other scales 100p is needed in the list of scale factors to retrieve and
   // store the favicons in both 100p for sync and 200p for display. cr/160503.
-  favicon_scale_factors.insert(favicon_scale_factors.begin() + insert_index,
-                               ui::SCALE_FACTOR_100P);
-  return favicon_scale_factors;
+  std::vector<float> favicon_scales(1, kScale1x);

[pkotwicz, 2014/06/20 00:35:41]

You can use std::find here

[oshima, 2014/06/20 04:16:34]

How?

If you're talking about the code at 190, I have a separate CL for it.

+  for (size_t i = 0; i < resource_scale_factors.size(); ++i) {
+    if (resource_scale_factors[i] != ui::SCALE_FACTOR_100P)
+      favicon_scales.push_back(
+          ui::GetScaleForScaleFactor(resource_scale_factors[i]));
+  }
+  return favicon_scales;
 }
 
 void SetFaviconColorSpace(gfx::Image* image) {
 #if defined(OS_MACOSX) && !defined(OS_IOS)
   image->SetSourceColorSpace(base::mac::GetSystemColorSpace());
 #endif  // defined(OS_MACOSX) && !defined(OS_IOS)
 }
 
 gfx::Image SelectFaviconFramesFromPNGs(
     const std::vector<favicon_base::FaviconRawBitmapResult>& png_data,
-    const std::vector<ui::ScaleFactor>& scale_factors,
+    const std::vector<float>& favicon_scales,
     int favicon_size) {
   // Create image reps for as many scale factors as possible without resizing

[pkotwicz, 2014/06/20 00:35:41]

scale factors -> scales

[oshima, 2014/06/20 04:16:34]

Done.

   // the bitmap data or decoding it. FaviconHandler stores already resized
   // favicons into history so no additional resizing should be needed in the
   // common case.
   // Creating the gfx::Image from |png_data| without resizing or decoding if
   // possible is important because:
   // - Sync does a byte-to-byte comparison of gfx::Image::As1xPNGBytes() to
   //   the data it put into the database in order to determine whether any
   //   updates should be pushed to sync.
   // - The decoding occurs on the UI thread and the decoding can be a
   //   significant performance hit if a user has many bookmarks.
   // TODO(pkotwicz): Move the decoding off the UI thread.
   std::vector<gfx::ImagePNGRep> png_reps =
       SelectFaviconFramesFromPNGsWithoutResizing(
-          png_data, scale_factors, favicon_size);
+          png_data, favicon_scales, favicon_size);
 
   // SelectFaviconFramesFromPNGsWithoutResizing() should have selected the
   // largest favicon if |favicon_size| == 0.
   if (favicon_size == 0)
     return gfx::Image(png_reps);
 
-  std::vector<ui::ScaleFactor> scale_factors_to_generate = scale_factors;
+  std::vector<float> favicon_scales_to_generate = favicon_scales;
   for (size_t i = 0; i < png_reps.size(); ++i) {
-    for (int j = static_cast<int>(scale_factors_to_generate.size()) - 1; j >= 0;
+    for (int j = static_cast<int>(favicon_scales_to_generate.size()) - 1;
+         j >= 0;
          --j) {
-      if (png_reps[i].scale ==
-          ui::GetScaleForScaleFactor(scale_factors_to_generate[j])) {
-        scale_factors_to_generate.erase(scale_factors_to_generate.begin() + j);
+      if (png_reps[i].scale == favicon_scales_to_generate[j]) {
+        favicon_scales_to_generate.erase(favicon_scales_to_generate.begin() +
+                                         j);
       }
     }
   }
 
-  if (scale_factors_to_generate.empty())
+  if (favicon_scales_to_generate.empty())
     return gfx::Image(png_reps);
 
   std::vector<SkBitmap> bitmaps;
   for (size_t i = 0; i < png_data.size(); ++i) {
     if (!png_data[i].is_valid())
       continue;
 
     SkBitmap bitmap;
     if (gfx::PNGCodec::Decode(png_data[i].bitmap_data->front(),
                               png_data[i].bitmap_data->size(),
                               &bitmap)) {
       bitmaps.push_back(bitmap);
     }
   }
 
   if (bitmaps.empty())
     return gfx::Image();
 
   gfx::ImageSkia resized_image_skia;
-  for (size_t i = 0; i < scale_factors_to_generate.size(); ++i) {
-    float scale = ui::GetScaleForScaleFactor(scale_factors_to_generate[i]);
-    int desired_size_in_pixel = ceil(favicon_size * scale);
+  for (size_t i = 0; i < favicon_scales_to_generate.size(); ++i) {
+    float scale = favicon_scales_to_generate[i];
+    int desired_size_in_pixel = std::ceil(favicon_size * scale);
     SkBitmap bitmap =
         ResizeBitmapByDownsamplingIfPossible(bitmaps, desired_size_in_pixel);
     resized_image_skia.AddRepresentation(gfx::ImageSkiaRep(bitmap, scale));
   }
 
   if (png_reps.empty())
     return gfx::Image(resized_image_skia);
 
   std::vector<gfx::ImageSkiaRep> resized_image_skia_reps =
       resized_image_skia.image_reps();
   for (size_t i = 0; i < resized_image_skia_reps.size(); ++i) {
     scoped_refptr<base::RefCountedBytes> png_bytes(new base::RefCountedBytes());
     if (gfx::PNGCodec::EncodeBGRASkBitmap(
             resized_image_skia_reps[i].sk_bitmap(),
             false,
             &png_bytes->data())) {
       png_reps.push_back(
           gfx::ImagePNGRep(png_bytes, resized_image_skia_reps[i].scale()));
     }
   }
 
   return gfx::Image(png_reps);
 }
 
 }  // namespace favicon_base